BERKLEY W R CORP, 10-K filed on 2/27/2026
Annual Report
v3.25.4
Cover Page - USD ($)
12 Months Ended
Dec. 31, 2025
Feb. 23, 2026
Jun. 30, 2025
Entity Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2025    
Document Transition Report false    
Entity File Number 1-15202    
Entity Registrant Name W. R. BERKLEY CORP    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 22-1867895    
Entity Address, Address Line One 475 Steamboat Road    
Entity Address, City or Town Greenwich,    
Entity Address, State or Province CT    
Entity Address, Postal Zip Code 06830    
City Area Code 203    
Local Phone Number 629-3000    
Title of 12(b) Security Common Stock, par value $.20 per share    
Trading Symbol WRB    
Security Exchange Name NYSE    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity Public Float     $ 21,940,921,884
Entity Common Stock, Shares Outstanding   374,490,856  
Entity Central Index Key 0000011544    
Current Fiscal Year End Date --12-31    
Document Fiscal Year Focus 2025    
Document Fiscal Period Focus FY    
Amendment Flag false    
Documents Incorporated by Reference [Text Block]
Portions of the Company’s definitive proxy statement, which will be filed with the Securities and Exchange Commission within 120 days after December 31, 2025, are incorporated herein by reference in Part III.
   
5.700% Subordinated Debentures due 2058      
Entity Information [Line Items]      
Title of 12(b) Security 5.700% Subordinated Debentures due 2058    
Trading Symbol WRB-PE    
Security Exchange Name NYSE    
5.100% Subordinated Debentures due 2059      
Entity Information [Line Items]      
Title of 12(b) Security 5.100% Subordinated Debentures due 2059    
Trading Symbol WRB-PF    
Security Exchange Name NYSE    
4.250% Subordinated Debentures due 2060      
Entity Information [Line Items]      
Title of 12(b) Security 4.250% Subordinated Debentures due 2060    
Trading Symbol WRB-PG    
Security Exchange Name NYSE    
4.125% Subordinated Debentures due 2061      
Entity Information [Line Items]      
Title of 12(b) Security 4.125% Subordinated Debentures due 2061    
Trading Symbol WRB-PH    
Security Exchange Name NYSE    
v3.25.4
Audit Information
12 Months Ended
Dec. 31, 2025
Auditor Information [Abstract]  
Auditor Name KPMG LLP
Auditor Location New York, New York
Auditor Firm ID 185
v3.25.4
Consolidated Statements of Income - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
REVENUES:      
Net premiums written $ 12,711,327 $ 11,972,096 $ 10,954,467
Change in net unearned premiums (264,389) (423,611) (553,780)
Net premiums earned 12,446,938 11,548,485 10,400,687
Net investment income 1,429,067 1,333,161 1,052,835
Net investment gains:      
Unrealized investment gains (losses), before tax 130,670 79,738 47,540
Change in allowance for expected credit losses on investments 1,550 37,970 (498)
Net investment gains (losses) 132,220 117,708 47,042
Revenues from non-insurance businesses 577,420 528,012 535,508
Insurance service fees 118,511 108,935 106,485
Other income 3,700 2,451 381
Total revenues 14,707,856 13,638,752 12,142,938
OPERATING COSTS AND EXPENSES:      
Losses and loss expenses 7,771,657 7,131,595 6,372,142
Other operating costs and expenses 3,976,834 3,602,306 3,363,936
Expenses from non-insurance businesses 551,930 513,451 524,998
Interest expense 126,892 126,907 127,459
Total operating costs and expenses 12,427,313 11,374,259 10,388,535
Pre-Tax Income (Loss) 2,280,543 2,264,493 1,754,403
Income tax expense (495,764) (509,916) (370,557)
Net income before noncontrolling interests 1,784,779 1,754,577 1,383,846
Noncontrolling interests (5,376) 1,538 (2,487)
Net income to common stockholders $ 1,779,403 $ 1,756,115 $ 1,381,359
NET INCOME PER SHARE:      
Basic (dollars per share) $ 4.48 $ 4.39 $ 3.40
Diluted (dollars per share) $ 4.45 $ 4.36 $ 3.37
v3.25.4
Consolidated Balance Sheets - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Investments:    
Fixed maturity securities (amortized cost of $25,170,368 and $23,010,899; allowance for expected credit losses of $74 and $671 at December 31, 2025 and 2024) $ 25,047,662 $ 22,397,865
Investment funds 1,361,802 1,468,246
Real estate 1,279,748 1,291,455
Arbitrage trading account 1,221,103 1,122,599
Equity securities 1,358,201 1,203,788
Loans receivable (net of allowance for expected credit losses of $161 and $1,114 at December 31, 2025 and 2024) 418,913 405,453
Total investments 30,687,429 27,889,406
Cash and cash equivalents 2,539,938 1,974,747
Premiums and fees receivable (net of allowance for expected credit losses of $42,006 and $39,884 at December 31, 2025 and 2024) 3,417,112 3,266,845
Due from reinsurers (net of allowance for expected credit losses of $6,378 and $8,350 at December 31, 2025 and 2024) 3,543,013 3,557,695
Deferred policy acquisition costs 1,000,691 951,728
Prepaid reinsurance premiums 881,831 823,207
Trading account receivable from brokers and clearing organizations 11,669 60,327
Property, furniture and equipment 596,235 478,511
Goodwill 184,332 184,332
Accrued investment income 255,199 243,772
Current federal and foreign income taxes 2,732 39,382
Deferred federal and foreign income taxes 141,496 220,217
Other assets 809,394 877,099
Total assets 44,071,071 40,567,268
Liabilities:    
Reserves for losses and loss expenses 22,207,773 20,368,030
Unearned premiums 6,721,570 6,375,112
Due to reinsurers 615,781 668,652
Trading account securities sold but not yet purchased 66,285 73,358
Current federal and foreign income taxes 83,373 53,482
Deferred federal and foreign income taxes 99,873 65,151
Senior notes and other debt 1,829,198 1,831,158
Subordinated debentures 1,010,527 1,009,808
Other liabilities 1,724,797 1,715,078
Total liabilities 34,359,177 32,159,829
Equity:    
Preferred stock, par value $.10 per share: Authorized 5,000,000 shares; issued and outstanding - none 0 0
Common stock, par value $.20 per share: Authorized 500,000,000 shares, issued and outstanding, net of treasury shares, 177,825,150 and 183,411,907 shares, respectively 158,705 158,705
Additional paid-in capital 987,708 984,825
Retained earnings 13,344,204 12,265,070
Accumulated other comprehensive loss (451,097) (934,269)
Treasury stock, at cost, 416,366,010 and 413,455,739 shares, respectively (4,338,702) (4,079,220)
Total common stockholders’ equity 9,700,818 8,395,111
Noncontrolling interests 11,076 12,328
Total equity 9,711,894 8,407,439
Total liabilities and equity $ 44,071,071 $ 40,567,268
Common stock, authorized (in shares) 1,875,000,000 1,875,000,000
v3.25.4
Consolidated Balance Sheets (Parenthetical) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Statement of Financial Position [Abstract]    
Fixed maturity securities, amortized cost $ 25,170,368 $ 23,010,899
Fixed maturity securities, allowance for credit loss 74 671
Financing receivable, allowance for credit loss 161 1,114
Premium receivable, allowance for credit loss 42,006 39,884
Uncollectible reinsurance $ 6,378 $ 8,350
Preferred stock, par value (in dollars per share) $ 0.10 $ 0.10
Preferred stock, authorized (in shares) 5,000,000 5,000,000
Preferred stock, issued (in shares) 0 0
Preferred stock, outstanding (in shares) 0 0
Common stock, par value (in dollars per share) $ 0.20 $ 0.20
Common stock, issued (in shares) 377,155,799 380,066,070
Common stock, outstanding (in shares) 377,155,799 380,066,070
Common stock, authorized (in shares) 1,875,000,000 1,875,000,000
Treasury stock, at cost (in shares) 416,366,010 413,455,739
v3.25.4
Consolidated Statements of Stockholders' Equity - USD ($)
$ in Thousands
Total
Common stocks
Additional Paid In Capital
Retained Earnings
Total accumulated other comprehensive loss
Unrealized investment (losses) gains:
Currency Translation Adjustments
Treasury Stock
Noncontrolling Interests
Beginning of period at Dec. 31, 2022   $ 158,705 $ 944,632 $ 10,161,005   $ (892,905) $ (371,676) $ (3,251,429) $ 19,829
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Restricted stock units issued     (29,043)            
Restricted stock units expensed     49,200            
Change in unrealized gains on securities without an allowance for expected credit losses $ 306,553         305,908      
Change in unrealized (losses) gains on securities with an allowance for expected credit losses           643      
Net change in period 32,192           32,192    
Stock exercised/vested               10,381  
Stock repurchased               (537,163)  
Other               (4,922)  
(Distributions) contributions                 (8,508)
Net income 1,383,846     1,381,359         2,487
Dividends ($1.85, $1.40, and $1.29 per share, respectively)       (501,456)          
Other comprehensive (loss) income, net of tax 338,745               (2)
End of period at Dec. 31, 2023   158,705 964,789 11,040,908 $ (925,838) (586,354) (339,484) (3,783,133) 13,806
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Restricted stock units issued     (32,344)            
Restricted stock units expensed     52,380            
Change in unrealized gains on securities without an allowance for expected credit losses 69,182         64,756      
Change in unrealized (losses) gains on securities with an allowance for expected credit losses           4,428      
Net change in period (77,615)           (77,615)    
Stock exercised/vested               10,066  
Stock repurchased               (303,655)  
Other               (2,498)  
(Distributions) contributions                 58
Net income 1,754,577     1,756,115         (1,538)
Dividends ($1.85, $1.40, and $1.29 per share, respectively)       (531,953)          
Other comprehensive (loss) income, net of tax (8,433)       (8,433) 69,182 (77,615)   2
End of period at Dec. 31, 2024 8,407,439 $ 158,705 984,825 12,265,070 (934,269) (517,170) (417,099) (4,079,220) 12,328
Increase (Decrease) in Stockholders' Equity [Roll Forward]                  
Restricted stock units issued     (49,641)            
Restricted stock units expensed     52,524            
Change in unrealized gains on securities without an allowance for expected credit losses 392,491         393,352      
Change in unrealized (losses) gains on securities with an allowance for expected credit losses           (862)      
Net change in period 90,682           90,682    
Stock exercised/vested               12,623  
Stock repurchased               (270,221)  
Other               (1,884)  
(Distributions) contributions                 (6,627)
Net income 1,784,779     1,779,403         5,376
Dividends ($1.85, $1.40, and $1.29 per share, respectively)       (700,269)          
Other comprehensive (loss) income, net of tax 483,173       483,173 392,491 90,682   (1)
End of period at Dec. 31, 2025 $ 9,711,894   $ 987,708 $ 13,344,204 $ (451,097) $ (124,680) $ (326,417) $ (4,338,702) $ 11,076
v3.25.4
Consolidated Statements of Stockholder's Equity (Parenthetical) - $ / shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Statement of Stockholders' Equity [Abstract]      
Dividends (in dollars per share) $ 1.85 $ 1.40 $ 1.29
v3.25.4
Consolidated Statements of Comprehensive Income - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Statement of Comprehensive Income [Abstract]      
Net income before noncontrolling interests $ 1,784,779 $ 1,754,577 $ 1,383,846
Other comprehensive gain (loss):      
Change in unrealized translation adjustments 90,682 (77,615) 32,192
Change in unrealized investment gains, net of taxes 392,491 69,182 306,553
Other comprehensive gain (loss) 483,173 (8,433) 338,745
Comprehensive income 2,267,952 1,746,144 1,722,591
Noncontrolling interests (5,375) 1,536 (2,485)
Comprehensive income to common stockholders $ 2,262,577 $ 1,747,680 $ 1,720,106
v3.25.4
Consolidated Statements of Cash Flows - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
CASH FROM OPERATING ACTIVITIES:      
Net income to common stockholders $ 1,779,403 $ 1,756,115 $ 1,381,359
Adjustments to reconcile net income to net cash from operating activities:      
Net investment gains (132,220) (117,708) (47,042)
Depreciation and (accretion) amortization (48,126) (170,638) (20,861)
Noncontrolling interests 5,376 (1,538) 2,487
Investment funds (27,582) 11,491 (16,743)
Stock incentive plans 54,524 54,381 51,000
Change in:      
Arbitrage trading account (56,919) 122,738 (54,213)
Premiums and fees receivable (129,586) (184,431) (334,178)
Reinsurance accounts (114,564) (31,738) (306,017)
Deferred policy acquisition costs (48,859) (91,150) (99,387)
Current income taxes 63,905 (28,526) 52,451
Deferred income taxes 9,437 95,311 (26,691)
Reserves for losses and loss expenses 1,766,882 1,707,722 1,715,076
Unearned premiums 321,735 485,488 617,535
Other 139,210 70,851 14,462
Net cash from operating activities 3,582,616 3,678,368 2,929,238
CASH FLOWS USED IN INVESTING ACTIVITIES:      
Proceeds from sale of fixed maturity securities 1,149,313 2,310,746 1,011,195
Proceeds from sale of equity securities 430,405 331,291 318,852
Proceeds From (Payments To) Equity Method Investments 139,711 134,853 (19,904)
Proceeds from maturities and prepayments of fixed maturity securities 5,312,043 4,890,572 3,506,903
Purchase of fixed maturity securities (8,428,883) (9,368,703) (6,664,763)
Purchase of equity securities (418,440) (207,457) (80,454)
Real estate disposed (purchased) 14,627 (66,632) (2,074)
Change in loans receivable 12,695 (210,816) (29,719)
Net additions to property, furniture and equipment (169,994) (105,623) (53,080)
Change in balances due from security brokers (70,812) 107,280 (33,929)
Cash received in connection with business disposition 0 0 96,567
Payment for business purchased, net of cash acquired 0 0 (11,558)
Net cash used in investing activities (2,029,335) (2,184,489) (1,961,964)
CASH FLOWS USED IN FINANCING ACTIVITIES:      
Net proceeds from issuance of debt 0 3,105 980
Repayment of senior notes and other debt (2,063) 0 (1,954)
Cash dividends to common stockholders (700,269) (531,953) (501,456)
Purchase of common treasury shares (270,221) (303,655) (537,163)
Other, net (53,894) (19,984) (22,902)
Net cash used in financing activities (1,026,447) (852,487) (1,062,495)
Net impact on cash due to change in foreign exchange rates 38,357 (29,840) 9,070
Net increase (decrease) in cash and cash equivalents 565,191 611,552 (86,151)
Cash and cash equivalents at beginning of year 1,974,747 1,363,195 1,449,346
Cash and cash equivalents at end of year $ 2,539,938 $ 1,974,747 $ 1,363,195
v3.25.4
Summary of Significant Accounting Policies
12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Summary of Significant Accounting Policies Summary of Significant Accounting Policies
(A) Principles of consolidation and basis of presentation
The consolidated financial statements, which include the accounts of W. R. Berkley Corporation and its subsidiaries (the "Company"), have been prepared on the basis of U.S. generally accepted accounting principles ("GAAP"). All significant intercompany transactions and balances have been eliminated. Shares outstanding and per share amounts were adjusted to reflect the 3-for-2 common stock split effected on July 10, 2024. Additionally, commencing with the first quarter of 2024, the Company reclassified a program management business from the Insurance segment to the Reinsurance & Monoline Excess segment. The reclassified business is a program management business offering support on a nationwide basis for commercial casualty and property program administrators. Reclassifications were made in the 2023 financial statements as originally reported to conform to the presentation of the 2025 and 2024 financial statements.
The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the revenues and expenses reflected during the reporting period. The most significant items on our balance sheet that involve a greater degree of accounting estimates that are subject to change in the future are the valuation of investments, allowance for expected credit losses on investments, reserves for losses and loss expenses and premium estimates. Actual results could differ from those estimates.
(B) Revenue recognition
Insurance premiums are recognized as written at the inception of the policy. Reinsurance premiums are estimated based upon information received from ceding companies, and subsequent differences from such estimates are recorded in the period they are determined. Insurance and reinsurance premiums are primarily earned on a pro rata basis over the policy term. Fees for services are earned over the period that the services are provided. Premiums and fees receivable are reported net of an allowance for expected credit losses, with the allowance being estimated based on current and future expected conditions, historical loss data and specific identification of collectability concerns where applicable. Changes in the allowance are reported within other operating costs and expenses.
Audit premiums are recognized when they are reliably determinable. The change in accruals for earned but unbilled audit premiums (decreased) increased net premiums written and premiums earned by $(2) million, $19 million and $19 million in 2025, 2024 and 2023, respectively.
Revenues from non-insurance businesses are derived from businesses engaged in the distribution of promotional merchandise, world-wide textile solutions, and aircraft services provided to the general, commercial and military aviation markets. These aircraft services include (i) the distribution, manufacturing, repair and overhaul of aircraft parts and components, (ii) the sale of new and used aircraft, and (iii) avionics, fuel, maintenance, storage and charter services. Revenue is recognized upon the shipment of products and parts, the delivery of aircraft, the delivery of fuel, and over the completion period of services.
Insurance service fee revenue represents servicing fees for program administration and claims management services provided by the Company, including workers' compensation assigned risk plans, as well as insurance brokerage and risk management services. Fees for program administration, claims management and risk management services are primarily recognized ratably over the related contract period for which the underlying services are rendered.
(C) Cash and cash equivalents
Cash equivalents consist of funds invested in money market accounts and investments with an effective maturity of three months or less when purchased.
(D) Investments
Fixed maturity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity. Fixed maturity securities that the Company has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Investment income from fixed maturity
securities is recognized based on the constant effective yield method. Premiums and discounts on mortgage-backed securities are adjusted for the effects of actual and anticipated prepayments on a retrospective basis.
Equity securities with readily determinable fair values are measured at fair value, with changes in the fair value recognized in net income within net realized and unrealized gains on investments.
Fixed maturity securities that the Company purchased with the intent to sell in the near-term are classified as trading account securities and are reported at estimated fair value. Realized and unrealized gains and losses from trading activity are reported as net investment income and are recorded at the trade date. Short sales and short call options are presented as trading securities sold but not yet purchased. Unsettled trades and the net margin balances held by the clearing broker are presented as a trading account receivable from brokers and clearing organizations.
Investment funds are carried under the equity method of accounting. The Company's share of the earnings or losses of investment funds is primarily reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.
Loans receivable primarily represent commercial and real estate loans and are carried at amortized cost. The accrual of interest on loans receivable is discontinued if the loan is 90 days past due based on the contractual terms of the loan unless the loan is adequately secured and in process of collection. In general, loans are placed on non-accrual status or charged off at an earlier date if collection of principal or interest is considered doubtful. Interest on these loans is accounted for on a cash basis until qualifying for return to accrual status. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured.
Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Fair value of investments is determined based on a fair value hierarchy that prioritizes the use of observable inputs over the use of unobservable inputs and requires the use of observable inputs when available. (See Note 12 of the Notes to Consolidated Financial Statements.)
Realized gains or losses represent the difference between the cost of securities sold and the proceeds realized upon sale and are recorded at the trade date. The Company uses primarily the first-in, first-out method to determine the cost of securities sold.
For available for sale securities in an unrealized loss position where the Company intends to sell, or it is more likely than not that it will be required to sell the security before recovery in value, the amortized cost basis is written down to fair value through net investment gains. For available for sale securities in an unrealized loss position where the Company does not intend to sell, or it is more likely than not that it will not be required to sell the security before recovery in value, the Company evaluates whether the decline in fair value has resulted from credit losses or all other factors (non-credit factors). In making this assessment, the Company considers the extent to which fair value is less than amortized cost, changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, an allowance for expected credit losses is recorded for the credit loss through net investment gains, limited by the amount that the fair value is less than the amortized cost basis. The allowance is adjusted for any change in expected credit losses and subsequent recoveries through net investment gains. The impairment related to non-credit factors is recognized in comprehensive income (loss).
For financial assets carried at amortized cost, which includes held to maturity securities and loans receivable, the Company estimates an allowance for expected credit losses based on relevant information about past events, including historical loss experience, current conditions and forecasts that affect the expected collectability of the amortized cost of the financial asset. The allowance for expected credit losses is presented as a reduction to amortized cost of the financial asset in the consolidated balance sheet and changes to the estimate for expected credit losses are recognized through net investment gains.
The Company’s credit assessment of allowance for expected credit losses uses a third party model for available for sale and held to maturity securities, as well as loans receivable. The allowance for expected credit losses is generally based on the performance of the underlying collateral under various economic and default scenarios that involve subjective judgments and estimates by management. Modeling these securities involves various factors, such as projected default rates, the nature and realizable value of the collateral, if any, the ability of the issuer to make scheduled payments, historical performance and other relevant economic and performance factors. A discounted cash flow analysis is used to ascertain the amount of the allowance for expected credit losses, if any. In general, the model reverts to the rating-level long-term average marginal default rates based on 10 years of historical data, beyond the forecast period. For other inputs, the model in most cases reverts to the baseline long-
term assumptions linearly over 5 years beyond the forecast period. The long-term assumptions are based on the historical averages.
The Company reports accrued investment income separately from fixed maturity securities, and has elected not to measure an allowance for expected credit losses for accrued investment income. Accrued investment income is written off through net investment income at the time the issuer of the bond defaults or is expected to default on payments.
Real estate held for investment purposes is initially recorded at the purchase price, which is generally fair value, and is subsequently reported at cost less accumulated depreciation. Real estate taxes, interest and other costs incurred during development and construction are capitalized. Buildings are depreciated on a straight-line basis over the estimated useful lives of the building. Minimum rental income is recognized on a straight-line basis over the lease term. Income and expenses from real estate are reported as net investment income. The carrying value of real estate is reviewed for impairment and an impairment loss is recognized if the estimated undiscounted cash flows from the use and disposition of the property are less than the carrying value of the property.
(E) Per share data
The Company presents both basic and diluted net income per share (“EPS”) amounts. Basic EPS is calculated by dividing net income by weighted average number of common shares outstanding during the year (including 17,378,810 common shares held in a grantor trust). The common shares held in the grantor trust are designated for delivery upon the settlement of restricted stock units ("RSUs") that are vested but mandatorily deferred. Accordingly, such shares deliverable under vested RSUs do not affect diluted shares outstanding since the shares are already included in basic shares outstanding (which includes the shares in the grantor trust referenced above). Diluted EPS is based upon the weighted average number of basic and common equivalent shares outstanding during the period and is calculated using the treasury stock method for stock incentive plans. Common equivalent shares are excluded from the computation in periods in which they have an anti-dilutive effect.
(F) Deferred policy acquisition costs
Acquisition costs associated with the successful acquisition of new and renewed insurance and reinsurance contracts are deferred and amortized ratably over the terms of the related contracts. Ceding commissions received on reinsurance contracts are netted against acquisition costs and are recognized ratably over the life of the contract. Deferred policy acquisition costs are presented net of unearned ceding commissions. Deferred policy acquisition costs are comprised primarily of commissions, as well as employment-related underwriting costs and premium taxes. Deferred policy acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. The recoverability of deferred policy acquisition costs is evaluated separately by each of our businesses. Future investment income is taken into account in measuring the recoverability of deferred policy acquisition costs.
(G) Reserves for losses and loss expenses
Reserves for losses and loss expenses are an accumulation of amounts determined on the basis of (1) evaluation of claims for business written directly by the Company; (2) estimates received from other companies for reinsurance assumed by the Company; and (3) estimates for losses incurred but not reported (based on Company and industry experience). These estimates are periodically reviewed and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments are reflected in the statements of income in the period in which they are determined. The Company discounts its reserves for excess and assumed workers' compensation claims using a risk-free or statutory rate. (See Note 13 of Notes to Consolidated Financial Statements.)
(H) Reinsurance ceded
The unearned portion of premiums ceded to reinsurers is reported as prepaid reinsurance premiums and earned ratably over the policy term. The estimated amounts of reinsurance recoverable on unpaid losses are reported as due from reinsurers. To the extent any reinsurer does not meet its obligations under reinsurance agreements, the Company must discharge its liability. Amounts due from reinsurers are reflected net of funds held where the right of offset is present. The Company has provided an allowance for expected credit losses for estimated uncollectible reinsurance. The allowance is estimated based on the composition of the recoverable balance, considering reinsurer credit ratings, collateral received from financial institutions and funds withheld arrangements, length of collection periods, probability of default methodology, and specific identification of collectability concerns. Changes in the allowance are reported within losses and loss expenses.
(I) Deposit accounting
Contracts that do not meet the risk transfer requirements of GAAP are accounted for using the deposit accounting method. Under this method, an asset or liability is recognized at the inception of the contract based on consideration paid or received. The amount of the deposit asset or liability is adjusted at subsequent reporting dates using the interest method with a corresponding credit or charge to interest income or expense. Deposit liabilities for assumed reinsurance contracts were $28 million and $29 million at December 31, 2025 and 2024, respectively.
(J) Federal and foreign income taxes
The Company files a consolidated income tax return in the U.S. and foreign tax returns in countries where it has overseas operations. The Company's method of accounting for income taxes is the asset and liability method. Under this method, deferred tax assets and liabilities are measured using tax rates currently in effect or expected to apply in the years in which those temporary differences are expected to reverse. Interest and penalties, if any, are reported as income tax expense. The Company believes there are no uncertain tax positions that would require disclosure under GAAP. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized.
(K) Foreign currency
Gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the entity's functional currency) are reported on the statements of income as other operating costs and expenses. Unrealized gains or losses resulting from translating the results of non-U.S. dollar denominated operations are reported in accumulated other comprehensive income. Revenues and expenses denominated in currencies other than U.S. dollars are generally translated at the weighted average exchange rate during the year. Assets and liabilities are translated at the rate of exchange in effect at the balance sheet date.
(L) Property, furniture and equipment
Property, furniture and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the estimated useful lives of the respective assets. Depreciation expense was $54 million, $55 million and $51 million for 2025, 2024 and 2023, respectively.
(M) Comprehensive income
Comprehensive income encompasses all changes in stockholders' equity (except those arising from transactions with stockholders) and includes net income, net unrealized holding gains or losses on available for sale securities and unrealized foreign currency translation adjustments.
(N) Goodwill and other intangible assets
Goodwill and other intangible assets are tested for impairment on an annual basis and at interim periods where circumstances require. The Company's impairment test as of December 31, 2025 indicated that there were no material impairment losses related to goodwill and other intangible assets. Intangible assets of $86 million and $97 million are included in other assets as of December 31, 2025 and 2024, respectively.
(O) Restricted stock units
The costs resulting from all share-based payment transactions with employees are recognized in the consolidated financial statements using a fair-value-based measurement method. Compensation cost is recognized for financial reporting purposes over the period in which the employee is required to provide service in exchange for the award (generally the vesting period).
(P) Statements of cash flows
Interest payments were $126 million, $138 million and $114 million in 2025, 2024 and 2023, respectively. Income taxes paid were $407 million (including $340 million to the United States, $40 million to Australia and $27 million to other jurisdictions), $410 million (including $361 million to the United States, $25 million to Australia and $24 million to other jurisdictions) and $332 million (including $296 million to the United States, $18 million to Australia and $18 million to other jurisdictions) in 2025, 2024 and 2023, respectively. Other non-cash items include unrealized investment gains and losses. (See Note 10 of Notes to Consolidated Financial Statements.)
(Q) Recent accounting pronouncements
Recently adopted accounting pronouncements:
In December 2023, the Financial Accounting Standards Board issued Accounting Standards Update 2023-09, Improvements to Income Tax Disclosures (Topic 740), to enhance the transparency and usefulness of income tax disclosures. The guidance requires additional disclosures primarily related to the rate reconciliation and income taxes paid. This guidance is effective for annual periods beginning after December 15, 2024. The Company adopted this guidance prospectively for the year ended December 31, 2025.
All other accounting and reporting standards that became effective in 2025 were either not applicable to the Company or their adoption did not have a material impact on the Company.
Accounting and reporting standards that are not yet effective:
In November 2024, the Financial Accounting Standards Board issued Accounting Standards Update 2024-03, Disaggregation of Income Statement Expenses, addressing investor requests for more transparent information. The guidance requires disclosure of specified information about certain costs and expenses in the notes to the financial statements. The guidance is effective for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Prospective application is required, with retrospective application permitted. The Company will adopt this guidance for the year ended December 31, 2027 and resulting impact will be disclosure only.
All other recently issued but not yet effective accounting and reporting standards are either not applicable to the Company or are not expected to have a material impact on the Company.
v3.25.4
Consolidated Statement of Comprehensive Income
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Consolidated Statement of Comprehensive Income Consolidated Statements of Comprehensive Income
The following tables present the components of the changes in accumulated other comprehensive income (loss) (AOCI) as of and for the years ended December 31, 2025 and 2024:
(In thousands)
December 31, 2025Unrealized Investment Gains (Losses)Currency Translation AdjustmentsAccumulated Other Comprehensive Income (Loss)
Changes in AOCI
Beginning of period$(517,170)$(417,099)$(934,269)
Other comprehensive income before reclassifications344,083 90,682 434,765 
Amounts reclassified from AOCI48,408 — 48,408 
Other comprehensive income392,491 90,682 483,173 
Unrealized investment loss related to noncontrolling interest(1)— (1)
Ending balance$(124,680)$(326,417)$(451,097)
Amounts reclassified from AOCI
Pre-tax$61,276 (1)$— $61,276 
Tax effect(12,868)(2)— (12,868)
After-tax amounts reclassified$48,408 $— $48,408 
Other comprehensive income
Pre-tax$497,765 $90,682 $588,447 
Tax effect(105,274)— (105,274)
Other comprehensive income $392,491 $90,682 $483,173 

(In thousands)
December 31, 2024Unrealized Investment Gains (Losses)Currency Translation AdjustmentsAccumulated Other Comprehensive Income (Loss)
Changes in AOCI
Beginning of period$(586,354)$(339,484)$(925,838)
Other comprehensive loss before reclassifications(26,128)(77,615)(103,743)
Amounts reclassified from AOCI95,310 — 95,310 
Other comprehensive income (loss)69,182 (77,615)(8,433)
Unrealized investment income related to non-controlling interest— 
Ending balance$(517,170)$(417,099)$(934,269)
Amounts reclassified from AOCI
Pre-tax$120,646 (1)$— $120,646 
Tax effect(25,336)(2)— (25,336)
After-tax amounts reclassified$95,310 $— $95,310 
Other comprehensive income (loss)
Pre-tax$84,474 $(77,615)$6,859 
Tax effect(15,292)— (15,292)
Other comprehensive income (loss)$69,182 $(77,615)$(8,433)
_______________
(1) Net investment gains in the consolidated statements of income.
(2) Income tax expense in the consolidated statements of income.
v3.25.4
Investments In Fixed Maturity Securities
12 Months Ended
Dec. 31, 2025
Schedule of Marketable Securities [Line Items]  
Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities
At December 31, 2025 and 2024, investments in fixed maturity securities were as follows:
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025
Held to maturity:
State and municipal$28,777 $(9)$796 $— $29,564 $28,768 
Residential mortgage-backed1,838 — 76 — 1,914 1,838 
Total held to maturity30,615 (9)872 — 31,478 30,606 
Available for sale:
U.S. government and government agency3,964,375 — 48,820 (15,157)3,998,038 3,998,038 
State and municipal:
                 Special revenue1,206,387 — 6,002 (27,943)1,184,446 1,184,446 
                 State general obligation203,543 — 3,465 (3,848)203,160 203,160 
                 Pre-refunded74,276 — 619 (111)74,784 74,784 
                 Corporate backed159,876 — 1,958 (3,459)158,375 158,375 
                 Local general obligation218,022 — 1,459 (3,052)216,429 216,429 
       Total state and municipal1,862,104 — 13,503 (38,413)1,837,194 1,837,194 
Mortgage-backed securities:
Residential4,584,970 (65)71,048 (132,645)4,523,308 4,523,308 
Commercial281,573 — 3,632 (35)285,170 285,170 
Total mortgage-backed securities4,866,543 (65)74,680 (132,680)4,808,478 4,808,478 
Asset-backed securities3,807,393 — 20,196 (17,243)3,810,346 3,810,346 
Corporate:
                 Industrial3,627,567 — 57,466 (36,499)3,648,534 3,648,534 
                 Financial3,438,348 — 61,180 (16,460)3,483,068 3,483,068 
                 Utilities1,300,506 — 22,593 (8,878)1,314,221 1,314,221 
                 Other240,374 — 2,356 (1,142)241,588 241,588 
Total corporate8,606,795 — 143,595 (62,979)8,687,411 8,687,411 
Foreign government2,032,543 — 20,906 (177,860)1,875,589 1,875,589 
Total available for sale25,139,753 (65)321,700 (444,332)25,017,056 25,017,056 
Total investments in fixed maturity securities$25,170,368 $(74)$322,572 $(444,332)$25,048,534 $25,047,662 
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2024
Held to maturity:
State and municipal$42,145 $(25)$1,492 $— $43,612 $42,120 
Residential mortgage-backed2,292 — 69 — 2,361 2,292 
Total held to maturity44,437 (25)1,561 — 45,973 44,412 
Available for sale:
U.S. government and government agency2,268,596 — 9,608 (42,863)2,235,341 2,235,341 
State and municipal:
                 Special revenue1,581,778 — 3,521 (67,591)1,517,708 1,517,708 
                 State general obligation272,936 — 1,439 (8,981)265,394 265,394 
                 Pre-refunded85,340 — 599 (347)85,592 85,592 
                 Corporate backed158,322 — 1,079 (5,827)153,574 153,574 
                 Local general obligation278,165 — 922 (6,711)272,376 272,376 
       Total state and municipal2,376,541 — 7,560 (89,457)2,294,644 2,294,644 
Mortgage-backed securities:
Residential3,411,796 (5)11,047 (189,630)3,233,208 3,233,208 
Commercial534,936 (425)1,201 (3,430)532,282 532,282 
Total mortgage-backed securities3,946,732 (430)12,248 (193,060)3,765,490 3,765,490 
Asset-backed securities3,910,363 — 16,161 (41,512)3,885,012 3,885,012 
Corporate:
                 Industrial3,746,501 — 14,518 (93,820)3,667,199 3,667,199 
                 Financial3,339,718 — 18,871 (38,076)3,320,513 3,320,513 
                 Utilities795,839 — 2,970 (20,115)778,694 778,694 
                 Other653,194 — 2,493 (4,452)651,235 651,235 
Total corporate8,535,252 — 38,852 (156,463)8,417,641 8,417,641 
Foreign government1,928,978 (216)11,936 (185,373)1,755,325 1,755,325 
Total available for sale22,966,462 (646)96,365 (708,728)22,353,453 22,353,453 
Total investments in fixed maturity securities$23,010,899 $(671)$97,926 $(708,728)$22,399,426 $22,397,865 
——————————
(1) Represents the amount of impairment that has resulted from credit-related factors. The change in the allowance for expected credit losses is recognized in the consolidated statements of income. Amount excludes unrealized losses relating to non-credit factors.


The following table presents the rollforward of the allowance for expected credit losses for held to maturity securities for the years ended December 31, 2025 and 2024:
State and Municipal
(In thousands)20252024
Balance, beginning of period$25 $43 
Provision for expected credit losses(16)(18)
Balance, end of period$$25 

The following table presents the rollforward of the allowance for expected credit losses for available for sale securities for the years ended December 31, 2025 and 2024:
20252024
(In thousands)Foreign GovernmentMortgage- BackedState and MunicipalTotalForeign GovernmentCorporateMortgage- BackedAsset-backedState and MunicipalTotal
Balance, beginning of period$216 $430 $— $646 $29,603 $5,026 $158 $1,164 $757 $36,708 
Change on securities for which credit losses were not previously recorded65 10 78 347 — 1,706 — — 2,053 
Change on securities for which credit losses were previously recorded(219)(430)(10)(659)(29,355)(5,026)(831)(1,164)(757)(37,133)
Reduction due to disposals— — — — (379)— (603)— — (982)
Balance, end of period$— $65 $— $65 $216 $— $430 $— $— $646 
During the year ended December 31, 2025, the allowance for expected credit losses for available for sale securities decreased primarily due to improved pricing related to foreign government securities and mortgage-backed securities. During the year ended December 31, 2024, the allowance for expected credit losses for available for sale securities decreased primarily due to improved pricing associated with foreign government securities and corporate securities.
The amortized cost and fair value of fixed maturity securities at December 31, 2025, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations.
(In thousands)Amortized
Cost (1)
Fair Value
Due in one year or less$1,789,587 $1,740,503 
Due after one year through five years8,131,346 8,060,983 
Due after five years through ten years3,791,177 3,828,290 
Due after ten years6,589,868 6,608,366 
Mortgage-backed securities4,868,381 4,810,392 
Total$25,170,359 $25,048,534 
________________
(1) Amortized cost is reduced by the allowance for expected credit losses of $9 thousand related to held to maturity securities.    
At December 31, 2025 and 2024, there were no investments, other than investments in United States government and government agency securities, which exceeded 10% of common stockholders’ equity. At December 31, 2025, investments with a carrying value of $2,131 million were on deposit in custodial or trust accounts, of which $1,149 million was on deposit with insurance regulators, $919 million was on deposit in support of the Company’s underwriting activities at Lloyd’s, $35 million was on deposit as security for reinsurance clients and $28 million was on deposit as security for letters of credit issued in support of the Company’s reinsurance operations.
Investments in Equity Securities
At December 31, 2025 and 2024, investments in equity securities were as follows:
(In thousands)CostGross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025     
Common stocks$566,577 $181,120 $(5,584)$742,113 $742,113 
Preferred stocks433,472 187,891 (5,275)616,088 616,088 
Total$1,000,049 $369,011 $(10,859)$1,358,201 $1,358,201 
December 31, 2024    
Common stocks$612,479 $223,981 $(76,293)$760,167 $760,167 
Preferred stocks329,495 122,716 (8,590)443,621 443,621 
Total$941,974 $346,697 $(84,883)$1,203,788 $1,203,788 
v3.25.4
Investments In Equity Securities
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Investments in Equity Securities Investments in Fixed Maturity Securities
At December 31, 2025 and 2024, investments in fixed maturity securities were as follows:
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025
Held to maturity:
State and municipal$28,777 $(9)$796 $— $29,564 $28,768 
Residential mortgage-backed1,838 — 76 — 1,914 1,838 
Total held to maturity30,615 (9)872 — 31,478 30,606 
Available for sale:
U.S. government and government agency3,964,375 — 48,820 (15,157)3,998,038 3,998,038 
State and municipal:
                 Special revenue1,206,387 — 6,002 (27,943)1,184,446 1,184,446 
                 State general obligation203,543 — 3,465 (3,848)203,160 203,160 
                 Pre-refunded74,276 — 619 (111)74,784 74,784 
                 Corporate backed159,876 — 1,958 (3,459)158,375 158,375 
                 Local general obligation218,022 — 1,459 (3,052)216,429 216,429 
       Total state and municipal1,862,104 — 13,503 (38,413)1,837,194 1,837,194 
Mortgage-backed securities:
Residential4,584,970 (65)71,048 (132,645)4,523,308 4,523,308 
Commercial281,573 — 3,632 (35)285,170 285,170 
Total mortgage-backed securities4,866,543 (65)74,680 (132,680)4,808,478 4,808,478 
Asset-backed securities3,807,393 — 20,196 (17,243)3,810,346 3,810,346 
Corporate:
                 Industrial3,627,567 — 57,466 (36,499)3,648,534 3,648,534 
                 Financial3,438,348 — 61,180 (16,460)3,483,068 3,483,068 
                 Utilities1,300,506 — 22,593 (8,878)1,314,221 1,314,221 
                 Other240,374 — 2,356 (1,142)241,588 241,588 
Total corporate8,606,795 — 143,595 (62,979)8,687,411 8,687,411 
Foreign government2,032,543 — 20,906 (177,860)1,875,589 1,875,589 
Total available for sale25,139,753 (65)321,700 (444,332)25,017,056 25,017,056 
Total investments in fixed maturity securities$25,170,368 $(74)$322,572 $(444,332)$25,048,534 $25,047,662 
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2024
Held to maturity:
State and municipal$42,145 $(25)$1,492 $— $43,612 $42,120 
Residential mortgage-backed2,292 — 69 — 2,361 2,292 
Total held to maturity44,437 (25)1,561 — 45,973 44,412 
Available for sale:
U.S. government and government agency2,268,596 — 9,608 (42,863)2,235,341 2,235,341 
State and municipal:
                 Special revenue1,581,778 — 3,521 (67,591)1,517,708 1,517,708 
                 State general obligation272,936 — 1,439 (8,981)265,394 265,394 
                 Pre-refunded85,340 — 599 (347)85,592 85,592 
                 Corporate backed158,322 — 1,079 (5,827)153,574 153,574 
                 Local general obligation278,165 — 922 (6,711)272,376 272,376 
       Total state and municipal2,376,541 — 7,560 (89,457)2,294,644 2,294,644 
Mortgage-backed securities:
Residential3,411,796 (5)11,047 (189,630)3,233,208 3,233,208 
Commercial534,936 (425)1,201 (3,430)532,282 532,282 
Total mortgage-backed securities3,946,732 (430)12,248 (193,060)3,765,490 3,765,490 
Asset-backed securities3,910,363 — 16,161 (41,512)3,885,012 3,885,012 
Corporate:
                 Industrial3,746,501 — 14,518 (93,820)3,667,199 3,667,199 
                 Financial3,339,718 — 18,871 (38,076)3,320,513 3,320,513 
                 Utilities795,839 — 2,970 (20,115)778,694 778,694 
                 Other653,194 — 2,493 (4,452)651,235 651,235 
Total corporate8,535,252 — 38,852 (156,463)8,417,641 8,417,641 
Foreign government1,928,978 (216)11,936 (185,373)1,755,325 1,755,325 
Total available for sale22,966,462 (646)96,365 (708,728)22,353,453 22,353,453 
Total investments in fixed maturity securities$23,010,899 $(671)$97,926 $(708,728)$22,399,426 $22,397,865 
——————————
(1) Represents the amount of impairment that has resulted from credit-related factors. The change in the allowance for expected credit losses is recognized in the consolidated statements of income. Amount excludes unrealized losses relating to non-credit factors.


The following table presents the rollforward of the allowance for expected credit losses for held to maturity securities for the years ended December 31, 2025 and 2024:
State and Municipal
(In thousands)20252024
Balance, beginning of period$25 $43 
Provision for expected credit losses(16)(18)
Balance, end of period$$25 

The following table presents the rollforward of the allowance for expected credit losses for available for sale securities for the years ended December 31, 2025 and 2024:
20252024
(In thousands)Foreign GovernmentMortgage- BackedState and MunicipalTotalForeign GovernmentCorporateMortgage- BackedAsset-backedState and MunicipalTotal
Balance, beginning of period$216 $430 $— $646 $29,603 $5,026 $158 $1,164 $757 $36,708 
Change on securities for which credit losses were not previously recorded65 10 78 347 — 1,706 — — 2,053 
Change on securities for which credit losses were previously recorded(219)(430)(10)(659)(29,355)(5,026)(831)(1,164)(757)(37,133)
Reduction due to disposals— — — — (379)— (603)— — (982)
Balance, end of period$— $65 $— $65 $216 $— $430 $— $— $646 
During the year ended December 31, 2025, the allowance for expected credit losses for available for sale securities decreased primarily due to improved pricing related to foreign government securities and mortgage-backed securities. During the year ended December 31, 2024, the allowance for expected credit losses for available for sale securities decreased primarily due to improved pricing associated with foreign government securities and corporate securities.
The amortized cost and fair value of fixed maturity securities at December 31, 2025, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations.
(In thousands)Amortized
Cost (1)
Fair Value
Due in one year or less$1,789,587 $1,740,503 
Due after one year through five years8,131,346 8,060,983 
Due after five years through ten years3,791,177 3,828,290 
Due after ten years6,589,868 6,608,366 
Mortgage-backed securities4,868,381 4,810,392 
Total$25,170,359 $25,048,534 
________________
(1) Amortized cost is reduced by the allowance for expected credit losses of $9 thousand related to held to maturity securities.    
At December 31, 2025 and 2024, there were no investments, other than investments in United States government and government agency securities, which exceeded 10% of common stockholders’ equity. At December 31, 2025, investments with a carrying value of $2,131 million were on deposit in custodial or trust accounts, of which $1,149 million was on deposit with insurance regulators, $919 million was on deposit in support of the Company’s underwriting activities at Lloyd’s, $35 million was on deposit as security for reinsurance clients and $28 million was on deposit as security for letters of credit issued in support of the Company’s reinsurance operations.
Investments in Equity Securities
At December 31, 2025 and 2024, investments in equity securities were as follows:
(In thousands)CostGross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025     
Common stocks$566,577 $181,120 $(5,584)$742,113 $742,113 
Preferred stocks433,472 187,891 (5,275)616,088 616,088 
Total$1,000,049 $369,011 $(10,859)$1,358,201 $1,358,201 
December 31, 2024    
Common stocks$612,479 $223,981 $(76,293)$760,167 $760,167 
Preferred stocks329,495 122,716 (8,590)443,621 443,621 
Total$941,974 $346,697 $(84,883)$1,203,788 $1,203,788 
v3.25.4
Arbitrage Trading Account
12 Months Ended
Dec. 31, 2025
Trading Securities and Derivative Instruments [Abstract]  
Arbitrage Trading Account Arbitrage Trading Account
At December 31, 2025 and 2024, the fair value and carrying value of the arbitrage trading account were $1,221 million and $1,123 million, respectively. The primary focus of the trading account is merger arbitrage. Merger arbitrage is the business of investing in the securities of publicly held companies which are the targets in announced tender offers and mergers. Arbitrage investing differs from other types of investing in its focus on transactions and events believed likely to bring about a change in value over a relatively short time period (usually four months or less).
The Company uses put options and call options in order to mitigate the impact of potential changes in market conditions on the merger arbitrage trading account. These options are reported at fair value. As of December 31, 2025, the fair value of long option contracts outstanding was $3 million (notional amount of $278 million) and the fair value of short option contracts outstanding was $66 million (notional amount of $278 million). Other than with respect to the use of these trading account securities, the Company does not make use of derivatives.
v3.25.4
Net Investment Income
12 Months Ended
Dec. 31, 2025
Net Investment Income [Abstract]  
Net Investment Income Net Investment Income
Net investment income consists of the following:
(In thousands)202520242023
Investment income (loss) earned on:   
Fixed maturity securities, including cash and cash equivalents and loans receivable$1,307,087 $1,260,429 $929,098 
Arbitrage trading account (1)74,407 69,573 69,369 
Equity securities50,529 48,920 55,726 
Investment funds27,582 (11,491)16,743 
Real estate
(18,450)(23,616)(11,185)
Gross investment income1,441,155 1,343,815 1,059,751 
Investment expense(12,088)(10,654)(6,916)
Net investment income$1,429,067 $1,333,161 $1,052,835 
v3.25.4
Investment Funds
12 Months Ended
Dec. 31, 2025
Equity Method Investments and Joint Ventures [Abstract]  
Investment Funds Investment Funds
The Company evaluates whether it is an investor in a variable interest entity ("VIE").  Such entities do not have sufficient equity at risk to finance their activities without additional subordinated financial support, or the equity investors, as a group, do not have the characteristics of a controlling financial interest (primary beneficiary). The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose, and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE and on an ongoing basis. The Company is not the primary beneficiary in any of its investment funds, and accordingly, carries its interests in investments funds under the equity method of accounting.
The Company’s maximum exposure to loss with respect to these investments is limited to the carrying amount reported on the Company’s consolidated balance sheet and its unfunded commitments of $274 million as of December 31, 2025.
Investment funds consist of the following:
Carrying Value
as of December 31,
Income (Loss) From Investment Funds For the Year Ended
(In thousands)20252024202520242023
Financial services (1)$360,320 $430,163 $(20,504)$(39,418)$(10,911)
Transportation272,775 286,426 32,441 13,335 40,607 
Infrastructure169,847 151,560 15,258 17,071 13,049 
Real estate163,098 178,685 4,023 12,195 (6,676)
Energy41,966 42,776 146 14,501 5,058 
Other funds353,796 378,636 (3,782)(29,175)(24,384)
Total$1,361,802 $1,468,246 $27,582 $(11,491)$16,743 
(1) Includes the Company’s minority investment in Lifson Re (see Note 26 Related-Party Transactions).
The Company's share of the earnings or losses of investment funds is primarily reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.
Other funds include deferred compensation trust assets of $43 million and $38 million in 2025 and 2024, respectively. These assets support other liabilities reflected in the balance sheet of an equal amount for employees who have elected to defer a portion of their compensation. The change in the net asset value of the trust is recorded in other funds within net investment income with an offsetting equal amount within corporate expenses.
v3.25.4
Real Estate
12 Months Ended
Dec. 31, 2025
Real Estate [Abstract]  
Real Estate Real Estate
Investment in real estate represents directly owned property held for investment, as follows:    
As of December 31,
(In thousands)20252024
Properties in operation$1,051,455 $1,063,687 
Properties under development228,293 227,768 
Total$1,279,748 $1,291,455 
In 2025, properties in operation primarily included a long-term ground lease in Washington, D.C., an office complex in New York City and the completed portion of a mixed-use project in Washington D.C. Properties in operation are net of accumulated depreciation and amortization of $41,942,000 and $38,671,000 as of December 31, 2025 and 2024, respectively. Depreciation expense was $9,453,000, $8,633,000 and $8,935,000 for the years ended December 31, 2025, 2024 and 2023, respectively. Future minimum rental income expected on operating leases relating to properties in operation is $36,767,697 in 2026, $39,898,012 in 2027, $42,512,029 in 2028, $37,191,356 in 2029, $31,563,792 in 2030 and $373,880,063 thereafter.
A mixed-use project in Washington, D.C. had been under development in 2025 and 2024, with the completed portion as noted above reported in properties in operation as of December 31, 2025.
The Company had commitments to invest up to $31 million in certain real estate investment projects as of December 31, 2025.
v3.25.4
Loans Receivable
12 Months Ended
Dec. 31, 2025
Receivables [Abstract]  
Loans Receivable Loans Receivable
At December 31, 2025 and 2024, loans receivable were as follows:
As of December 31,
(In thousands)20252024
Amortized cost (net of allowance for expected credit losses):
Real estate loans$418,913 $402,382 
Commercial loans— 3,071 
Total$418,913 $405,453 
Fair value:
Real estate loans$419,074 $402,177 
Commercial loans— 3,071 
Total$419,074 $405,248 
The real estate loans are secured by commercial and residential real estate primarily located in the U.K. and New York. These loans generally earn interest at fixed or stepped interest rates and have maturities through 2028.
The following table presents the rollforward of the allowance for expected credit losses for loans receivable for the years ended December 31, 2025 and 2024:
20252024
(In thousands)Real Estate LoansCommercial LoansTotalReal Estate LoansCommercial LoansTotal
Balance, beginning of period$1,088 $26 $1,114 $2,983 $21 $3,004 
Change in expected credit losses(927)(26)(953)(1,895)(1,890)
Balance, end of period$161 $— $161 $1,088 $26 $1,114 
During the year ended December 31, 2025, the allowance for expected credit losses decreased primarily due to the redemption of one loan and a decrease in the weighted average life of the remaining loan portfolio. During the year ended December 31, 2024, the allowance for expected credit losses decreased due to a decrease in the weighted average life of the loan portfolio.
The Company monitors the performance of its loans receivable and assesses the ability of the borrower to pay principal and interest based upon loan structure, underlying property values, cash flow and related financial and operating performance of the property and market conditions.
In evaluating the real estate loans, the Company considers their credit quality indicators, including loan to value ratios, which compare the outstanding loan amount to the estimated value of the property, the borrower’s financial condition and performance with respect to loan terms, the position in the capital structure, the overall leverage in the capital structure and other market conditions.
v3.25.4
Net Investment Gains
12 Months Ended
Dec. 31, 2025
Realized and Unrealized Investment Gains (Losses) [Abstract]  
Net Investment Gains Net Investment Gains
Net investment gains were as follows:
(In thousands)202520242023
Net investment gains:   
Fixed maturity securities:   
Gains$18,544 $15,486 $2,003 
Losses(19,191)(32,866)(25,429)
Equity securities (1):
Net realized gains on investment sales (2)70,042 116,475 161,271 
Change in unrealized gains96,337 120,799 70,448 
Investment funds(292)1,835 (25,625)
Real estate (3) 26,544 (2,647)(70,934)
Loans receivable(87)— (18,841)
Other (4)(61,227)(139,344)(45,353)
Net realized and unrealized gains on investments in earnings before allowance for expected credit losses130,670 79,738 47,540 
Change in allowance for expected credit losses on investments:
    Fixed maturity securities597 36,080 715 
    Loans receivable953 1,890 (1,213)
Change in allowance for expected credit losses on investments1,550 37,970 (498)
Net investment gains 132,220 117,708 47,042 
Income tax expense(28,512)(29,205)(10,250)
  After-tax net investment gains$103,708 $88,503 $36,792 
Change in unrealized investment gains (losses):   
Fixed maturity securities without allowance for expected credit losses$490,594 $83,395 $389,839 
Fixed maturity securities with allowance for expected credit losses(862)4,428 643 
Investment funds8,203 (3,217)3,989 
Other(170)(132)(1,568)
Total change in unrealized investment gains 497,765 84,474 392,903 
Income tax expense(105,274)(15,292)(86,350)
Noncontrolling interests(1)(2)
 After-tax change in unrealized investment gains $392,490 $69,184 $306,551 
____________________
(1) The net realized gains or losses on investment sales represent the total gains or losses from the purchase dates of the equity securities. The change in unrealized gains (losses) consists of two components: (i) the reversal of the gain or loss recognized in previous periods on equity securities sold and (ii) the change in unrealized gain or loss resulting from mark-to-market adjustments on equity securities still held.
(2) In 2023, the Company completed a sale of the property and casualty insurance services division of Breckenridge IS, Inc. and recognized a pre-tax net realized gain on investment of $89 million on the sale (proceeds from the sale is presented on the business disposition line within the Consolidated Statements of Cash Flows).
(3) The Company recognized impairments on real estate of $72 million in 2023.
(4) Primarily relates to realized foreign currency losses upon the disposition of fixed maturity securities.
v3.25.4
Fixed Maturity Securities in an Unrealized Loss Position
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Fixed Maturity Securities in an Unrealized Loss Position Fixed Maturity Securities in an Unrealized Loss Position
The following tables summarize all fixed maturity securities in an unrealized loss position at December 31, 2025 and 2024 by the length of time those securities have been continuously in an unrealized loss position.
 Less Than 12 Months12 Months or GreaterTotal
(In thousands)Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
December 31, 2025      
U.S. government and government agency$790,077 $8,902 $183,896 $6,255 $973,973 $15,157 
State and municipal141,680 1,520 1,053,168 36,893 1,194,848 38,413 
Mortgage-backed securities251,861 2,265 839,061 130,415 1,090,922 132,680 
Asset-backed securities644,346 1,643 503,876 15,600 1,148,222 17,243 
Corporate494,240 4,308 1,786,925 58,671 2,281,165 62,979 
Foreign government666,054 9,770 285,640 168,090 951,694 177,860 
Fixed maturity securities$2,988,258 $28,408 $4,652,566 $415,924 $7,640,824 $444,332 
December 31, 2024     
U.S. government and government agency$767,515 $9,637 $560,260 $33,226 $1,327,775 $42,863 
State and municipal348,116 8,027 1,411,761 81,430 1,759,877 89,457 
Mortgage-backed securities1,541,464 21,326 1,060,823 171,734 2,602,287 193,060 
Asset-backed securities411,763 4,613 626,237 36,899 1,038,000 41,512 
Corporate1,791,970 21,346 2,951,377 135,117 4,743,347 156,463 
Foreign government600,103 17,933 476,479 167,440 1,076,582 185,373 
Fixed maturity securities$5,460,931 $82,882 $7,086,937 $625,846 $12,547,868 $708,728 
Substantially all of the securities in an unrealized loss position are rated investment grade, except for the securities in the foreign government classification. A significant amount of the unrealized loss on foreign government securities is the result of changes in currency exchange rates.
Fixed Maturity Securities — A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at December 31, 2025 is presented in the table below:
($ in thousands)Number of
Securities
Aggregate
Fair Value
Gross
Unrealized
Loss
Foreign government67 $151,002 $165,721 
Corporate24 43,968 814 
State and municipal28,958 1,047 
Mortgage-backed securities14 2,244 113 
Total110 $226,172 $167,695 
For fixed maturity securities that management does not intend to sell or to be required to sell, the portion of the decline in value that is considered to be due to credit factors is recognized in earnings, and the portion of the decline in value that is considered to be due to non-credit factors is recognized in other comprehensive income.
The Company has evaluated its fixed maturity securities in an unrealized loss position and believes the unrealized losses are due primarily to temporary market and sector-related factors rather than to issuer-specific factors. None of these securities are delinquent or in default under financial covenants. Based on its assessment of these issuers, the Company expects them to continue to meet their contractual payment obligations as they become due.
v3.25.4
Fair Value Measurements
12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value Measurements Fair Value Measurements
The Company’s fixed maturity and equity securities classified as available for sale and its trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date”. The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels, as follows:
Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.  
Level 2 - Quoted prices for similar assets or valuations based on inputs that are observable.     
Level 3 - Estimates of fair value based on internal pricing methodologies using unobservable inputs. Unobservable inputs are only used to measure fair value to the extent that observable inputs are not available.
Substantially all of the Company’s fixed maturity securities were priced by independent pricing services (generally one U.S. pricing service plus additional pricing services with respect to a limited number of foreign securities held by the Company). The prices provided by the independent pricing services are estimated based on observable market data in active markets utilizing pricing models and processes, which may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, sector groupings, matrix pricing and reference data. The pricing services may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs are available for each security evaluation on any given day. The pricing services used by the Company have indicated that they will only produce an estimate of fair value if objectively verifiable information is available. The determination of whether markets are active or inactive is based upon the volume and level of activity for a particular asset class. The Company reviews the prices provided by pricing services for reasonableness and periodically performs independent price tests of a sample of securities to ensure proper valuation.
If prices from independent pricing services are not available for fixed maturity securities, the Company estimates the fair value. For Level 2 securities, the Company utilizes pricing models and processes which may include benchmark yields, sector groupings, matrix pricing, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, bids, offers and reference data. Where broker quotes are used, the Company generally requests two or more quotes and sets a price within the range of quotes received based on its assessment of the credibility of the quote and its own evaluation of the security. The Company generally does not adjust quotes received from brokers. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information.
For Level 3 securities, the Company generally uses a discounted cash flow model to estimate the fair value of fixed maturity securities. The cash flow models are based upon assumptions as to prevailing credit spreads, interest rate and interest rate volatility, time to maturity and subordination levels. Projected cash flows are discounted at rates that are adjusted to reflect illiquidity, where appropriate.
The following tables present the assets and liabilities measured at fair value as of December 31, 2025 and 2024 by level:
(In thousands)TotalLevel 1Level 2Level 3
December 31, 2025    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$3,998,038 $— $3,998,038 $— 
State and municipal1,837,194 — 1,837,194 — 
Mortgage-backed securities4,808,478 — 4,808,478 — 
Asset-backed securities3,810,346 — 3,810,346 — 
Corporate8,687,411 — 8,667,410 20,001 
Foreign government1,875,589 — 1,875,589 — 
Total fixed maturity securities available for sale25,017,056 — 24,997,055 20,001 
Equity securities:    
Common stocks742,113 739,186 786 2,141 
Preferred stocks616,088 — 607,414 8,674 
Total equity securities1,358,201 739,186 608,200 10,815 
Arbitrage trading account1,221,103 1,139,447 81,543 113 
Total$27,596,360 $1,878,633 $25,686,798 $30,929 
Liabilities:    
Trading account securities sold but not yet purchased$66,285 $66,285 $— $— 
December 31, 2024    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$2,235,341 $— $2,235,341 $— 
State and municipal2,294,644 — 2,294,644 — 
Mortgage-backed securities3,765,490 — 3,765,490 — 
Asset-backed securities3,885,012 — 3,885,012 — 
Corporate8,417,641 — 8,397,974 19,667 
Foreign government1,755,325 — 1,755,325 — 
Total fixed maturity securities available for sale22,353,453 — 22,333,786 19,667 
Equity securities:    
Common stocks760,167 757,115 1,011 2,041 
Preferred stocks443,621 — 439,947 3,674 
Total equity securities1,203,788 757,115 440,958 5,715 
Arbitrage trading account1,122,599 1,062,459 56,630 3,510 
Total$24,679,840 $1,819,574 $22,831,374 $28,892 
Liabilities:    
Trading account securities sold but not yet purchased$73,358 $73,358 $— $— 
The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2025 and 2024:
 Gains (Losses) Included in:
(In thousands)Beginning BalanceEarnings (Losses)Other Comprehensive Income (Loss)ImpairmentsPurchasesSalesPaydowns/MaturitiesTransfers In / OutEnding Balance
Year ended December 31, 2025        
Assets:
Fixed maturity securities available for sale:        
Corporate$19,667 $— $334 $— $— $— $— $— $20,001 
Total19,667 — 334 — — — — — 20,001 
Equity securities:
Common stocks2,041 226 — — — (126)— — 2,141 
Preferred stocks3,674 — — — 6,160 (1,160)— — 8,674 
Total5,715 226 — — 6,160 (1,286)— — 10,815 
Arbitrage trading account3,510 1,745 — — — (5,143)— 113 
Total$28,892 $1,971 $334 $— $6,160 $(6,429)$— $$30,929 
Year ended December 31, 2024        
Assets:
Fixed maturity securities available for sale:        
Corporate$— $— $(333)$— $— $— $— $20,000 $19,667 
Total— — (333)— — — — 20,000 19,667 
Equity securities:
Common stocks1,558 611 — — — (128)— — 2,041 
Preferred stocks3,695 36 — — — (57)— — 3,674 
Total5,253 647 — — — (185)— — 5,715 
Arbitrage trading account3,772 (261)— — — (38)— 37 3,510 
Total$9,025 $386 $(333)$— $— $(223)$— $20,037 $28,892 
For the years ended December 31, 2025 and 2024, one security in each year within the arbitrage trading account portfolio was transferred into Level 3 from Level 2 given there were no available quoted prices or observable inputs.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2025 and 2024:
 20252024
(In thousands)Carrying ValueFair ValueCarrying ValueFair Value
Assets:    
Fixed maturity securities$25,047,662 $25,048,534 $22,397,865 $22,399,426 
Equity securities1,358,201 1,358,201 1,203,788 1,203,788 
Arbitrage trading account1,221,103 1,221,103 1,122,599 1,122,599 
Loans receivable418,913 419,074 405,453 405,248 
Cash and cash equivalents2,539,938 2,539,938 1,974,747 1,974,747 
Trading accounts receivable from brokers and clearing organizations11,669 11,669 60,327 60,327 
Due from broker629 629 — — 
Liabilities:
Due to broker— — 70,483 70,483 
Trading account securities sold but not yet purchased66,285 66,285 73,358 73,358 
Senior notes and other debt1,829,198 1,440,055 1,831,158 1,425,852 
Subordinated debentures1,010,527 760,400 1,009,808 805,864 
The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 12 above. The fair value of loans receivable is estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.
v3.25.4
Reserves For Losses And Loss Expenses
12 Months Ended
Dec. 31, 2025
Insurance [Abstract]  
Reserves For Losses And Loss Expenses Reserves for Losses and Loss Expenses
The Company's reserves for losses and loss expenses are comprised of case reserves and incurred but not reported liabilities (IBNR). When a claim is reported, a case reserve is established for the estimated ultimate payment based upon known information about the claim. As more information about the claim becomes available over time, case reserves are adjusted up or down as appropriate. Reserves are also established on an aggregate basis to provide for IBNR liabilities and expected loss reserve development on reported claims.
Loss reserves included in the Company’s financial statements represent management’s best estimates based upon an actuarially derived point estimate and other considerations. The Company uses a variety of actuarial techniques and methods to derive an actuarial point estimate for each business. These methods may include paid loss development, incurred loss development, paid and incurred Bornhuetter-Ferguson methods and frequency and severity methods. In circumstances where one actuarial method is considered more credible than the others, that method is used to set the point estimate. The actuarial point estimate may also be based on a judgmental weighting of estimates produced from each of the methods considered. Industry loss experience is used to supplement the Company’s own data in selecting “tail factors” in areas where the Company’s own data is limited. The actuarial data is analyzed by line of business, coverage and accident or policy year, as appropriate, for each business.
The establishment of the actuarially derived loss reserve point estimate also includes consideration of qualitative factors that may affect the ultimate losses. These qualitative considerations include, among others, the impact of re-underwriting initiatives, changes in claims handling procedures, changes in the mix of business, changes in distribution sources and changes in policy terms and conditions.
The key assumptions used to arrive at the best estimate of loss reserves are the expected loss ratios, rate of loss cost inflation, and reported and paid loss emergence patterns. Expected loss ratios represent management’s expectation of losses at the time the business is priced and written, before any actual claims experience has emerged. This expectation is a significant determinant of the estimate of loss reserves for recently written business where there is little paid or incurred loss data to consider. Expected loss ratios are generally derived from historical loss ratios adjusted for the impact of rate changes, loss cost trends and known changes in the type of risks underwritten. Expected loss ratios are estimated for each key line of business within each business. Expected loss cost inflation is particularly important for the long-tail lines, such as excess casualty, and claims with a high medical component, such as workers’ compensation. Reported and paid loss emergence patterns are used to project current reported or paid loss amounts to their ultimate settlement value. Loss development factors are based on the historical emergence patterns of paid and incurred losses, and are derived from the Company’s own experience and industry data. The paid loss emergence pattern is also significant to excess and assumed workers’ compensation reserves because those reserves are discounted to their estimated present value based upon such estimated payout patterns.
Loss frequency and severity are measures of loss activity that are considered in determining the key assumptions described in our discussion of loss and loss expense reserves, including expected loss ratios, rate of loss cost inflation and reported and paid loss emergence patterns. Loss frequency is a measure of the number of claims per unit of insured exposure, and loss severity is a measure of the average size of claims. Factors affecting loss frequency include the effectiveness of loss controls and safety programs and changes in economic activity or weather patterns. Factors affecting loss severity include changes in policy limits, retentions, rate of inflation and judicial interpretations.
Another factor affecting estimates of loss frequency and severity is the loss reporting lag, which is the period of time between the occurrence of a loss and the date the loss is reported to the Company. The length of the loss reporting lag affects our ability to accurately predict loss frequency (loss frequencies are more predictable for lines with short reporting lags) as well as the amount of reserves needed for incurred but not reported losses (less IBNR is required for lines with short reporting lags). As a result, loss reserves for lines with short reporting lags are likely to have less variation from initial loss estimates. For lines with short reporting lags, which include auto, primary workers’ compensation, other liability (claims-made) and property business, the key assumption is the loss emergence pattern used to project ultimate loss estimates from known losses paid or reported to date. For lines of business with long reporting lags, which include other liability (occurrence), products liability, excess workers’ compensation and liability reinsurance, the key assumption is the expected loss ratio since there is often little paid or incurred loss data to consider. Historically, the Company has experienced less variation from its initial loss estimates for lines of businesses with short reporting lags than for lines of business with long reporting lags.
The key assumptions used in calculating the most recent estimate of the loss reserves are reviewed each quarter and adjusted, to the extent necessary, to reflect the latest reported loss data, current trends and other factors observed.
A claim may be defined as an event, as a claimant (number of parties claiming damages from an event) or by exposure type (e.g., an event may give rise to two parties, each claiming loss for bodily injury and property damage).
The most commonly used claim count method is by event. Most of the Company's businesses use the number of events to define and quantify the number of claims. However, in certain lines of business, where it is common for multiple parties to claim damages arising from a single event, a business may quantify claims on the basis of the number of separate parties involved in an event. This may be the case with businesses writing substantial auto or transportation exposure.
Claim counts for assumed reinsurance will vary based on whether the business is written on a facultative or treaty basis. Further variability as respects treaty claim counts may be reflective of the nature of the treaty, line of business coverage, and type of participation such as quota share or excess of loss contracts. Accordingly, the claim counts have been excluded from the below Reinsurance & Monoline Excess segment tables due to this variability.
The claim count information set forth in the tables presented below may not provide an accurate reflection of ultimate loss payouts by product line.
The following tables present undiscounted incurred and paid claims development as of December 31, 2025, net of reinsurance, as well as cumulative claim frequency and the total of incurred but not reported liabilities (IBNR). The information about incurred and paid claims development for the years ended December 31, 2016 to 2024 is presented as supplementary information. To enhance the comparability of the loss development data, the Company has removed the impact of foreign exchange rate movements by using the December 31, 2025 exchange rate for all periods.
Insurance
Other Liability
(In thousands)
Loss and Loss Expenses Incurred, Net of Reinsurance As of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$1,005,612 $997,545 $1,007,537 $1,019,724 $1,033,882 $1,049,653 $1,080,784 $1,122,522 $1,123,417 $1,112,764 $40,882 29
2017— 1,056,364 1,089,751 1,112,499 1,130,172 1,169,911 1,239,544 1,257,401 1,289,835 1,312,455 67,962 28
2018— — 1,096,770 1,124,246 1,114,611 1,150,004 1,226,496 1,292,474 1,374,968 1,438,893 82,877 29
2019— — — 1,234,191 1,230,155 1,231,387 1,288,106 1,363,275 1,396,896 1,439,633 100,286 31
2020— — — — 1,332,123 1,205,740 1,150,267 1,158,609 1,188,675 1,234,607 122,379 25
2021— — — — — 1,525,082 1,380,843 1,334,315 1,354,190 1,440,014 177,217 28
2022— — — — — — 1,813,543 1,818,251 1,800,663 1,889,294 444,128 30
2023— — — — — — — 2,114,315 2,077,833 2,054,648 837,033 29
2024— — — — — — — — 2,383,071 2,325,325 1,602,853 25
2025— — — — — — — — — 2,626,044 2,237,259 19
Total$16,873,677 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$67,371 $204,063 $384,280 $551,150 $668,420 $757,859 $861,245 $944,882 $997,545 $1,035,353 
2017— 77,838 251,375 447,980 633,015 768,021 922,491 1,039,147 1,119,561 1,177,876 
2018— — 85,190 261,870 432,342 611,576 801,704 979,655 1,123,197 1,247,469 
2019— — — 86,586 271,989 467,450 700,121 902,947 1,074,214 1,196,228 
2020— — — — 70,510 222,319 417,957 614,487 812,670 949,161 
2021— — — — — 75,175 265,238 484,808 794,700 1,039,910 
2022— — — — — — 92,298 353,014 704,534 1,079,369 
2023— — — — — — — 91,761 366,667 751,329 
2024— — — — — — — — 95,165 341,419 
2025— — — — — — — — — 111,115 
Total$8,929,229 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance226,423 
Reserves for loss and loss adjustment expenses, net of reinsurance$8,170,871 
Workers' Compensation
(In thousands)
Loss and Loss Expenses Incurred, Net of Reinsurance As of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$702,716 $696,339 $684,700 $660,520 $651,278 $657,972 $654,385 $641,549 $639,412 $645,507 $17,158 58
2017— 762,093 733,505 689,622 673,216 683,880 682,153 675,871 669,988 673,458 15,991 58
2018— — 778,964 724,697 715,055 724,056 721,170 715,018 708,336 717,051 17,063 56
2019— — — 784,281 721,018 732,762 734,034 722,456 714,086 717,703 17,158 54
2020— — — — 725,245 716,430 704,008 668,222 652,424 656,816 8,156 42
2021— — — — — 742,687 701,703 667,517 649,222 648,190 10,705 46
2022— — — — — — 772,620 745,218 715,578 715,628 26,775 46
2023— — — — — — — 784,906 758,657 734,685 56,380 46
2024— — — — — — — — 811,614 777,646 142,325 48
2025— — — — — — — — — 833,324 350,183 47
Total$7,120,008 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$142,998 $338,835 $446,072 $504,850 $537,861 $558,934 $572,669 $584,330 $591,005 $598,518 
2017— 153,456 362,299 468,817 525,753 559,198 583,258 603,006 617,243 628,306 
2018— — 171,006 397,464 508,546 574,889 613,675 642,292 660,237 671,916 
2019— — — 184,715 397,376 515,914 581,003 618,324 644,772 663,649 
2020— — — — 172,478 380,454 485,203 548,585 579,332 600,913 
2021— — — — — 172,729 384,867 490,648 547,863 582,994 
2022— — — — — — 180,982 408,929 527,145 598,841 
2023— — — — — — — 195,204 418,788 539,016 
2024— — — — — — — — 196,104 441,748 
2025— — — — — — — — — 212,080 
Total$5,537,981 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance264,217 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,846,244 
Professional Liability
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$310,177 $324,519 $361,292 $402,423 $439,705 $469,048 $464,492 $450,620 $454,376 $451,120 $13,801 9
2017— 332,545 331,841 337,990 376,818 383,720 392,719 401,348 402,042 401,753 23,170 10
2018— — 334,850 322,109 333,268 359,430 382,222 397,629 393,555 389,344 43,168 10
2019— — — 336,064 332,104 345,373 354,054 363,011 364,872 368,639 48,621 11
2020— — — — 393,872 375,336 337,654 313,348 300,725 296,916 26,890 11
2021— — — — — 524,981 471,273 446,441 410,248 415,009 91,622 12
2022— — — — — — 649,151 586,058 556,019 533,621 207,921 12
2023— — — — — — — 647,434 638,138 596,455 264,670 13
2024— — — — — — — — 652,871 647,813 362,839 15
2025— — — — — — — — — 692,538 529,514 16
Total$4,793,208 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$28,514 $102,444 $201,586 $255,458 $297,756 $357,868 $405,866 $413,456 $422,901 $427,370 
2017— 36,445 96,150 162,623 242,971 261,069 306,582 329,340 349,730 362,678 
2018— — 28,167 99,595 155,138 198,574 244,079 283,645 315,703 327,645 
2019— — — 31,652 97,328 147,779 200,255 235,114 270,992 298,961 
2020— — — — 27,932 80,099 128,777 168,902 196,626 237,215 
2021— — — — — 28,539 85,866 153,032 220,397 276,769 
2022— — — — — — 33,412 90,574 161,334 255,314 
2023— — — — — — — 41,073 122,356 215,591 
2024— — — — — — — — 40,369 136,010 
2025— — — — — — — — — 54,712 
Total$2,592,265 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance58,601 
Reserves for loss and loss adjustment expenses, net of reinsurance$2,259,544 
Auto
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$417,591 $418,263 $428,927 $429,436 $426,313 $426,265 $428,158 $429,911 $428,352 $427,441 $1,129 48
2017— 413,468 410,860 413,230 417,437 423,681 427,964 428,541 430,149 430,995 1,544 44
2018— — 423,455 443,583 460,219 474,879 502,611 511,694 513,912 512,884 2,518 43
2019— — — 463,232 466,184 483,737 508,810 525,412 532,678 532,577 4,645 43
2020— — — — 493,539 396,628 407,526 433,991 440,637 445,804 1,301 29
2021— — — — — 552,005 517,236 552,222 583,696 608,850 11,077 35
2022— — — — — — 723,267 740,688 763,806 802,255 35,392 41
2023— — — — — — — 890,682 907,503 930,020 91,528 43
2024— — — — — — — — 1,062,427 1,022,138 276,533 44
2025— — — — — — — — — 1,153,852 603,269 40
Total$6,866,816 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$180,603 $273,083 $333,092 $378,826 $397,671 $407,239 $415,630 $421,684 $424,338 $424,501 
2017— 173,964 257,335 314,739 357,282 386,260 403,864 414,486 422,351 425,108 
2018— — 173,955 272,312 337,926 397,867 445,885 479,508 494,308 502,832 
2019— — — 180,027 280,089 361,142 423,458 474,177 500,234 518,787 
2020— — — — 136,907 213,648 285,885 346,903 402,187 425,583 
2021— — — — — 168,499 289,019 379,969 476,465 550,804 
2022— — — — — — 237,885 394,137 531,324 657,551 
2023— — — — — — — 271,552 467,227 661,466 
2024— — — — — — — — 295,450 537,738 
2025— — — — — — — — — 317,147 
Total$5,021,517 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance5,042 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,850,341 
Short-tail lines
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$754,787 $758,453 $745,814 $740,062 $734,292 $736,723 $735,410 $735,706 $733,948 $734,213 $1,563 32
2017— 731,043 730,031 724,245 723,194 722,906 724,139 722,842 722,404 722,888 1,686 40
2018— — 741,978 732,244 728,956 727,513 724,921 724,069 719,517 719,947 3,791 47
2019— — — 703,739 685,145 675,146 669,008 669,126 658,750 657,296 3,574 42
2020— — — — 883,190 888,216 906,102 910,086 913,270 907,269 4,297 36
2021— — — — — 805,775 810,447 793,743 790,837 790,146 9,499 33
2022— — — — — — 905,427 889,716 880,655 880,999 18,124 32
2023— — — — — — — 1,036,001 997,840 989,593 37,413 28
2024— — — — — — — — 1,255,511 1,114,550 97,447 30
2025— — — — — — — — — 1,436,694 610,043 22
Total$8,953,595 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$404,261 $653,463 $694,726 $709,649 $714,504 $721,214 $722,046 $727,037 $729,261 $730,279 
2017— 429,297 667,922 695,780 707,688 710,855 718,026 723,385 725,808 725,326 
2018— — 401,786 645,593 691,916 708,876 707,915 712,992 715,706 718,309 
2019— — — 392,224 600,542 629,728 642,116 650,202 652,285 653,178 
2020— — — — 447,119 768,708 829,695 884,658 888,968 889,801 
2021— — — — — 389,015 677,203 733,205 756,084 770,016 
2022— — — — — — 440,972 762,169 827,800 850,260 
2023— — — — — — — 531,859 847,059 911,546 
2024— — — — — — — — 559,412 923,661 
2025— — — — — — — — — 587,273 
Total$7,759,649 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance(445)
Reserves for loss and loss adjustment expenses, net of reinsurance$1,193,501 
Reinsurance & Monoline Excess
Casualty
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$266,797 $278,899 $271,026 $293,396 $327,222 $326,843 $333,682 $328,995 $332,892 $337,165 $9,541 
2017— 257,234 247,785 265,054 286,643 305,992 321,755 335,173 345,090 357,493 16,254 
2018— — 247,465 236,747 256,413 272,487 283,962 311,426 328,553 341,329 21,566 
2019— — — 262,465 259,821 266,712 266,965 296,080 316,801 336,042 28,772 
2020— — — — 336,854 332,164 330,205 349,072 347,967 356,608 42,420 
2021— — — — — 430,770 432,251 424,891 427,481 453,576 86,204 
2022— — — — — — 494,853 507,154 479,837 486,146 140,864 
2023— — — — — — — 479,858 472,917 484,781 222,872 
2024— — — — — — — — 436,374 413,652 295,429 
2025— — — — — — — — — 443,941 395,239 
Total$4,010,733 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$26,586 $73,567 $115,091 $159,774 $193,329 $228,350 $249,234 $267,601 $279,732 $294,864 
2017— 25,292 54,455 86,635 144,009 169,593 198,765 233,392 269,624 290,428 
2018— — 18,942 52,766 93,374 128,903 164,086 207,741 245,388 270,913 
2019— — — 21,522 52,707 81,367 116,771 170,418 220,154 255,525 
2020— — — — 28,319 67,078 109,610 171,832 218,359 254,833 
2021— — — — — 24,696 77,110 146,076 212,227 280,381 
2022— — — — — — 28,077 83,762 159,448 233,285 
2023— — — — — — — 17,685 66,831 131,943 
2024— — — — — — — — 16,875 55,767 
2025— — — — — — — — — 13,573 
Total$2,081,512 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance331,375 
Reserves for loss and loss adjustment expenses, net of reinsurance$2,260,596 
Monoline Excess
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$72,657 $70,281 $71,404 $64,957 $65,485 $65,222 $63,932 $59,804 $55,371 $57,373 $1,048 
2017— 76,701 80,508 70,749 71,025 66,795 65,147 62,213 57,073 48,281 2,751 
2018— — 77,820 72,505 71,448 66,180 60,347 58,244 54,784 46,233 3,299 
2019— — — 78,929 77,482 76,242 76,478 73,571 70,929 63,702 4,822 
2020— — — — 84,354 83,468 82,952 80,946 70,219 60,759 10,403 
2021— — — — — 98,110 90,980 89,220 84,681 85,078 15,135 
2022— — — — — — 128,923 101,725 100,612 90,351 13,742 
2023— — — — — — — 110,446 86,901 85,509 22,170 
2024— — — — — — — — 120,046 89,794 45,243 
2025— — — — — — — — — 133,713 89,175 
Total$760,793 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$2,498 $4,783 $5,573 $5,928 $7,685 $9,883 $11,819 $13,569 $16,872 $18,766 
2017— 6,282 12,810 15,356 17,327 18,375 19,275 21,275 23,523 25,457 
2018— — 6,141 8,230 9,368 10,359 12,414 13,583 14,952 16,828 
2019— — — 6,241 10,884 12,728 15,436 18,836 21,094 24,642 
2020— — — — 4,869 8,699 10,471 12,869 15,427 18,072 
2021— — — — — 4,586 6,026 8,872 11,412 13,973 
2022— — — — — — 5,898 10,564 17,778 26,975 
2023— — — — — — — 6,390 12,471 16,547 
2024— — — — — — — — 5,723 9,436 
2025— — — — — — — — — 6,014 
Total$176,710 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance576,839 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,160,922 
Property
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$186,014 $192,180 $199,087 $198,635 $204,166 $202,119 $203,126 $204,261 $203,249 $204,044 $666 
2017— 228,476 223,694 222,774 221,753 215,552 216,037 217,179 216,027 216,352 290 
2018— — 126,458 129,079 120,813 122,516 120,712 119,094 118,023 117,318 749 
2019— — — 120,797 93,545 98,085 97,060 96,996 96,129 96,760 1,209 
2020— — — — 132,262 134,287 133,004 137,810 136,468 141,563 3,737 
2021— — — — — 156,684 168,907 166,320 162,159 158,306 2,286 
2022— — — — — — 207,282 206,632 203,495 197,161 12,674 
2023— — — — — — — 177,380 173,605 165,333 14,323 
2024— — — — — — — — 256,437 231,060 65,848 
2025— — — — — — — — — 307,718 181,307 
Total$1,835,615 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$91,496 $150,392 $174,539 $186,047 $193,716 $195,856 $200,197 $202,117 $202,537 $203,237 
2017— 87,893 163,021 194,423 202,727 206,293 209,510 212,117 212,868 213,968 
2018— — 46,928 81,241 98,836 104,285 112,511 113,835 114,461 114,560 
2019— — — 35,584 70,147 84,513 87,111 89,023 90,942 92,024 
2020— — — — 39,668 81,413 102,822 111,751 118,775 126,803 
2021— — — — — 31,657 92,757 130,615 145,630 148,460 
2022— — — — — — 56,561 129,019 152,660 171,165 
2023— — — — — — — 58,403 110,388 133,772 
2024— — — — — — — — 69,398 139,970 
2025— — — — — — — — — 86,168 
Total$1,430,127 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance3,639 
Reserves for loss and loss adjustment expenses, net of reinsurance$409,127 
The reconciliation of the net incurred and paid claims development tables to the reserves for losses and loss expenses in the consolidated balance sheet is as follows:
(In thousands)December 31, 2025
Undiscounted reserves for loss and loss expenses, net of reinsurance:
Other liability$8,170,871 
Workers' compensation1,846,244 
Professional liability2,259,544 
Auto1,850,341 
Short-tail lines1,193,501 
Other222,930 
  Insurance15,543,431 
Casualty2,260,596 
Monoline excess1,160,922 
Property409,127 
  Reinsurance & Monoline Excess3,830,645 
Total undiscounted reserves for loss and loss expenses, net of reinsurance$19,374,076 
(In thousands)December 31, 2025
Due from reinsurers on unpaid claims:
Other liability$1,162,055 
Workers' compensation164,412 
Professional liability1,086,923 
Auto65,748 
Short-tail lines429,944 
Other145,790 
  Insurance3,054,872 
Casualty97,489 
Monoline excess41,132 
Property60,606 
  Reinsurance & Monoline Excess199,227 
Total due from reinsurers on unpaid claims$3,254,099 
(In thousands)December 31, 2025
Loss reserve discount:
Other liability$— 
Workers' compensation(9,263)
Professional liability— 
Auto— 
Short-tail lines— 
Other— 
  Insurance(9,263)
Casualty(64,732)
Monoline excess(346,407)
Property— 
  Reinsurance & Monoline Excess(411,139)
Total loss reserve discount$(420,402)
Total gross reserves for loss and loss expenses$22,207,773 
The following is supplementary information regarding average historical claims duration as of December 31, 2025:
Insurance
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years12345678910
Other liability5.3 %12.7 %15.6 %16.4 %13.5 %11.0 %9.2 %7.4 %4.6 %3.4 %
Workers' compensation25.0 %31.2 %16.2 %9.2 %5.1 %3.6 %2.5 %1.8 %1.3 %1.2 %
Professional liability7.5 %15.3 %16.0 %15.0 %9.7 %11.6 %8.0 %3.3 %2.7 %1.0 %
Auto32.4 %20.0 %15.6 %12.7 %9.1 %4.6 %2.7 %1.6 %0.6 %— %
Short-tail lines52.3 %33.9 %6.0 %2.8 %0.7 %0.6 %0.3 %0.5 %0.1 %0.1 %
Reinsurance & Monoline Excess
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years12345678910
Casualty5.7 %10.5 %12.2 %13.9 %11.9 %11.3 %9.4 %7.7 %4.7 %4.5 %
Monoline excess7.9 %6.0 %3.9 %4.0 %3.7 %3.2 %4.0 %3.9 %4.9 %3.3 %
Property33.2 %32.8 %15.2 %6.0 %3.5 %2.3 %1.2 %0.5 %0.4 %0.3 %
The table below provides a reconciliation of the beginning and ending reserve balances:
(In thousands)202520242023
Net reserves at beginning of year$17,166,641 $15,661,820 $14,248,879 
Net provision for losses and loss expenses:
Claims occurring during the current year (1)7,702,638 7,083,999 6,311,780 
Increase in estimates for claims occurring in prior years (2)34,446 14,350 29,681 
Loss reserve discount accretion34,573 33,246 30,681 
Total7,771,657 7,131,595 6,372,142 
Net payments for claims:   
Current year1,375,478 1,278,585 1,217,078 
Prior year4,758,098 4,205,845 3,764,532 
Total6,133,576 5,484,430 4,981,610 
Foreign currency translation148,952 (142,344)22,409 
Net reserves at end of year18,953,674 17,166,641 15,661,820 
Ceded reserve at end of year3,254,099 3,201,389 3,077,832 
Gross reserves at end of year$22,207,773 $20,368,030 $18,739,652 
Net change in premiums and losses occurring in prior years:
Increase in estimates for claims occurring in prior years (2)$(34,446)$(14,350)$(29,681)
Retrospective premium adjustments for claims occurring in prior years (3)37,692 18,782 10,782 
Net premium and reserve development on prior years$3,246 $4,432 $(18,899)
_______________________________________
(1)Claims occurring during the current year are net of loss reserve discounts of $56 million, $49 million and $47 million in 2025, 2024, and 2023, respectively.
(2)The change in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years increased by $29 million in 2025, increased by $13 million in 2024 and decreased by $13 million in 2023.
(3)For certain retrospectively rated insurance polices and reinsurance agreements, changes in loss and loss expenses for prior years are offset by additional or return premiums.
Favorable prior year development (net of additional and return premiums) was $3 million in 2025.
Insurance – Reserves for the Insurance segment developed unfavorably by $44 million in 2025 (net of additional and return premiums). The adverse development was driven by the other liability and auto liability lines of business, and was partially offset by favorable development for short tail lines of business, auto physical damage, professional liability and workers’ compensation.
The adverse other liability development was driven mainly by umbrella and excess liability claims, and to a lesser degree from the Company’s primary surplus lines casualty business. The umbrella and excess liability development included a significant component stemming from underlying auto exposures. The other liability development was concentrated in accident years 2017 through 2022. The adverse auto liability development was concentrated in accident years 2021 through 2023. The Company believes that auto-related claims are being particularly impacted by social inflation, which is contributing to an increase in the frequency of large losses beyond expectations. An increase in the frequency of litigated claims is also driving up both indemnity and loss adjustment expense in these lines of business beyond expectations. Social inflation can include higher settlement demands from plaintiffs, use of tactics such as litigation funding by the plaintiffs’ bar, negative public sentiment towards large businesses and corporations, and erosion of tort reforms, among others.
The favorable development for both short tail lines of business and auto physical damage related to the 2024 accident year, and resulted from favorable settlements of both catastrophe and non-catastrophe property claims below our expectations. The favorable professional liability development related mainly to accident years 2022 and 2023, and was driven by lower reported claim frequency and incurred losses than expected. The favorable workers’ compensation development was mainly related to accident years 2023 and 2024, and resulted from a continuation of favorable reported claim frequency below
expectations, although the magnitude of the favorable development in this line has moderated from levels seen in previous years.
Reinsurance & Monoline Excess – Reserves for the Reinsurance & Monoline Excess segment developed favorably by $47 million in 2025 (net of additional and return premiums). The favorable development was driven mainly by property and workers’ compensation business, and was partially offset by adverse development in casualty reinsurance assumed. Similar to the Insurance segment, the favorable property development related primarily to the 2024 accident year and resulted from favorable claims settlements below our expectations. The favorable workers’ compensation development was driven by continued lower claim frequency and reported losses relative to expectations, and was spread across many prior accident years, mainly 2017 through 2024. The unfavorable development for casualty reinsurance was concentrated mainly in accident years 2019 through 2023 and was associated primarily with non-proportional assumed reinsurance.
Favorable prior year development (net of additional and return premiums) was $4 million in 2024.
Insurance – Reserves for the Insurance segment developed unfavorably by $8 million in 2024 (net of additional and return premiums). The adverse development was driven by the commercial auto liability and other liability occurrence lines of business, and was largely offset by favorable development for workers’ compensation, professional liability, products liability, and commercial property lines of business.
The adverse commercial auto liability development was concentrated in accident years 2021 through 2023, while the adverse other liability occurrence development was focused across accident years 2015 through 2022. The majority of the other liability occurrence development was driven by umbrella and excess liability claims, of which a significant portion related to underlying commercial auto exposures. The Company believes that commercial auto-related claims are being particularly impacted by social inflation, which is contributing to an increase in the frequency of large losses beyond expectations. Social inflation can include higher settlement demands from plaintiffs, use of aggressive actions by the plaintiffs’ bar such as litigation funding, negative public sentiment towards large businesses and corporations, and erosion of tort reforms, among other factors.
The favorable workers’ compensation development for the Insurance segment was mainly related to accident years 2016 through 2023, with accident years 2020 through 2023 contributing the most. For workers’ compensation, favorable reported claim frequency, below expectations, continued to be the main driver of the favorable reserve development. The favorable development for both the professional liability and products liability lines of business was related mainly to accident years 2020 through 2023. For both of these lines, reported claim frequency and incurred losses for accident years 2020 through 2023 were better than expected, which drove the favorable reserve development. Business written in these years also benefitted from significant price increases, which the Company now believes will result in higher profitability than initially anticipated. The favorable development for commercial property was mainly associated with the 2023 accident year, and resulted from better than expected settlements for both catastrophe related and non-catastrophe claims.
Reinsurance & Monoline Excess – Reserves for the Reinsurance & Monoline Excess segment developed favorably by $12 million in 2024 (net of additional and return premiums). The favorable development was driven mainly by excess workers’ compensation business, partially offset by adverse development in the non-proportional reinsurance assumed liability line of business. The favorable excess workers’ compensation development was driven by continued lower claim frequency and reported losses relative to expectations, and favorable claim settlements spread across many prior accident years. The unfavorable development for non-proportional reinsurance was concentrated mainly in accident years 2015 through 2019 and was associated primarily with our U.S. and U.K. excess general liability reinsurance businesses, including coverage for cedants insuring construction projects.
Unfavorable prior year development (net of additional and return premiums) was $19 million in 2023.
Insurance – Reserves for the Insurance segment developed unfavorably by $21 million in 2023 (net of additional and return premiums). The unfavorable development for the segment was concentrated in the early part of the year. A key driver of the unfavorable development early in 2023 was property catastrophe losses related to 2022 events which were still being adjusted and settled during the early part of 2023. In particular, losses related to U.S. winter storms which occurred during the month of December 2022 were a significant contributor to the development, as information gathering and evaluation of many of these claims were still ongoing into the new year.
In addition to the property prior year development discussed above, during 2023 the Insurance segment also experienced adverse prior year development on casualty lines of business for the 2016 through 2019 accident years, which was offset by favorable prior year development on casualty lines of business for the 2020 through 2022 accident years. The unfavorable development on the 2016 through 2019 accident years was concentrated in the general liability and commercial auto liability lines of business. The development, which particularly impacted business attaching excess of primary policy limits, was driven by a larger than expected number of large losses reported. The Company believes social inflation is contributing to an increase in the frequency of large losses for these accident years. Social inflation can include higher
settlement demands from plaintiffs, use of tactics such as litigation funding by the plaintiffs’ bar, negative public sentiment towards large businesses and corporations, and erosion of tort reforms, among others.
The favorable prior year development on casualty lines for the 2020 through 2022 accident years in the Insurance segment was concentrated in the professional liability, workers’ compensation, and general liability lines of business. Due to elevated uncertainty regarding incurred loss frequency and severity as a result of ongoing social inflation and the impacts of the COVID-19 pandemic, the Company set its initial loss ratios for the 2020 through 2022 accident years prudently, and largely maintained these estimates through the end of each respective accident year. The reported loss experience to date for these lines of business for the 2020 through 2022 accident years has been significantly better than was expected, and the Company has begun to react to this favorable emergence as the accident years mature beyond the age of twelve months. It should also be noted that commercial auto liability experienced adverse prior year development for the 2020 through 2022 accident years, which partially offset the favorable development discussed above; the adverse development was driven by a larger than expected number of large losses reported.
Reinsurance & Monoline Excess – Reserves for the Reinsurance & Monoline Excess segment developed favorably by $2 million in 2023 (net of additional and return premiums). The overall favorable prior year development for the segment was driven mainly by favorable development in excess workers’ compensation, substantially offset by unfavorable development in the non-proportional reinsurance assumed liability, excess general liability (including umbrella), and commercial auto liability lines of business. The favorable excess workers’ compensation development was driven by continued lower claim frequency and reported losses relative to our expectations, and to favorable claim settlements. The favorable development was spread across many prior accident years. The unfavorable development for non-proportional reinsurance assumed liability and excess general liability was associated primarily with our U.S. assumed reinsurance business, and related to accounts reinsuring excess and umbrella business and construction projects. The adverse development was concentrated mainly in accident years 2017 through 2020. The unfavorable development for commercial auto liability was concentrated in the 2022 accident year and related to commercial auto program business.
Environmental and Asbestos — To date, known environmental and asbestos claims have not had a material impact on the Company’s operations, because its subsidiaries generally did not insure large industrial companies that are subject to significant environmental or asbestos exposures prior to 1986 when an absolute exclusion was incorporated into standard policy language.
The Company’s net reserves for losses and loss expenses relating to asbestos and environmental claims on policies written before adoption of the absolute exclusion was $13 million and $16 million at December 31, 2025 and 2024, respectively. The estimation of these liabilities is subject to significantly greater than normal variation and uncertainty because it is difficult to make an actuarial estimate of these liabilities due to the absence of a generally accepted actuarial methodology for these exposures and the potential effect of significant unresolved legal matters, including coverage issues, as well as the cost of litigating the legal issues. Additionally, the determination of ultimate damages and the final allocation of such damages to financially responsible parties are highly uncertain.
Discounting — The Company discounts its liabilities for certain workers’ compensation reserves. The amount of workers’ compensation reserves that were discounted was $1,400 million and $1,358 million at December 31, 2025 and 2024, respectively. The aggregate net discount for those reserves, after reflecting the effects of ceded reinsurance, was $420 million and $405 million at December 31, 2025 and 2024, respectively. At December 31, 2025, discount rates by year ranged from 0.7% to 6.5%, with a weighted average discount rate of 3.6%.
Substantially all discounted workers’ compensation reserves (97% of total discounted reserves at December 31, 2025) are excess workers’ compensation reserves. In order to properly match loss expenses with income earned on investment securities supporting the liabilities, reserves for excess workers’ compensation business are discounted using risk-free discount rates determined by reference to the U.S. Treasury yield curve. These rates are determined annually based on the weighted average rate for the period. Once established, no adjustments are made to the discount rate for that period, and any increases or decreases in loss reserves in subsequent years are discounted at the same rate, without regard to when any such adjustments are recognized. The expected loss and loss expense payout patterns subject to discounting are derived from the Company’s loss payout experience.
The Company also discounts reserves for certain other long-duration workers’ compensation reserves (representing approximately 3% of total discounted reserves at December 31, 2025), including reserves for quota share reinsurance and reserves related to losses regarding occupational lung disease. These reserves are discounted at statutory rates prescribed or permitted by the Department of Insurance of the State of Delaware.
v3.25.4
Reinsurance
12 Months Ended
Dec. 31, 2025
Reinsurance Disclosures [Abstract]  
Reinsurance Premiums and Reinsurance Related Information
The Company reinsures a portion of its insurance exposures in order to reduce its net liability on individual risks and catastrophe losses. Reinsurance coverage and retentions vary depending on the line of business, location of the risk and nature of loss. The Company’s reinsurance purchases include the following: property reinsurance treaties that reduce exposure to large individual property losses and catastrophe events; casualty reinsurance treaties that reduce its exposure to large individual casualty losses, workers’ compensation catastrophe losses and casualty losses involving multiple claimants or insureds; and facultative reinsurance that reduces exposure on individual policies or risks for losses that exceed treaty reinsurance capacity. Depending on the business, the Company purchases specific additional reinsurance to supplement the above programs.
The following is a summary of reinsurance financial information:
(In thousands)202520242023
Written premiums:   
Direct$13,694,521 $12,904,893 $11,676,743 
Assumed1,410,548 1,306,198 1,295,263 
Ceded(2,393,742)(2,238,995)(2,017,539)
Total net written premiums$12,711,327 $11,972,096 $10,954,467 
Earned premiums:  
Direct$13,401,453 $12,346,924 $11,112,980 
Assumed1,387,726 1,364,774 1,246,288 
Ceded(2,342,241)(2,163,213)(1,958,581)
Total net earned premiums$12,446,938 $11,548,485 $10,400,687 
Ceded losses and loss expenses incurred$1,400,570 $1,368,279 $1,376,144 
Ceded commission earned$555,763 $505,753 $471,841 

The following table presents the rollforward of the allowance for expected credit losses for premiums and fees receivable for the years ended December 31, 2025 and 2024:
(In thousands)20252024
Allowance for expected credit losses, beginning of period$39,884 $35,110 
Change in expected credit losses2,122 4,774 
Allowance for expected credit losses, end of period$42,006 $39,884 
The following table presents the rollforward of the allowance for expected credit losses associated with due from reinsurers for the years ended December 31, 2025 and 2024:
(In thousands)20252024
Allowance for expected credit losses, beginning of period$8,350 $8,404 
Change in expected credit losses(1,972)(54)
Allowance for expected credit losses, end of period$6,378 $8,350 
The following table presents the amounts due from reinsurers as of December 31, 2025:
(In thousands)
Lifson Re$537,366 
Lloyd’s of London358,718 
Partner Re 295,800 
Munich Re250,080 
Berkshire Hathaway246,729 
Hannover Re222,358 
Renaissance Re217,251 
Swiss Re 132,731 
Liberty Mutual124,916 
Everest Re86,017 
Arch Capital76,095 
Axis Capital 70,166 
Sompo Holdings64,383 
Fairfax Financial60,919 
Nationwide Corp60,342 
TOA Reinsurance51,290 
Korean Re45,858 
Axa Insurance42,361 
MS & AD Insurance 38,179 
Markel Corp 34,949 
Chubb 27,873 
Helvetia Holdings25,542 
Other reinsurers less than $20,000378,336 
Subtotal3,448,259 
Residual market pools (1)101,132 
Allowance for expected credit losses(6,378)
Total$3,543,013 
(1)Many states require licensed insurers that provide workers' compensation insurance to participate in programs that provide workers' compensation to employers that cannot procure coverage from an insurer on a voluntary basis. Insurers can fulfill this residual market obligation by participating in pools where results are shared by the participating companies. The Company acts as a servicing carrier for workers' compensation pools in certain states. As a servicing carrier, the Company writes residual market business directly and then cedes 100% of this business to the respective pool. As a servicing carrier, the Company receives fee income for its services. The Company does not retain underwriting risk, and credit risk is limited as ceded balances are jointly shared by all the pool members.
v3.25.4
Indebtedness
12 Months Ended
Dec. 31, 2025
Debt Disclosure [Abstract]  
Indebtedness Indebtedness
Indebtedness consisted of the following as of December 31, 2025 (the difference between the face value and the carrying value is unamortized discount and debt issuance costs):
Carrying Value
(In thousands)Interest RateFace Value20252024
Senior notes and other debt due on:    
February 15, 20376.250%$250,000 $248,776 $248,666 
August 1, 20444.750%350,000 346,574 346,389 
May 12, 20504.000%470,000 488,449 489,207 
March 30, 20523.550%400,000 394,807 394,609 
September 30, 20613.150%350,000 343,498 343,314 
Subsidiary debt and other (1)Various7,094 7,094 8,973 
  Total senior notes and other debt $1,827,094 $1,829,198 $1,831,158 
Subordinated debentures due on:
March 30, 20585.700%$185,000 $179,811 $179,489 
December 30, 20595.100%300,000 291,895 291,418 
September 30, 20604.250%250,000 244,958 244,668 
March 30, 20614.125%300,000 293,863 293,515 
Total subordinated debentures $1,035,000 $1,010,527 $1,009,090 
________________
(1) Subsidiary debt of $7.3 million is due in 2026, partially offset by the unamortized cost of $0.2 million due to entering into the $300 million senior unsecured revolving credit facility.
v3.25.4
Income Taxes
12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Income Taxes Income Taxes
Income tax expense (benefit) consists of:
(In thousands)Current
Expense
Deferred Expense (Benefit)Total
December 31, 2025   
U.S. Federal$399,800 $(16,709)$383,091 
State & Local13,597 (561)13,036 
Foreign96,856 2,781 99,637 
Total expense (benefit)$510,253 $(14,489)$495,764 
December 31, 2024   
Domestic$344,210 $51,754 $395,964 
Foreign69,312 44,640 113,952 
Total expense$413,522 $96,394 $509,916 
December 31, 2023   
Domestic$352,891 $(43,456)$309,435 
Foreign44,372 16,750 61,122 
Total expense (benefit)$397,263 $(26,706)$370,557 
        

Income before income taxes from domestic operations was $1,881 million, $1,840 million and $1,430 million for the years ended December 31, 2025, 2024 and 2023, respectively. Income before income taxes from foreign operations was $400 million, $424 million and $324 million for the years ended December 31, 2025, 2024 and 2023, respectively.
A reconciliation of the income tax expense and the amounts computed by applying the Federal and foreign income tax rate of 21% for 2025, 2024 and 2023 to pre-tax income are as follows:
(In thousands)2025%20242023
U.S. Federal Statutory Tax Rate$478,914 21.0 %$475,543 $368,425 
State and Local Taxes, Net of Federal Benefit (1)10,299 0.4 %12,329 12,271 
Foreign Tax Effects11,635 0.5 %19,317 (1,896)
Effect of Cross-Border Tax Laws(14,727)(0.7)%— — 
Changes in Valuation Allowances19,726 0.9 %(220)(10,883)
Nontaxable or Nondeductible Items(10,083)(0.4)%2,947 2,640 
Total $495,764 21.7 %$509,916 $370,557 
(1) State income taxes in Florida and Illinois made up the majority (greater than 50%) of the tax effect in this category.
At December 31, 2025 and 2024, the tax effects of differences that give rise to significant portions of the deferred tax asset and deferred tax liability are as follows:
(In thousands)20252024
Deferred tax asset:  
Loss reserve discounting$253,980 $218,222 
Unearned premiums228,752 216,721 
Unrealized investment losses— 58,701 
Net operating losses & foreign tax credits77,810 62,159 
Other-than-temporary impairments5,006 7,149 
Employee compensation plans83,034 70,529 
Other82,948 81,915 
Gross deferred tax asset731,530 715,396 
Less valuation allowance(55,789)(36,063)
Deferred tax asset675,741 679,333 
Deferred tax liability:  
Amortization of intangibles15,541 15,124 
Unrealized investment gains41,641 — 
Deferred policy acquisition costs204,979 195,150 
Property, furniture and equipment61,479 45,276 
Investment funds229,694 184,899 
Other80,784 83,818 
Deferred tax liability634,118 524,267 
Net deferred tax asset$41,623 $155,066 
The Company had a net current tax payable of $81 million and $14 million at December 31, 2025 and 2024, respectively. At December 31, 2025, the Company had foreign net operating loss carryforwards of $179 million that have no expiration date. At December 31, 2025, the Company had a valuation allowance of $56 million. The Company has provided a valuation allowance against the utilization of $33 million of foreign tax credits and the future net operating loss carryforward benefits of $23 million for certain foreign operations. The statute of limitations for the Company’s U.S. Federal income tax returns has closed for all years through December 31, 2021.
The realization of the deferred tax asset is dependent upon the Company’s ability to generate sufficient taxable income in future periods. Based on historical results and the prospects for future current operations, management anticipates that it is more likely than not that future taxable income will be sufficient for the realization of this asset.
The Company has not provided U.S. deferred income taxes on the undistributed earnings of approximately $585 million of its non-U.S. subsidiaries since these earnings are intended to be permanently reinvested in the non-U.S. subsidiaries. In the future, if such earnings were distributed the Company projects that the incremental tax, if any, will be immaterial.
v3.25.4
Dividends From Subsidiaries And Statutory Financial Information
12 Months Ended
Dec. 31, 2025
Insurance [Abstract]  
Dividends From Subsidiaries And Statutory Financial Information Dividends from Subsidiaries and Statutory Financial Information
The Company’s insurance subsidiaries are restricted by law as to the amount of dividends they may pay without the approval of regulatory authorities. The Company’s lead insurer, Berkley Insurance Company ("BIC"), directly or indirectly owns all of the Company’s other insurance companies. During 2026, the maximum amount of dividends that can be paid by BIC without such approval is approximately $1.4 billion.
BIC’s combined net income and statutory capital and surplus, as determined in accordance with statutory accounting practices ("SAP"), are as follows:
(In thousands)202520242023
Net income$1,588,605 $1,624,686 $1,176,255 
Statutory capital and surplus$9,857,138 $9,421,874 $8,776,138 
    The significant variances between SAP and GAAP are that for statutory purposes bonds are carried at amortized cost, unrealized gains and losses on equity securities are recorded in surplus, acquisition costs are charged to income as incurred, deferred Federal income taxes are subject to limitations, excess and assumed workers’ compensation reserves are discounted at different discount rates and certain assets designated as “non-admitted assets” are charged against surplus. The Commissioner of Insurance of the State of Delaware has allowed BIC to recognize a non-tabular discount on certain workers' compensation loss reserves, which is a permitted practice that differs from SAP. The effect of using this permitted practice was an increase to BIC’s statutory capital and surplus by $167 million at December 31, 2025.
The National Association of Insurance Commissioners (“NAIC”) has risk-based capital (“RBC”) requirements that require insurance companies to calculate and report information under a risk-based formula which measures statutory capital and surplus needs based on a regulatory definition of risk in a company’s mix of products and its balance sheet. This guidance is used to calculate two capital measurements: Total Adjusted Capital and RBC Authorized Control Level. Total Adjusted Capital is equal to the Company’s statutory capital and surplus excluding capital and surplus derived from the use of permitted practices that differ from statutory accounting practices. RBC Authorized Control Level is the capital level used by regulatory authorities to determine whether remedial action is required. Generally, no remedial action is required if Total Adjusted Capital is 200% or more of the RBC Authorized Control Level. At December 31, 2025, BIC’s Total Adjusted Capital of $9.7 billion was 397% of its RBC Authorized Control Level.
See Note 3, Investments in Fixed Maturity Securities, for a description of assets held on deposit as security.
v3.25.4
Common Stockholders' Equity
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Common Stockholders' Equity Common Stockholders’ Equity
The weighted average number of shares used in the computation of net income per share was as follows:
(In thousands)202520242023
Basic396,968 399,734 406,500 
Diluted399,861 403,224 409,948 

Treasury shares have been excluded from average outstanding shares from the date of acquisition. The weighted average number of basic shares outstanding includes the impact of 17,378,810 common shares held in a grantor trust. The common shares held in the grantor trust are for delivery upon settlement of vested but mandatorily deferred restricted stock units ("RSUs"). Shares held by the grantor trust do not affect diluted shares outstanding since shares deliverable under vested RSUs were already included in diluted shares outstanding. The difference in calculating basic and diluted net income per share is attributable entirely to the dilutive effect of stock-based compensation plans. Changes in shares of common stock outstanding, net of treasury shares, are presented below. Shares of common stock issued and outstanding do not include shares related to unissued restricted stock units (including shares held in the grantor trust).
202520242023
Balance, beginning of year380,066,070 384,817,136396,819,150
Shares issued1,158,755 951,930 1,059,500
Shares repurchased(4,069,026)(5,702,996)(13,061,514)
Balance, end of year377,155,799 380,066,070384,817,136

The amount of dividends paid is dependent upon factors such as the receipt of dividends from our subsidiaries, our results of operations, cash flow, financial condition and business needs, the capital and surplus requirements of our subsidiaries, and applicable insurance regulations that limit the amount of dividends that may be paid by our regulated insurance subsidiaries.
v3.25.4
Fair Value Of Financial Instruments
12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
Fair Value Of Financial Instruments Fair Value Measurements
The Company’s fixed maturity and equity securities classified as available for sale and its trading account securities are carried at fair value. Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date”. The Company utilizes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels, as follows:
Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.  
Level 2 - Quoted prices for similar assets or valuations based on inputs that are observable.     
Level 3 - Estimates of fair value based on internal pricing methodologies using unobservable inputs. Unobservable inputs are only used to measure fair value to the extent that observable inputs are not available.
Substantially all of the Company’s fixed maturity securities were priced by independent pricing services (generally one U.S. pricing service plus additional pricing services with respect to a limited number of foreign securities held by the Company). The prices provided by the independent pricing services are estimated based on observable market data in active markets utilizing pricing models and processes, which may include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, sector groupings, matrix pricing and reference data. The pricing services may prioritize inputs differently on any given day for any security based on market conditions, and not all inputs are available for each security evaluation on any given day. The pricing services used by the Company have indicated that they will only produce an estimate of fair value if objectively verifiable information is available. The determination of whether markets are active or inactive is based upon the volume and level of activity for a particular asset class. The Company reviews the prices provided by pricing services for reasonableness and periodically performs independent price tests of a sample of securities to ensure proper valuation.
If prices from independent pricing services are not available for fixed maturity securities, the Company estimates the fair value. For Level 2 securities, the Company utilizes pricing models and processes which may include benchmark yields, sector groupings, matrix pricing, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, bids, offers and reference data. Where broker quotes are used, the Company generally requests two or more quotes and sets a price within the range of quotes received based on its assessment of the credibility of the quote and its own evaluation of the security. The Company generally does not adjust quotes received from brokers. For securities traded only in private negotiations, the Company determines fair value based primarily on the cost of such securities, which is adjusted to reflect prices of recent placements of securities of the same issuer, financial projections, credit quality and business developments of the issuer and other relevant information.
For Level 3 securities, the Company generally uses a discounted cash flow model to estimate the fair value of fixed maturity securities. The cash flow models are based upon assumptions as to prevailing credit spreads, interest rate and interest rate volatility, time to maturity and subordination levels. Projected cash flows are discounted at rates that are adjusted to reflect illiquidity, where appropriate.
The following tables present the assets and liabilities measured at fair value as of December 31, 2025 and 2024 by level:
(In thousands)TotalLevel 1Level 2Level 3
December 31, 2025    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$3,998,038 $— $3,998,038 $— 
State and municipal1,837,194 — 1,837,194 — 
Mortgage-backed securities4,808,478 — 4,808,478 — 
Asset-backed securities3,810,346 — 3,810,346 — 
Corporate8,687,411 — 8,667,410 20,001 
Foreign government1,875,589 — 1,875,589 — 
Total fixed maturity securities available for sale25,017,056 — 24,997,055 20,001 
Equity securities:    
Common stocks742,113 739,186 786 2,141 
Preferred stocks616,088 — 607,414 8,674 
Total equity securities1,358,201 739,186 608,200 10,815 
Arbitrage trading account1,221,103 1,139,447 81,543 113 
Total$27,596,360 $1,878,633 $25,686,798 $30,929 
Liabilities:    
Trading account securities sold but not yet purchased$66,285 $66,285 $— $— 
December 31, 2024    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$2,235,341 $— $2,235,341 $— 
State and municipal2,294,644 — 2,294,644 — 
Mortgage-backed securities3,765,490 — 3,765,490 — 
Asset-backed securities3,885,012 — 3,885,012 — 
Corporate8,417,641 — 8,397,974 19,667 
Foreign government1,755,325 — 1,755,325 — 
Total fixed maturity securities available for sale22,353,453 — 22,333,786 19,667 
Equity securities:    
Common stocks760,167 757,115 1,011 2,041 
Preferred stocks443,621 — 439,947 3,674 
Total equity securities1,203,788 757,115 440,958 5,715 
Arbitrage trading account1,122,599 1,062,459 56,630 3,510 
Total$24,679,840 $1,819,574 $22,831,374 $28,892 
Liabilities:    
Trading account securities sold but not yet purchased$73,358 $73,358 $— $— 
The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2025 and 2024:
 Gains (Losses) Included in:
(In thousands)Beginning BalanceEarnings (Losses)Other Comprehensive Income (Loss)ImpairmentsPurchasesSalesPaydowns/MaturitiesTransfers In / OutEnding Balance
Year ended December 31, 2025        
Assets:
Fixed maturity securities available for sale:        
Corporate$19,667 $— $334 $— $— $— $— $— $20,001 
Total19,667 — 334 — — — — — 20,001 
Equity securities:
Common stocks2,041 226 — — — (126)— — 2,141 
Preferred stocks3,674 — — — 6,160 (1,160)— — 8,674 
Total5,715 226 — — 6,160 (1,286)— — 10,815 
Arbitrage trading account3,510 1,745 — — — (5,143)— 113 
Total$28,892 $1,971 $334 $— $6,160 $(6,429)$— $$30,929 
Year ended December 31, 2024        
Assets:
Fixed maturity securities available for sale:        
Corporate$— $— $(333)$— $— $— $— $20,000 $19,667 
Total— — (333)— — — — 20,000 19,667 
Equity securities:
Common stocks1,558 611 — — — (128)— — 2,041 
Preferred stocks3,695 36 — — — (57)— — 3,674 
Total5,253 647 — — — (185)— — 5,715 
Arbitrage trading account3,772 (261)— — — (38)— 37 3,510 
Total$9,025 $386 $(333)$— $— $(223)$— $20,037 $28,892 
For the years ended December 31, 2025 and 2024, one security in each year within the arbitrage trading account portfolio was transferred into Level 3 from Level 2 given there were no available quoted prices or observable inputs.
Fair Value of Financial Instruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2025 and 2024:
 20252024
(In thousands)Carrying ValueFair ValueCarrying ValueFair Value
Assets:    
Fixed maturity securities$25,047,662 $25,048,534 $22,397,865 $22,399,426 
Equity securities1,358,201 1,358,201 1,203,788 1,203,788 
Arbitrage trading account1,221,103 1,221,103 1,122,599 1,122,599 
Loans receivable418,913 419,074 405,453 405,248 
Cash and cash equivalents2,539,938 2,539,938 1,974,747 1,974,747 
Trading accounts receivable from brokers and clearing organizations11,669 11,669 60,327 60,327 
Due from broker629 629 — — 
Liabilities:
Due to broker— — 70,483 70,483 
Trading account securities sold but not yet purchased66,285 66,285 73,358 73,358 
Senior notes and other debt1,829,198 1,440,055 1,831,158 1,425,852 
Subordinated debentures1,010,527 760,400 1,009,808 805,864 
The estimated fair values of the Company’s fixed maturity securities, equity securities available for sale and arbitrage trading account securities are based on various valuation techniques that rely on fair value measurements as described in Note 12 above. The fair value of loans receivable is estimated by using current institutional purchaser yield requirements for loans with similar credit characteristics, which is considered a Level 2 input. The fair value of the senior notes and other debt and the subordinated debentures is based on spreads for similar securities, which is considered a Level 2 input.
v3.25.4
Commitments, Litigation And Contingent Liabilities
12 Months Ended
Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]  
Commitments, Litigation And Contingent Liabilities Commitments, Litigation and Contingent Liabilities
In the ordinary course of business, the Company is subject to disputes, litigation and arbitration arising from its insurance and reinsurance businesses. These matters are generally related to insurance and reinsurance claims and are considered in the establishment of loss and loss expense reserves. In addition, the Company may also become involved in legal actions which seek extra-contractual damages, punitive damages or penalties, including claims alleging bad faith in handling of insurance claims. The Company expects its ultimate liability with respect to such matters will not be material to its financial condition. However, adverse outcomes on such matters are possible, from time to time, and could be material to the Company’s results of operations in any particular financial reporting period.
On December 22, 2023, one of the Company’s subsidiaries filed a lawsuit against certain reinsurers to recover in excess of $90 million in respect of certain losses paid to its policyholders under certain event cancellation and related insurance policies. The Company believes its claims against the reinsurers are meritorious and expects a positive resolution to its lawsuit. While an adverse outcome is possible, the Company believes that the outcome, in any case, will not be material to the Company’s financial condition.
At December 31, 2025, the Company had commitments to invest up to $274 million and $31 million in certain investment funds and real estate construction projects, respectively.
v3.25.4
Leases
12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
Leases Leases
    Lessees are required to recognize a right-of-use asset and a lease liability for leases with terms of more than 12 months on the balance sheet. All leases disclosed within this note are classified as operating leases. Recognized right-of-use asset and lease liability are reported within other assets and other liabilities, respectively, in the consolidated balance sheet. Lease expense is reported in other operating costs and expenses in the consolidated statement of income and accounted for on a straight-line basis over the lease term.
    To determine the discount rate used to calculate present value of future minimum lease payments, the Company uses its incremental borrowing rate during the lease commencement period in line with the respective lease duration. In certain
cases, the Company has the option to renew the lease. Lease renewal future payments are included in the present value of the future minimum lease payments when the Company determines it is reasonably certain to renew.
    The main leases entered into by the Company are for office space used by the Company’s businesses across the world. Additionally, the Company, to a lesser extent, has equipment leases mainly for office equipment. Further information relating to operating lease expense and other operating lease information is as follows:
 For the Year Ended December 31,
(In thousands)20252024
Leases:
Lease cost$54,261 $45,718 
Cash paid for amounts included in the measurement of lease liabilities reported in operating cash flows$49,421 $49,441 
Right-of-use assets obtained in exchange for new lease liabilities$74,451 $43,624 

As of December 31,
($ in thousands)20252024
Right-of-use assets$221,480 $180,035 
Lease liabilities$260,451 $218,397 
Weighted-average remaining lease term7.1 years7.2 years
Weighted-average discount rate5.98 %5.59 %
    
Contractual maturities of the Company’s future minimum lease payments are as follows:
(In thousands)December 31, 2025
Contractual Maturities:
2026$54,475 
202747,249 
202845,830 
202941,825 
203037,008 
Thereafter96,197 
Total undiscounted future minimum lease payments322,584 
Less: Discount impact62,133 
Total lease liability$260,451 
v3.25.4
Stock Incentive Plan
12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Stock Incentive Plan Stock Incentive Plan
Pursuant to the Company's stock incentive plan, the Company may issue restricted stock units ("RSUs") to employees of the Company and its subsidiaries. The RSUs generally vest three to five years from the award date and are subject to other vesting and forfeiture provisions contained in the award agreement. The following table summarizes RSU information for the three years ended December 31, 2025:
202520242023
RSUs granted and unvested at beginning of period:5,734,397 6,435,267 6,927,639 
Granted1,043,988 1,217,056 1,647,690 
Vested(1,470,318)(1,594,183)(1,726,956)
Canceled(376,921)(323,743)(413,106)
RSUs granted and unvested at end of period:4,931,146 5,734,397 6,435,267 
    
Upon vesting, shares of the Company’s common stock equal to the number of vested RSUs are issued or deferred to a later date, depending on the terms of the specific award agreement. As of December 31, 2025, 17,375,058 RSUs had been deferred. RSUs that have not yet vested and vested RSUs that have been deferred are not considered to be issued and outstanding shares.

The fair value of RSUs at the date of grant are recorded as unearned compensation, a component of stockholders’ equity, and expensed over the vesting period. Following is a summary of changes in unearned compensation for the three years ended December 31, 2025:
(In thousands)202520242023
Unearned compensation at beginning of year$153,329 $148,080 $142,060 
RSUs granted, net of cancellations65,901 63,347 62,418 
  RSUs expensed(52,524)(52,380)(49,200)
  RSUs forfeitures(8,653)(5,718)(7,198)
Unearned compensation at end of year$158,053 $153,329 $148,080 
v3.25.4
Compensation Plans
12 Months Ended
Dec. 31, 2025
Compensation Related Costs [Abstract]  
Compensation Plans Compensation Plans
The Company and its subsidiaries have profit sharing plans in which substantially all employees participate. The plans provide for minimum annual contributions of 5% of eligible compensation; contributions above the minimum are discretionary and vary with each participating businesses's profitability. Employees become eligible to participate in the plan on the first day of the calendar quarter following the first full calendar quarter after the employee's date of hire provided the employee has completed 250 hours of service during the calendar quarter. The plans provide that 40% of the contributions vest immediately and that the remaining 60% vest at varying percentages based upon years of service. Profit sharing expense was $80 million, $72 million and $75 million in 2025, 2024 and 2023, respectively.
The Company has a long-term incentive compensation plan ("LTIP") that provides for compensation to key executives based on the growth in the Company's book value per share over a five year period.
The following table summarizes the outstanding LTIP awards as of December 31, 2025:
Units OutstandingMaximum Value
Inception to date earned through December 31, 2025 on outstanding units
2021 grant197,500 $19,750,000 $19,750,000 
2022 grant220,500 22,050,000 22,050,000 
2023 grant235,000 23,500,000 20,014,894 
2024 grant252,500 25,250,000 13,598,077 
2025 grant244,750 24,475,000 5,767,601 
The following table summarizes the LTIP expense for each of the three years ended December 31, 2025:
(In thousands)202520242023
2019 grant— — 3,241 
2020 grant— 135 7,047 
2021 grant(39)3,543 6,561 
2022 grant2,523 8,167 6,155 
2023 grant7,799 7,076 5,424 
2024 grant7,154 6,476 — 
2025 grant5,768 — — 
Total$23,205 $25,397 $28,428 
v3.25.4
Supplemental Financial Statement Data
12 Months Ended
Dec. 31, 2025
Other Income and Expenses [Abstract]  
Supplemental Financial Statement Data Supplemental Financial Statement Data
Other operating costs and expenses consist of the following:
(In thousands)202520242023
Amortization of deferred policy acquisition costs$1,384,739 $1,219,849 $1,038,975 
Insurance operating expenses2,131,785 2,075,053 1,915,711 
Insurance service expenses94,374 90,640 91,714 
Net foreign currency losses (gains)68,006 (52,376)31,799 
Other costs and expenses297,930 269,140 285,737 
Total$3,976,834 $3,602,306 $3,363,936 
v3.25.4
Industry Segments
12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
Industry Segments Industry Segments
The Company’s reportable segments include the following two business segments, plus a corporate segment:
Insurance - predominantly commercial insurance business, including excess and surplus lines, admitted lines and specialty personal lines throughout the United States, as well as insurance business in Asia, Australia, Canada, Continental Europe, Mexico, Scandinavia, South America and the United Kingdom.

Reinsurance & Monoline Excess - reinsurance business on a facultative and treaty basis, primarily in the United States, United Kingdom, Continental Europe, Australia, the Asia-Pacific region and South Africa, as well as operations that solely retain risk on an excess basis and certain program management business.
The Company's chief operating decision maker ("CODM") is the President and Chief Executive Officer. The CODM assesses performance, makes decisions and allocates resources for each of the three reportable segments based on their contribution towards the Company's profitability and balance sheet strength. Certain key metrics such as combined ratio and return on allocated capital for the Insurance and Reinsurance & Monoline Excess segments, as well as Corporate segment expenditures, are examples of key components of the assessment, decision-making and resource-allocation process.
The accounting policies of the segments are the same as those described in the summary of significant accounting policies. Income tax expense and benefits are calculated based upon the Company’s overall effective tax rate.
Summary financial information about the Company’s reporting segments is presented in the following table. Income before income taxes by segment includes allocated investment income. Identifiable assets by segment are those assets used in or allocated to the operation of each segment.
RevenuesExpenses
(In thousands)Earned
Premiums (1)
Investment
Income
OtherTotal (2)Losses and Loss ExpensesPolicy Acquisition and Insurance Operating ExpensesOtherTotalPre-Tax
Income
(Loss)
Net
Income
(Loss)
to Common Stockholders
Year ended December 31, 2025      
Insurance $10,936,028 $1,118,607 $40,966 $12,095,601 $6,947,232 $3,076,726 $44,399 $10,068,357 $2,027,244 $1,584,440 
Reinsurance & Monoline Excess1,510,910 270,851 — 1,781,761 824,425 439,798 — 1,264,223 517,538 407,659 
Corporate, other and eliminations (3)— 39,609 658,665 698,274 — — 1,094,733 1,094,733 (396,459)(316,404)
Net investment gains— — 132,220 132,220 — — — — 132,220 103,708 
Consolidated$12,446,938 $1,429,067 $831,851 $14,707,856 $7,771,657 $3,516,524 $1,139,132 $12,427,313 $2,280,543 $1,779,403 
Year ended December 31, 2024
Insurance$10,086,308 $1,057,738 $37,455 $11,181,501 $6,332,490 $2,863,697 $43,231 $9,239,418 $1,942,083 $1,503,875 
Reinsurance & Monoline Excess1,462,177 234,728 — 1,696,905 799,105 431,205 — 1,230,310 466,595 367,569 
Corporate, other and eliminations (3)— 40,695 601,943 642,638 — — 904,531 904,531 (261,893)(203,832)
Net investment gains— — 117,708 117,708 — — — — 117,708 88,503 
Consolidated$11,548,485 $1,333,161 $757,106 $13,638,752 $7,131,595 $3,294,902 $947,762 $11,374,259 $2,264,493 $1,756,115 
Year ended December 31, 2023
Insurance$9,007,376 $783,660 $36,830 $9,827,866 $5,615,526 $2,545,310 $37,112 $8,197,948 $1,629,918 $1,283,281 
Reinsurance & Monoline Excess1,393,311 221,966 — 1,615,277 756,616 409,376 — 1,165,992 449,285 355,155 
Corporate, other and eliminations (3)— 47,209 605,544 652,753 — — 1,024,595 1,024,595 (371,842)(293,869)
Net investment gains— — 47,042 47,042 — — — — 47,042 36,792 
Consolidated$10,400,687 $1,052,835 $689,416 $12,142,938 $6,372,142 $2,954,686 $1,061,707 $10,388,535 $1,754,403 $1,381,359 

Identifiable Assets
(In thousands)December 31,
20252024
Insurance$35,830,534 $33,030,140 
Reinsurance & Monoline Excess5,891,538 5,669,729 
Corporate, other and eliminations (3)2,348,999 1,867,399 
Consolidated$44,071,071 $40,567,268 
_______________________________________
(1) Certain amounts included in earned premiums of each segment are related to inter-segment transactions.
(2) Revenues for Insurance includes $1,408 million, $1,471 million, and $1,171 million in 2025, 2024 and 2023, respectively, from foreign countries. Revenues for Reinsurance & Monoline Excess includes $516 million, $485 million, and $463 million in 2025, 2024 and 2023, respectively, from foreign countries.
(3) Corporate, other and eliminations represent corporate revenues and expenses and certain other items that are not allocated to business segments.
Net premiums earned by major line of business were as follows:
(In thousands)202520242023
Insurance   
Other liability$4,429,621 $4,068,662 $3,605,298 
Short-tail lines (1)2,496,481 2,201,661 1,825,027 
Auto1,617,908 1,481,569 1,270,907 
Workers' compensation1,259,290 1,237,888 1,212,294 
Professional liability1,132,728 1,096,528 1,093,850 
Total Insurance10,936,028 10,086,308 9,007,376 
Reinsurance & Monoline Excess
Casualty (2)741,671 771,329 821,826 
Property (2)478,682 424,296 330,359 
Monoline Excess (3)290,557 266,552 241,126 
Total Reinsurance & Monoline Excess1,510,910 1,462,177 1,393,311 
Total$12,446,938 $11,548,485 $10,400,687 

(1) Short-tail lines include commercial multi-peril (non-liability), inland marine, accident and health, fidelity and surety, boiler and machinery, high net worth homeowners and other lines.
(2) Includes reinsurance casualty and property and certain program management business.
(3) Monoline excess includes operations that solely retain risk on an excess basis.
v3.25.4
Related-Party Transactions
12 Months Ended
Dec. 31, 2025
Related Party Transactions [Abstract]  
Related-Party Transactions Related-Party Transactions
Lifson Re
Lifson Re, a Bermuda reinsurance company, participated on a fully collateralized basis in a majority of the Company’s reinsurance placements, with a 30% share of the amounts placed commencing on July 1, 2022, which was increased to 32.5% effective January 1, 2025. This pertains to all traditional reinsurance/retrocessional placements for both property and casualty business where there is more than one open market reinsurer participating. Lifson Re is currently capitalized with $418 million from a small group of sophisticated global investors with long-term investment horizons, including a minority participation by the Company (which is included in Note 7, Investment Funds, within Financial services).
Transactions between the Company and Lifson Re were as follows:

(In thousands)Year Ended December 31,
Consolidated statements of income202520242023
Ceded written premiums$494,359 $416,509 $436,941 
Ceded commissions and brokerage133,479 104,075 123,510 
As of December 31,
Consolidated balance sheets20252024
Due from reinsurers$537,366 $471,689 
Due to reinsurers118,788 166,304 

The Company earned certain management and performance fees from Lifson Re of $11 million, $6 million and $5 million for the years ended December 31, 2025, 2024, and 2023, respectively.
Mitsui Sumitomo Insurance Co., Ltd.
As of December 31, 2025, Mitsui Sumitomo Insurance Co., Ltd. (“MSI”) owned 13.4% of the Company’s outstanding common stock excluding shares held in a deferred compensation grantor trust.
On March 28, 2025, MSI entered into an arrangement (the “Framework Agreement”) with a company owned by members of the Berkley family and trusts for their benefit (collectively, the “Berkley Family”) providing for MSI to purchase 15% of the Company’s outstanding common stock (as defined in the Framework Agreement). In addition, pursuant to the Framework Agreement, the Berkley Family recommended to the Company’s Board of Directors (the “Board”) that MSI’s designee be nominated to stand for election to the Board at the Company’s 2026 annual stockholders meeting. Upon recommendation of the Board’s Nominating and Corporate Governance Committee, the Board approved MSI’s designee standing for election.
In the normal course of its operations, the Company from time to time enters into reinsurance transactions with MSI or one of its affiliates (including its Lloyd’s of London operations), including the following:
During the year ended December 31, 2025, the Company ceded written premiums and had commissions with MSI or one of its affiliates of $70 million and $13 million, respectively, and in connection with such ceded reinsurance as of December 31, 2025, had an amount due from reinsurers of $58 million and an amount due to reinsurers of $16 million.
During the year ended December 31, 2025, the Company assumed written premiums from MSI or one of its affiliates of $12 million, and in connection with such assumed reinsurance as of December 31, 2025, had assumed premiums receivable of $4 million and amounts due to reinsured of $11 million.
MSI has a minority investment in Lifson Re.
The Lifson Re and MSI transactions discussed above were entered into at arm's-length.
v3.25.4
Schedule II - Condensed Financial Information of Registrant
12 Months Ended
Dec. 31, 2023
Condensed Financial Information Disclosure [Abstract]  
Schedule II - Condensed Financial Information of Registrant
Schedule II
W. R. Berkley Corporation
Condensed Financial Information of Registrant
Balance Sheets (Parent Company)

 December 31,
(In thousands)20252024
Assets:  
Cash and cash equivalents$55,322 $112,931 
Fixed maturity securities available for sale at fair value (cost $641,917 and $251,938 at December 31, 2025 and 2024)
642,451 251,800 
Loans receivable (net of allowance for expected credit losses of $161 and $591 at December 31, 2025 and 2024)
23,089 27,659 
Equity securities, at fair value (cost $3,430 at both December 31, 2025 and 2024)
3,430 3,430 
Investment in subsidiaries11,940,355 10,770,734 
Current federal income taxes— 36,417 
Deferred federal income taxes151,031 228,329 
Property, furniture and equipment at cost, less accumulated depreciation8,581 9,320 
Other assets62,179 126,799 
Total assets$12,886,438 $11,567,419 
Liabilities and stockholders’ equity: 
Liabilities: 
Due to subsidiaries$144,740 $182,445 
Other liabilities188,851 158,281 
Current federal income taxes19,626 — 
Subordinated debentures1,010,527 1,009,808 
Senior notes1,821,876 1,821,774 
Total liabilities3,185,620 3,172,308 
Stockholders’ equity: 
Preferred stock, par value $.10 per share:
Authorized 5,000,000 shares; issued and outstanding — none
— — 
Common stock, par value $.20 per share:
Authorized 1,875,000,000 shares; issued and outstanding, net of treasury shares, 377,155,799 and 380,066,070 shares, respectively
158,705 158,705 
Additional paid-in capital987,708 984,825 
Retained earnings (including accumulated undistributed net income of subsidiaries of $9,674,616 and $9,216,210 at December 31, 2025 and 2024, respectively)
13,344,204 12,265,070 
Accumulated other comprehensive loss(451,097)(934,269)
Treasury stock, at cost, 416,366,010 and 413,455,739 shares, respectively
(4,338,702)(4,079,220)
Total stockholders’ equity9,700,818 8,395,111 
Total liabilities and stockholders’ equity$12,886,438 $11,567,419 
________________
See Report of Independent Registered Public Accounting Firm and note to condensed financial information.
Schedule II, Continued

W. R. Berkley Corporation
Condensed Financial Information of Registrant, Continued
Statements of Income (Parent Company)
 Year Ended December 31,
(In thousands)
202520242023
Management fees and investment income including dividends from subsidiaries of $1,643,345, $1,196,538, and $1,261,166 for the years ended December 31, 2025, 2024 and 2023, respectively
$1,716,680 $1,252,194 $1,325,997 
Net investment gains (losses)945 90,284 (5,895)
Other income834 853 368 
  Total revenues1,718,459 1,343,331 1,320,470 
Operating costs and expense315,233 277,679 272,750 
Interest expense126,400 126,400 126,397 
Income before federal income taxes1,276,826 939,252 921,323 
Federal income taxes:   
Federal income taxes provided by subsidiaries on a separate return basis422,289 424,456 253,292 
Federal income tax expense on a consolidated return basis(378,117)(356,943)(284,757)
  Net federal income tax benefit (expense) 44,172 67,513 (31,465)
Income before undistributed equity in net income of subsidiaries1,320,998 1,006,765 889,858 
Equity in undistributed net income of subsidiaries458,405 749,350 491,501 
  Net income$1,779,403 $1,756,115 $1,381,359 
________________
See Report of Independent Registered Public Accounting Firm and note to condensed financial information.
Schedule II, Continued

W. R. Berkley Corporation
Condensed Financial Information of Registrant, Continued
Statements of Cash Flows (Parent Company)
 Year Ended December 31,
(In thousands)202520242023
Cash flow from operating activities:   
Net income$1,779,403 $1,756,115 $1,381,359 
Adjustments to reconcile net income to net cash from operating activities:
Net investment (gains) losses(945)(90,284)5,895 
Depreciation and (accretion) amortization(5,780)(5,120)(6,753)
Equity in undistributed earnings of subsidiaries(458,405)(749,350)(491,501)
Tax payments received from subsidiaries372,731 432,402 373,504 
Federal income taxes provided by subsidiaries on a separate return basis(422,289)(424,456)(253,292)
Stock incentive plans54,524 54,381 51,000 
Change in:
Federal income taxes34,361 (9,346)(15,793)
Equity in undistributed earnings of other investments(15,047)(10,444)— 
Other assets(4,552)(9,888)(5,647)
Other liabilities30,248 114,418 (88,954)
Accrued investment income(1,810)(1,740)1,200 
Net cash from operating activities1,362,439 1,056,688 951,018 
Cash (used in) from investing activities:   
Proceeds from sales of fixed maturity securities81,035 598,915 748,825 
Proceeds from maturities and prepayments of fixed maturity securities562,308 260,999 82,075 
Cost of purchases of fixed maturity securities(1,029,227)(824,476)(732,685)
Change in loans receivable5,000 64,200 17,843 
Investments in and advances to subsidiaries, net(102,615)(238,337)21,605 
Change in balance due to security broker71,083 (71,143)(38)
Net additions to real estate, furniture & equipment(63)(37)(18)
Other, net3,823 73 290 
Net cash (used in) from investing activities(408,656)(209,806)137,897 
Cash used in financing activities:   
Purchase of common treasury shares(270,221)(303,655)(537,163)
Cash dividends to common stockholders(700,269)(531,953)(501,456)
Other, net(40,902)(26,777)(25,384)
Net cash used in financing activities(1,011,392)(862,385)(1,064,003)
Net (decrease) increase in cash and cash equivalents(57,609)(15,503)24,912 
Cash and cash equivalents at beginning of year112,931 128,434 103,522 
Cash and cash equivalents at end of year$55,322 $112,931 $128,434 
________________
See Report of Independent Registered Public Accounting Firm and note to condensed financial information.
W. R. Berkley Corporation
Condensed Financial Information of Registrant, Continued
December 31, 2025
Note to Condensed Financial Information (Parent Company)
The accompanying condensed financial information should be read in conjunction with the notes to consolidated financial statements included elsewhere herein. Reclassifications have been made in the 2024 and 2023 financial statements as originally reported to conform them to the presentation of the 2025 financial statements.
The Company files a consolidated federal income tax return with the results of its domestic insurance subsidiaries included on a statutory basis. Under present Company policy, federal income taxes payable by subsidiary companies on a separate-return basis are paid to W. R. Berkley Corporation, and the Company pays the tax due on a consolidated return basis.
v3.25.4
Schedule III - Supplementary Insurance Information
12 Months Ended
Dec. 31, 2025
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]  
Schedule III - Supplementary Insurance Information
Schedule III

W. R. Berkley Corporation and Subsidiaries
Supplementary Insurance Information
December 31, 2025, 2024 and 2023
(In thousands)Deferred
Policy
Acquisition
Cost
Reserve for
Losses and
Loss Expenses
Unearned
Premiums
Net Premiums
Earned
Net
Investment
Income
Loss and Loss
Expenses
Amortization of
Deferred Policy
Acquisition
Cost
Other
Operating Costs
and Expenses
Net
Premiums
Written
December 31, 2025         
Insurance$887,406 $18,589,040 $6,158,703 $10,936,028 $1,118,607 $6,947,232 $1,248,382 $1,872,742 $11,183,713 
Reinsurance & Monoline Excess113,285 3,618,733 562,867 1,510,910 270,851 824,425 136,357 303,441 1,527,614 
Corporate, other and eliminations — — — — 39,609 — — 415,912 — 
Total$1,000,691 $22,207,773 $6,721,570 $12,446,938 $1,429,067 $7,771,657 $1,384,739 $2,592,095 $12,711,327 
December 31, 2024         
Insurance$840,917 $16,887,821 $5,836,435 $10,086,308 $1,057,738 $6,332,490 $1,081,170 $1,825,758 $10,549,550 
Reinsurance & Monoline Excess110,811 3,480,209 538,677 1,462,177 234,728 799,105 138,679 292,526 1,422,546 
Corporate, other and eliminations — — — — 40,695 — — 264,173 — 
Total$951,728 $20,368,030 $6,375,112 $11,548,485 $1,333,161 $7,131,595 $1,219,849 $2,382,457 $11,972,096 
December 31, 2023         
Insurance$736,348 $15,298,372 $5,322,869 $9,007,376 $783,660 $5,615,526 $897,908 $1,684,514 $9,560,533 
Reinsurance & Monoline Excess125,261 3,441,280 599,457 1,393,311 221,966 756,616 141,067 268,309 1,393,934 
Corporate, other and eliminations — — — — 47,209 — — 372,138 — 
Total$861,609 $18,739,652 $5,922,326 $10,400,687 $1,052,835 $6,372,142 $1,038,975 $2,324,961 $10,954,467 
__________________________
See Report of Independent Registered Public Accounting Firm.
v3.25.4
Schedule IV - Reinsurance
12 Months Ended
Dec. 31, 2025
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]  
Schedule IV - Reinsurance
Schedule IV

W. R. Berkley Corporation and Subsidiaries
Reinsurance
Years ended December 31, 2025, 2024 and 2023
Premiums Written
(In thousands, other than percentages)Direct
Amount
Ceded
to Other
Companies
Assumed
from Other
Companies
Net
Amount
Percentage
of Amount
Assumed
to Net
Year ended December 31, 2025     
Insurance$13,151,705 $2,281,783 $313,791 $11,183,713 2.8 %
Reinsurance & Monoline Excess542,816 111,959 1,096,757 1,527,614 71.8 %
Total$13,694,521 $2,393,742 $1,410,548 $12,711,327 11.1 %
Year ended December 31, 2024     
Insurance$12,417,129 $2,112,582 $245,003 $10,549,550 2.3 %
Reinsurance & Monoline Excess487,764 126,413 1,061,195 1,422,546 74.6 %
Total$12,904,893 $2,238,995 $1,306,198 $11,972,096 10.9 %
Year ended December 31, 2023     
Insurance$11,209,325 $1,900,560 $251,768 $9,560,533 2.6 %
Reinsurance & Monoline Excess467,418 116,979 1,043,495 1,393,934 74.9 %
Total$11,676,743 $2,017,539 $1,295,263 $10,954,467 11.8 %
___________________________
See Report of Independent Registered Public Accounting Firm.
v3.25.4
Schedule V - Valuation and Qualifying Accounts
12 Months Ended
Dec. 31, 2025
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]  
Schedule V - Valuation and Qualifying Accounts
Schedule V

W. R. Berkley Corporation and Subsidiaries
Valuation and Qualifying Accounts
Years ended December 31, 2025, 2024 and 2023
(In thousands)Opening Allowance
Balance
Additions-
Charged to
Expense
Deduction-
Amounts
Written Off
Ending Allowance
Balance
Year ended December 31, 2025
Premiums, fees and other receivables$49,481 $19,120 $(12,746)$55,855 
Due from reinsurers8,350 508 (2,480)6,378 
Deferred federal and foreign income taxes36,063 20,184 (458)55,789 
Fixed maturity securities671 78 (675)74 
Loan loss reserves1,114 — (953)161 
Total$95,679 $39,890 $(17,312)$118,257 
Year ended December 31, 2024    
Premiums, fees and other receivables$42,325 $15,743 $(8,587)$49,481 
Due from reinsurers8,404 568 (622)8,350 
Deferred federal and foreign income taxes36,283 9,219 (9,439)36,063 
Fixed maturity securities36,751 2,053 (38,133)671 
Loan loss reserves3,004 (1,895)1,114 
Total$126,767 $27,588 $(58,676)$95,679 
Year ended December 31, 2023    
Premiums, fees and other receivables$36,931 $13,637 $(8,243)$42,325 
Due from reinsurers8,064 340 — 8,404 
Deferred federal and foreign income taxes47,166 3,864 (14,747)36,283 
Fixed maturity securities37,466 5,013 (5,728)36,751 
Loan loss reserves1,791 1,782 (569)3,004 
Total$131,418 $24,636 $(29,287)$126,767 
_______________________
See Report of Independent Registered Public Accounting Firm.
v3.25.4
Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations
12 Months Ended
Dec. 31, 2025
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]  
Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations
Schedule VI

W. R. Berkley Corporation and Subsidiaries
Supplementary Information Concerning Property-Casualty Insurance Operations
Years Ended December 31, 2025, 2024 and 2023
(In thousands)202520242023
Deferred policy acquisition costs$1,000,691 $951,728 $861,609 
Reserves for losses and loss expenses22,207,773 20,368,030 18,739,652 
Unearned premiums6,721,570 6,375,112 5,922,326 
Net premiums earned12,446,938 11,548,485 10,400,687 
Net investment income1,429,067 1,333,161 1,052,835 
Losses and loss expenses incurred:
Current year7,702,638 7,083,999 6,311,780 
Prior years34,446 14,350 29,681 
Loss reserve discount accretion34,573 33,246 30,681 
Amortization of deferred policy acquisition costs1,384,739 1,219,849 1,038,975 
Paid losses and loss expenses6,133,576 5,484,430 4,981,610 
Net premiums written12,711,327 11,972,096 10,954,467 
___________________
See Report of Independent Registered Public Accounting Firm.
v3.25.4
Insider Trading Arrangements
3 Months Ended
Dec. 31, 2025
Trading Arrangements, by Individual  
Rule 10b5-1 Arrangement Adopted false
Non-Rule 10b5-1 Arrangement Adopted false
Rule 10b5-1 Arrangement Terminated false
Non-Rule 10b5-1 Arrangement Terminated false
v3.25.4
Cybersecurity Risk Management and Strategy Disclosure
12 Months Ended
Dec. 31, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]  
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]
Cybersecurity Risk Management and Strategy
The Company has a documented information security program (the "Program"), which is integrated into its overall risk management processes, to identify, assess, monitor and manage potential cybersecurity threats and incidents. The Program is designed to protect the confidentiality, integrity and availability of our information systems and assets that store, process, or transmit information, as well as the information processed thereon. The Program is modeled on the global standard for information security management systems, International Organization for Standardization 27001, and is guided by the six domains of cybersecurity established by the National Institute of Standards and Technology Cybersecurity Framework (i.e., govern, identify, protect, detect, respond, and recovery). The Program seeks to adhere to applicable U.S. and international laws and regulations, including New York State’s cybersecurity regulation applicable to financial services institutions authorized by the New York State Department of Financial Services.
The Program’s security and risk policies and standards, implemented by either the Company or third party assessors or consultants, include:
information security management tools, such as firewalls, intrusion prevention and detection systems, anti-malware functionality, and access privilege controls;
vulnerability management, including penetration and control testing and vulnerability scans of information systems, and patching of systems when vulnerabilities have been identified;
incident monitoring, breach notification and escalation procedures, including disaster recovery and incident response plans and resources;
risk based assessment of third party service providers; and
annual cybersecurity awareness training for employees and contractors.
The Company engages third party consultants with respect to cybersecurity, including to conduct vulnerability assessments and penetration testing of its information technology systems. The Company has established a regular vendor risk management process to evaluate and address potential risks associated with the use of such third parties.
The Company has not identified any cybersecurity incidents that have materially affected or are reasonably likely to materially affect the Company, including its business strategy, results of operations, or financial condition, for the period covered by this annual report. For a discussion regarding risks associated with cybersecurity threats, see “Risk Factors – Risks Relating to Our Business – If our information technology, telecommunications or other computer systems become unavailable or unreliable, our ability to conduct our business could be negatively or severely impacted” and “Failure to maintain the security of information technology systems and confidential data may expose us to liability”; and “Use of artificial intelligence technologies, by us or third-parties on whom we rely, could expose us to technological, security, legal, and other risks.”
Cybersecurity Risk Management Processes Integrated [Flag] true
Cybersecurity Risk Management Processes Integrated [Text Block]
The Company has a documented information security program (the "Program"), which is integrated into its overall risk management processes, to identify, assess, monitor and manage potential cybersecurity threats and incidents. The Program is designed to protect the confidentiality, integrity and availability of our information systems and assets that store, process, or transmit information, as well as the information processed thereon. The Program is modeled on the global standard for information security management systems, International Organization for Standardization 27001, and is guided by the six domains of cybersecurity established by the National Institute of Standards and Technology Cybersecurity Framework (i.e., govern, identify, protect, detect, respond, and recovery). The Program seeks to adhere to applicable U.S. and international laws and regulations, including New York State’s cybersecurity regulation applicable to financial services institutions authorized by the New York State Department of Financial Services.
Cybersecurity Risk Management Third Party Engaged [Flag] true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag] true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag] false
Cybersecurity Risk Board of Directors Oversight [Text Block]
The entire Board of Directors has oversight of risks from cybersecurity threats and receives periodic updates on such risks from the Company’s management, including from the Company’s President and CEO and its Senior Vice President - Chief Information Security Officer (CISO).
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block] Our CISO, who has over 25 years of information security experience and is licensed as a Certified Information Systems Security Professional, is principally responsible for assessing and managing all aspects of the Program, including the Company’s Regional Information Security Officers (RISOs), third-party consultants, development of industry trends and control testing and tracking by risk level.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]
Our CISO, who has over 25 years of information security experience and is licensed as a Certified Information Systems Security Professional, is principally responsible for assessing and managing all aspects of the Program, including the Company’s Regional Information Security Officers (RISOs), third-party consultants, development of industry trends and control testing and tracking by risk level. Our CISO meets periodically with senior executives, including the Company’s President and CEO, to discuss the Company’s cybersecurity strategy, and its monitoring, prevention, detection, mitigation, and remediation of cybersecurity risks. Regular reporting on the Program is also provided to the Company’s Enterprise Risk Management Committee, which is comprised of the President and CEO, Senior Vice President – Enterprise Risk Management, Executive Vice President – Investments, Executive Vice President – Chief Financial Officer, and Executive Vice President – Secretary. Collectively, the CISO and RISOs, along with their teams, in collaboration with the technology and business owners,
implement the Program. Legal, Compliance, and Internal Audit functions also assess the Program’s adherence to regulatory requirements and internal controls.
Cybersecurity Risk Role of Management [Text Block]
Our CISO, who has over 25 years of information security experience and is licensed as a Certified Information Systems Security Professional, is principally responsible for assessing and managing all aspects of the Program, including the Company’s Regional Information Security Officers (RISOs), third-party consultants, development of industry trends and control testing and tracking by risk level. Our CISO meets periodically with senior executives, including the Company’s President and CEO, to discuss the Company’s cybersecurity strategy, and its monitoring, prevention, detection, mitigation, and remediation of cybersecurity risks. Regular reporting on the Program is also provided to the Company’s Enterprise Risk Management Committee, which is comprised of the President and CEO, Senior Vice President – Enterprise Risk Management, Executive Vice President – Investments, Executive Vice President – Chief Financial Officer, and Executive Vice President – Secretary. Collectively, the CISO and RISOs, along with their teams, in collaboration with the technology and business owners,
implement the Program. Legal, Compliance, and Internal Audit functions also assess the Program’s adherence to regulatory requirements and internal controls.
In the event of a potentially material cybersecurity incident, the Company’s incident response plans establish escalation protocols for relevant IT leaders and functional leaders within Legal, Compliance and Internal Audit to engage management as appropriate.
Cybersecurity Risk Management Positions or Committees Responsible [Flag] true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block] Our CISO, who has over 25 years of information security experience and is licensed as a Certified Information Systems Security Professional, is principally responsible for assessing and managing all aspects of the Program, including the Company’s Regional Information Security Officers (RISOs), third-party consultants, development of industry trends and control testing and tracking by risk level.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block] 25 years of information security experience
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]
Our CISO, who has over 25 years of information security experience and is licensed as a Certified Information Systems Security Professional, is principally responsible for assessing and managing all aspects of the Program, including the Company’s Regional Information Security Officers (RISOs), third-party consultants, development of industry trends and control testing and tracking by risk level. Our CISO meets periodically with senior executives, including the Company’s President and CEO, to discuss the Company’s cybersecurity strategy, and its monitoring, prevention, detection, mitigation, and remediation of cybersecurity risks. Regular reporting on the Program is also provided to the Company’s Enterprise Risk Management Committee, which is comprised of the President and CEO, Senior Vice President – Enterprise Risk Management, Executive Vice President – Investments, Executive Vice President – Chief Financial Officer, and Executive Vice President – Secretary. Collectively, the CISO and RISOs, along with their teams, in collaboration with the technology and business owners,
implement the Program. Legal, Compliance, and Internal Audit functions also assess the Program’s adherence to regulatory requirements and internal controls.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag] false
v3.25.4
Summary of Significant Accounting Policies (Policies)
12 Months Ended
Dec. 31, 2025
Accounting Policies [Abstract]  
Principles of consolidation and basis of presentation Principles of consolidation and basis of presentation
The consolidated financial statements, which include the accounts of W. R. Berkley Corporation and its subsidiaries (the "Company"), have been prepared on the basis of U.S. generally accepted accounting principles ("GAAP"). All significant intercompany transactions and balances have been eliminated. Shares outstanding and per share amounts were adjusted to reflect the 3-for-2 common stock split effected on July 10, 2024. Additionally, commencing with the first quarter of 2024, the Company reclassified a program management business from the Insurance segment to the Reinsurance & Monoline Excess segment. The reclassified business is a program management business offering support on a nationwide basis for commercial casualty and property program administrators. Reclassifications were made in the 2023 financial statements as originally reported to conform to the presentation of the 2025 and 2024 financial statements.
The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the revenues and expenses reflected during the reporting period. The most significant items on our balance sheet that involve a greater degree of accounting estimates that are subject to change in the future are the valuation of investments, allowance for expected credit losses on investments, reserves for losses and loss expenses and premium estimates. Actual results could differ from those estimates.
Revenue recognition Revenue recognition
Insurance premiums are recognized as written at the inception of the policy. Reinsurance premiums are estimated based upon information received from ceding companies, and subsequent differences from such estimates are recorded in the period they are determined. Insurance and reinsurance premiums are primarily earned on a pro rata basis over the policy term. Fees for services are earned over the period that the services are provided. Premiums and fees receivable are reported net of an allowance for expected credit losses, with the allowance being estimated based on current and future expected conditions, historical loss data and specific identification of collectability concerns where applicable. Changes in the allowance are reported within other operating costs and expenses.
Audit premiums are recognized when they are reliably determinable. The change in accruals for earned but unbilled audit premiums (decreased) increased net premiums written and premiums earned by $(2) million, $19 million and $19 million in 2025, 2024 and 2023, respectively.
Revenues from non-insurance businesses are derived from businesses engaged in the distribution of promotional merchandise, world-wide textile solutions, and aircraft services provided to the general, commercial and military aviation markets. These aircraft services include (i) the distribution, manufacturing, repair and overhaul of aircraft parts and components, (ii) the sale of new and used aircraft, and (iii) avionics, fuel, maintenance, storage and charter services. Revenue is recognized upon the shipment of products and parts, the delivery of aircraft, the delivery of fuel, and over the completion period of services.
Insurance service fee revenue represents servicing fees for program administration and claims management services provided by the Company, including workers' compensation assigned risk plans, as well as insurance brokerage and risk management services. Fees for program administration, claims management and risk management services are primarily recognized ratably over the related contract period for which the underlying services are rendered.
Cash and cash equivalents Cash and cash equivalents
Cash equivalents consist of funds invested in money market accounts and investments with an effective maturity of three months or less when purchased.
Investments Investments
Fixed maturity securities classified as available for sale are carried at estimated fair value, with unrealized gains and losses, net of applicable income taxes, excluded from earnings and reported as a component of comprehensive income and a separate component of stockholders' equity. Fixed maturity securities that the Company has the positive intent and ability to hold to maturity are classified as held to maturity and reported at amortized cost. Investment income from fixed maturity
securities is recognized based on the constant effective yield method. Premiums and discounts on mortgage-backed securities are adjusted for the effects of actual and anticipated prepayments on a retrospective basis.
Equity securities with readily determinable fair values are measured at fair value, with changes in the fair value recognized in net income within net realized and unrealized gains on investments.
Fixed maturity securities that the Company purchased with the intent to sell in the near-term are classified as trading account securities and are reported at estimated fair value. Realized and unrealized gains and losses from trading activity are reported as net investment income and are recorded at the trade date. Short sales and short call options are presented as trading securities sold but not yet purchased. Unsettled trades and the net margin balances held by the clearing broker are presented as a trading account receivable from brokers and clearing organizations.
Investment funds are carried under the equity method of accounting. The Company's share of the earnings or losses of investment funds is primarily reported on a one-quarter lag in order to facilitate the timely completion of the Company's consolidated financial statements.
Loans receivable primarily represent commercial and real estate loans and are carried at amortized cost. The accrual of interest on loans receivable is discontinued if the loan is 90 days past due based on the contractual terms of the loan unless the loan is adequately secured and in process of collection. In general, loans are placed on non-accrual status or charged off at an earlier date if collection of principal or interest is considered doubtful. Interest on these loans is accounted for on a cash basis until qualifying for return to accrual status. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured.
Fair value is defined as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Fair value of investments is determined based on a fair value hierarchy that prioritizes the use of observable inputs over the use of unobservable inputs and requires the use of observable inputs when available. (See Note 12 of the Notes to Consolidated Financial Statements.)
Realized gains or losses represent the difference between the cost of securities sold and the proceeds realized upon sale and are recorded at the trade date. The Company uses primarily the first-in, first-out method to determine the cost of securities sold.
For available for sale securities in an unrealized loss position where the Company intends to sell, or it is more likely than not that it will be required to sell the security before recovery in value, the amortized cost basis is written down to fair value through net investment gains. For available for sale securities in an unrealized loss position where the Company does not intend to sell, or it is more likely than not that it will not be required to sell the security before recovery in value, the Company evaluates whether the decline in fair value has resulted from credit losses or all other factors (non-credit factors). In making this assessment, the Company considers the extent to which fair value is less than amortized cost, changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, an allowance for expected credit losses is recorded for the credit loss through net investment gains, limited by the amount that the fair value is less than the amortized cost basis. The allowance is adjusted for any change in expected credit losses and subsequent recoveries through net investment gains. The impairment related to non-credit factors is recognized in comprehensive income (loss).
For financial assets carried at amortized cost, which includes held to maturity securities and loans receivable, the Company estimates an allowance for expected credit losses based on relevant information about past events, including historical loss experience, current conditions and forecasts that affect the expected collectability of the amortized cost of the financial asset. The allowance for expected credit losses is presented as a reduction to amortized cost of the financial asset in the consolidated balance sheet and changes to the estimate for expected credit losses are recognized through net investment gains.
The Company’s credit assessment of allowance for expected credit losses uses a third party model for available for sale and held to maturity securities, as well as loans receivable. The allowance for expected credit losses is generally based on the performance of the underlying collateral under various economic and default scenarios that involve subjective judgments and estimates by management. Modeling these securities involves various factors, such as projected default rates, the nature and realizable value of the collateral, if any, the ability of the issuer to make scheduled payments, historical performance and other relevant economic and performance factors. A discounted cash flow analysis is used to ascertain the amount of the allowance for expected credit losses, if any. In general, the model reverts to the rating-level long-term average marginal default rates based on 10 years of historical data, beyond the forecast period. For other inputs, the model in most cases reverts to the baseline long-
term assumptions linearly over 5 years beyond the forecast period. The long-term assumptions are based on the historical averages.
The Company reports accrued investment income separately from fixed maturity securities, and has elected not to measure an allowance for expected credit losses for accrued investment income. Accrued investment income is written off through net investment income at the time the issuer of the bond defaults or is expected to default on payments.
Real estate held for investment purposes is initially recorded at the purchase price, which is generally fair value, and is subsequently reported at cost less accumulated depreciation. Real estate taxes, interest and other costs incurred during development and construction are capitalized. Buildings are depreciated on a straight-line basis over the estimated useful lives of the building. Minimum rental income is recognized on a straight-line basis over the lease term. Income and expenses from real estate are reported as net investment income. The carrying value of real estate is reviewed for impairment and an impairment loss is recognized if the estimated undiscounted cash flows from the use and disposition of the property are less than the carrying value of the property.
Per share data Per share data
The Company presents both basic and diluted net income per share (“EPS”) amounts. Basic EPS is calculated by dividing net income by weighted average number of common shares outstanding during the year (including 17,378,810 common shares held in a grantor trust). The common shares held in the grantor trust are designated for delivery upon the settlement of restricted stock units ("RSUs") that are vested but mandatorily deferred. Accordingly, such shares deliverable under vested RSUs do not affect diluted shares outstanding since the shares are already included in basic shares outstanding (which includes the shares in the grantor trust referenced above). Diluted EPS is based upon the weighted average number of basic and common equivalent shares outstanding during the period and is calculated using the treasury stock method for stock incentive plans. Common equivalent shares are excluded from the computation in periods in which they have an anti-dilutive effect.
Deferred policy acquisition costs Deferred policy acquisition costs
Acquisition costs associated with the successful acquisition of new and renewed insurance and reinsurance contracts are deferred and amortized ratably over the terms of the related contracts. Ceding commissions received on reinsurance contracts are netted against acquisition costs and are recognized ratably over the life of the contract. Deferred policy acquisition costs are presented net of unearned ceding commissions. Deferred policy acquisition costs are comprised primarily of commissions, as well as employment-related underwriting costs and premium taxes. Deferred policy acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. The recoverability of deferred policy acquisition costs is evaluated separately by each of our businesses. Future investment income is taken into account in measuring the recoverability of deferred policy acquisition costs.
Reserves for losses and loss expenses Reserves for losses and loss expenses
Reserves for losses and loss expenses are an accumulation of amounts determined on the basis of (1) evaluation of claims for business written directly by the Company; (2) estimates received from other companies for reinsurance assumed by the Company; and (3) estimates for losses incurred but not reported (based on Company and industry experience). These estimates are periodically reviewed and, as experience develops and new information becomes known, the reserves are adjusted as necessary. Such adjustments are reflected in the statements of income in the period in which they are determined. The Company discounts its reserves for excess and assumed workers' compensation claims using a risk-free or statutory rate. (See Note 13 of Notes to Consolidated Financial Statements.)
Reinsurance ceded Reinsurance ceded
The unearned portion of premiums ceded to reinsurers is reported as prepaid reinsurance premiums and earned ratably over the policy term. The estimated amounts of reinsurance recoverable on unpaid losses are reported as due from reinsurers. To the extent any reinsurer does not meet its obligations under reinsurance agreements, the Company must discharge its liability. Amounts due from reinsurers are reflected net of funds held where the right of offset is present. The Company has provided an allowance for expected credit losses for estimated uncollectible reinsurance. The allowance is estimated based on the composition of the recoverable balance, considering reinsurer credit ratings, collateral received from financial institutions and funds withheld arrangements, length of collection periods, probability of default methodology, and specific identification of collectability concerns. Changes in the allowance are reported within losses and loss expenses.
Deposit accounting Deposit accounting Contracts that do not meet the risk transfer requirements of GAAP are accounted for using the deposit accounting method. Under this method, an asset or liability is recognized at the inception of the contract based on consideration paid or received. The amount of the deposit asset or liability is adjusted at subsequent reporting dates using the interest method with a corresponding credit or charge to interest income or expense.
Federal and foreign income taxes Federal and foreign income taxesThe Company files a consolidated income tax return in the U.S. and foreign tax returns in countries where it has overseas operations. The Company's method of accounting for income taxes is the asset and liability method. Under this method, deferred tax assets and liabilities are measured using tax rates currently in effect or expected to apply in the years in which those temporary differences are expected to reverse. Interest and penalties, if any, are reported as income tax expense. The Company believes there are no uncertain tax positions that would require disclosure under GAAP. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or a portion of the deferred tax assets will not be realized.
Foreign currency Foreign currency Gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the entity's functional currency) are reported on the statements of income as other operating costs and expenses. Unrealized gains or losses resulting from translating the results of non-U.S. dollar denominated operations are reported in accumulated other comprehensive income. Revenues and expenses denominated in currencies other than U.S. dollars are generally translated at the weighted average exchange rate during the year. Assets and liabilities are translated at the rate of exchange in effect at the balance sheet date.
Property, furniture and equipment Property, furniture and equipment Property, furniture and equipment are carried at cost less accumulated depreciation. Depreciation is calculated using the estimated useful lives of the respective assets.
Comprehensive income Comprehensive income
Comprehensive income encompasses all changes in stockholders' equity (except those arising from transactions with stockholders) and includes net income, net unrealized holding gains or losses on available for sale securities and unrealized foreign currency translation adjustments.
Goodwill and other intangible assets Goodwill and other intangible assets Goodwill and other intangible assets are tested for impairment on an annual basis and at interim periods where circumstances require.
Stock options Restricted stock units
The costs resulting from all share-based payment transactions with employees are recognized in the consolidated financial statements using a fair-value-based measurement method. Compensation cost is recognized for financial reporting purposes over the period in which the employee is required to provide service in exchange for the award (generally the vesting period).
Recent accounting pronouncements Recent accounting pronouncements
Recently adopted accounting pronouncements:
In December 2023, the Financial Accounting Standards Board issued Accounting Standards Update 2023-09, Improvements to Income Tax Disclosures (Topic 740), to enhance the transparency and usefulness of income tax disclosures. The guidance requires additional disclosures primarily related to the rate reconciliation and income taxes paid. This guidance is effective for annual periods beginning after December 15, 2024. The Company adopted this guidance prospectively for the year ended December 31, 2025.
All other accounting and reporting standards that became effective in 2025 were either not applicable to the Company or their adoption did not have a material impact on the Company.
Accounting and reporting standards that are not yet effective:
In November 2024, the Financial Accounting Standards Board issued Accounting Standards Update 2024-03, Disaggregation of Income Statement Expenses, addressing investor requests for more transparent information. The guidance requires disclosure of specified information about certain costs and expenses in the notes to the financial statements. The guidance is effective for annual periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Prospective application is required, with retrospective application permitted. The Company will adopt this guidance for the year ended December 31, 2027 and resulting impact will be disclosure only.
All other recently issued but not yet effective accounting and reporting standards are either not applicable to the Company or are not expected to have a material impact on the Company.
v3.25.4
Consolidated Statement of Comprehensive Income (Tables)
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Schedule of Accumulated Other Comprehensive (Loss) Income
The following tables present the components of the changes in accumulated other comprehensive income (loss) (AOCI) as of and for the years ended December 31, 2025 and 2024:
(In thousands)
December 31, 2025Unrealized Investment Gains (Losses)Currency Translation AdjustmentsAccumulated Other Comprehensive Income (Loss)
Changes in AOCI
Beginning of period$(517,170)$(417,099)$(934,269)
Other comprehensive income before reclassifications344,083 90,682 434,765 
Amounts reclassified from AOCI48,408 — 48,408 
Other comprehensive income392,491 90,682 483,173 
Unrealized investment loss related to noncontrolling interest(1)— (1)
Ending balance$(124,680)$(326,417)$(451,097)
Amounts reclassified from AOCI
Pre-tax$61,276 (1)$— $61,276 
Tax effect(12,868)(2)— (12,868)
After-tax amounts reclassified$48,408 $— $48,408 
Other comprehensive income
Pre-tax$497,765 $90,682 $588,447 
Tax effect(105,274)— (105,274)
Other comprehensive income $392,491 $90,682 $483,173 

(In thousands)
December 31, 2024Unrealized Investment Gains (Losses)Currency Translation AdjustmentsAccumulated Other Comprehensive Income (Loss)
Changes in AOCI
Beginning of period$(586,354)$(339,484)$(925,838)
Other comprehensive loss before reclassifications(26,128)(77,615)(103,743)
Amounts reclassified from AOCI95,310 — 95,310 
Other comprehensive income (loss)69,182 (77,615)(8,433)
Unrealized investment income related to non-controlling interest— 
Ending balance$(517,170)$(417,099)$(934,269)
Amounts reclassified from AOCI
Pre-tax$120,646 (1)$— $120,646 
Tax effect(25,336)(2)— (25,336)
After-tax amounts reclassified$95,310 $— $95,310 
Other comprehensive income (loss)
Pre-tax$84,474 $(77,615)$6,859 
Tax effect(15,292)— (15,292)
Other comprehensive income (loss)$69,182 $(77,615)$(8,433)
_______________
(1) Net investment gains in the consolidated statements of income.
(2) Income tax expense in the consolidated statements of income.
v3.25.4
Investments In Fixed Maturity Securities (Tables)
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Investments In Fixed Maturity Securities
At December 31, 2025 and 2024, investments in fixed maturity securities were as follows:
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025
Held to maturity:
State and municipal$28,777 $(9)$796 $— $29,564 $28,768 
Residential mortgage-backed1,838 — 76 — 1,914 1,838 
Total held to maturity30,615 (9)872 — 31,478 30,606 
Available for sale:
U.S. government and government agency3,964,375 — 48,820 (15,157)3,998,038 3,998,038 
State and municipal:
                 Special revenue1,206,387 — 6,002 (27,943)1,184,446 1,184,446 
                 State general obligation203,543 — 3,465 (3,848)203,160 203,160 
                 Pre-refunded74,276 — 619 (111)74,784 74,784 
                 Corporate backed159,876 — 1,958 (3,459)158,375 158,375 
                 Local general obligation218,022 — 1,459 (3,052)216,429 216,429 
       Total state and municipal1,862,104 — 13,503 (38,413)1,837,194 1,837,194 
Mortgage-backed securities:
Residential4,584,970 (65)71,048 (132,645)4,523,308 4,523,308 
Commercial281,573 — 3,632 (35)285,170 285,170 
Total mortgage-backed securities4,866,543 (65)74,680 (132,680)4,808,478 4,808,478 
Asset-backed securities3,807,393 — 20,196 (17,243)3,810,346 3,810,346 
Corporate:
                 Industrial3,627,567 — 57,466 (36,499)3,648,534 3,648,534 
                 Financial3,438,348 — 61,180 (16,460)3,483,068 3,483,068 
                 Utilities1,300,506 — 22,593 (8,878)1,314,221 1,314,221 
                 Other240,374 — 2,356 (1,142)241,588 241,588 
Total corporate8,606,795 — 143,595 (62,979)8,687,411 8,687,411 
Foreign government2,032,543 — 20,906 (177,860)1,875,589 1,875,589 
Total available for sale25,139,753 (65)321,700 (444,332)25,017,056 25,017,056 
Total investments in fixed maturity securities$25,170,368 $(74)$322,572 $(444,332)$25,048,534 $25,047,662 
(In thousands)Amortized
Cost
Allowance for Expected Credit Losses (1)Gross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2024
Held to maturity:
State and municipal$42,145 $(25)$1,492 $— $43,612 $42,120 
Residential mortgage-backed2,292 — 69 — 2,361 2,292 
Total held to maturity44,437 (25)1,561 — 45,973 44,412 
Available for sale:
U.S. government and government agency2,268,596 — 9,608 (42,863)2,235,341 2,235,341 
State and municipal:
                 Special revenue1,581,778 — 3,521 (67,591)1,517,708 1,517,708 
                 State general obligation272,936 — 1,439 (8,981)265,394 265,394 
                 Pre-refunded85,340 — 599 (347)85,592 85,592 
                 Corporate backed158,322 — 1,079 (5,827)153,574 153,574 
                 Local general obligation278,165 — 922 (6,711)272,376 272,376 
       Total state and municipal2,376,541 — 7,560 (89,457)2,294,644 2,294,644 
Mortgage-backed securities:
Residential3,411,796 (5)11,047 (189,630)3,233,208 3,233,208 
Commercial534,936 (425)1,201 (3,430)532,282 532,282 
Total mortgage-backed securities3,946,732 (430)12,248 (193,060)3,765,490 3,765,490 
Asset-backed securities3,910,363 — 16,161 (41,512)3,885,012 3,885,012 
Corporate:
                 Industrial3,746,501 — 14,518 (93,820)3,667,199 3,667,199 
                 Financial3,339,718 — 18,871 (38,076)3,320,513 3,320,513 
                 Utilities795,839 — 2,970 (20,115)778,694 778,694 
                 Other653,194 — 2,493 (4,452)651,235 651,235 
Total corporate8,535,252 — 38,852 (156,463)8,417,641 8,417,641 
Foreign government1,928,978 (216)11,936 (185,373)1,755,325 1,755,325 
Total available for sale22,966,462 (646)96,365 (708,728)22,353,453 22,353,453 
Total investments in fixed maturity securities$23,010,899 $(671)$97,926 $(708,728)$22,399,426 $22,397,865 
Debt Securities, Held-to-maturity, Allowance for Credit Loss
The following table presents the rollforward of the allowance for expected credit losses for held to maturity securities for the years ended December 31, 2025 and 2024:
State and Municipal
(In thousands)20252024
Balance, beginning of period$25 $43 
Provision for expected credit losses(16)(18)
Balance, end of period$$25 
Debt Securities, Available-for-sale, Allowance for Credit Loss
The following table presents the rollforward of the allowance for expected credit losses for available for sale securities for the years ended December 31, 2025 and 2024:
20252024
(In thousands)Foreign GovernmentMortgage- BackedState and MunicipalTotalForeign GovernmentCorporateMortgage- BackedAsset-backedState and MunicipalTotal
Balance, beginning of period$216 $430 $— $646 $29,603 $5,026 $158 $1,164 $757 $36,708 
Change on securities for which credit losses were not previously recorded65 10 78 347 — 1,706 — — 2,053 
Change on securities for which credit losses were previously recorded(219)(430)(10)(659)(29,355)(5,026)(831)(1,164)(757)(37,133)
Reduction due to disposals— — — — (379)— (603)— — (982)
Balance, end of period$— $65 $— $65 $216 $— $430 $— $— $646 
The Amortized Cost And Fair Value of Fixed Maturity Securities
The amortized cost and fair value of fixed maturity securities at December 31, 2025, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations.
(In thousands)Amortized
Cost (1)
Fair Value
Due in one year or less$1,789,587 $1,740,503 
Due after one year through five years8,131,346 8,060,983 
Due after five years through ten years3,791,177 3,828,290 
Due after ten years6,589,868 6,608,366 
Mortgage-backed securities4,868,381 4,810,392 
Total$25,170,359 $25,048,534 
________________
(1) Amortized cost is reduced by the allowance for expected credit losses of $9 thousand related to held to maturity securities.
v3.25.4
Investments In Equity Securities (Tables)
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Schedule of Investments in Equity Securities
At December 31, 2025 and 2024, investments in equity securities were as follows:
(In thousands)CostGross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025     
Common stocks$566,577 $181,120 $(5,584)$742,113 $742,113 
Preferred stocks433,472 187,891 (5,275)616,088 616,088 
Total$1,000,049 $369,011 $(10,859)$1,358,201 $1,358,201 
December 31, 2024    
Common stocks$612,479 $223,981 $(76,293)$760,167 $760,167 
Preferred stocks329,495 122,716 (8,590)443,621 443,621 
Total$941,974 $346,697 $(84,883)$1,203,788 $1,203,788 
Investment funds consist of the following:
Carrying Value
as of December 31,
Income (Loss) From Investment Funds For the Year Ended
(In thousands)20252024202520242023
Financial services (1)$360,320 $430,163 $(20,504)$(39,418)$(10,911)
Transportation272,775 286,426 32,441 13,335 40,607 
Infrastructure169,847 151,560 15,258 17,071 13,049 
Real estate163,098 178,685 4,023 12,195 (6,676)
Energy41,966 42,776 146 14,501 5,058 
Other funds353,796 378,636 (3,782)(29,175)(24,384)
Total$1,361,802 $1,468,246 $27,582 $(11,491)$16,743 
(1) Includes the Company’s minority investment in Lifson Re (see Note 26 Related-Party Transactions).
v3.25.4
Net Investment Income (Tables)
12 Months Ended
Dec. 31, 2025
Net Investment Income [Abstract]  
Net Investment Income
Net investment income consists of the following:
(In thousands)202520242023
Investment income (loss) earned on:   
Fixed maturity securities, including cash and cash equivalents and loans receivable$1,307,087 $1,260,429 $929,098 
Arbitrage trading account (1)74,407 69,573 69,369 
Equity securities50,529 48,920 55,726 
Investment funds27,582 (11,491)16,743 
Real estate
(18,450)(23,616)(11,185)
Gross investment income1,441,155 1,343,815 1,059,751 
Investment expense(12,088)(10,654)(6,916)
Net investment income$1,429,067 $1,333,161 $1,052,835 
v3.25.4
Investment Funds (Tables)
12 Months Ended
Dec. 31, 2025
Equity Method Investments and Joint Ventures [Abstract]  
Schedule of Investment Funds
At December 31, 2025 and 2024, investments in equity securities were as follows:
(In thousands)CostGross UnrealizedFair
Value
Carrying
Value
GainsLosses
December 31, 2025     
Common stocks$566,577 $181,120 $(5,584)$742,113 $742,113 
Preferred stocks433,472 187,891 (5,275)616,088 616,088 
Total$1,000,049 $369,011 $(10,859)$1,358,201 $1,358,201 
December 31, 2024    
Common stocks$612,479 $223,981 $(76,293)$760,167 $760,167 
Preferred stocks329,495 122,716 (8,590)443,621 443,621 
Total$941,974 $346,697 $(84,883)$1,203,788 $1,203,788 
Investment funds consist of the following:
Carrying Value
as of December 31,
Income (Loss) From Investment Funds For the Year Ended
(In thousands)20252024202520242023
Financial services (1)$360,320 $430,163 $(20,504)$(39,418)$(10,911)
Transportation272,775 286,426 32,441 13,335 40,607 
Infrastructure169,847 151,560 15,258 17,071 13,049 
Real estate163,098 178,685 4,023 12,195 (6,676)
Energy41,966 42,776 146 14,501 5,058 
Other funds353,796 378,636 (3,782)(29,175)(24,384)
Total$1,361,802 $1,468,246 $27,582 $(11,491)$16,743 
(1) Includes the Company’s minority investment in Lifson Re (see Note 26 Related-Party Transactions).
v3.25.4
Real Estate (Tables)
12 Months Ended
Dec. 31, 2025
Real Estate [Abstract]  
Schedule of real estate properties
Investment in real estate represents directly owned property held for investment, as follows:    
As of December 31,
(In thousands)20252024
Properties in operation$1,051,455 $1,063,687 
Properties under development228,293 227,768 
Total$1,279,748 $1,291,455 
v3.25.4
Loans Receivable Loans Receivable (Tables)
12 Months Ended
Dec. 31, 2025
Receivables [Abstract]  
Schedule of Loans Receivable
At December 31, 2025 and 2024, loans receivable were as follows:
As of December 31,
(In thousands)20252024
Amortized cost (net of allowance for expected credit losses):
Real estate loans$418,913 $402,382 
Commercial loans— 3,071 
Total$418,913 $405,453 
Fair value:
Real estate loans$419,074 $402,177 
Commercial loans— 3,071 
Total$419,074 $405,248 
Financing Receivable, Allowance for Credit Loss
The following table presents the rollforward of the allowance for expected credit losses for loans receivable for the years ended December 31, 2025 and 2024:
20252024
(In thousands)Real Estate LoansCommercial LoansTotalReal Estate LoansCommercial LoansTotal
Balance, beginning of period$1,088 $26 $1,114 $2,983 $21 $3,004 
Change in expected credit losses(927)(26)(953)(1,895)(1,890)
Balance, end of period$161 $— $161 $1,088 $26 $1,114 
v3.25.4
Net Investment Gains (Tables)
12 Months Ended
Dec. 31, 2025
Realized and Unrealized Investment Gains (Losses) [Abstract]  
Realized And Unrealized Investment Gains (Losses)
Net investment gains were as follows:
(In thousands)202520242023
Net investment gains:   
Fixed maturity securities:   
Gains$18,544 $15,486 $2,003 
Losses(19,191)(32,866)(25,429)
Equity securities (1):
Net realized gains on investment sales (2)70,042 116,475 161,271 
Change in unrealized gains96,337 120,799 70,448 
Investment funds(292)1,835 (25,625)
Real estate (3) 26,544 (2,647)(70,934)
Loans receivable(87)— (18,841)
Other (4)(61,227)(139,344)(45,353)
Net realized and unrealized gains on investments in earnings before allowance for expected credit losses130,670 79,738 47,540 
Change in allowance for expected credit losses on investments:
    Fixed maturity securities597 36,080 715 
    Loans receivable953 1,890 (1,213)
Change in allowance for expected credit losses on investments1,550 37,970 (498)
Net investment gains 132,220 117,708 47,042 
Income tax expense(28,512)(29,205)(10,250)
  After-tax net investment gains$103,708 $88,503 $36,792 
Change in unrealized investment gains (losses):   
Fixed maturity securities without allowance for expected credit losses$490,594 $83,395 $389,839 
Fixed maturity securities with allowance for expected credit losses(862)4,428 643 
Investment funds8,203 (3,217)3,989 
Other(170)(132)(1,568)
Total change in unrealized investment gains 497,765 84,474 392,903 
Income tax expense(105,274)(15,292)(86,350)
Noncontrolling interests(1)(2)
 After-tax change in unrealized investment gains $392,490 $69,184 $306,551 
____________________
(1) The net realized gains or losses on investment sales represent the total gains or losses from the purchase dates of the equity securities. The change in unrealized gains (losses) consists of two components: (i) the reversal of the gain or loss recognized in previous periods on equity securities sold and (ii) the change in unrealized gain or loss resulting from mark-to-market adjustments on equity securities still held.
(2) In 2023, the Company completed a sale of the property and casualty insurance services division of Breckenridge IS, Inc. and recognized a pre-tax net realized gain on investment of $89 million on the sale (proceeds from the sale is presented on the business disposition line within the Consolidated Statements of Cash Flows).
(3) The Company recognized impairments on real estate of $72 million in 2023.
(4) Primarily relates to realized foreign currency losses upon the disposition of fixed maturity securities.
v3.25.4
Fixed Maturity Securities in an Unrealized Loss Position (Tables)
12 Months Ended
Dec. 31, 2025
Investments, Debt and Equity Securities [Abstract]  
Securities In An Unrealized Loss Position
The following tables summarize all fixed maturity securities in an unrealized loss position at December 31, 2025 and 2024 by the length of time those securities have been continuously in an unrealized loss position.
 Less Than 12 Months12 Months or GreaterTotal
(In thousands)Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
December 31, 2025      
U.S. government and government agency$790,077 $8,902 $183,896 $6,255 $973,973 $15,157 
State and municipal141,680 1,520 1,053,168 36,893 1,194,848 38,413 
Mortgage-backed securities251,861 2,265 839,061 130,415 1,090,922 132,680 
Asset-backed securities644,346 1,643 503,876 15,600 1,148,222 17,243 
Corporate494,240 4,308 1,786,925 58,671 2,281,165 62,979 
Foreign government666,054 9,770 285,640 168,090 951,694 177,860 
Fixed maturity securities$2,988,258 $28,408 $4,652,566 $415,924 $7,640,824 $444,332 
December 31, 2024     
U.S. government and government agency$767,515 $9,637 $560,260 $33,226 $1,327,775 $42,863 
State and municipal348,116 8,027 1,411,761 81,430 1,759,877 89,457 
Mortgage-backed securities1,541,464 21,326 1,060,823 171,734 2,602,287 193,060 
Asset-backed securities411,763 4,613 626,237 36,899 1,038,000 41,512 
Corporate1,791,970 21,346 2,951,377 135,117 4,743,347 156,463 
Foreign government600,103 17,933 476,479 167,440 1,076,582 185,373 
Fixed maturity securities$5,460,931 $82,882 $7,086,937 $625,846 $12,547,868 $708,728 
Non-Investment Grade Fixed Maturity Securities A summary of the Company’s non-investment grade fixed maturity securities that were in an unrealized loss position at December 31, 2025 is presented in the table below:
($ in thousands)Number of
Securities
Aggregate
Fair Value
Gross
Unrealized
Loss
Foreign government67 $151,002 $165,721 
Corporate24 43,968 814 
State and municipal28,958 1,047 
Mortgage-backed securities14 2,244 113 
Total110 $226,172 $167,695 
v3.25.4
Fair Value Measurements (Tables)
12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
Assets And Liabilities Measured At Fair value, On A Recurring Basis
The following tables present the assets and liabilities measured at fair value as of December 31, 2025 and 2024 by level:
(In thousands)TotalLevel 1Level 2Level 3
December 31, 2025    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$3,998,038 $— $3,998,038 $— 
State and municipal1,837,194 — 1,837,194 — 
Mortgage-backed securities4,808,478 — 4,808,478 — 
Asset-backed securities3,810,346 — 3,810,346 — 
Corporate8,687,411 — 8,667,410 20,001 
Foreign government1,875,589 — 1,875,589 — 
Total fixed maturity securities available for sale25,017,056 — 24,997,055 20,001 
Equity securities:    
Common stocks742,113 739,186 786 2,141 
Preferred stocks616,088 — 607,414 8,674 
Total equity securities1,358,201 739,186 608,200 10,815 
Arbitrage trading account1,221,103 1,139,447 81,543 113 
Total$27,596,360 $1,878,633 $25,686,798 $30,929 
Liabilities:    
Trading account securities sold but not yet purchased$66,285 $66,285 $— $— 
December 31, 2024    
Assets:    
Fixed maturity securities available for sale:   
U.S. government and government agency$2,235,341 $— $2,235,341 $— 
State and municipal2,294,644 — 2,294,644 — 
Mortgage-backed securities3,765,490 — 3,765,490 — 
Asset-backed securities3,885,012 — 3,885,012 — 
Corporate8,417,641 — 8,397,974 19,667 
Foreign government1,755,325 — 1,755,325 — 
Total fixed maturity securities available for sale22,353,453 — 22,333,786 19,667 
Equity securities:    
Common stocks760,167 757,115 1,011 2,041 
Preferred stocks443,621 — 439,947 3,674 
Total equity securities1,203,788 757,115 440,958 5,715 
Arbitrage trading account1,122,599 1,062,459 56,630 3,510 
Total$24,679,840 $1,819,574 $22,831,374 $28,892 
Liabilities:    
Trading account securities sold but not yet purchased$73,358 $73,358 $— $— 
Summarize Changes In Level 3 Assets and Liabilities
The following tables summarize changes in Level 3 assets and liabilities for the years ended December 31, 2025 and 2024:
 Gains (Losses) Included in:
(In thousands)Beginning BalanceEarnings (Losses)Other Comprehensive Income (Loss)ImpairmentsPurchasesSalesPaydowns/MaturitiesTransfers In / OutEnding Balance
Year ended December 31, 2025        
Assets:
Fixed maturity securities available for sale:        
Corporate$19,667 $— $334 $— $— $— $— $— $20,001 
Total19,667 — 334 — — — — — 20,001 
Equity securities:
Common stocks2,041 226 — — — (126)— — 2,141 
Preferred stocks3,674 — — — 6,160 (1,160)— — 8,674 
Total5,715 226 — — 6,160 (1,286)— — 10,815 
Arbitrage trading account3,510 1,745 — — — (5,143)— 113 
Total$28,892 $1,971 $334 $— $6,160 $(6,429)$— $$30,929 
Year ended December 31, 2024        
Assets:
Fixed maturity securities available for sale:        
Corporate$— $— $(333)$— $— $— $— $20,000 $19,667 
Total— — (333)— — — — 20,000 19,667 
Equity securities:
Common stocks1,558 611 — — — (128)— — 2,041 
Preferred stocks3,695 36 — — — (57)— — 3,674 
Total5,253 647 — — — (185)— — 5,715 
Arbitrage trading account3,772 (261)— — — (38)— 37 3,510 
Total$9,025 $386 $(333)$— $— $(223)$— $20,037 $28,892 
v3.25.4
Reserves For Losses And Loss Expenses (Tables)
12 Months Ended
Dec. 31, 2025
Insurance [Abstract]  
Loss and loss expenses incurred, net of reinsurance, and cumulative paid claims and claim adjustment expenses, net of reinsurance
Insurance
Other Liability
(In thousands)
Loss and Loss Expenses Incurred, Net of Reinsurance As of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$1,005,612 $997,545 $1,007,537 $1,019,724 $1,033,882 $1,049,653 $1,080,784 $1,122,522 $1,123,417 $1,112,764 $40,882 29
2017— 1,056,364 1,089,751 1,112,499 1,130,172 1,169,911 1,239,544 1,257,401 1,289,835 1,312,455 67,962 28
2018— — 1,096,770 1,124,246 1,114,611 1,150,004 1,226,496 1,292,474 1,374,968 1,438,893 82,877 29
2019— — — 1,234,191 1,230,155 1,231,387 1,288,106 1,363,275 1,396,896 1,439,633 100,286 31
2020— — — — 1,332,123 1,205,740 1,150,267 1,158,609 1,188,675 1,234,607 122,379 25
2021— — — — — 1,525,082 1,380,843 1,334,315 1,354,190 1,440,014 177,217 28
2022— — — — — — 1,813,543 1,818,251 1,800,663 1,889,294 444,128 30
2023— — — — — — — 2,114,315 2,077,833 2,054,648 837,033 29
2024— — — — — — — — 2,383,071 2,325,325 1,602,853 25
2025— — — — — — — — — 2,626,044 2,237,259 19
Total$16,873,677 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$67,371 $204,063 $384,280 $551,150 $668,420 $757,859 $861,245 $944,882 $997,545 $1,035,353 
2017— 77,838 251,375 447,980 633,015 768,021 922,491 1,039,147 1,119,561 1,177,876 
2018— — 85,190 261,870 432,342 611,576 801,704 979,655 1,123,197 1,247,469 
2019— — — 86,586 271,989 467,450 700,121 902,947 1,074,214 1,196,228 
2020— — — — 70,510 222,319 417,957 614,487 812,670 949,161 
2021— — — — — 75,175 265,238 484,808 794,700 1,039,910 
2022— — — — — — 92,298 353,014 704,534 1,079,369 
2023— — — — — — — 91,761 366,667 751,329 
2024— — — — — — — — 95,165 341,419 
2025— — — — — — — — — 111,115 
Total$8,929,229 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance226,423 
Reserves for loss and loss adjustment expenses, net of reinsurance$8,170,871 
Workers' Compensation
(In thousands)
Loss and Loss Expenses Incurred, Net of Reinsurance As of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$702,716 $696,339 $684,700 $660,520 $651,278 $657,972 $654,385 $641,549 $639,412 $645,507 $17,158 58
2017— 762,093 733,505 689,622 673,216 683,880 682,153 675,871 669,988 673,458 15,991 58
2018— — 778,964 724,697 715,055 724,056 721,170 715,018 708,336 717,051 17,063 56
2019— — — 784,281 721,018 732,762 734,034 722,456 714,086 717,703 17,158 54
2020— — — — 725,245 716,430 704,008 668,222 652,424 656,816 8,156 42
2021— — — — — 742,687 701,703 667,517 649,222 648,190 10,705 46
2022— — — — — — 772,620 745,218 715,578 715,628 26,775 46
2023— — — — — — — 784,906 758,657 734,685 56,380 46
2024— — — — — — — — 811,614 777,646 142,325 48
2025— — — — — — — — — 833,324 350,183 47
Total$7,120,008 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$142,998 $338,835 $446,072 $504,850 $537,861 $558,934 $572,669 $584,330 $591,005 $598,518 
2017— 153,456 362,299 468,817 525,753 559,198 583,258 603,006 617,243 628,306 
2018— — 171,006 397,464 508,546 574,889 613,675 642,292 660,237 671,916 
2019— — — 184,715 397,376 515,914 581,003 618,324 644,772 663,649 
2020— — — — 172,478 380,454 485,203 548,585 579,332 600,913 
2021— — — — — 172,729 384,867 490,648 547,863 582,994 
2022— — — — — — 180,982 408,929 527,145 598,841 
2023— — — — — — — 195,204 418,788 539,016 
2024— — — — — — — — 196,104 441,748 
2025— — — — — — — — — 212,080 
Total$5,537,981 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance264,217 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,846,244 
Professional Liability
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$310,177 $324,519 $361,292 $402,423 $439,705 $469,048 $464,492 $450,620 $454,376 $451,120 $13,801 9
2017— 332,545 331,841 337,990 376,818 383,720 392,719 401,348 402,042 401,753 23,170 10
2018— — 334,850 322,109 333,268 359,430 382,222 397,629 393,555 389,344 43,168 10
2019— — — 336,064 332,104 345,373 354,054 363,011 364,872 368,639 48,621 11
2020— — — — 393,872 375,336 337,654 313,348 300,725 296,916 26,890 11
2021— — — — — 524,981 471,273 446,441 410,248 415,009 91,622 12
2022— — — — — — 649,151 586,058 556,019 533,621 207,921 12
2023— — — — — — — 647,434 638,138 596,455 264,670 13
2024— — — — — — — — 652,871 647,813 362,839 15
2025— — — — — — — — — 692,538 529,514 16
Total$4,793,208 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$28,514 $102,444 $201,586 $255,458 $297,756 $357,868 $405,866 $413,456 $422,901 $427,370 
2017— 36,445 96,150 162,623 242,971 261,069 306,582 329,340 349,730 362,678 
2018— — 28,167 99,595 155,138 198,574 244,079 283,645 315,703 327,645 
2019— — — 31,652 97,328 147,779 200,255 235,114 270,992 298,961 
2020— — — — 27,932 80,099 128,777 168,902 196,626 237,215 
2021— — — — — 28,539 85,866 153,032 220,397 276,769 
2022— — — — — — 33,412 90,574 161,334 255,314 
2023— — — — — — — 41,073 122,356 215,591 
2024— — — — — — — — 40,369 136,010 
2025— — — — — — — — — 54,712 
Total$2,592,265 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance58,601 
Reserves for loss and loss adjustment expenses, net of reinsurance$2,259,544 
Auto
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$417,591 $418,263 $428,927 $429,436 $426,313 $426,265 $428,158 $429,911 $428,352 $427,441 $1,129 48
2017— 413,468 410,860 413,230 417,437 423,681 427,964 428,541 430,149 430,995 1,544 44
2018— — 423,455 443,583 460,219 474,879 502,611 511,694 513,912 512,884 2,518 43
2019— — — 463,232 466,184 483,737 508,810 525,412 532,678 532,577 4,645 43
2020— — — — 493,539 396,628 407,526 433,991 440,637 445,804 1,301 29
2021— — — — — 552,005 517,236 552,222 583,696 608,850 11,077 35
2022— — — — — — 723,267 740,688 763,806 802,255 35,392 41
2023— — — — — — — 890,682 907,503 930,020 91,528 43
2024— — — — — — — — 1,062,427 1,022,138 276,533 44
2025— — — — — — — — — 1,153,852 603,269 40
Total$6,866,816 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$180,603 $273,083 $333,092 $378,826 $397,671 $407,239 $415,630 $421,684 $424,338 $424,501 
2017— 173,964 257,335 314,739 357,282 386,260 403,864 414,486 422,351 425,108 
2018— — 173,955 272,312 337,926 397,867 445,885 479,508 494,308 502,832 
2019— — — 180,027 280,089 361,142 423,458 474,177 500,234 518,787 
2020— — — — 136,907 213,648 285,885 346,903 402,187 425,583 
2021— — — — — 168,499 289,019 379,969 476,465 550,804 
2022— — — — — — 237,885 394,137 531,324 657,551 
2023— — — — — — — 271,552 467,227 661,466 
2024— — — — — — — — 295,450 537,738 
2025— — — — — — — — — 317,147 
Total$5,021,517 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance5,042 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,850,341 
Short-tail lines
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
UnauditedIBNRCumulative Number of Reported Claims
Accident Year2016201720182019202020212022202320242025
2016$754,787 $758,453 $745,814 $740,062 $734,292 $736,723 $735,410 $735,706 $733,948 $734,213 $1,563 32
2017— 731,043 730,031 724,245 723,194 722,906 724,139 722,842 722,404 722,888 1,686 40
2018— — 741,978 732,244 728,956 727,513 724,921 724,069 719,517 719,947 3,791 47
2019— — — 703,739 685,145 675,146 669,008 669,126 658,750 657,296 3,574 42
2020— — — — 883,190 888,216 906,102 910,086 913,270 907,269 4,297 36
2021— — — — — 805,775 810,447 793,743 790,837 790,146 9,499 33
2022— — — — — — 905,427 889,716 880,655 880,999 18,124 32
2023— — — — — — — 1,036,001 997,840 989,593 37,413 28
2024— — — — — — — — 1,255,511 1,114,550 97,447 30
2025— — — — — — — — — 1,436,694 610,043 22
Total$8,953,595 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$404,261 $653,463 $694,726 $709,649 $714,504 $721,214 $722,046 $727,037 $729,261 $730,279 
2017— 429,297 667,922 695,780 707,688 710,855 718,026 723,385 725,808 725,326 
2018— — 401,786 645,593 691,916 708,876 707,915 712,992 715,706 718,309 
2019— — — 392,224 600,542 629,728 642,116 650,202 652,285 653,178 
2020— — — — 447,119 768,708 829,695 884,658 888,968 889,801 
2021— — — — — 389,015 677,203 733,205 756,084 770,016 
2022— — — — — — 440,972 762,169 827,800 850,260 
2023— — — — — — — 531,859 847,059 911,546 
2024— — — — — — — — 559,412 923,661 
2025— — — — — — — — — 587,273 
Total$7,759,649 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance(445)
Reserves for loss and loss adjustment expenses, net of reinsurance$1,193,501 
Reinsurance & Monoline Excess
Casualty
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$266,797 $278,899 $271,026 $293,396 $327,222 $326,843 $333,682 $328,995 $332,892 $337,165 $9,541 
2017— 257,234 247,785 265,054 286,643 305,992 321,755 335,173 345,090 357,493 16,254 
2018— — 247,465 236,747 256,413 272,487 283,962 311,426 328,553 341,329 21,566 
2019— — — 262,465 259,821 266,712 266,965 296,080 316,801 336,042 28,772 
2020— — — — 336,854 332,164 330,205 349,072 347,967 356,608 42,420 
2021— — — — — 430,770 432,251 424,891 427,481 453,576 86,204 
2022— — — — — — 494,853 507,154 479,837 486,146 140,864 
2023— — — — — — — 479,858 472,917 484,781 222,872 
2024— — — — — — — — 436,374 413,652 295,429 
2025— — — — — — — — — 443,941 395,239 
Total$4,010,733 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$26,586 $73,567 $115,091 $159,774 $193,329 $228,350 $249,234 $267,601 $279,732 $294,864 
2017— 25,292 54,455 86,635 144,009 169,593 198,765 233,392 269,624 290,428 
2018— — 18,942 52,766 93,374 128,903 164,086 207,741 245,388 270,913 
2019— — — 21,522 52,707 81,367 116,771 170,418 220,154 255,525 
2020— — — — 28,319 67,078 109,610 171,832 218,359 254,833 
2021— — — — — 24,696 77,110 146,076 212,227 280,381 
2022— — — — — — 28,077 83,762 159,448 233,285 
2023— — — — — — — 17,685 66,831 131,943 
2024— — — — — — — — 16,875 55,767 
2025— — — — — — — — — 13,573 
Total$2,081,512 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance331,375 
Reserves for loss and loss adjustment expenses, net of reinsurance$2,260,596 
Monoline Excess
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$72,657 $70,281 $71,404 $64,957 $65,485 $65,222 $63,932 $59,804 $55,371 $57,373 $1,048 
2017— 76,701 80,508 70,749 71,025 66,795 65,147 62,213 57,073 48,281 2,751 
2018— — 77,820 72,505 71,448 66,180 60,347 58,244 54,784 46,233 3,299 
2019— — — 78,929 77,482 76,242 76,478 73,571 70,929 63,702 4,822 
2020— — — — 84,354 83,468 82,952 80,946 70,219 60,759 10,403 
2021— — — — — 98,110 90,980 89,220 84,681 85,078 15,135 
2022— — — — — — 128,923 101,725 100,612 90,351 13,742 
2023— — — — — — — 110,446 86,901 85,509 22,170 
2024— — — — — — — — 120,046 89,794 45,243 
2025— — — — — — — — — 133,713 89,175 
Total$760,793 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$2,498 $4,783 $5,573 $5,928 $7,685 $9,883 $11,819 $13,569 $16,872 $18,766 
2017— 6,282 12,810 15,356 17,327 18,375 19,275 21,275 23,523 25,457 
2018— — 6,141 8,230 9,368 10,359 12,414 13,583 14,952 16,828 
2019— — — 6,241 10,884 12,728 15,436 18,836 21,094 24,642 
2020— — — — 4,869 8,699 10,471 12,869 15,427 18,072 
2021— — — — — 4,586 6,026 8,872 11,412 13,973 
2022— — — — — — 5,898 10,564 17,778 26,975 
2023— — — — — — — 6,390 12,471 16,547 
2024— — — — — — — — 5,723 9,436 
2025— — — — — — — — — 6,014 
Total$176,710 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance576,839 
Reserves for loss and loss adjustment expenses, net of reinsurance$1,160,922 
Property
(In thousands)
Loss and Loss Expenses Incurred, Net of ReinsuranceAs of December 31, 2025
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025IBNR
2016$186,014 $192,180 $199,087 $198,635 $204,166 $202,119 $203,126 $204,261 $203,249 $204,044 $666 
2017— 228,476 223,694 222,774 221,753 215,552 216,037 217,179 216,027 216,352 290 
2018— — 126,458 129,079 120,813 122,516 120,712 119,094 118,023 117,318 749 
2019— — — 120,797 93,545 98,085 97,060 96,996 96,129 96,760 1,209 
2020— — — — 132,262 134,287 133,004 137,810 136,468 141,563 3,737 
2021— — — — — 156,684 168,907 166,320 162,159 158,306 2,286 
2022— — — — — — 207,282 206,632 203,495 197,161 12,674 
2023— — — — — — — 177,380 173,605 165,333 14,323 
2024— — — — — — — — 256,437 231,060 65,848 
2025— — — — — — — — — 307,718 181,307 
Total$1,835,615 
Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance
For the Year Ended December 31,
Unaudited
Accident Year2016201720182019202020212022202320242025
2016$91,496 $150,392 $174,539 $186,047 $193,716 $195,856 $200,197 $202,117 $202,537 $203,237 
2017— 87,893 163,021 194,423 202,727 206,293 209,510 212,117 212,868 213,968 
2018— — 46,928 81,241 98,836 104,285 112,511 113,835 114,461 114,560 
2019— — — 35,584 70,147 84,513 87,111 89,023 90,942 92,024 
2020— — — — 39,668 81,413 102,822 111,751 118,775 126,803 
2021— — — — — 31,657 92,757 130,615 145,630 148,460 
2022— — — — — — 56,561 129,019 152,660 171,165 
2023— — — — — — — 58,403 110,388 133,772 
2024— — — — — — — — 69,398 139,970 
2025— — — — — — — — — 86,168 
Total$1,430,127 
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance3,639 
Reserves for loss and loss adjustment expenses, net of reinsurance$409,127 
Reconciliation of net incurred and paid claims development to reserves for loss and loss adjustment expenses
The reconciliation of the net incurred and paid claims development tables to the reserves for losses and loss expenses in the consolidated balance sheet is as follows:
(In thousands)December 31, 2025
Undiscounted reserves for loss and loss expenses, net of reinsurance:
Other liability$8,170,871 
Workers' compensation1,846,244 
Professional liability2,259,544 
Auto1,850,341 
Short-tail lines1,193,501 
Other222,930 
  Insurance15,543,431 
Casualty2,260,596 
Monoline excess1,160,922 
Property409,127 
  Reinsurance & Monoline Excess3,830,645 
Total undiscounted reserves for loss and loss expenses, net of reinsurance$19,374,076 
(In thousands)December 31, 2025
Due from reinsurers on unpaid claims:
Other liability$1,162,055 
Workers' compensation164,412 
Professional liability1,086,923 
Auto65,748 
Short-tail lines429,944 
Other145,790 
  Insurance3,054,872 
Casualty97,489 
Monoline excess41,132 
Property60,606 
  Reinsurance & Monoline Excess199,227 
Total due from reinsurers on unpaid claims$3,254,099 
(In thousands)December 31, 2025
Loss reserve discount:
Other liability$— 
Workers' compensation(9,263)
Professional liability— 
Auto— 
Short-tail lines— 
Other— 
  Insurance(9,263)
Casualty(64,732)
Monoline excess(346,407)
Property— 
  Reinsurance & Monoline Excess(411,139)
Total loss reserve discount$(420,402)
Total gross reserves for loss and loss expenses$22,207,773 
Supplementary information regarding average historical claims duration
The following is supplementary information regarding average historical claims duration as of December 31, 2025:
Insurance
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years12345678910
Other liability5.3 %12.7 %15.6 %16.4 %13.5 %11.0 %9.2 %7.4 %4.6 %3.4 %
Workers' compensation25.0 %31.2 %16.2 %9.2 %5.1 %3.6 %2.5 %1.8 %1.3 %1.2 %
Professional liability7.5 %15.3 %16.0 %15.0 %9.7 %11.6 %8.0 %3.3 %2.7 %1.0 %
Auto32.4 %20.0 %15.6 %12.7 %9.1 %4.6 %2.7 %1.6 %0.6 %— %
Short-tail lines52.3 %33.9 %6.0 %2.8 %0.7 %0.6 %0.3 %0.5 %0.1 %0.1 %
Reinsurance & Monoline Excess
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance
Years12345678910
Casualty5.7 %10.5 %12.2 %13.9 %11.9 %11.3 %9.4 %7.7 %4.7 %4.5 %
Monoline excess7.9 %6.0 %3.9 %4.0 %3.7 %3.2 %4.0 %3.9 %4.9 %3.3 %
Property33.2 %32.8 %15.2 %6.0 %3.5 %2.3 %1.2 %0.5 %0.4 %0.3 %
Reconciliation of beginning and ending reserve balance
The table below provides a reconciliation of the beginning and ending reserve balances:
(In thousands)202520242023
Net reserves at beginning of year$17,166,641 $15,661,820 $14,248,879 
Net provision for losses and loss expenses:
Claims occurring during the current year (1)7,702,638 7,083,999 6,311,780 
Increase in estimates for claims occurring in prior years (2)34,446 14,350 29,681 
Loss reserve discount accretion34,573 33,246 30,681 
Total7,771,657 7,131,595 6,372,142 
Net payments for claims:   
Current year1,375,478 1,278,585 1,217,078 
Prior year4,758,098 4,205,845 3,764,532 
Total6,133,576 5,484,430 4,981,610 
Foreign currency translation148,952 (142,344)22,409 
Net reserves at end of year18,953,674 17,166,641 15,661,820 
Ceded reserve at end of year3,254,099 3,201,389 3,077,832 
Gross reserves at end of year$22,207,773 $20,368,030 $18,739,652 
Net change in premiums and losses occurring in prior years:
Increase in estimates for claims occurring in prior years (2)$(34,446)$(14,350)$(29,681)
Retrospective premium adjustments for claims occurring in prior years (3)37,692 18,782 10,782 
Net premium and reserve development on prior years$3,246 $4,432 $(18,899)
_______________________________________
(1)Claims occurring during the current year are net of loss reserve discounts of $56 million, $49 million and $47 million in 2025, 2024, and 2023, respectively.
(2)The change in estimates for claims occurring in prior years is net of loss reserve discount. On an undiscounted basis, the estimates for claims occurring in prior years increased by $29 million in 2025, increased by $13 million in 2024 and decreased by $13 million in 2023.
(3)For certain retrospectively rated insurance polices and reinsurance agreements, changes in loss and loss expenses for prior years are offset by additional or return premiums.
v3.25.4
Reinsurance (Tables)
12 Months Ended
Dec. 31, 2025
Reinsurance Disclosures [Abstract]  
Reinsurance Financial Information
The following is a summary of reinsurance financial information:
(In thousands)202520242023
Written premiums:   
Direct$13,694,521 $12,904,893 $11,676,743 
Assumed1,410,548 1,306,198 1,295,263 
Ceded(2,393,742)(2,238,995)(2,017,539)
Total net written premiums$12,711,327 $11,972,096 $10,954,467 
Earned premiums:  
Direct$13,401,453 $12,346,924 $11,112,980 
Assumed1,387,726 1,364,774 1,246,288 
Ceded(2,342,241)(2,163,213)(1,958,581)
Total net earned premiums$12,446,938 $11,548,485 $10,400,687 
Ceded losses and loss expenses incurred$1,400,570 $1,368,279 $1,376,144 
Ceded commission earned$555,763 $505,753 $471,841 
Schedule of Premium Receivable Allowance for Credit Loss
The following table presents the rollforward of the allowance for expected credit losses for premiums and fees receivable for the years ended December 31, 2025 and 2024:
(In thousands)20252024
Allowance for expected credit losses, beginning of period$39,884 $35,110 
Change in expected credit losses2,122 4,774 
Allowance for expected credit losses, end of period$42,006 $39,884 
Schedule of Reinsurance Recoverable Allowance for Credit Loss
The following table presents the rollforward of the allowance for expected credit losses associated with due from reinsurers for the years ended December 31, 2025 and 2024:
(In thousands)20252024
Allowance for expected credit losses, beginning of period$8,350 $8,404 
Change in expected credit losses(1,972)(54)
Allowance for expected credit losses, end of period$6,378 $8,350 
Schedule of Ceded Credit Risk by Reinsurer
The following table presents the amounts due from reinsurers as of December 31, 2025:
(In thousands)
Lifson Re$537,366 
Lloyd’s of London358,718 
Partner Re 295,800 
Munich Re250,080 
Berkshire Hathaway246,729 
Hannover Re222,358 
Renaissance Re217,251 
Swiss Re 132,731 
Liberty Mutual124,916 
Everest Re86,017 
Arch Capital76,095 
Axis Capital 70,166 
Sompo Holdings64,383 
Fairfax Financial60,919 
Nationwide Corp60,342 
TOA Reinsurance51,290 
Korean Re45,858 
Axa Insurance42,361 
MS & AD Insurance 38,179 
Markel Corp 34,949 
Chubb 27,873 
Helvetia Holdings25,542 
Other reinsurers less than $20,000378,336 
Subtotal3,448,259 
Residual market pools (1)101,132 
Allowance for expected credit losses(6,378)
Total$3,543,013 
(1)Many states require licensed insurers that provide workers' compensation insurance to participate in programs that provide workers' compensation to employers that cannot procure coverage from an insurer on a voluntary basis. Insurers can fulfill this residual market obligation by participating in pools where results are shared by the participating companies. The Company acts as a servicing carrier for workers' compensation pools in certain states. As a servicing carrier, the Company writes residual market business directly and then cedes 100% of this business to the respective pool. As a servicing carrier, the Company receives fee income for its services. The Company does not retain underwriting risk, and credit risk is limited as ceded balances are jointly shared by all the pool members.
v3.25.4
Indebtedness (Tables)
12 Months Ended
Dec. 31, 2024
Debt Disclosure [Abstract]  
Schedule of Debt
Indebtedness consisted of the following as of December 31, 2025 (the difference between the face value and the carrying value is unamortized discount and debt issuance costs):
Carrying Value
(In thousands)Interest RateFace Value20252024
Senior notes and other debt due on:    
February 15, 20376.250%$250,000 $248,776 $248,666 
August 1, 20444.750%350,000 346,574 346,389 
May 12, 20504.000%470,000 488,449 489,207 
March 30, 20523.550%400,000 394,807 394,609 
September 30, 20613.150%350,000 343,498 343,314 
Subsidiary debt and other (1)Various7,094 7,094 8,973 
  Total senior notes and other debt $1,827,094 $1,829,198 $1,831,158 
Subordinated debentures due on:
March 30, 20585.700%$185,000 $179,811 $179,489 
December 30, 20595.100%300,000 291,895 291,418 
September 30, 20604.250%250,000 244,958 244,668 
March 30, 20614.125%300,000 293,863 293,515 
Total subordinated debentures $1,035,000 $1,010,527 $1,009,090 
________________
(1) Subsidiary debt of $7.3 million is due in 2026, partially offset by the unamortized cost of $0.2 million due to entering into the $300 million senior unsecured revolving credit facility.
v3.25.4
Income Taxes (Tables)
12 Months Ended
Dec. 31, 2025
Income Tax Disclosure [Abstract]  
Schedule of Components of Income Tax Expense (Benefit)
Income tax expense (benefit) consists of:
(In thousands)Current
Expense
Deferred Expense (Benefit)Total
December 31, 2025   
U.S. Federal$399,800 $(16,709)$383,091 
State & Local13,597 (561)13,036 
Foreign96,856 2,781 99,637 
Total expense (benefit)$510,253 $(14,489)$495,764 
December 31, 2024   
Domestic$344,210 $51,754 $395,964 
Foreign69,312 44,640 113,952 
Total expense$413,522 $96,394 $509,916 
December 31, 2023   
Domestic$352,891 $(43,456)$309,435 
Foreign44,372 16,750 61,122 
Total expense (benefit)$397,263 $(26,706)$370,557 
Schedule of Effective Income Tax Rate Reconciliation
A reconciliation of the income tax expense and the amounts computed by applying the Federal and foreign income tax rate of 21% for 2025, 2024 and 2023 to pre-tax income are as follows:
(In thousands)2025%20242023
U.S. Federal Statutory Tax Rate$478,914 21.0 %$475,543 $368,425 
State and Local Taxes, Net of Federal Benefit (1)10,299 0.4 %12,329 12,271 
Foreign Tax Effects11,635 0.5 %19,317 (1,896)
Effect of Cross-Border Tax Laws(14,727)(0.7)%— — 
Changes in Valuation Allowances19,726 0.9 %(220)(10,883)
Nontaxable or Nondeductible Items(10,083)(0.4)%2,947 2,640 
Total $495,764 21.7 %$509,916 $370,557 
Schedule of Deferred Tax Assets and Liabilities
(In thousands)2025%20242023
U.S. Federal Statutory Tax Rate$478,914 21.0 %$475,543 $368,425 
State and Local Taxes, Net of Federal Benefit (1)10,299 0.4 %12,329 12,271 
Foreign Tax Effects11,635 0.5 %19,317 (1,896)
Effect of Cross-Border Tax Laws(14,727)(0.7)%— — 
Changes in Valuation Allowances19,726 0.9 %(220)(10,883)
Nontaxable or Nondeductible Items(10,083)(0.4)%2,947 2,640 
Total $495,764 21.7 %$509,916 $370,557 
(1) State income taxes in Florida and Illinois made up the majority (greater than 50%) of the tax effect in this category.
At December 31, 2025 and 2024, the tax effects of differences that give rise to significant portions of the deferred tax asset and deferred tax liability are as follows:
(In thousands)20252024
Deferred tax asset:  
Loss reserve discounting$253,980 $218,222 
Unearned premiums228,752 216,721 
Unrealized investment losses— 58,701 
Net operating losses & foreign tax credits77,810 62,159 
Other-than-temporary impairments5,006 7,149 
Employee compensation plans83,034 70,529 
Other82,948 81,915 
Gross deferred tax asset731,530 715,396 
Less valuation allowance(55,789)(36,063)
Deferred tax asset675,741 679,333 
Deferred tax liability:  
Amortization of intangibles15,541 15,124 
Unrealized investment gains41,641 — 
Deferred policy acquisition costs204,979 195,150 
Property, furniture and equipment61,479 45,276 
Investment funds229,694 184,899 
Other80,784 83,818 
Deferred tax liability634,118 524,267 
Net deferred tax asset$41,623 $155,066 
v3.25.4
Dividends From Subsidiaries And Statutory Financial Information (Tables)
12 Months Ended
Dec. 31, 2025
Insurance [Abstract]  
Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices
BIC’s combined net income and statutory capital and surplus, as determined in accordance with statutory accounting practices ("SAP"), are as follows:
(In thousands)202520242023
Net income$1,588,605 $1,624,686 $1,176,255 
Statutory capital and surplus$9,857,138 $9,421,874 $8,776,138 
v3.25.4
Common Stockholders' Equity (Tables)
12 Months Ended
Dec. 31, 2025
Equity [Abstract]  
Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share
The weighted average number of shares used in the computation of net income per share was as follows:
(In thousands)202520242023
Basic396,968 399,734 406,500 
Diluted399,861 403,224 409,948 
Schedule of Changes in Shares of Common Stock Outstanding Changes in shares of common stock outstanding, net of treasury shares, are presented below. Shares of common stock issued and outstanding do not include shares related to unissued restricted stock units (including shares held in the grantor trust).
202520242023
Balance, beginning of year380,066,070 384,817,136396,819,150
Shares issued1,158,755 951,930 1,059,500
Shares repurchased(4,069,026)(5,702,996)(13,061,514)
Balance, end of year377,155,799 380,066,070384,817,136
v3.25.4
Fair Value of Financial Instruments (Tables)
12 Months Ended
Dec. 31, 2025
Fair Value Disclosures [Abstract]  
Carrying Amounts and Estimated Fair Values of Financial Insruments
The following table presents the carrying amounts and estimated fair values of the Company’s financial instruments as of December 31, 2025 and 2024:
 20252024
(In thousands)Carrying ValueFair ValueCarrying ValueFair Value
Assets:    
Fixed maturity securities$25,047,662 $25,048,534 $22,397,865 $22,399,426 
Equity securities1,358,201 1,358,201 1,203,788 1,203,788 
Arbitrage trading account1,221,103 1,221,103 1,122,599 1,122,599 
Loans receivable418,913 419,074 405,453 405,248 
Cash and cash equivalents2,539,938 2,539,938 1,974,747 1,974,747 
Trading accounts receivable from brokers and clearing organizations11,669 11,669 60,327 60,327 
Due from broker629 629 — — 
Liabilities:
Due to broker— — 70,483 70,483 
Trading account securities sold but not yet purchased66,285 66,285 73,358 73,358 
Senior notes and other debt1,829,198 1,440,055 1,831,158 1,425,852 
Subordinated debentures1,010,527 760,400 1,009,808 805,864 
v3.25.4
Leases (Tables)
12 Months Ended
Dec. 31, 2025
Leases [Abstract]  
Lease, Cost Further information relating to operating lease expense and other operating lease information is as follows:
 For the Year Ended December 31,
(In thousands)20252024
Leases:
Lease cost$54,261 $45,718 
Cash paid for amounts included in the measurement of lease liabilities reported in operating cash flows$49,421 $49,441 
Right-of-use assets obtained in exchange for new lease liabilities$74,451 $43,624 
Supplemental Balance Sheet Information
As of December 31,
($ in thousands)20252024
Right-of-use assets$221,480 $180,035 
Lease liabilities$260,451 $218,397 
Weighted-average remaining lease term7.1 years7.2 years
Weighted-average discount rate5.98 %5.59 %
Maturities of Operating Lease Liabilities
Contractual maturities of the Company’s future minimum lease payments are as follows:
(In thousands)December 31, 2025
Contractual Maturities:
2026$54,475 
202747,249 
202845,830 
202941,825 
203037,008 
Thereafter96,197 
Total undiscounted future minimum lease payments322,584 
Less: Discount impact62,133 
Total lease liability$260,451 
v3.25.4
Stock Incentive Plan (Tables)
12 Months Ended
Dec. 31, 2025
Share-Based Payment Arrangement [Abstract]  
Schedule of Nonvested Restricted Stock Units Activity The following table summarizes RSU information for the three years ended December 31, 2025:
202520242023
RSUs granted and unvested at beginning of period:5,734,397 6,435,267 6,927,639 
Granted1,043,988 1,217,056 1,647,690 
Vested(1,470,318)(1,594,183)(1,726,956)
Canceled(376,921)(323,743)(413,106)
RSUs granted and unvested at end of period:4,931,146 5,734,397 6,435,267 
Schedule of Share-based Compensation, Unearned Compensation Related to RSU's
The fair value of RSUs at the date of grant are recorded as unearned compensation, a component of stockholders’ equity, and expensed over the vesting period. Following is a summary of changes in unearned compensation for the three years ended December 31, 2025:
(In thousands)202520242023
Unearned compensation at beginning of year$153,329 $148,080 $142,060 
RSUs granted, net of cancellations65,901 63,347 62,418 
  RSUs expensed(52,524)(52,380)(49,200)
  RSUs forfeitures(8,653)(5,718)(7,198)
Unearned compensation at end of year$158,053 $153,329 $148,080 
v3.25.4
Compensation Plans (Tables)
12 Months Ended
Dec. 31, 2025
Compensation Related Costs [Abstract]  
Long-Term Incentive Compensation Plan Expense
The following table summarizes the outstanding LTIP awards as of December 31, 2025:
Units OutstandingMaximum Value
Inception to date earned through December 31, 2025 on outstanding units
2021 grant197,500 $19,750,000 $19,750,000 
2022 grant220,500 22,050,000 22,050,000 
2023 grant235,000 23,500,000 20,014,894 
2024 grant252,500 25,250,000 13,598,077 
2025 grant244,750 24,475,000 5,767,601 
The following table summarizes the LTIP expense for each of the three years ended December 31, 2025:
(In thousands)202520242023
2019 grant— — 3,241 
2020 grant— 135 7,047 
2021 grant(39)3,543 6,561 
2022 grant2,523 8,167 6,155 
2023 grant7,799 7,076 5,424 
2024 grant7,154 6,476 — 
2025 grant5,768 — — 
Total$23,205 $25,397 $28,428 
v3.25.4
Supplemental Financial Statement Data (Tables)
12 Months Ended
Dec. 31, 2025
Other Income and Expenses [Abstract]  
Schedule of Other Operating Cost and Expense, by Component
Other operating costs and expenses consist of the following:
(In thousands)202520242023
Amortization of deferred policy acquisition costs$1,384,739 $1,219,849 $1,038,975 
Insurance operating expenses2,131,785 2,075,053 1,915,711 
Insurance service expenses94,374 90,640 91,714 
Net foreign currency losses (gains)68,006 (52,376)31,799 
Other costs and expenses297,930 269,140 285,737 
Total$3,976,834 $3,602,306 $3,363,936 
v3.25.4
Industry Segments (Tables)
12 Months Ended
Dec. 31, 2025
Segment Reporting [Abstract]  
Financial Information Of Company Operating Segments
Summary financial information about the Company’s reporting segments is presented in the following table. Income before income taxes by segment includes allocated investment income. Identifiable assets by segment are those assets used in or allocated to the operation of each segment.
RevenuesExpenses
(In thousands)Earned
Premiums (1)
Investment
Income
OtherTotal (2)Losses and Loss ExpensesPolicy Acquisition and Insurance Operating ExpensesOtherTotalPre-Tax
Income
(Loss)
Net
Income
(Loss)
to Common Stockholders
Year ended December 31, 2025      
Insurance $10,936,028 $1,118,607 $40,966 $12,095,601 $6,947,232 $3,076,726 $44,399 $10,068,357 $2,027,244 $1,584,440 
Reinsurance & Monoline Excess1,510,910 270,851 — 1,781,761 824,425 439,798 — 1,264,223 517,538 407,659 
Corporate, other and eliminations (3)— 39,609 658,665 698,274 — — 1,094,733 1,094,733 (396,459)(316,404)
Net investment gains— — 132,220 132,220 — — — — 132,220 103,708 
Consolidated$12,446,938 $1,429,067 $831,851 $14,707,856 $7,771,657 $3,516,524 $1,139,132 $12,427,313 $2,280,543 $1,779,403 
Year ended December 31, 2024
Insurance$10,086,308 $1,057,738 $37,455 $11,181,501 $6,332,490 $2,863,697 $43,231 $9,239,418 $1,942,083 $1,503,875 
Reinsurance & Monoline Excess1,462,177 234,728 — 1,696,905 799,105 431,205 — 1,230,310 466,595 367,569 
Corporate, other and eliminations (3)— 40,695 601,943 642,638 — — 904,531 904,531 (261,893)(203,832)
Net investment gains— — 117,708 117,708 — — — — 117,708 88,503 
Consolidated$11,548,485 $1,333,161 $757,106 $13,638,752 $7,131,595 $3,294,902 $947,762 $11,374,259 $2,264,493 $1,756,115 
Year ended December 31, 2023
Insurance$9,007,376 $783,660 $36,830 $9,827,866 $5,615,526 $2,545,310 $37,112 $8,197,948 $1,629,918 $1,283,281 
Reinsurance & Monoline Excess1,393,311 221,966 — 1,615,277 756,616 409,376 — 1,165,992 449,285 355,155 
Corporate, other and eliminations (3)— 47,209 605,544 652,753 — — 1,024,595 1,024,595 (371,842)(293,869)
Net investment gains— — 47,042 47,042 — — — — 47,042 36,792 
Consolidated$10,400,687 $1,052,835 $689,416 $12,142,938 $6,372,142 $2,954,686 $1,061,707 $10,388,535 $1,754,403 $1,381,359 
Identifiable Assets by Segments
Identifiable Assets
(In thousands)December 31,
20252024
Insurance$35,830,534 $33,030,140 
Reinsurance & Monoline Excess5,891,538 5,669,729 
Corporate, other and eliminations (3)2,348,999 1,867,399 
Consolidated$44,071,071 $40,567,268 
_______________________________________
(1) Certain amounts included in earned premiums of each segment are related to inter-segment transactions.
(2) Revenues for Insurance includes $1,408 million, $1,471 million, and $1,171 million in 2025, 2024 and 2023, respectively, from foreign countries. Revenues for Reinsurance & Monoline Excess includes $516 million, $485 million, and $463 million in 2025, 2024 and 2023, respectively, from foreign countries.
(3) Corporate, other and eliminations represent corporate revenues and expenses and certain other items that are not allocated to business segments.
Net Premiums Earned By Major Line Of Business
Net premiums earned by major line of business were as follows:
(In thousands)202520242023
Insurance   
Other liability$4,429,621 $4,068,662 $3,605,298 
Short-tail lines (1)2,496,481 2,201,661 1,825,027 
Auto1,617,908 1,481,569 1,270,907 
Workers' compensation1,259,290 1,237,888 1,212,294 
Professional liability1,132,728 1,096,528 1,093,850 
Total Insurance10,936,028 10,086,308 9,007,376 
Reinsurance & Monoline Excess
Casualty (2)741,671 771,329 821,826 
Property (2)478,682 424,296 330,359 
Monoline Excess (3)290,557 266,552 241,126 
Total Reinsurance & Monoline Excess1,510,910 1,462,177 1,393,311 
Total$12,446,938 $11,548,485 $10,400,687 

(1) Short-tail lines include commercial multi-peril (non-liability), inland marine, accident and health, fidelity and surety, boiler and machinery, high net worth homeowners and other lines.
(2) Includes reinsurance casualty and property and certain program management business.
(3) Monoline excess includes operations that solely retain risk on an excess basis.
v3.25.4
Related-Party Transactions (Tables)
12 Months Ended
Dec. 31, 2025
Related Party Transactions [Abstract]  
Schedule of Related Party Transactions
Transactions between the Company and Lifson Re were as follows:

(In thousands)Year Ended December 31,
Consolidated statements of income202520242023
Ceded written premiums$494,359 $416,509 $436,941 
Ceded commissions and brokerage133,479 104,075 123,510 
As of December 31,
Consolidated balance sheets20252024
Due from reinsurers$537,366 $471,689 
Due to reinsurers118,788 166,304 
v3.25.4
Summary of Significant Accounting Policies (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Accounting Policies [Abstract]      
Unbilled Audit Premiums $ (2) $ 19 $ 19
Deposit contracts, liabilities 28 29  
Depreciation $ 54 55 $ 51
Weighted average shares held in grantor trust 17,378,810    
Intangible assets, net (excluding goodwill) $ 86 $ 97  
v3.25.4
Summary of Significant Accounting Policies - Statement of Cash Flows (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Paid, by Individual Jurisdiction [Line Items]      
Interest payments $ 126 $ 138 $ 114
Income taxes paid 407 410 332
UNITED STATES | Domestic Tax Jurisdiction | Internal Revenue Service (IRS)      
Income Tax Paid, by Individual Jurisdiction [Line Items]      
Income taxes paid 340 361 296
AUSTRALIA | Foreign Tax Jurisdiction | Australian Taxation Office      
Income Tax Paid, by Individual Jurisdiction [Line Items]      
Income taxes paid 40 25 18
Other Countries | Foreign Tax Jurisdiction, Other | Other Jurisdictions      
Income Tax Paid, by Individual Jurisdiction [Line Items]      
Income taxes paid $ 27 $ 24 $ 18
v3.25.4
Consolidated Statement of Comprehensive Income (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning of period $ 8,407,439    
Other comprehensive gain (loss) 483,173 $ (8,433) $ 338,745
End of period 9,711,894 8,407,439  
Unrealized investment gains (losses), before tax 130,670 79,738 47,540
Pre-Tax Income (Loss) 2,280,543 2,264,493 1,754,403
Federal and foreign income taxes (495,764) (509,916) (370,557)
Net income 1,784,779 1,754,577 1,383,846
Unrealized investment gains, before tax 497,765 84,474 392,903
Currency translation adjustments, before tax 90,682 (77,615)  
Other comprehensive income (loss), before tax 588,447 6,859  
Unrealized investment gains, tax (105,274) (15,292)  
Currency translation adjustments, tax 0 0  
Other comprehensive income (loss), tax (105,274) (15,292)  
Unrealized investment gains, net of tax 392,491 69,182  
Change in unrealized translation adjustments 90,682 (77,615) 32,192
Unrealized Investment Gains (Losses)      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning of period (517,170) (586,354) (892,905)
Other comprehensive income before reclassifications 344,083 (26,128)  
Amounts reclassified from AOCI 48,408 95,310  
Other comprehensive gain (loss) 392,491 69,182  
Unrealized investment loss related to noncontrolling interest (1) 2  
End of period (124,680) (517,170) (586,354)
Unrealized Investment Gains (Losses) | Reclassification out of Accumulated Other Comprehensive Income      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Unrealized investment gains (losses), before tax 61,276 120,646  
Federal and foreign income taxes (12,868) (25,336)  
Net income 48,408 95,310  
Currency Translation Adjustments      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning of period (417,099) (339,484) (371,676)
Other comprehensive income before reclassifications 90,682 (77,615)  
Amounts reclassified from AOCI 0 0  
Other comprehensive gain (loss) 90,682 (77,615)  
Unrealized investment loss related to noncontrolling interest 0 0  
End of period (326,417) (417,099) (339,484)
Change in unrealized translation adjustments 90,682 (77,615) 32,192
Currency Translation Adjustments | Reclassification out of Accumulated Other Comprehensive Income      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Pre-Tax Income (Loss) 0 0  
Federal and foreign income taxes 0 0  
Net income 0 0  
Accumulated Other Comprehensive Income (Loss)      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Beginning of period (934,269) (925,838)  
Other comprehensive income before reclassifications 434,765 (103,743)  
Amounts reclassified from AOCI 48,408 95,310  
Other comprehensive gain (loss) 483,173 (8,433)  
Unrealized investment loss related to noncontrolling interest (1) 2  
End of period (451,097) (934,269) $ (925,838)
Accumulated Other Comprehensive Income (Loss) | Reclassification out of Accumulated Other Comprehensive Income      
Accumulated Other Comprehensive Income (Loss) [Line Items]      
Pre-Tax Income (Loss) 61,276 120,646  
Federal and foreign income taxes (12,868) (25,336)  
Net income $ 48,408 $ 95,310  
v3.25.4
Investments in Fixed Maturity Securities (Investments in Fixed Maturity Securities) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Amortized Cost $ 30,615 $ 44,437  
Held-to-maturity, allowance for credit loss (9) (25) $ (43)
Total held to maturity, Gross Unrealized Gains 872 1,561  
Total held to maturity, Gross Unrealized Losses 0 0  
Total held to maturity, Fair Value 31,478 45,973  
Carrying Value 30,606 44,412  
Fixed maturity securities available for sale at cost 25,139,753 22,966,462  
Cumulative effect adjustment resulting from changes in accounting principles (65) (646) (36,708)
Total available for sale, Gross Unrealized Gains 321,700 96,365  
Total available for sale, Gross Unrealized Losses (444,332) (708,728)  
Total available for sale, Fair Value 25,017,056 22,353,453  
Total available for sale, Carrying Value 25,017,056 22,353,453  
Fixed maturity securities, amortized cost 25,170,368 23,010,899  
Total investments in fixed maturity securities, Gross Unrealized Gains 322,572 97,926  
Total investments in fixed maturity securities, Gross Unrealized Losses (444,332) (708,728)  
Total investments in fixed maturity securities, Fair Value 25,048,534 22,399,426  
Total investments in fixed maturity securities, carrying value 25,047,662 22,397,865  
Fixed maturity securities, allowance for credit loss (74) (671)  
State and municipal      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Amortized Cost 28,777 42,145  
Held-to-maturity, allowance for credit loss (9) (25)  
Total held to maturity, Gross Unrealized Gains 796 1,492  
Total held to maturity, Gross Unrealized Losses 0 0  
Total held to maturity, Fair Value 29,564 43,612  
Carrying Value 28,768 42,120  
Fixed maturity securities available for sale at cost 1,862,104 2,376,541  
Cumulative effect adjustment resulting from changes in accounting principles 0 0 (757)
Total available for sale, Gross Unrealized Gains 13,503 7,560  
Total available for sale, Gross Unrealized Losses (38,413) (89,457)  
Total available for sale, Fair Value 1,837,194 2,294,644  
Total available for sale, Carrying Value 1,837,194 2,294,644  
Residential mortgage-backed      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Amortized Cost 1,838 2,292  
Held-to-maturity, allowance for credit loss 0 0  
Total held to maturity, Gross Unrealized Gains 76 69  
Total held to maturity, Gross Unrealized Losses 0 0  
Total held to maturity, Fair Value 1,914 2,361  
Carrying Value 1,838 2,292  
Fixed maturity securities available for sale at cost 4,584,970 3,411,796  
Cumulative effect adjustment resulting from changes in accounting principles (65) (5)  
Total available for sale, Gross Unrealized Gains 71,048 11,047  
Total available for sale, Gross Unrealized Losses (132,645) (189,630)  
Total available for sale, Fair Value 4,523,308 3,233,208  
Total available for sale, Carrying Value 4,523,308 3,233,208  
U.S. government and government agency      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 3,964,375 2,268,596  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 48,820 9,608  
Total available for sale, Gross Unrealized Losses (15,157) (42,863)  
Total available for sale, Fair Value 3,998,038 2,235,341  
Total available for sale, Carrying Value 3,998,038 2,235,341  
Special Revenue      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 1,206,387 1,581,778  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 6,002 3,521  
Total available for sale, Gross Unrealized Losses (27,943) (67,591)  
Total available for sale, Fair Value 1,184,446 1,517,708  
Total available for sale, Carrying Value 1,184,446 1,517,708  
Debt, State Government      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 203,543 272,936  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 3,465 1,439  
Total available for sale, Gross Unrealized Losses (3,848) (8,981)  
Total available for sale, Fair Value 203,160 265,394  
Total available for sale, Carrying Value 203,160 265,394  
Revenue Subject to Refund      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 74,276 85,340  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 619 599  
Total available for sale, Gross Unrealized Losses (111) (347)  
Total available for sale, Fair Value 74,784 85,592  
Total available for sale, Carrying Value 74,784 85,592  
Corporation      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 159,876 158,322  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 1,958 1,079  
Total available for sale, Gross Unrealized Losses (3,459) (5,827)  
Total available for sale, Fair Value 158,375 153,574  
Total available for sale, Carrying Value 158,375 153,574  
Debt, Local Government      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 218,022 278,165  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 1,459 922  
Total available for sale, Gross Unrealized Losses (3,052) (6,711)  
Total available for sale, Fair Value 216,429 272,376  
Total available for sale, Carrying Value 216,429 272,376  
Commercial Mortgage Backed Securities      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 281,573 534,936  
Cumulative effect adjustment resulting from changes in accounting principles 0 (425)  
Total available for sale, Gross Unrealized Gains 3,632 1,201  
Total available for sale, Gross Unrealized Losses (35) (3,430)  
Total available for sale, Fair Value 285,170 532,282  
Total available for sale, Carrying Value 285,170 532,282  
Mortgage- Backed      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 4,866,543 3,946,732  
Cumulative effect adjustment resulting from changes in accounting principles (65) (430) (158)
Total available for sale, Gross Unrealized Gains 74,680 12,248  
Total available for sale, Gross Unrealized Losses (132,680) (193,060)  
Total available for sale, Fair Value 4,808,478 3,765,490  
Total available for sale, Carrying Value 4,808,478 3,765,490  
Asset-backed Securities      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 3,807,393 3,910,363  
Cumulative effect adjustment resulting from changes in accounting principles 0 0 (1,164)
Total available for sale, Gross Unrealized Gains 20,196 16,161  
Total available for sale, Gross Unrealized Losses (17,243) (41,512)  
Total available for sale, Fair Value 3,810,346 3,885,012  
Total available for sale, Carrying Value 3,810,346 3,885,012  
Industrial Property      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 3,627,567 3,746,501  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 57,466 14,518  
Total available for sale, Gross Unrealized Losses (36,499) (93,820)  
Total available for sale, Fair Value 3,648,534 3,667,199  
Total available for sale, Carrying Value 3,648,534 3,667,199  
Debt Security, Corporate, US      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 3,438,348 3,339,718  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 61,180 18,871  
Total available for sale, Gross Unrealized Losses (16,460) (38,076)  
Total available for sale, Fair Value 3,483,068 3,320,513  
Total available for sale, Carrying Value 3,483,068 3,320,513  
Public Utility, Bonds      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 1,300,506 795,839  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 22,593 2,970  
Total available for sale, Gross Unrealized Losses (8,878) (20,115)  
Total available for sale, Fair Value 1,314,221 778,694  
Total available for sale, Carrying Value 1,314,221 778,694  
Other Security Investments      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 240,374 653,194  
Cumulative effect adjustment resulting from changes in accounting principles 0 0  
Total available for sale, Gross Unrealized Gains 2,356 2,493  
Total available for sale, Gross Unrealized Losses (1,142) (4,452)  
Total available for sale, Fair Value 241,588 651,235  
Total available for sale, Carrying Value 241,588 651,235  
Corporate      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 8,606,795 8,535,252  
Cumulative effect adjustment resulting from changes in accounting principles 0 0 (5,026)
Total available for sale, Gross Unrealized Gains 143,595 38,852  
Total available for sale, Gross Unrealized Losses (62,979) (156,463)  
Total available for sale, Fair Value 8,687,411 8,417,641  
Total available for sale, Carrying Value 8,687,411 8,417,641  
Foreign government      
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]      
Fixed maturity securities available for sale at cost 2,032,543 1,928,978  
Cumulative effect adjustment resulting from changes in accounting principles 0 (216) $ (29,603)
Total available for sale, Gross Unrealized Gains 20,906 11,936  
Total available for sale, Gross Unrealized Losses (177,860) (185,373)  
Total available for sale, Fair Value 1,875,589 1,755,325  
Total available for sale, Carrying Value $ 1,875,589 $ 1,755,325  
v3.25.4
Investments in Fixed Maturity Securities (HTM Allowance for Credit Loss) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 $ 25 $ 43
Provision for expected credit losses (16) (18)
Allowance for expected credit losses at September 30, 2020 $ 9 $ 25
v3.25.4
Investments in Fixed Maturity Securities (AFS Allowance for Credit Loss) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 $ 646 $ 36,708
Expected credit losses on securities for which credit losses were not previously recorded 78 2,053
Expected credit losses on securities for which credit losses were previously recorded (659) (37,133)
Reduction due to disposals 0 (982)
Allowance for expected credit losses at September 30, 2020 65 646
Foreign Government    
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 216 29,603
Expected credit losses on securities for which credit losses were not previously recorded 3 347
Expected credit losses on securities for which credit losses were previously recorded (219) (29,355)
Reduction due to disposals 0 (379)
Allowance for expected credit losses at September 30, 2020 0 216
Corporate    
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 0 5,026
Expected credit losses on securities for which credit losses were not previously recorded   0
Expected credit losses on securities for which credit losses were previously recorded   (5,026)
Reduction due to disposals   0
Allowance for expected credit losses at September 30, 2020 0 0
Mortgage- Backed    
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 430 158
Expected credit losses on securities for which credit losses were not previously recorded 65 1,706
Expected credit losses on securities for which credit losses were previously recorded (430) (831)
Reduction due to disposals 0 (603)
Allowance for expected credit losses at September 30, 2020 65 430
Asset-backed    
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 0 1,164
Expected credit losses on securities for which credit losses were not previously recorded   0
Expected credit losses on securities for which credit losses were previously recorded   (1,164)
Reduction due to disposals   0
Allowance for expected credit losses at September 30, 2020 0 0
State and municipal    
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses at January 1, 2020 0 757
Expected credit losses on securities for which credit losses were not previously recorded 10 0
Expected credit losses on securities for which credit losses were previously recorded (10) (757)
Reduction due to disposals 0 0
Allowance for expected credit losses at September 30, 2020 $ 0 $ 0
v3.25.4
Investments in Fixed Maturity Securities (The Amortized Cost and Fair Value of Fixed Maturity Securities) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]      
Amortized Cost, Due in one year or less $ 1,789,587    
Amortized Cost, Due after one year through five years 8,131,346    
Amortized Cost, Due after five years through ten years 3,791,177    
Amortized Cost, Due after ten years 6,589,868    
Amortized Cost, Mortgage-backed securities 4,868,381    
Total investment in fixed maturity securities, Amortized Cost 25,170,359    
Fair Value, Due in one year or less 1,740,503    
Fair Value, Due after one year through five years 8,060,983    
Fair Value, Due after five years through ten years 3,828,290    
Fair Value, Due after ten years 6,608,366    
Fair Value, Mortgage-backed securities 4,810,392    
Total investments in fixed maturity securities, Fair Value 25,048,534    
Held-to-maturity, allowance for credit loss $ 9 $ 25 $ 43
v3.25.4
Investments in Fixed Maturity Securities (Narrative) (Details)
$ in Millions
Dec. 31, 2025
USD ($)
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]  
Debt Securities, Held-to-maturity, Restricted $ 1,149
Insurance  
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]  
Debt Securities, Held-to-maturity, Restricted 919
Reinsurance & Monoline Excess  
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]  
Debt Securities, Held-to-maturity, Restricted 35
Letters of Credit Outstanding, Amount 28
523991 Trust, Fiduciary, and Custody Activities  
Schedule of Available-for-sale and Held-to-maturity Securities [Table] [Line Items]  
Debt Securities, Held-to-maturity, Restricted $ 2,131
v3.25.4
Investments in Equity Securities (Investments in Equity Securities Available for Sale) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Fair Value    
Debt Securities, Available-for-sale [Line Items]    
Cost $ 1,000,049 $ 941,974
Gross unrealized gains 369,011 346,697
Gross unrealized losses (10,859) (84,883)
Equity securities 1,358,201 1,203,788
Fair Value | Common stocks    
Debt Securities, Available-for-sale [Line Items]    
Cost 566,577 612,479
Gross unrealized gains 181,120 223,981
Gross unrealized losses (5,584) (76,293)
Equity securities 742,113 760,167
Fair Value | Preferred stocks    
Debt Securities, Available-for-sale [Line Items]    
Cost 433,472 329,495
Gross unrealized gains 187,891 122,716
Gross unrealized losses (5,275) (8,590)
Equity securities 616,088 443,621
Carrying Value    
Debt Securities, Available-for-sale [Line Items]    
Equity securities 1,358,201 1,203,788
Carrying Value | Common stocks    
Debt Securities, Available-for-sale [Line Items]    
Equity securities 742,113 760,167
Carrying Value | Preferred stocks    
Debt Securities, Available-for-sale [Line Items]    
Equity securities $ 616,088 $ 443,621
v3.25.4
Arbitrage Trading Account (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Trading Securities and Derivative Instruments [Abstract]    
Arbitrage trading account $ 1,221 $ 1,123
Options Held | Short    
Derivative [Line Items]    
Other derivatives not designated as hedging instruments at fair value, net 66  
Derivative, notional amount 278  
Options Held | Long    
Derivative [Line Items]    
Other derivatives not designated as hedging instruments at fair value, net 3  
Derivative, notional amount $ 278  
v3.25.4
Net Investment Income (Net Investment Income) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Net Investment Income [Line Items]      
Gross investment income $ 1,441,155 $ 1,343,815 $ 1,059,751
Investment expense (12,088) (10,654) (6,916)
Net investment income 1,429,067 1,333,161 1,052,835
Fixed maturity securities, including cash and cash equivalents and loans receivable      
Net Investment Income [Line Items]      
Gross investment income 1,307,087 1,260,429 929,098
Investment funds      
Net Investment Income [Line Items]      
Gross investment income 27,582 (11,491) 16,743
Arbitrage trading account (1)      
Net Investment Income [Line Items]      
Gross investment income 74,407 69,573 69,369
Real estate      
Net Investment Income [Line Items]      
Gross investment income (18,450) (23,616) (11,185)
Equity securities      
Net Investment Income [Line Items]      
Gross investment income $ 50,529 $ 48,920 $ 55,726
v3.25.4
Investment Funds (Schedule of Investment Funds) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]      
Maximum loss exposure $ 274,000    
Investment funds 1,361,802 $ 1,468,246  
Income (Loss) From Investment Funds For the Year Ended 27,582 (11,491) $ 16,743
Deferred compensation trust assets 43,000 38,000  
Financial services (1)      
Schedule of Equity Method Investments [Line Items]      
Investment funds 360,320 430,163  
Income (Loss) From Investment Funds For the Year Ended (20,504) (39,418) (10,911)
Transportation      
Schedule of Equity Method Investments [Line Items]      
Investment funds 272,775 286,426  
Income (Loss) From Investment Funds For the Year Ended 32,441 13,335 40,607
Real estate      
Schedule of Equity Method Investments [Line Items]      
Investment funds 163,098 178,685  
Income (Loss) From Investment Funds For the Year Ended 4,023 12,195 (6,676)
Energy      
Schedule of Equity Method Investments [Line Items]      
Investment funds 41,966 42,776  
Income (Loss) From Investment Funds For the Year Ended 146 14,501 5,058
Other funds      
Schedule of Equity Method Investments [Line Items]      
Investment funds 353,796 378,636  
Income (Loss) From Investment Funds For the Year Ended (3,782) (29,175) (24,384)
Infrastructure      
Schedule of Equity Method Investments [Line Items]      
Investment funds 169,847 151,560  
Income (Loss) From Investment Funds For the Year Ended $ 15,258 $ 17,071 $ 13,049
v3.25.4
Real Estate (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Real Estate [Abstract]    
Properties in operation $ 1,051,455 $ 1,063,687
Properties under development 228,293 227,768
Total $ 1,279,748 $ 1,291,455
v3.25.4
Real Estate (Narrative) (Details) - USD ($)
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Real Estate [Abstract]      
Accumulated depreciation and amortization on properites $ 41,942,000 $ 38,671,000  
Depreciation 9,453,000 $ 8,633,000 $ 8,935,000
Lease future minimum payments, year one 36,767,697    
Lease future minimum payments, year two 39,898,012    
Lease future minimum payments, year three 42,512,029    
Lease future minimum payments, year four 37,191,356    
Lease future minimum payments, year five 31,563,792    
Lease future minimum payments thereafter 373,880,063    
Real estate investment commitment amount $ 31,000,000    
v3.25.4
Loans Receivable (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Loans Receivable [Line Items]    
Amortized cost (net of allowance for expected credit losses): $ 418,913 $ 405,453
Fair value: 419,074 405,248
Real Estate Loans    
Loans Receivable [Line Items]    
Amortized cost (net of allowance for expected credit losses): 418,913 402,382
Fair value: 419,074 402,177
Commercial    
Loans Receivable [Line Items]    
Amortized cost (net of allowance for expected credit losses): 0 3,071
Fair value: $ 0 $ 3,071
v3.25.4
Loans Receivable - Allowance For Credit Loss (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Line Items]    
Balance, beginning of period $ 1,114 $ 3,004
Change in expected credit losses (953) (1,890)
Balance, end of period 161 1,114
Real Estate Loans    
Financing Receivable, Allowance for Credit Loss [Line Items]    
Balance, beginning of period 1,088 2,983
Change in expected credit losses (927) (1,895)
Balance, end of period 161 1,088
Commercial    
Financing Receivable, Allowance for Credit Loss [Line Items]    
Balance, beginning of period 26 21
Change in expected credit losses (26) 5
Balance, end of period $ 0 $ 26
v3.25.4
Net Investment Gains (Losses) (Net Investment Gains (Losses)) (Details) - USD ($)
$ in Thousands
1 Months Ended 12 Months Ended
Jun. 30, 2023
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]        
Fixed maturity securities, Gains   $ 18,544 $ 15,486 $ 2,003
Fixed maturity securities, losses   (19,191) (32,866) (25,429)
Net realized gains on investment sales (2)   70,042 116,475 161,271
Change in unrealized gains   96,337 120,799 70,448
Investment funds   (292) 1,835 (25,625)
Real estate (3)   26,544 (2,647) (70,934)
Loans receivable   (87) 0 (18,841)
Other   (61,227) (139,344) (45,353)
Net realized and unrealized gains on investments in earnings before allowance for expected credit losses   130,670 79,738 47,540
Fixed maturity securities   597 36,080 715
Loans receivable   953 1,890 (1,213)
Change in allowance for expected credit losses on investments   1,550 37,970 (498)
Net investment gains   132,220 117,708 47,042
Income tax expense   (28,512) (29,205) (10,250)
  After-tax net investment gains   $ 103,708 $ 88,503 36,792
Gain on Sale of Investments $ 89,000      
Impairment of real estate       $ 72,000
v3.25.4
Net Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Realized and Unrealized Investment Gains Losses [Line Items]      
Unrealized investment gains, before tax $ 497,765 $ 84,474 $ 392,903
Income tax expense (105,274) (15,292) (86,350)
Noncontrolling interests (1) 2 (2)
Total change in unrealized gains and losses 392,490 69,184 306,551
Debt Securities      
Realized and Unrealized Investment Gains Losses [Line Items]      
Unrealized investment gains, before tax 490,594 83,395 389,839
Fixed maturity securities with allowance for expected credit losses      
Realized and Unrealized Investment Gains Losses [Line Items]      
Unrealized investment gains, before tax (862) 4,428 643
Investment funds      
Realized and Unrealized Investment Gains Losses [Line Items]      
Unrealized investment gains, before tax 8,203 (3,217) 3,989
Other      
Realized and Unrealized Investment Gains Losses [Line Items]      
Unrealized investment gains, before tax $ (170) $ (132) $ (1,568)
v3.25.4
Fixed Maturity Securities in an Unrealized Loss Position (Securities in an Unrealized Loss Position) (Details) - External Credit Rating, Investment Grade - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
U.S. government and government agency    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value $ 790,077 $ 767,515
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 8,902 9,637
Available-for-sale Securities, 12 Months or Greater, Fair Value 183,896 560,260
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 6,255 33,226
Available-for-sale Securities, Fair Value 973,973 1,327,775
Available For Sale Securities, Gross Unrealized Losses 15,157 42,863
State and municipal    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 141,680 348,116
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 1,520 8,027
Available-for-sale Securities, 12 Months or Greater, Fair Value 1,053,168 1,411,761
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 36,893 81,430
Available-for-sale Securities, Fair Value 1,194,848 1,759,877
Available For Sale Securities, Gross Unrealized Losses 38,413 89,457
Mortgage- Backed    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 251,861 1,541,464
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 2,265 21,326
Available-for-sale Securities, 12 Months or Greater, Fair Value 839,061 1,060,823
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 130,415 171,734
Available-for-sale Securities, Fair Value 1,090,922 2,602,287
Available For Sale Securities, Gross Unrealized Losses 132,680 193,060
Asset-backed    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 644,346 411,763
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 1,643 4,613
Available-for-sale Securities, 12 Months or Greater, Fair Value 503,876 626,237
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 15,600 36,899
Available-for-sale Securities, Fair Value 1,148,222 1,038,000
Available For Sale Securities, Gross Unrealized Losses 17,243 41,512
Corporate    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 494,240 1,791,970
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 4,308 21,346
Available-for-sale Securities, 12 Months or Greater, Fair Value 1,786,925 2,951,377
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 58,671 135,117
Available-for-sale Securities, Fair Value 2,281,165 4,743,347
Available For Sale Securities, Gross Unrealized Losses 62,979 156,463
Foreign government    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 666,054 600,103
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 9,770 17,933
Available-for-sale Securities, 12 Months or Greater, Fair Value 285,640 476,479
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 168,090 167,440
Available-for-sale Securities, Fair Value 951,694 1,076,582
Available For Sale Securities, Gross Unrealized Losses 177,860 185,373
Debt Securities    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale Securities, Less Than 12 Months, Fair Value 2,988,258 5,460,931
Available-for-sale Securities, Less Than 12 Months, Gross Unrealized Losses 28,408 82,882
Available-for-sale Securities, 12 Months or Greater, Fair Value 4,652,566 7,086,937
Available-for-sale Securities, 12 Months or Greater, Gross Unrealized Losses 415,924 625,846
Available-for-sale Securities, Fair Value 7,640,824 12,547,868
Available For Sale Securities, Gross Unrealized Losses $ 444,332 $ 708,728
v3.25.4
Fixed Maturity Securities in an Unrealized Loss Position (Non-Investment Grade Fixed Maturity Securities) (Details) - External Credit Rating, Noninvestment Grade
$ in Thousands
Dec. 31, 2025
USD ($)
Foreign government  
Debt Securities, Available-for-sale [Line Items]  
Number of Securities 67
Aggregate Fair Value $ 151,002
Gross Unrealized Loss $ 165,721
Corporate  
Debt Securities, Available-for-sale [Line Items]  
Number of Securities 24
Aggregate Fair Value $ 43,968
Gross Unrealized Loss $ 814
State and municipal  
Debt Securities, Available-for-sale [Line Items]  
Number of Securities 5
Aggregate Fair Value $ 28,958
Gross Unrealized Loss $ 1,047
Mortgage- Backed  
Debt Securities, Available-for-sale [Line Items]  
Number of Securities 14
Aggregate Fair Value $ 2,244
Gross Unrealized Loss $ 113
Debt Securities  
Debt Securities, Available-for-sale [Line Items]  
Number of Securities 110
Aggregate Fair Value $ 226,172
Gross Unrealized Loss $ 167,695
v3.25.4
Fair Value Measurements (Assets and Liabilities Measured At Fair Value, On a Recurring Basis) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale $ 25,017,056 $ 22,353,453
Arbitrage trading account 1,221,000 1,123,000
Recurring    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 25,017,056 22,353,453
Equity securities 1,358,201 1,203,788
Arbitrage trading account 1,221,103 1,122,599
Total 27,596,360 24,679,840
Trading account securities sold but not yet purchased 66,285 73,358
Recurring | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Equity securities 739,186 757,115
Arbitrage trading account 1,139,447 1,062,459
Total 1,878,633 1,819,574
Trading account securities sold but not yet purchased 66,285 73,358
Recurring | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 24,997,055 22,333,786
Equity securities 608,200 440,958
Arbitrage trading account 81,543 56,630
Total 25,686,798 22,831,374
Trading account securities sold but not yet purchased 0 0
Recurring | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 20,001 19,667
Equity securities 10,815 5,715
Arbitrage trading account 113 3,510
Total 30,929 28,892
Trading account securities sold but not yet purchased 0 0
Recurring | U.S. government and government agency    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 3,998,038 2,235,341
Recurring | U.S. government and government agency | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | U.S. government and government agency | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 3,998,038 2,235,341
Recurring | U.S. government and government agency | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | State and municipal    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 1,837,194 2,294,644
Recurring | State and municipal | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | State and municipal | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 1,837,194 2,294,644
Recurring | State and municipal | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Mortgage- Backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 4,808,478 3,765,490
Recurring | Mortgage- Backed | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Mortgage- Backed | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 4,808,478 3,765,490
Recurring | Mortgage- Backed | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Asset-backed    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 3,810,346 3,885,012
Recurring | Asset-backed | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Asset-backed | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 3,810,346 3,885,012
Recurring | Asset-backed | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Corporate    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 8,687,411 8,417,641
Recurring | Corporate | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Corporate | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 8,667,410 8,397,974
Recurring | Corporate | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 20,001 19,667
Recurring | Foreign government    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 1,875,589 1,755,325
Recurring | Foreign government | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Foreign government | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 1,875,589 1,755,325
Recurring | Foreign government | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Fixed maturity securities available for sale 0 0
Recurring | Common stocks    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 742,113 760,167
Recurring | Common stocks | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 739,186 757,115
Recurring | Common stocks | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 786 1,011
Recurring | Common stocks | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 2,141 2,041
Recurring | Preferred stocks    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 616,088 443,621
Recurring | Preferred stocks | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 0 0
Recurring | Preferred stocks | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities 607,414 439,947
Recurring | Preferred stocks | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Equity securities $ 8,674 $ 3,674
v3.25.4
Fair Value Measurements (Summarize Changes in Level 3 Assets and Liabilities) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Assets:    
Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain Loss Statement Of Income Extensible List Not Disclosed Flag Earnings (Losses) Earnings (Losses)
Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain Loss Statement Of Other Comprehensive Income Extensible List Not Disclosed Flag Other Comprehensive Income (Loss) Other Comprehensive Income (Loss)
Level 3    
Assets:    
Beginning Balance $ 28,892 $ 9,025
Earnings (Losses) 1,971 386
Other Comprehensive Income (Loss) 334 (333)
Impairments 0 0
Purchases 6,160 0
Sales (6,429) (223)
Paydowns/Maturities 0 0
Transfers In / Out 1 20,037
Ending Balance 30,929 28,892
Level 3 | Debt Securities    
Assets:    
Beginning Balance 19,667 0
Earnings (Losses) 0 0
Other Comprehensive Income (Loss) 334 (333)
Impairments 0 0
Purchases 0 0
Sales 0 0
Paydowns/Maturities 0 0
Transfers In / Out 0 20,000
Ending Balance 20,001 19,667
Level 3 | Corporate    
Assets:    
Beginning Balance 19,667 0
Earnings (Losses) 0 0
Other Comprehensive Income (Loss) 334 (333)
Impairments 0 0
Purchases 0 0
Sales 0 0
Paydowns/Maturities 0 0
Transfers In / Out 0 20,000
Ending Balance 20,001 19,667
Level 3 | Equity securities    
Assets:    
Beginning Balance 5,715 5,253
Earnings (Losses) 226 647
Other Comprehensive Income (Loss) 0 0
Impairments 0 0
Purchases 6,160 0
Sales (1,286) (185)
Paydowns/Maturities 0 0
Transfers In / Out 0 0
Ending Balance 10,815 5,715
Level 3 | Common stocks    
Assets:    
Beginning Balance 2,041 1,558
Earnings (Losses) 226 611
Other Comprehensive Income (Loss) 0 0
Impairments 0 0
Purchases 0 0
Sales (126) (128)
Paydowns/Maturities 0 0
Transfers In / Out 0 0
Ending Balance 2,141 2,041
Level 3 | Preferred stocks    
Assets:    
Beginning Balance 3,674 3,695
Earnings (Losses) 0 36
Other Comprehensive Income (Loss) 0 0
Impairments 0 0
Purchases 6,160 0
Sales (1,160) (57)
Paydowns/Maturities 0 0
Transfers In / Out 0 0
Ending Balance 8,674 3,674
Level 3 | Trading account    
Assets:    
Beginning Balance 3,510 3,772
Earnings (Losses) 1,745 (261)
Other Comprehensive Income (Loss) 0 0
Impairments 0 0
Purchases 0 0
Sales (5,143) (38)
Paydowns/Maturities 0 0
Transfers In / Out 1 37
Ending Balance $ 113 $ 3,510
v3.25.4
Reserves For Losses And Loss Expenses (Loss and Loss Expenses Incurred, Net of Reinsurance, and Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance) (Details)
$ in Thousands
Dec. 31, 2025
USD ($)
claim
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Claims Development [Line Items]                        
Reserves for loss and loss adjustment expenses, net of reinsurance $ 19,374,076                      
Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 16,873,677                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 8,929,229                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 226,423                      
Reserves for loss and loss adjustment expenses, net of reinsurance 8,170,871                      
Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 7,120,008                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 5,537,981                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 264,217                      
Reserves for loss and loss adjustment expenses, net of reinsurance 1,846,244                      
Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 4,793,208                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 2,592,265                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 58,601                      
Reserves for loss and loss adjustment expenses, net of reinsurance 2,259,544                      
Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 6,866,816                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 5,021,517                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 5,042                      
Reserves for loss and loss adjustment expenses, net of reinsurance 1,850,341                      
Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 8,953,595                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 7,759,649                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance (445)                      
Reserves for loss and loss adjustment expenses, net of reinsurance 1,193,501                      
Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 4,010,733                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 2,081,512                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 331,375                      
Reserves for loss and loss adjustment expenses, net of reinsurance 2,260,596                      
Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 760,793                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 176,710                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 576,839                      
Reserves for loss and loss adjustment expenses, net of reinsurance 1,160,922                      
Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,835,615                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,430,127                      
Reserves for loss and loss adjustment expenses before 2016, net of reinsurance 3,639                      
Reserves for loss and loss adjustment expenses, net of reinsurance 409,127                      
Accident Year 2014 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,112,764 $ 1,123,417 $ 1,122,522 $ 1,080,784 $ 1,049,653 $ 1,033,882 $ 1,019,724 $ 1,007,537 $ 997,545 $ 1,005,612    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,035,353 997,545 944,882 861,245 757,859 668,420 551,150 384,280 204,063 67,371    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 40,882                      
Short-duration insurance contract, cumulative number of reported claims | claim 29,000                      
Accident Year 2014 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 645,507 639,412 641,549 654,385 657,972 651,278 660,520 684,700 696,339 702,716    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 598,518 591,005 584,330 572,669 558,934 537,861 504,850 446,072 338,835 142,998    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 17,158                      
Short-duration insurance contract, cumulative number of reported claims | claim 58,000                      
Accident Year 2014 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 451,120 454,376 450,620 464,492 469,048 439,705 402,423 361,292 324,519 310,177    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 427,370 422,901 413,456 405,866 357,868 297,756 255,458 201,586 102,444 28,514    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 13,801                      
Short-duration insurance contract, cumulative number of reported claims | claim 9,000                      
Accident Year 2014 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 427,441 428,352 429,911 428,158 426,265 426,313 429,436 428,927 418,263 417,591    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 424,501 424,338 421,684 415,630 407,239 397,671 378,826     333,092 $ 273,083 $ 180,603
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,129                      
Short-duration insurance contract, cumulative number of reported claims | claim 48,000                      
Accident Year 2014 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 734,213 733,948 735,706 735,410 736,723 734,292 740,062 745,814 758,453 754,787    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 730,279 729,261 727,037 722,046 721,214 714,504 709,649 694,726 653,463 404,261    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,563                      
Short-duration insurance contract, cumulative number of reported claims | claim 32,000                      
Accident Year 2014 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 337,165 332,892 328,995 333,682 326,843 327,222 293,396 271,026 278,899 266,797    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 294,864 279,732 267,601 249,234 228,350 193,329 159,774 115,091 73,567 26,586    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 9,541                      
Accident Year 2014 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 57,373 55,371 59,804 63,932 65,222 65,485 64,957 71,404 70,281 72,657    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 18,766 16,872 13,569 11,819 9,883 7,685 5,928 5,573 4,783 2,498    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 1,048                      
Accident Year 2014 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 204,044 203,249 204,261 203,126 202,119 204,166 198,635 199,087 192,180 186,014    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 203,237 202,537 202,117 200,197 195,856 193,716 186,047 174,539 150,392 91,496    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 666                      
Accident Year 2015 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,312,455 1,289,835 1,257,401 1,239,544 1,169,911 1,130,172 1,112,499 1,089,751 1,056,364      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,177,876 1,119,561 1,039,147 922,491 768,021 633,015 447,980 251,375 77,838      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 67,962                      
Short-duration insurance contract, cumulative number of reported claims | claim 28,000                      
Accident Year 2015 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 673,458 669,988 675,871 682,153 683,880 673,216 689,622 733,505 762,093      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 628,306 617,243 603,006 583,258 559,198 525,753 468,817 362,299 153,456      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 15,991                      
Short-duration insurance contract, cumulative number of reported claims | claim 58,000                      
Accident Year 2015 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 401,753 402,042 401,348 392,719 383,720 376,818 337,990 331,841 332,545      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 362,678 349,730 329,340 306,582 261,069 242,971 162,623 96,150 36,445      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 23,170                      
Short-duration insurance contract, cumulative number of reported claims | claim 10,000                      
Accident Year 2015 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 430,995 430,149 428,541 427,964 423,681 417,437 413,230 410,860 413,468      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 425,108 422,351 414,486 403,864 386,260 357,282 314,739     257,335 $ 173,964  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,544                      
Short-duration insurance contract, cumulative number of reported claims | claim 44,000                      
Accident Year 2015 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 722,888 722,404 722,842 724,139 722,906 723,194 724,245 730,031 731,043      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 725,326 725,808 723,385 718,026 710,855 707,688 695,780 667,922 429,297      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,686                      
Short-duration insurance contract, cumulative number of reported claims | claim 40,000                      
Accident Year 2015 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 357,493 345,090 335,173 321,755 305,992 286,643 265,054 247,785 257,234      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 290,428 269,624 233,392 198,765 169,593 144,009 86,635 54,455 25,292      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 16,254                      
Accident Year 2015 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 48,281 57,073 62,213 65,147 66,795 71,025 70,749 80,508 76,701      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 25,457 23,523 21,275 19,275 18,375 17,327 15,356 12,810 6,282      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 2,751                      
Accident Year 2015 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 216,352 216,027 217,179 216,037 215,552 221,753 222,774 223,694 228,476      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 213,968 212,868 212,117 209,510 206,293 202,727 194,423 163,021 $ 87,893      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 290                      
Accident Year 2016 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,438,893 1,374,968 1,292,474 1,226,496 1,150,004 1,114,611 1,124,246 1,096,770        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,247,469 1,123,197 979,655 801,704 611,576 432,342 261,870 85,190        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 82,877                      
Short-duration insurance contract, cumulative number of reported claims | claim 29,000                      
Accident Year 2016 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 717,051 708,336 715,018 721,170 724,056 715,055 724,697 778,964        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 671,916 660,237 642,292 613,675 574,889 508,546 397,464 171,006        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 17,063                      
Short-duration insurance contract, cumulative number of reported claims | claim 56,000                      
Accident Year 2016 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 389,344 393,555 397,629 382,222 359,430 333,268 322,109 334,850        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 327,645 315,703 283,645 244,079 198,574 155,138 99,595 28,167        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 43,168                      
Short-duration insurance contract, cumulative number of reported claims | claim 10,000                      
Accident Year 2016 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 512,884 513,912 511,694 502,611 474,879 460,219 443,583 423,455        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 502,832 494,308 479,508 445,885 397,867 337,926 272,312     $ 173,955    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 2,518                      
Short-duration insurance contract, cumulative number of reported claims | claim 43,000                      
Accident Year 2016 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 719,947 719,517 724,069 724,921 727,513 728,956 732,244 741,978        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 718,309 715,706 712,992 707,915 708,876 691,916 645,593 401,786        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 3,791                      
Short-duration insurance contract, cumulative number of reported claims | claim 47,000                      
Accident Year 2016 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 341,329 328,553 311,426 283,962 272,487 256,413 236,747 247,465        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 270,913 245,388 207,741 164,086 128,903 93,374 52,766 18,942        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 21,566                      
Accident Year 2016 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 46,233 54,784 58,244 60,347 66,180 71,448 72,505 77,820        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 16,828 14,952 13,583 12,414 10,359 9,368 8,230 6,141        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 3,299                      
Accident Year 2016 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 117,318 118,023 119,094 120,712 122,516 120,813 129,079 126,458        
Cumulative paid claims and claim adjustment expenses, net of reinsurance 114,560 114,461 113,835 112,511 104,285 98,836 81,241 $ 46,928        
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 749                      
Accident Year 2017 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,439,633 1,396,896 1,363,275 1,288,106 1,231,387 1,230,155 1,234,191          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,196,228 1,074,214 902,947 700,121 467,450 271,989 86,586          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 100,286                      
Short-duration insurance contract, cumulative number of reported claims | claim 31,000                      
Accident Year 2017 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 717,703 714,086 722,456 734,034 732,762 721,018 784,281          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 663,649 644,772 618,324 581,003 515,914 397,376 184,715          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 17,158                      
Short-duration insurance contract, cumulative number of reported claims | claim 54,000                      
Accident Year 2017 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 368,639 364,872 363,011 354,054 345,373 332,104 336,064          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 298,961 270,992 235,114 200,255 147,779 97,328 31,652          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 48,621                      
Short-duration insurance contract, cumulative number of reported claims | claim 11,000                      
Accident Year 2017 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 532,577 532,678 525,412 508,810 483,737 466,184 463,232          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 518,787 500,234 474,177 423,458 361,142 280,089 180,027          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 4,645                      
Short-duration insurance contract, cumulative number of reported claims | claim 43,000                      
Accident Year 2017 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 657,296 658,750 669,126 669,008 675,146 685,145 703,739          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 653,178 652,285 650,202 642,116 629,728 600,542 392,224          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 3,574                      
Short-duration insurance contract, cumulative number of reported claims | claim 42,000                      
Accident Year 2017 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 336,042 316,801 296,080 266,965 266,712 259,821 262,465          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 255,525 220,154 170,418 116,771 81,367 52,707 21,522          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 28,772                      
Accident Year 2017 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 63,702 70,929 73,571 76,478 76,242 77,482 78,929          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 24,642 21,094 18,836 15,436 12,728 10,884 6,241          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 4,822                      
Accident Year 2017 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 96,760 96,129 96,996 97,060 98,085 93,545 120,797          
Cumulative paid claims and claim adjustment expenses, net of reinsurance 92,024 90,942 89,023 87,111 84,513 70,147 $ 35,584          
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 1,209                      
Accident Year 2018 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,234,607 1,188,675 1,158,609 1,150,267 1,205,740 1,332,123            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 949,161 812,670 614,487 417,957 222,319 70,510            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 122,379                      
Short-duration insurance contract, cumulative number of reported claims | claim 25,000                      
Accident Year 2018 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 656,816 652,424 668,222 704,008 716,430 725,245            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 600,913 579,332 548,585 485,203 380,454 172,478            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 8,156                      
Short-duration insurance contract, cumulative number of reported claims | claim 42,000                      
Accident Year 2018 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 296,916 300,725 313,348 337,654 375,336 393,872            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 237,215 196,626 168,902 128,777 80,099 27,932            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 26,890                      
Short-duration insurance contract, cumulative number of reported claims | claim 11,000                      
Accident Year 2018 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 445,804 440,637 433,991 407,526 396,628 493,539            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 425,583 402,187 346,903 285,885 213,648 136,907            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,301                      
Short-duration insurance contract, cumulative number of reported claims | claim 29,000                      
Accident Year 2018 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 907,269 913,270 910,086 906,102 888,216 883,190            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 889,801 888,968 884,658 829,695 768,708 447,119            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 4,297                      
Short-duration insurance contract, cumulative number of reported claims | claim 36,000                      
Accident Year 2018 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 356,608 347,967 349,072 330,205 332,164 336,854            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 254,833 218,359 171,832 109,610 67,078 28,319            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 42,420                      
Accident Year 2018 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 60,759 70,219 80,946 82,952 83,468 84,354            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 18,072 15,427 12,869 10,471 8,699 4,869            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 10,403                      
Accident Year 2018 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 141,563 136,468 137,810 133,004 134,287 132,262            
Cumulative paid claims and claim adjustment expenses, net of reinsurance 126,803 118,775 111,751 102,822 81,413 $ 39,668            
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 3,737                      
Accident Year 2019 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,440,014 1,354,190 1,334,315 1,380,843 1,525,082              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,039,910 794,700 484,808 265,238 75,175              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 177,217                      
Short-duration insurance contract, cumulative number of reported claims | claim 28,000                      
Accident Year 2019 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 648,190 649,222 667,517 701,703 742,687              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 582,994 547,863 490,648 384,867 172,729              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 10,705                      
Short-duration insurance contract, cumulative number of reported claims | claim 46,000                      
Accident Year 2019 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 415,009 410,248 446,441 471,273 524,981              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 276,769 220,397 153,032 85,866 28,539              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 91,622                      
Short-duration insurance contract, cumulative number of reported claims | claim 12,000                      
Accident Year 2019 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 608,850 583,696 552,222 517,236 552,005              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 550,804 476,465 379,969 289,019 168,499              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 11,077                      
Short-duration insurance contract, cumulative number of reported claims | claim 35,000                      
Accident Year 2019 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 790,146 790,837 793,743 810,447 805,775              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 770,016 756,084 733,205 677,203 389,015              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 9,499                      
Short-duration insurance contract, cumulative number of reported claims | claim 33,000                      
Accident Year 2019 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 453,576 427,481 424,891 432,251 430,770              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 280,381 212,227 146,076 77,110 24,696              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 86,204                      
Accident Year 2019 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 85,078 84,681 89,220 90,980 98,110              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 13,973 11,412 8,872 6,026 4,586              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 15,135                      
Accident Year 2019 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 158,306 162,159 166,320 168,907 156,684              
Cumulative paid claims and claim adjustment expenses, net of reinsurance 148,460 145,630 130,615 92,757 $ 31,657              
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 2,286                      
Accident Year 2020 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 1,889,294 1,800,663 1,818,251 1,813,543                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 1,079,369 704,534 353,014 92,298                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 444,128                      
Short-duration insurance contract, cumulative number of reported claims | claim 30,000                      
Accident Year 2020 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 715,628 715,578 745,218 772,620                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 598,841 527,145 408,929 180,982                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 26,775                      
Short-duration insurance contract, cumulative number of reported claims | claim 46,000                      
Accident Year 2020 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 533,621 556,019 586,058 649,151                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 255,314 161,334 90,574 33,412                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 207,921                      
Short-duration insurance contract, cumulative number of reported claims | claim 12,000                      
Accident Year 2020 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 802,255 763,806 740,688 723,267                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 657,551 531,324 394,137 237,885                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 35,392                      
Short-duration insurance contract, cumulative number of reported claims | claim 41,000                      
Accident Year 2020 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 880,999 880,655 889,716 905,427                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 850,260 827,800 762,169 440,972                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 18,124                      
Short-duration insurance contract, cumulative number of reported claims | claim 32,000                      
Accident Year 2020 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 486,146 479,837 507,154 494,853                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 233,285 159,448 83,762 28,077                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 140,864                      
Accident Year 2020 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 90,351 100,612 101,725 128,923                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 26,975 17,778 10,564 5,898                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 13,742                      
Accident Year 2020 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 197,161 203,495 206,632 207,282                
Cumulative paid claims and claim adjustment expenses, net of reinsurance 171,165 152,660 129,019 $ 56,561                
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 12,674                      
Accident Year 2021 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 2,054,648 2,077,833 2,114,315                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 751,329 366,667 91,761                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 837,033                      
Short-duration insurance contract, cumulative number of reported claims | claim 29,000                      
Accident Year 2021 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 734,685 758,657 784,906                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 539,016 418,788 195,204                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 56,380                      
Short-duration insurance contract, cumulative number of reported claims | claim 46,000                      
Accident Year 2021 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 596,455 638,138 647,434                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 215,591 122,356 41,073                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 264,670                      
Short-duration insurance contract, cumulative number of reported claims | claim 13,000                      
Accident Year 2021 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 930,020 907,503 890,682                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 661,466 467,227 271,552                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 91,528                      
Short-duration insurance contract, cumulative number of reported claims | claim 43,000                      
Accident Year 2021 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 989,593 997,840 1,036,001                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 911,546 847,059 531,859                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 37,413                      
Short-duration insurance contract, cumulative number of reported claims | claim 28,000                      
Accident Year 2021 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 484,781 472,917 479,858                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 131,943 66,831 17,685                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 222,872                      
Accident Year 2021 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 85,509 86,901 110,446                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 16,547 12,471 6,390                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 22,170                      
Accident Year 2021 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 165,333 173,605 177,380                  
Cumulative paid claims and claim adjustment expenses, net of reinsurance 133,772 110,388 $ 58,403                  
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 14,323                      
Accident Year 2022 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 2,325,325 2,383,071                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 341,419 95,165                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 1,602,853                      
Short-duration insurance contract, cumulative number of reported claims | claim 25,000                      
Accident Year 2022 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 777,646 811,614                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 441,748 196,104                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 142,325                      
Short-duration insurance contract, cumulative number of reported claims | claim 48,000                      
Accident Year 2022 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 647,813 652,871                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 136,010 40,369                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 362,839                      
Short-duration insurance contract, cumulative number of reported claims | claim 15,000                      
Accident Year 2022 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 1,022,138 1,062,427                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 537,738 295,450                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 276,533                      
Short-duration insurance contract, cumulative number of reported claims | claim 44,000                      
Accident Year 2022 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 1,114,550 1,255,511                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 923,661 559,412                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 97,447                      
Short-duration insurance contract, cumulative number of reported claims | claim 30,000                      
Accident Year 2022 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 413,652 436,374                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 55,767 16,875                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 295,429                      
Accident Year 2022 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 89,794 120,046                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 9,436 5,723                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 45,243                      
Accident Year 2022 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 231,060 256,437                    
Cumulative paid claims and claim adjustment expenses, net of reinsurance 139,970 $ 69,398                    
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 65,848                      
Accident Year 2023 | Other liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 2,626,044                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 111,115                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 2,237,259                      
Short-duration insurance contract, cumulative number of reported claims | claim 19,000                      
Accident Year 2023 | Workers' compensation                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 833,324                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 212,080                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 350,183                      
Short-duration insurance contract, cumulative number of reported claims | claim 47,000                      
Accident Year 2023 | Professional liability                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 692,538                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 54,712                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 529,514                      
Short-duration insurance contract, cumulative number of reported claims | claim 16,000                      
Accident Year 2023 | Auto                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 1,153,852                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 317,147                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 603,269                      
Short-duration insurance contract, cumulative number of reported claims | claim 40,000                      
Accident Year 2023 | Short-tail lines                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 1,436,694                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 587,273                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 610,043                      
Short-duration insurance contract, cumulative number of reported claims | claim 22,000                      
Accident Year 2023 | Casualty                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance $ 443,941                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 13,573                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 395,239                      
Accident Year 2023 | Monoline excess                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 133,713                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 6,014                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net 89,175                      
Accident Year 2023 | Property                        
Claims Development [Line Items]                        
Loss and loss expenses incurred, net of reinsurance 307,718                      
Cumulative paid claims and claim adjustment expenses, net of reinsurance 86,168                      
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net $ 181,307                      
v3.25.4
Reserves For Losses And Loss Expenses (Reconciliation of Net Incurred and Paid Claims Development to Reserves for Loss and Loss Adjustment Expenses) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance $ 19,374,076    
Total due from reinsurers on unpaid claims 3,254,099    
Total loss reserve discount (420,402)    
Gross reserves at end of year 22,207,773 $ 20,368,030 $ 18,739,652
Other liability      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 8,170,871    
Workers' compensation      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,846,244    
Professional liability      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 2,259,544    
Auto      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,850,341    
Short-tail lines      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,193,501    
Casualty      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 2,260,596    
Monoline excess      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,160,922    
Property      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 409,127    
Insurance      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 15,543,431    
Total due from reinsurers on unpaid claims 3,054,872    
Total loss reserve discount (9,263)    
Insurance | Other liability      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 8,170,871    
Total due from reinsurers on unpaid claims 1,162,055    
Total loss reserve discount 0    
Insurance | Workers' compensation      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,846,244    
Total due from reinsurers on unpaid claims 164,412    
Total loss reserve discount (9,263)    
Insurance | Professional liability      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 2,259,544    
Total due from reinsurers on unpaid claims 1,086,923    
Total loss reserve discount 0    
Insurance | Auto      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,850,341    
Total due from reinsurers on unpaid claims 65,748    
Total loss reserve discount 0    
Insurance | Short-tail lines      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,193,501    
Total due from reinsurers on unpaid claims 429,944    
Total loss reserve discount 0    
Insurance | Other      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 222,930    
Total due from reinsurers on unpaid claims 145,790    
Total loss reserve discount 0    
Reinsurance & Monoline Excess      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 3,830,645    
Total due from reinsurers on unpaid claims 199,227    
Total loss reserve discount (411,139)    
Reinsurance & Monoline Excess | Casualty      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 2,260,596    
Total due from reinsurers on unpaid claims 97,489    
Total loss reserve discount (64,732)    
Reinsurance & Monoline Excess | Monoline excess      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 1,160,922    
Total due from reinsurers on unpaid claims 41,132    
Total loss reserve discount 346,407    
Reinsurance & Monoline Excess | Property      
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]      
Total undiscounted reserves for loss and loss expenses, net of reinsurance 409,127    
Total due from reinsurers on unpaid claims 60,606    
Total loss reserve discount $ 0    
v3.25.4
Reserves For Losses And Loss Expenses (Supplementary Information Regarding Average Historical Claims Duration) (Details)
Dec. 31, 2025
Insurance | Other liability  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 5.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 12.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 15.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 16.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 13.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 11.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 9.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 7.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 4.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 3.40%
Insurance | Workers' compensation  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 25.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 31.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 16.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 9.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 5.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 3.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 2.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 1.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 1.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 1.20%
Insurance | Professional liability  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 7.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 15.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 16.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 15.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 9.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 11.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 8.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 3.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 2.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 1.00%
Insurance | Auto  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 32.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 20.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 15.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 12.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 9.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 4.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 2.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 1.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 0.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 0.00%
Insurance | Short-tail lines  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 52.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 33.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 6.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 2.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 0.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 0.60%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 0.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 0.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 0.10%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 0.10%
Reinsurance & Monoline Excess | Casualty  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 5.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 10.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 12.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 13.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 11.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 11.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 9.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 7.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 4.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 4.50%
Reinsurance & Monoline Excess | Monoline excess  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 7.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 6.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 3.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 4.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 3.70%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 3.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 4.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 3.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 4.90%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 3.30%
Reinsurance & Monoline Excess | Property  
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]  
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 1 33.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 2 32.80%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 3 15.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 4 6.00%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 5 3.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 6 2.30%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 7 1.20%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 8 0.50%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 9 0.40%
Average annual percentage payout of incurred claims by age, net of reinsurance, Year 10 0.30%
v3.25.4
Reserves For Losses And Loss Expenses (Schedule of Liability for Unpaid Claims and Claims Adjustment Expense) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]      
Net reserves at beginning of year $ 17,166,641 $ 15,661,820 $ 14,248,879
Net provision for losses and loss expenses:      
Claims occuring during the current year 7,702,638 7,083,999 6,311,780
Increase in estimates for claims occurring in prior years (2) 34,446 14,350 29,681
Loss reserve discount accretion 34,573 33,246 30,681
Total 7,771,657 7,131,595 6,372,142
Net payments for claims:      
Current year 1,375,478 1,278,585 1,217,078
Prior year 4,758,098 4,205,845 3,764,532
Total 6,133,576 5,484,430 4,981,610
Foreign currency translation 148,952 (142,344) 22,409
Net reserves at end of year 18,953,674 17,166,641 15,661,820
Ceded reserve at end of year 3,254,099 3,201,389 3,077,832
Gross reserves at end of year 22,207,773 20,368,030 18,739,652
Increase in estimates for claims occurring in prior years (2) (34,446) (14,350) (29,681)
Retrospective premium adjustments for claims occurring in prior years (3) 37,692 18,782 10,782
Net premium and reserve development on prior years 3,246 4,432 (18,899)
Workers' compensation discount, amount 56,000 49,000 47,000
Increase (decrease) in estimates for claims occurring in prior years, undiscounted basis $ 29,000 $ 13,000 $ (13,000)
v3.25.4
Reserves For Losses And Loss Expenses (Narrative) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Reserves For Losses And Loss Expenses [Line Items]      
Favorable reserve development net of premium offsets $ 3,246 $ 4,432 $ (18,899)
Reserve for losses and loss adjustment expenses relating to asbestos and environmental claims, net 13,000 16,000  
Workers' Compensation Discount, Prior Year Amount 1,400,000 1,358,000  
Workers' compensation discount after effects of ceded reinsurance, amount $ 420,000 405,000  
Minimum      
Reserves For Losses And Loss Expenses [Line Items]      
Workers' compensation discount, percent 0.70%    
Maximum      
Reserves For Losses And Loss Expenses [Line Items]      
Workers' compensation discount, percent 6.50%    
Weighted Average      
Reserves For Losses And Loss Expenses [Line Items]      
Workers' compensation discount, percent 3.60%    
Discounted [Member]      
Reserves For Losses And Loss Expenses [Line Items]      
Workers' compensation discount, percent 3.00%    
Insurance      
Reserves For Losses And Loss Expenses [Line Items]      
Unfavorable reserve development net of premium offsets $ 44,000 8,000 21,000
Reinsurance & Monoline Excess      
Reserves For Losses And Loss Expenses [Line Items]      
Favorable reserve development net of premium offsets $ 47,000 $ 12,000 $ 2,000
Excess workers' compensation      
Reserves For Losses And Loss Expenses [Line Items]      
Workers' compensation discount, percent 97.00%    
v3.25.4
Reinsurance (Reinsurance Financial Information) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Reinsurance Disclosures [Abstract]      
Written premiums, Direct $ 13,694,521 $ 12,904,893 $ 11,676,743
Assumed written premiums 1,410,548 1,306,198 1,295,263
Written premiums, Ceded (2,393,742) (2,238,995) (2,017,539)
Total net premiums written 12,711,327 11,972,096 10,954,467
Earned premiums, Direct 13,401,453 12,346,924 11,112,980
Earned premiums, Assumed 1,387,726 1,364,774 1,246,288
Earned premiums, Ceded (2,342,241) (2,163,213) (1,958,581)
Net premiums earned 12,446,938 11,548,485 10,400,687
Ceded losses and loss expenses incurred 1,400,570 1,368,279 1,376,144
Ceded commission earned 555,763 505,753 471,841
Uncollectible reinsurance $ 6,378 $ 8,350 $ 8,404
v3.25.4
Reinsurance (Schedule of Premium Receivable Allowance for Credit Loss) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Premium Receivable, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses, beginning of period $ 39,884 $ 35,110
Change in expected credit losses 2,122 4,774
Allowance for expected credit losses, end of period $ 42,006 $ 39,884
v3.25.4
Reinsurance (Schedule of Reinsurance Recoverable Allowance for Credit Loss) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]    
Allowance for expected credit losses, beginning of period $ 8,350 $ 8,404
Change in expected credit losses (1,972) (54)
Allowance for expected credit losses, end of period $ 6,378 $ 8,350
v3.25.4
Reinsurance (Schedule Of Ceded Credit Risk by Reinsurer) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Ceded Credit Risk [Line Items]      
Uncollectible reinsurance $ (6,378) $ (8,350) $ (8,404)
Ceded reserve at end of year 3,543,013    
Credit Risk Reinsurers, Subtotal, Excluding Residual Market Pools      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 3,448,259    
Lifson Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 537,366    
Lloyds of London      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 358,718    
Partner Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 295,800    
Munich Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 250,080    
Berkshire Hathaway      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 246,729    
Hannover Re Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 222,358    
Renaissance Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 217,251    
Swiss Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 132,731    
Liberty Mutual      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 124,916    
Everest Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 86,017    
Arch Capital Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 76,095    
Axis Capital      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 70,166    
Sompo Holdings Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 64,383    
Fairfax Financial      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 60,919    
Nationwide Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 60,342    
TOA Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 51,290    
Korean Re      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 45,858    
Axa Insurance      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 42,361    
MS & AD Insurance Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 38,179    
Markel Corp Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 34,949    
Chubb Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 27,873    
Helvetia Holdings Group      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 25,542    
Other Reinsurers Less than $20,000      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year 378,336    
Residual Market Pools      
Ceded Credit Risk [Line Items]      
Ceded reserve at end of year $ 101,132    
v3.25.4
Indebtedness (Details) - USD ($)
Dec. 31, 2025
Dec. 31, 2024
Apr. 01, 2022
Debt Instrument [Line Items]      
Unsecured borrowings, limit increase     $ 500,000,000
Standby Letters of Credit      
Debt Instrument [Line Items]      
Unsecured borrowings     50,000,000
Subsidiary Debt      
Debt Instrument [Line Items]      
Face Value $ 7,094,000    
Carrying Value 7,094,000 $ 8,973,000  
Repayments thereafter 7,300,000    
Total senior notes and other debt      
Debt Instrument [Line Items]      
Face Value 1,827,094,000    
Carrying Value $ 1,829,198,000 1,831,158,000  
Senior Notes | Senior Notes due February 15, 2037      
Debt Instrument [Line Items]      
Interest Rate 6.25%    
Face Value $ 250,000,000    
Carrying Value $ 248,776,000 248,666,000  
Senior Notes | Senior Notes due August 1, 2044      
Debt Instrument [Line Items]      
Interest Rate 4.75%    
Face Value $ 350,000,000    
Carrying Value $ 346,574,000 346,389,000  
Senior Notes | Senior Notes Due May 12 2050      
Debt Instrument [Line Items]      
Interest Rate 4.00%    
Face Value $ 470,000,000    
Carrying Value $ 488,449,000 489,207,000  
Senior Notes | Senior Notes Due September 30, 2061      
Debt Instrument [Line Items]      
Interest Rate 3.15%    
Face Value $ 350,000,000    
Carrying Value $ 343,498,000 343,314,000  
Senior Notes | Senior Notes Due March 30, 2052      
Debt Instrument [Line Items]      
Interest Rate 3.55%    
Face Value $ 400,000,000    
Carrying Value 394,807,000 394,609,000  
Total subordinated debentures      
Debt Instrument [Line Items]      
Face Value 1,035,000,000    
Carrying Value $ 1,010,527,000 1,009,090,000  
Total subordinated debentures | Subordinated Debt due March 30, 2058      
Debt Instrument [Line Items]      
Interest Rate 5.70%    
Face Value $ 185,000,000    
Carrying Value $ 179,811,000 179,489,000  
Total subordinated debentures | Subordinated Debt due December 30, 2059      
Debt Instrument [Line Items]      
Interest Rate 5.10%    
Face Value $ 300,000,000    
Carrying Value $ 291,895,000 291,418,000  
Total subordinated debentures | Subordinated Debt Due September 30 2060      
Debt Instrument [Line Items]      
Interest Rate 4.25%    
Face Value $ 250,000,000    
Carrying Value $ 244,958,000 244,668,000  
Total subordinated debentures | Subordinated Debt Due March 30, 2061      
Debt Instrument [Line Items]      
Interest Rate 4.125%    
Face Value $ 300,000,000    
Carrying Value $ 293,863,000 $ 293,515,000  
Line of Credit | Revolving Credit Facility      
Debt Instrument [Line Items]      
Unsecured borrowings     $ 300,000,000
v3.25.4
Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]      
Current Expense, Domestic $ 399,800 $ 344,210 $ 352,891
Deferred Expense (Benefit), Domestic (16,709) 51,754 (43,456)
Domestic, Total 383,091 395,964 309,435
State and Local Income Tax Expense (Benefit), Continuing Operations 13,036    
Deferred State and Local Income Tax Expense (Benefit) (561)    
Current State and Local Tax Expense (Benefit) 13,597    
Current Expense, Foreign 96,856 69,312 44,372
Deferred Expense (Benefit), Foreign 2,781 44,640 16,750
Foreign, Total 99,637 113,952 61,122
Current Expense, Total 510,253 413,522 397,263
Deferred Expense (Benefit), Total (14,489) 96,394 (26,706)
Total 495,764 509,916 370,557
Income (Loss) from Continuing Operations before Income Taxes, Domestic 1,881,000 1,840,000 1,430,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign $ 400,000 $ 424,000 $ 324,000
v3.25.4
Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Amount [Abstract]      
U.S. Federal Statutory Tax Rate $ 478,914 $ 475,543 $ 368,425
State and Local Taxes, Net of Federal Benefit (1) 10,299 12,329 12,271
Foreign Tax Effects 11,635 19,317 (1,896)
Effect of Cross-Border Tax Laws (14,727) 0 0
Changes in Valuation Allowances 19,726 (220) (10,883)
Nontaxable or Nondeductible Items (10,083) 2,947 2,640
Total $ 495,764 $ 509,916 $ 370,557
Percent [Abstract]      
U.S. Federal Statutory Tax Rate 21.00%    
State and Local Taxes, Net of Federal Benefit (1) 0.40%    
Foreign Tax Effects 0.50%    
Effect of Cross-Border Tax Laws (0.70%)    
Changes in Valuation Allowances 0.90%    
Nontaxable or Nondeductible Items (0.40%)    
Total 21.70%    
v3.25.4
Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Deferred tax asset:    
Loss reserve discounting $ 253,980 $ 218,222
Unearned premiums 228,752 216,721
Unrealized investment losses 0 58,701
Net operating losses & foreign tax credits 77,810 62,159
Other-than-temporary impairments 5,006 7,149
Employee compensation plans 83,034 70,529
Other 82,948 81,915
Gross deferred tax asset 731,530 715,396
Less valuation allowance (55,789) (36,063)
Deferred tax asset 675,741 679,333
Deferred tax liability:    
Amortization of intangibles 15,541 15,124
Unrealized investment gains 41,641 0
Deferred policy acquisition costs 204,979 195,150
Property, furniture and equipment 61,479 45,276
Investment funds 229,694 184,899
Other 80,784 83,818
Deferred tax liability 634,118 524,267
Net deferred tax asset 41,623 155,066
Operating Loss Carryforwards [Line Items]    
Current federal income taxes 81,000 $ 14,000
Valuation allowance 56,000  
Foreign Tax Jurisdiction    
Deferred tax asset:    
Net operating losses & foreign tax credits 23,000  
Less valuation allowance (33,000)  
Operating Loss Carryforwards [Line Items]    
Operating loss carryforwards, subject to expire $ 179,000  
v3.25.4
Income Taxes (Narrative) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Income Tax Disclosure [Abstract]      
Income (Loss) from Continuing Operations before Income Taxes, Domestic $ 1,881,000 $ 1,840,000 $ 1,430,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign 400,000 424,000 $ 324,000
Taxes Payable 81,000 14,000  
Operating Loss Carryforwards [Line Items]      
Deferred Tax Assets, Valuation Allowance 55,789 36,063  
Net operating losses & foreign tax credits 77,810 $ 62,159  
undistributed earnings of non-U.S. subsidiaries 585,000    
Foreign Tax Jurisdiction      
Operating Loss Carryforwards [Line Items]      
Operating loss carryforwards, subject to expire 179,000    
Deferred Tax Assets, Valuation Allowance 33,000    
Net operating losses & foreign tax credits $ 23,000    
v3.25.4
Dividends From Subsidiaries And Statutory Financial Information (Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Insurance [Abstract]      
Amount available for dividend distribution without prior approval from regulatory authorities $ 1,400,000    
Net income 1,588,605 $ 1,624,686 $ 1,176,255
Policyholders' surplus 9,857,138 $ 9,421,874 $ 8,776,138
Increase in BIC's statutory capital and surplus $ 167,000    
Total Adjusted Capital percentage threshold 200.00%    
BIC's Total Adjusted Capital balance $ 9,700,000    
BIC's Total Adjusted Capital balance as percentage of RBC Authorized Control Level 397.00%    
v3.25.4
Common Stockholders' Equity (Weighted Average Number of Common Shares Used In the Computation of Basic and Diluted Earnings per Share) (Details) - shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Equity [Abstract]      
Basic 396,968,000 399,734,000 406,500,000
Diluted 399,861,000 403,224,000 409,948,000
Weighted average shares held in grantor trust 17,378,810    
v3.25.4
Common Stockholders' Equity (Schedule of Changes in Shares of Common Stock Outstanding) (Details) - shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Common Stock Shares Outstanding [Roll Forward]      
Balance, beginning of year 380,066,070 384,817,136 396,819,150
Shares issued 1,158,755 951,930 1,059,500
Shares repurchased (4,069,026) (5,702,996) (13,061,514)
Balance, end of year 377,155,799 380,066,070 384,817,136
v3.25.4
Fair Value of Financial Instruments (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Assets:    
Equity securities $ 1,358,201 $ 1,203,788
Arbitrage trading account 1,221,000 1,123,000
Loans Receivable, Fair Value Disclosure 419,074 405,248
Liabilities:    
Due to broker 0 70,483
Carrying Value    
Assets:    
Fixed maturity securities 25,047,662 22,397,865
Equity securities 1,358,201 1,203,788
Arbitrage trading account 1,221,103 1,122,599
Loans Receivable, Fair Value Disclosure 418,913 405,453
Cash and cash equivalents 2,539,938 1,974,747
Trading accounts receivable from brokers and clearing organizations 11,669 60,327
Due from broker 629 0
Liabilities:    
Trading account securities sold but not yet purchased 66,285 73,358
Carrying Value | Total senior notes and other debt    
Liabilities:    
Long-term debt fair value 1,829,198 1,831,158
Carrying Value | Total subordinated debentures    
Liabilities:    
Long-term debt fair value 1,010,527 1,009,808
Fair Value    
Assets:    
Fixed maturity securities 25,048,534 22,399,426
Equity securities 1,358,201 1,203,788
Arbitrage trading account 1,221,103 1,122,599
Loans Receivable, Fair Value Disclosure 419,074 405,248
Cash and cash equivalents 2,539,938 1,974,747
Trading accounts receivable from brokers and clearing organizations 11,669 60,327
Due from broker 629 0
Liabilities:    
Trading account securities sold but not yet purchased 66,285 73,358
Fair Value | Total senior notes and other debt    
Liabilities:    
Long-term debt fair value 1,440,055 1,425,852
Fair Value | Total subordinated debentures    
Liabilities:    
Long-term debt fair value $ 760,400 $ 805,864
v3.25.4
Commitments, Litigation And Contingent Liabilities (Details)
$ in Millions
12 Months Ended
Dec. 31, 2025
USD ($)
Commitments and Contingencies Disclosure [Abstract]  
Commitment to Invest in Certain Investment Funds $ 274
Commitment to Invest in Real Estate Construction Projects $ 31
v3.25.4
Leases (Lease Cost) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
Lease cost $ 54,261 $ 45,718
Cash paid for amounts included in the measurement of lease liabilities reported in operating cash flows 49,421 49,441
Right-of-use assets obtained in exchange for new lease liabilities $ 74,451 $ 43,624
v3.25.4
Leases (Supplemental Balance Sheet Information) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Other assets Other assets
Right-of-use assets $ 221,480 $ 180,035
Operating Lease, Liability, Statement of Financial Position [Extensible List] Other liabilities Other liabilities
Lease liabilities $ 260,451 $ 218,397
Weighted-average remaining lease term 7 years 1 month 6 days 7 years 2 months 12 days
Weighted-average discount rate 5.98% 5.59%
v3.25.4
Leases (Maturities of Operating Lease Liabilities) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Leases [Abstract]    
2021 $ 54,475  
2022 47,249  
2023 45,830  
2024 41,825  
2025 37,008  
Thereafter 96,197  
Total undiscounted future minimum lease payments 322,584  
Less: Discount impact 62,133  
Total lease liability $ 260,451 $ 218,397
v3.25.4
Stock Incentive Plan (Schedule of Share-based Compensation, Stock Options, Activity) (Details)
12 Months Ended
Dec. 31, 2025
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Deferred shares 17,375,058
Restricted Stock Units (RSUs) | Minimum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 3 years
Restricted Stock Units (RSUs) | Maximum  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 5 years
v3.25.4
Stock Incentive Plan (Schedule of Nonvested Restricted Stock Units Activity) (Details) - Restricted Stock Units (RSUs) - shares
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]      
RSUs granted and unvested at beginning of period: 5,734,397 6,435,267 6,927,639
Granted 1,043,988 1,217,056 1,647,690
Vested (1,470,318) (1,594,183) (1,726,956)
Canceled (376,921) (323,743) (413,106)
RSUs granted and unvested at end of period: 4,931,146 5,734,397 6,435,267
v3.25.4
Stock Incentive Plan (Schedule of Share-based Compensation, Unearned Compensation Related to RSU's) (Details) - Restricted Stock Units (RSUs) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Changes In Unearned Compensation [Roll Forward]      
Unearned compensation at beginning of year $ 153,329 $ 148,080 $ 142,060
RSUs granted, net of cancellations 65,901 63,347 62,418
RSUs expensed 52,524 (52,380) (49,200)
RSUs forfeitures 8,653 (5,718) (7,198)
Unearned compensation at end of year $ 158,053 $ 153,329 $ 148,080
v3.25.4
Compensation Plans (Details)
12 Months Ended
Dec. 31, 2025
USD ($)
hour
shares
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
LTIP Expense $ 23,205,000 $ 25,397,000 $ 28,428,000
Deferred Profit Sharing      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Profit Sharing Plan Minimum Contribution, Percent 5.00%    
Number of service hours required (in hours) | hour 250    
Profit Sharing Plan, Contributions Vesting Immediately, Percent 40.00%    
Profit Sharing Plan, Contributions Vesting Based on Years of Service, Percent 60.00%    
Profit sharing expense $ 80,000,000 72,000,000 75,000,000
2019 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
LTIP Expense 0 0 3,241,000
2020 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
LTIP Expense $ 0 135,000 7,047,000
2021 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Long-Term Incentive Compensation Plan, Number of Units Oustanding | shares 197,500    
Long-Term Incentive Compensation Plan, Maximum Value $ 19,750,000    
Long-Term Incentive Compensation Plan, Earned 19,750,000    
LTIP Expense $ (39,000) 3,543,000 6,561,000
2022 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Long-Term Incentive Compensation Plan, Number of Units Oustanding | shares 220,500    
Long-Term Incentive Compensation Plan, Maximum Value $ 22,050,000    
Long-Term Incentive Compensation Plan, Earned 22,050,000    
LTIP Expense $ 2,523,000 8,167,000 6,155,000
2023 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Long-Term Incentive Compensation Plan, Number of Units Oustanding | shares 235,000    
Long-Term Incentive Compensation Plan, Maximum Value $ 23,500,000    
Long-Term Incentive Compensation Plan, Earned 20,014,894    
LTIP Expense $ 7,799,000 7,076,000 5,424,000
2024 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Long-Term Incentive Compensation Plan, Number of Units Oustanding | shares 252,500    
Long-Term Incentive Compensation Plan, Maximum Value $ 25,250,000    
Long-Term Incentive Compensation Plan, Earned 13,598,077    
LTIP Expense $ 7,154,000 6,476,000 0
2025 grant      
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]      
Long-Term Incentive Compensation Plan, Number of Units Oustanding | shares 244,750    
Long-Term Incentive Compensation Plan, Maximum Value $ 24,475,000    
Long-Term Incentive Compensation Plan, Earned 5,767,601    
LTIP Expense $ 5,768,000 $ 0 $ 0
v3.25.4
Supplemental Financial Statement Data (Schedule of Other Operating Cost and Expense, by Component) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Other Income and Expenses [Abstract]      
Amortization of deferred policy acquisition costs   $ 1,219,849 $ 1,038,975
Insurance operating expenses $ 2,131,785 2,075,053 1,915,711
Insurance service expenses 94,374 90,640 91,714
Net foreign currency losses (gains) 68,006 (52,376) 31,799
Other costs and expenses 297,930 269,140 285,737
Total $ 3,976,834 $ 3,602,306 $ 3,363,936
v3.25.4
Industry Segments (Financial Information of Company Operating Segments) (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2025
USD ($)
segment
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Segment Reporting Information [Line Items]      
Number of reportable segments | segment 2    
Earned Premiums $ 12,446,938 $ 11,548,485 $ 10,400,687
Investment Income 1,429,067 1,333,161 1,052,835
Net investment gains 132,220 117,708 47,042
Other Revenues 831,851 757,106 689,416
Total revenues 14,707,856 13,638,752 12,142,938
Losses and Loss Expenses 7,771,657 7,131,595 6,372,142
Policy Acquisition and Insurance Operating Expenses 3,516,524 3,294,902 2,954,686
Other 1,139,132 947,762 1,061,707
Total operating costs and expenses 12,427,313 11,374,259 10,388,535
Pre-Tax Income (Loss) 2,280,543 2,264,493 1,754,403
Net income to common stockholders 1,779,403 1,756,115 1,381,359
Insurance      
Segment Reporting Information [Line Items]      
Earned Premiums 10,936,028 10,086,308 9,007,376
Reinsurance & Monoline Excess      
Segment Reporting Information [Line Items]      
Earned Premiums 1,510,910 1,462,177 1,393,311
Operating Segments | Insurance      
Segment Reporting Information [Line Items]      
Earned Premiums 10,936,028 10,086,308 9,007,376
Investment Income 1,118,607 1,057,738 783,660
Other Revenues 40,966 37,455 36,830
Total revenues 12,095,601 11,181,501 9,827,866
Losses and Loss Expenses 6,947,232 6,332,490 5,615,526
Policy Acquisition and Insurance Operating Expenses 3,076,726 2,863,697 2,545,310
Other 44,399 43,231 37,112
Total operating costs and expenses 10,068,357 9,239,418 8,197,948
Pre-Tax Income (Loss) 2,027,244 1,942,083 1,629,918
Net income to common stockholders 1,584,440 1,503,875 1,283,281
Operating Segments | Reinsurance & Monoline Excess      
Segment Reporting Information [Line Items]      
Earned Premiums 1,510,910 1,462,177 1,393,311
Investment Income 270,851 234,728 221,966
Other Revenues 0 0 0
Total revenues 1,781,761 1,696,905 1,615,277
Losses and Loss Expenses 824,425 799,105 756,616
Policy Acquisition and Insurance Operating Expenses 439,798 431,205 409,376
Total operating costs and expenses 1,264,223 1,230,310 1,165,992
Pre-Tax Income (Loss) 517,538 466,595 449,285
Net income to common stockholders 407,659 367,569 355,155
Corporate, other and eliminations      
Segment Reporting Information [Line Items]      
Investment Income 39,609 40,695 47,209
Other Revenues 658,665 601,943 605,544
Total revenues 698,274 642,638 652,753
Other 1,094,733 904,531 1,024,595
Total operating costs and expenses 1,094,733 904,531 1,024,595
Pre-Tax Income (Loss) (396,459) (261,893) (371,842)
Net income to common stockholders (316,404) (203,832) (293,869)
Net investment gains      
Segment Reporting Information [Line Items]      
Net investment gains 132,220 117,708 47,042
Pre-Tax Income (Loss) 132,220 117,708 47,042
Net income to common stockholders $ 103,708 $ 88,503 $ 36,792
v3.25.4
Industry Segments (Identifiable Assets by Segment) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting, Asset Reconciling Item [Line Items]      
Identifiable Assets $ 44,071,071 $ 40,567,268  
Revenues 14,707,856 13,638,752 $ 12,142,938
Operating Segments | Insurance      
Segment Reporting, Asset Reconciling Item [Line Items]      
Identifiable Assets 35,830,534 33,030,140  
Revenues 12,095,601 11,181,501 9,827,866
Operating Segments | Insurance | Foreign countries      
Segment Reporting, Asset Reconciling Item [Line Items]      
Revenues 1,408,000 1,471,000 1,171,000
Operating Segments | Reinsurance & Monoline Excess      
Segment Reporting, Asset Reconciling Item [Line Items]      
Identifiable Assets 5,891,538 5,669,729  
Revenues 1,781,761 1,696,905 1,615,277
Operating Segments | Reinsurance & Monoline Excess | Foreign countries      
Segment Reporting, Asset Reconciling Item [Line Items]      
Revenues 516,000 485,000 463,000
Corporate, other and eliminations      
Segment Reporting, Asset Reconciling Item [Line Items]      
Identifiable Assets 2,348,999 1,867,399  
Revenues $ 698,274 $ 642,638 $ 652,753
v3.25.4
Industry Segments (Net Premiums Earned By Major Line of Business) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Net premiums earned $ 12,446,938 $ 11,548,485 $ 10,400,687
Insurance      
Segment Reporting Information [Line Items]      
Net premiums earned 10,936,028 10,086,308 9,007,376
Insurance | Other liability      
Segment Reporting Information [Line Items]      
Net premiums earned 4,429,621 4,068,662 3,605,298
Insurance | Short-tail lines      
Segment Reporting Information [Line Items]      
Net premiums earned 2,496,481 2,201,661 1,825,027
Insurance | Workers' compensation      
Segment Reporting Information [Line Items]      
Net premiums earned 1,259,290 1,237,888 1,212,294
Insurance | Auto      
Segment Reporting Information [Line Items]      
Net premiums earned 1,617,908 1,481,569 1,270,907
Insurance | Professional liability      
Segment Reporting Information [Line Items]      
Net premiums earned 1,132,728 1,096,528 1,093,850
Reinsurance & Monoline Excess      
Segment Reporting Information [Line Items]      
Net premiums earned 1,510,910 1,462,177 1,393,311
Reinsurance & Monoline Excess | Casualty      
Segment Reporting Information [Line Items]      
Net premiums earned 741,671 771,329 821,826
Reinsurance & Monoline Excess | Monoline Excess (3)      
Segment Reporting Information [Line Items]      
Net premiums earned 290,557 266,552 241,126
Reinsurance & Monoline Excess | Property (2)      
Segment Reporting Information [Line Items]      
Net premiums earned $ 478,682 $ 424,296 $ 330,359
v3.25.4
Related-Party Transactions - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Jan. 01, 2025
Jul. 01, 2022
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Mar. 28, 2025
Related Party Transaction [Line Items]            
Current capitalization     $ 9,700,818 $ 8,395,111    
Ceded commission earned     555,763 505,753 $ 471,841  
Written premiums, Ceded     2,393,742 2,238,995 2,017,539  
Due to reinsurers     615,781 668,652    
Assumed from Other Companies     1,410,548 1,306,198 1,295,263  
Nonrelated Party | Lifson Re            
Related Party Transaction [Line Items]            
Current capitalization     418,000      
Nonrelated Party | Lifson Re | Management And Performance Fees            
Related Party Transaction [Line Items]            
Ceded commission earned     11,000 6,000 5,000  
Nonrelated Party | Reinsurer Concentration Risk | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Lifson Re            
Related Party Transaction [Line Items]            
Concentration risk, percentage 32.50% 30.00%        
Written premiums, Ceded     494,359 416,509 436,941  
Ceded commissions and brokerage     133,479 104,075 $ 123,510  
Due from reinsurers     537,366 471,689    
Due to reinsurers     118,788 $ 166,304    
Nonrelated Party | Reinsurer Concentration Risk | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Mitsui Sumitomo Insurance Co., Ltd.            
Related Party Transaction [Line Items]            
Written premiums, Ceded     70,000      
Ceded commissions and brokerage     13,000      
Due from reinsurers     58,000      
Due to reinsurers     16,000      
Assumed from Other Companies     12,000      
Assumed premiums receivable     4,000      
Assumed loss reserve/claims payable     $ 11,000      
Mitsui Sumitomo Insurance Co., Ltd. | Common Stock [Member]            
Related Party Transaction [Line Items]            
Percent of stock held by related party     13.40%      
Investment And Voting Arrangement, agreement to acquire stock, percent           15.00%
v3.25.4
Related-Party Transactions - Schedule (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Related Party Transaction [Line Items]      
Ceded to Other Companies $ 2,393,742 $ 2,238,995 $ 2,017,539
Due to reinsurers 615,781 668,652  
Nonrelated Party | Lifson Re | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk      
Related Party Transaction [Line Items]      
Ceded to Other Companies 494,359 416,509 436,941
Ceded commissions and brokerage 133,479 104,075 $ 123,510
Due from reinsurers 537,366 471,689  
Due to reinsurers 118,788 $ 166,304  
Nonrelated Party | Mitsui Sumitomo Insurance Co., Ltd. | Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments | Reinsurer Concentration Risk      
Related Party Transaction [Line Items]      
Ceded to Other Companies 70,000    
Ceded commissions and brokerage 13,000    
Due from reinsurers 58,000    
Due to reinsurers $ 16,000    
v3.25.4
Schedule II - Condensed Financial Information of Registrant (Balance Sheets (Parent Company)) (Details) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Assets:      
Cash and cash equivalents $ 2,539,938 $ 1,974,747  
Fixed maturity securities available for sale at fair value (cost $641,917 and $251,938 at December 31, 2025 and 2024) 25,047,662 22,397,865  
Loans receivable (net of allowance for expected credit losses of $161 and $591 at December 31, 2025 and 2024) 418,913 405,453  
Current federal income taxes 2,732 39,382  
Deferred federal and foreign income taxes 141,496 220,217  
Property, furniture and equipment at cost, less accumulated depreciation 596,235 478,511  
Other assets 809,394 877,099  
Total assets 44,071,071 40,567,268  
Liabilities:      
Other liabilities 1,724,797 1,715,078  
Current federal income taxes 83,373 53,482  
Deferred federal income taxes 99,873 65,151  
Subordinated debentures 1,010,527 1,009,808  
Total liabilities 34,359,177 32,159,829  
Stockholders' equity:      
Preferred stock, par value $.10 per share: 0 0  
Common stock, par value $.20 per share: 158,705 158,705  
Additional paid-in capital 987,708 984,825  
Retained earnings (including accumulated undistributed net income of subsidiaries of $9,674,616 and $9,216,210 at December 31, 2025 and 2024, respectively) 13,344,204 12,265,070  
Accumulated other comprehensive loss (451,097) (934,269)  
Treasury stock, at cost, 416,366,010 and 413,455,739 shares, respectively (4,338,702) (4,079,220)  
Total common stockholders’ equity 9,700,818 8,395,111  
Total liabilities and equity 44,071,071 40,567,268  
Fixed maturity securities available for sale at cost 25,139,753 22,966,462  
Financing receivable, allowance for credit loss 161 1,114 $ 3,004
Parent Company      
Assets:      
Cash and cash equivalents 55,322 112,931  
Fixed maturity securities available for sale at fair value (cost $641,917 and $251,938 at December 31, 2025 and 2024) 642,451 251,800  
Loans receivable (net of allowance for expected credit losses of $161 and $591 at December 31, 2025 and 2024) 23,089 27,659  
Equity securities, at fair value (cost $3,430 at both December 31, 2025 and 2024) 3,430 3,430  
Investment in subsidiaries 11,940,355 10,770,734  
Current federal income taxes 0 36,417  
Deferred federal and foreign income taxes 151,031 228,329  
Property, furniture and equipment at cost, less accumulated depreciation 8,581 9,320  
Other assets 62,179 126,799  
Total assets 12,886,438 11,567,419  
Liabilities:      
Current federal income taxes 19,626 0  
Subordinated debentures 1,010,527 1,009,808  
Senior notes 1,821,876 1,821,774  
Total liabilities 3,185,620 3,172,308  
Stockholders' equity:      
Preferred stock, par value $.10 per share: 0 0  
Common stock, par value $.20 per share: 158,705 158,705  
Additional paid-in capital 987,708 984,825  
Retained earnings (including accumulated undistributed net income of subsidiaries of $9,674,616 and $9,216,210 at December 31, 2025 and 2024, respectively) 13,344,204 12,265,070  
Accumulated other comprehensive loss (451,097) (934,269)  
Treasury stock, at cost, 416,366,010 and 413,455,739 shares, respectively (4,338,702) (4,079,220)  
Total common stockholders’ equity 9,700,818 8,395,111  
Total liabilities and equity 12,886,438 11,567,419  
Fixed maturity securities available for sale at cost 641,917 251,938  
Financing receivable, allowance for credit loss 161 591  
Equity securities available for sale at cost 3,430 3,430  
Accumulated undistributed net income of subsidiaries 9,674,616 9,216,210  
Parent Company | Related Party      
Liabilities:      
Other liabilities 144,740 182,445  
Parent Company | Nonrelated Party      
Liabilities:      
Other liabilities $ 188,851 $ 158,281  
v3.25.4
Schedule II - Condensed Financial Information of Registrant (Statements of Income (Parent Company)) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Condensed Income Statements, Captions [Line Items]      
Net investment gains (losses) $ 132,220 $ 117,708 $ 47,042
Other income 3,700 2,451 381
Revenues 14,707,856 13,638,752 12,142,938
Operating costs and expense 12,427,313 11,374,259 10,388,535
Pre-Tax Income (Loss) 2,280,543 2,264,493 1,754,403
Federal income taxes:      
Federal and foreign income taxes (495,764) (509,916) (370,557)
Income (Loss) From Investment Funds For the Year Ended 27,582 (11,491) 16,743
Net income to common stockholders 1,779,403 1,756,115 1,381,359
Dividends from subsidiaries 1,643,345 1,196,538 1,261,166
Parent Company      
Condensed Income Statements, Captions [Line Items]      
Management fees and investment income including dividends from subsidiaries of $1,643,345, $1,196,538, and $1,261,166 for the years ended December 31, 2025, 2024 and 2023, respectively 1,716,680 1,252,194 1,325,997
Net investment gains (losses) 945 90,284 (5,895)
Other income 834 853 368
Revenues 1,718,459 1,343,331 1,320,470
Operating costs and expense 315,233 277,679 272,750
Interest expense 126,400 126,400 126,397
Pre-Tax Income (Loss) 1,276,826 939,252 921,323
Federal income taxes:      
Federal income taxes provided by subsidiaries on a separate return basis 422,289 424,456 253,292
Federal income tax expense on a consolidated return basis (378,117) (356,943) (284,757)
Federal and foreign income taxes 44,172 67,513 (31,465)
Income before undistributed equity in net income of subsidiaries 1,320,998 1,006,765 889,858
Income (Loss) From Investment Funds For the Year Ended 458,405 749,350 491,501
Net income to common stockholders $ 1,779,403 $ 1,756,115 $ 1,381,359
v3.25.4
Schedule II - Condensed Financial Information of Registrant (Statements of Cash Flows (Parent Company)) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Cash flows from operating activities:      
Net income $ 1,779,403 $ 1,756,115 $ 1,381,359
Adjustments to reconcile net income to net cash from operating activities:      
Depreciation and (accretion) amortization (48,126) (170,638) (20,861)
Equity in undistributed earnings of subsidiaries (27,582) 11,491 (16,743)
Stock incentive plans 54,524 54,381 51,000
Change in:      
Other liabilities 139,210 70,851 14,462
Net cash from operating activities 3,582,616 3,678,368 2,929,238
Cash (used in) from investing activities:      
Proceeds from sale of fixed maturity securities 1,149,313 2,310,746 1,011,195
Proceeds from maturities and prepayments of fixed maturity securities 5,312,043 4,890,572 3,506,903
Cost of purchases of fixed maturity securities (8,428,883) (9,368,703) (6,664,763)
Change in loans receivable 12,695 (210,816) (29,719)
Change in balances due from security brokers (70,812) 107,280 (33,929)
Net cash used in investing activities (2,029,335) (2,184,489) (1,961,964)
Cash used in financing activities:      
Purchase of common treasury shares (270,221) (303,655) (537,163)
Cash dividends to common stockholders (700,269) (531,953) (501,456)
Other, net (53,894) (19,984) (22,902)
Net cash used in financing activities (1,026,447) (852,487) (1,062,495)
Net increase (decrease) in cash and cash equivalents 565,191 611,552 (86,151)
Cash and cash equivalents at beginning of year 1,974,747 1,363,195 1,449,346
Cash and cash equivalents at end of year 2,539,938 1,974,747 1,363,195
Parent Company      
Cash flows from operating activities:      
Net income 1,779,403 1,756,115 1,381,359
Adjustments to reconcile net income to net cash from operating activities:      
Net investment (gains) losses (945) (90,284) 5,895
Depreciation and (accretion) amortization (5,780) (5,120) (6,753)
Equity in undistributed earnings of subsidiaries (458,405) (749,350) (491,501)
Tax payments received from subsidiaries 372,731 432,402 373,504
Federal income taxes provided by subsidiaries on a separate return basis (422,289) (424,456) (253,292)
Stock incentive plans 54,524 54,381 51,000
Change in:      
Federal income taxes 34,361 (9,346) (15,793)
Equity in undistributed earnings of other investments (15,047) (10,444) 0
Other assets (4,552) (9,888) (5,647)
Other liabilities 30,248 114,418 (88,954)
Accrued investment income (1,810) (1,740) 1,200
Net cash from operating activities 1,362,439 1,056,688 951,018
Cash (used in) from investing activities:      
Proceeds from sale of fixed maturity securities 81,035 598,915 748,825
Proceeds from maturities and prepayments of fixed maturity securities 562,308 260,999 82,075
Cost of purchases of fixed maturity securities (1,029,227) (824,476) (732,685)
Change in loans receivable 5,000 64,200 17,843
Investments in and advances to subsidiaries, net (102,615) (238,337) 21,605
Change in balances due from security brokers 71,083 (71,143) (38)
Net additions to real estate, furniture & equipment (63) (37) (18)
Other, net 3,823 73 290
Net cash used in investing activities (408,656) (209,806) 137,897
Cash used in financing activities:      
Purchase of common treasury shares (270,221) (303,655) (537,163)
Cash dividends to common stockholders (700,269) (531,953) (501,456)
Other, net (40,902) (26,777) (25,384)
Net cash used in financing activities (1,011,392) (862,385) (1,064,003)
Net increase (decrease) in cash and cash equivalents (57,609) (15,503) 24,912
Cash and cash equivalents at beginning of year 112,931 128,434 103,522
Cash and cash equivalents at end of year $ 55,322 $ 112,931 $ 128,434
v3.25.4
Schedule III - Supplementary Insurance Information (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]      
Deferred Policy Acquisition Cost $ 1,000,691 $ 951,728 $ 861,609
Reserve for Losses and Loss Expenses 22,207,773 20,368,030 18,739,652
Unearned Premiums 6,721,570 6,375,112 5,922,326
Net Premiums Earned 12,446,938 11,548,485 10,400,687
Net Investment Income 1,429,067 1,333,161 1,052,835
Loss and Loss Expenses 7,771,657 7,131,595 6,372,142
Amortization of Deferred Policy Acquisition Cost 1,384,739 1,219,849 1,038,975
Other Operating Costs and Expenses 2,592,095 2,382,457 2,324,961
Net Premiums Written 12,711,327 11,972,096 10,954,467
Operating Segments | Insurance      
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]      
Deferred Policy Acquisition Cost 887,406 840,917 736,348
Reserve for Losses and Loss Expenses 18,589,040 16,887,821 15,298,372
Unearned Premiums 6,158,703 5,836,435 5,322,869
Net Premiums Earned 10,936,028 10,086,308 9,007,376
Net Investment Income 1,118,607 1,057,738 783,660
Loss and Loss Expenses 6,947,232 6,332,490 5,615,526
Amortization of Deferred Policy Acquisition Cost 1,248,382 1,081,170 897,908
Other Operating Costs and Expenses 1,872,742 1,825,758 1,684,514
Net Premiums Written 11,183,713 10,549,550 9,560,533
Operating Segments | Reinsurance & Monoline Excess      
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]      
Deferred Policy Acquisition Cost 113,285 110,811 125,261
Reserve for Losses and Loss Expenses 3,618,733 3,480,209 3,441,280
Unearned Premiums 562,867 538,677 599,457
Net Premiums Earned 1,510,910 1,462,177 1,393,311
Net Investment Income 270,851 234,728 221,966
Loss and Loss Expenses 824,425 799,105 756,616
Amortization of Deferred Policy Acquisition Cost 136,357 138,679 141,067
Other Operating Costs and Expenses 303,441 292,526 268,309
Net Premiums Written 1,527,614 1,422,546 1,393,934
Corporate, other and eliminations      
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]      
Deferred Policy Acquisition Cost 0 0 0
Reserve for Losses and Loss Expenses 0 0 0
Unearned Premiums 0 0 0
Net Premiums Earned 0 0 0
Net Investment Income 39,609 40,695 47,209
Loss and Loss Expenses 0 0 0
Amortization of Deferred Policy Acquisition Cost 0 0 0
Other Operating Costs and Expenses 415,912 264,173 372,138
Net Premiums Written $ 0 $ 0 $ 0
v3.25.4
Schedule IV - Reinsurance (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Direct Amount $ 13,694,521 $ 12,904,893 $ 11,676,743
Ceded to Other Companies 2,393,742 2,238,995 2,017,539
Assumed from Other Companies 1,410,548 1,306,198 1,295,263
Total net premiums written $ 12,711,327 $ 11,972,096 $ 10,954,467
Percentage of Amount Assumed to Net 11.10% 10.90% 11.80%
Insurance      
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Direct Amount $ 13,151,705 $ 12,417,129 $ 11,209,325
Ceded to Other Companies 2,281,783 2,112,582 1,900,560
Assumed from Other Companies 313,791 245,003 251,768
Total net premiums written $ 11,183,713 $ 10,549,550 $ 9,560,533
Percentage of Amount Assumed to Net 2.80% 2.30% 2.60%
Reinsurance & Monoline Excess      
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Direct Amount $ 542,816 $ 487,764 $ 467,418
Ceded to Other Companies 111,959 126,413 116,979
Assumed from Other Companies 1,096,757 1,061,195 1,043,495
Total net premiums written $ 1,527,614 $ 1,422,546 $ 1,393,934
Percentage of Amount Assumed to Net 71.80% 74.60% 74.90%
v3.25.4
Schedule V - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Premiums, fees and other receivables      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance $ 49,481 $ 42,325 $ 36,931
Additions - Charged to Expense 19,120 15,743 13,637
Deductions - Amounts Written Off (12,746) (8,587) (8,243)
Ending Balance 55,855 49,481 42,325
Due from reinsurers      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance 8,350 8,404 8,064
Additions - Charged to Expense 508 568 340
Deductions - Amounts Written Off (2,480) (622) 0
Ending Balance 6,378 8,350 8,404
Deferred federal and foreign income taxes      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance 36,063 36,283 47,166
Additions - Charged to Expense 20,184 9,219 3,864
Deductions - Amounts Written Off (458) (9,439) (14,747)
Ending Balance 55,789 36,063 36,283
Loan loss reserves      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance 1,114 3,004 1,791
Additions - Charged to Expense 0 5 1,782
Deductions - Amounts Written Off (953) (1,895) (569)
Ending Balance 161 1,114 3,004
Fixed maturity securities      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance 671 36,751 37,466
Additions - Charged to Expense 78 2,053 5,013
Deductions - Amounts Written Off (675) (38,133) (5,728)
Ending Balance 74 671 36,751
General Valuation Allowance      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Opening Balance 95,679 126,767 131,418
Additions - Charged to Expense 39,890 27,588 24,636
Deductions - Amounts Written Off (17,312) (58,676) (29,287)
Ending Balance $ 118,257 $ 95,679 $ 126,767
v3.25.4
Schedule VI - Supplementary Information Concerning Property-Casualty Insurance Operations (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]      
Deferred policy acquisition costs $ 1,000,691 $ 951,728 $ 861,609
Reserves for losses and loss expenses 22,207,773 20,368,030 18,739,652
Unearned premiums 6,721,570 6,375,112 5,922,326
Net premiums earned 12,446,938 11,548,485 10,400,687
Net investment income 1,429,067 1,333,161 1,052,835
Losses and loss expenses incurred:      
Current year 7,702,638 7,083,999 6,311,780
Prior years 34,446 14,350 29,681
Loss reserve discount accretion 34,573 33,246 30,681
Amortization of deferred policy acquisition costs 1,384,739 1,219,849 1,038,975
Paid losses and loss expenses 6,133,576 5,484,430 4,981,610
Net premiums written $ 12,711,327 $ 11,972,096 $ 10,954,467