Document and Entity Information Document and Entity Information - shares	3 Months Ended	6 Months Ended
	Mar. 28, 2018	Jun. 27, 2018	Jul. 25, 2018
Document Information [Line Items]
Document type	10-Q	10-Q
Amendment flag	false
Document Period End Date		Jun. 27, 2018
Document fiscal year focus	2018
Document fiscal period focus	Q2
Entity registrant name		SHAKE SHACK INC.
Entity central index key	0001620533
Current fiscal year end date	--12-26
Entity filer category	Large Accelerated Filer
Entity current reporting status	Yes
Class A Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)			29,214,077
Class B Common Stock
Document Information [Line Items]
Entity common stock, shares outstanding (in shares)			7,818,921

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017
Current assets:
Cash and cash equivalents	$ 30,879	$ 21,507
Marketable securities	61,399	63,036
Accounts receivable	7,110	5,641
Inventories	1,238	1,258
Prepaid expenses and other current assets	1,474	1,757
Total current assets	102,100	93,199
Property and equipment, net	216,763	187,095
Deferred income taxes, net	214,037	185,914
Other assets	3,835	4,398
TOTAL ASSETS	536,735	470,606
Current liabilities:
Accounts payable	8,344	8,210
Accrued expenses	15,988	11,649
Accrued wages and related liabilities	6,815	6,228
Other current liabilities	7,655	7,937
Total current liabilities	38,802	34,024
Deemed landlord financing	18,340	14,518
Deferred rent	39,463	36,596
Liabilities under tax receivable agreement, net of current portion	176,427	158,436
Other long-term liabilities	7,256	2,553
Total liabilities	280,288	246,127
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value—10,000,000 shares authorized; none issued and outstanding as of June 27, 2018 and December 27, 2017.	0	0
Additional paid-in capital	177,650	153,105
Retained earnings	26,337	16,399
Accumulated other comprehensive income (loss)	0	(49)
Total stockholders' equity attributable to Shake Shack Inc.	204,024	169,492
Non-controlling interests	52,423	54,987
Total equity	256,447	224,479
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	536,735	470,606
Class A Common Stock
Stockholders' equity:
Common stock	28	27
Class B Common Stock
Stockholders' equity:
Common stock	$ 9	$ 10

CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Jun. 27, 2018	Dec. 27, 2017
Preferred Stock, no par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Class A Common Stock
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares, issued (in shares)	28,106,331	26,527,477
Common stock, shares, outstanding (in shares)	28,106,331	26,527,477
Class B Common Stock
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares, issued (in shares)	8,924,592	10,250,007
Common stock, shares, outstanding (in shares)	8,924,592	10,250,007

CONDENSED CONSOLIDATED STATEMENT OF INCOME (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Income Statement [Abstract]
Document Period End Date			Jun. 27, 2018
Shack sales	$ 112,898	$ 88,003	$ 208,987	$ 162,158
Licensing revenue	3,384	3,313	6,411	5,907
TOTAL REVENUE	116,282	91,316	215,398	168,065
Shack-level operating expenses:
Food and paper costs	31,678	24,712	58,633	45,886
Labor and related expenses	29,732	22,426	56,419	42,886
Other operating expenses	12,281	8,486	23,040	16,151
Occupancy and related expenses	7,401	7,043	15,076	13,219
General and administrative expenses	12,587	9,678	24,396	18,148
Depreciation expense	6,968	5,258	13,466	10,006
Pre-opening costs	2,421	1,876	4,450	4,291
Loss on disposal of property and equipment	196	100	386	113
TOTAL EXPENSES	103,264	79,579	195,866	150,700
OPERATING INCOME	13,018	11,737	19,532	17,365
Other income, net	406	198	634	393
Interest expense	(613)	(366)	(1,178)	(669)
INCOME BEFORE INCOME TAXES	12,811	11,569	18,988	17,089
Income tax expense	2,240	3,385	3,438	5,043
NET INCOME	10,571	8,184	15,550	12,046
Less: net income attributable to non-controlling interests	2,967	3,305	4,438	4,900
NET INCOME ATTRIBUTABLE TO SHAKE SHACK INC.	$ 7,604	$ 4,879	$ 11,112	$ 7,146
Earnings per share of Class A common stock:
Basic (in dollars per share)	$ 0.27	$ 0.19	$ 0.41	$ 0.28
Diluted (in dollars per share)	$ 0.26	$ 0.19	$ 0.39	$ 0.27
Weighted-average shares of Class A common stock outstanding:
Basic (in shares)	27,796	25,798	27,418	25,587
Diluted (in shares)	28,754	26,312	28,288	26,133

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 27, 2018

Jun. 28, 2017

Jun. 27, 2018

Jun. 28, 2017

Statement of Comprehensive Income [Abstract]

Net income

$ 10,571

$ 8,184

$ 15,550

$ 12,046

Available-for-sale securities:

Change in net unrealized holding gains (losses)

^[1]

0

(8)

(3)

(17)

Less: reclassification adjustments for net realized losses included in net income

^[1]

0

11

16

14

Net change

0

3

13

(3)

OTHER COMPREHENSIVE INCOME

0

3

13

(3)

COMPREHENSIVE INCOME

10,571

8,187

15,563

12,043

Less: comprehensive income attributable to non-controlling interest

2,967

3,306

4,441

4,899

COMPREHENSIVE INCOME ATTRIBUTABLE TO SHAKE SHACK INC.

$ 7,604

$ 4,881

$ 11,122

$ 7,144

[1]	Net of tax benefit (expense) of $0 for the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Statement of Comprehensive Income [Abstract]
Income tax benefit	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common Stock [Member] Class A Common Stock	Common Stock [Member] Class B Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non- Controlling Interest
Beginning balance (shares) at Dec. 27, 2017		26,527,477	10,250,007	26,527,477	10,250,007
Beginning balance at Dec. 27, 2017	$ 224,479			$ 27	$ 10	$ 153,105	$ 16,399	$ (49)	$ 54,987
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,550						11,112		4,438
Other comprehensive income:
Net change related to available-for-sale securities	13							10	3
Equity-based compensation	2,873					2,873
Activity under stock compensation plans (in shares)				253,439
Activity under stock compensation plans	3,566					2,103			1,463
Redemption of LLC Interests (in shares)				1,325,415	1,325,415
Redemption of LLC Interests	0			$ 1	$ (1)	7,359			(7,359)
Establishment of liabilities under tax receivable agreement and related changes to deferred tax assets associated with increases in tax basis	12,210					12,210
Distributions paid to non-controlling interest holders	(670)								(670)
Ending balance (shares) at Jun. 27, 2018		28,106,331	8,924,592	28,106,331	8,924,592
Ending balance at Jun. 27, 2018	256,447			$ 28	$ 9	177,650	26,337	0	52,423
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting changes \| Adjustments for New Accounting Pronouncement	(1,574)						(1,174)	39	(439)
Net income	10,571
Other comprehensive income:
Net change related to available-for-sale securities	0							0
Ending balance (shares) at Jun. 27, 2018		28,106,331	8,924,592	28,106,331	8,924,592
Ending balance at Jun. 27, 2018	$ 256,447			$ 28	$ 9	$ 177,650	$ 26,337	$ 0	$ 52,423

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017
OPERATING ACTIVITIES
Net income (including amounts attributable to non-controlling interests)	$ 15,550	$ 12,046
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation expense	13,466	10,006
Equity-based compensation	2,834	2,534
Deferred income taxes	805	2,561
Non-cash interest expense	72	154
Loss on sale of marketable securities	16	15
Loss on disposal of property and equipment	386	113
Unrealized loss on available-for-sale securities	61	0
Net loss on sublease	672	0
Changes in operating assets and liabilities:
Accounts receivable	1,777	3,964
Inventories	20	(162)
Prepaid expenses and other current assets	105	2,310
Other assets	(487)	(633)
Accounts payable	188	1,024
Accrued expenses	2,590	1,324
Accrued wages and related liabilities	587	(1,326)
Other current liabilities	(661)	(1,390)
Deferred rent	(71)	603
Other long-term liabilities	2,964	587
NET CASH PROVIDED BY OPERATING ACTIVITIES	40,874	33,730
INVESTING ACTIVITIES
Purchases of property and equipment	(36,364)	(24,986)
Purchases of marketable securities	(570)	(5,993)
Sales of marketable securities	2,144	5,628
NET CASH USED IN INVESTING ACTIVITIES	(34,790)	(25,351)
FINANCING ACTIVITIES
Proceeds from deemed landlord financing	559	530
Payments on deemed landlord financing	(167)	(101)
Distributions paid to non-controlling interest holders	(670)	(2,379)
Payments under tax receivable agreement	0	(1,471)
Proceeds from stock option exercises	3,566	6,187
Payments Related to Tax Withholding for Share-based Compensation	0	316
NET CASH PROVIDED BY FINANCING ACTIVITIES	3,288	2,450
NET INCREASE IN CASH AND CASH EQUIVALENTS	9,372	10,829
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	21,507	11,607
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 30,879	$ 22,436

NATURE OF OPERATIONS

6 Months Ended

Jun. 27, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

NATURE OF OPERATIONS

Shake Shack Inc. ("we," "us," "our," "Shake Shack" and the "Company") was formed on September 23, 2014 as a Delaware corporation for the purpose of facilitating an initial public offering and other related transactions in order to carry on the business of SSE Holdings, LLC and its subsidiaries ("SSE Holdings"). We are the sole managing member of SSE Holdings and, as sole managing member, we operate and control all of the business and affairs of SSE Holdings. As a result, we consolidate the financial results of SSE Holdings and report a non-controlling interest representing the economic interest in SSE Holdings held by the other members of SSE Holdings. As of June 27, 2018 we owned 75.9% of SSE Holdings. Unless the context otherwise requires, "we," "us," "our," "Shake Shack," the "Company" and other similar references, refer to Shake Shack Inc. and, unless otherwise stated, all of its subsidiaries, including SSE Holdings.

We operate and license Shake Shack restaurants ("Shacks"), which serve hamburgers, chicken sandwiches, hot dogs, crinkle-cut fries, shakes, frozen custard, beer, wine and more. As of June 27, 2018, there were 179 Shacks in operation, system-wide, of which 100 were domestic company-operated Shacks, 10 were domestic licensed Shacks and 69 were international licensed Shacks.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

6 Months Ended

Jun. 27, 2018

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of Shake Shack Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. These interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") and on a basis consistent in all material respects with the accounting policies described in our Annual Report on Form 10-K for the fiscal year ended December 27, 2017 ("2017 Form 10-K"). In our opinion, all adjustments, which are normal and recurring in nature, necessary for a fair presentation of our financial position and results of operation have been included. Certain reclassifications have been made to prior period amounts to conform to the current year presentation. Operating results for interim periods are not necessarily indicative of the results that may be expected for a full fiscal year.

The accompanying Condensed Consolidated Balance Sheet as of December 27, 2017 has been derived from the audited financial statements at that date but does not include all of the disclosures required by GAAP. These interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes thereto included in our 2017 Form 10-K.

SSE Holdings is considered a variable interest entity. Shake Shack Inc. is the primary beneficiary as we have the majority economic interest in SSE Holdings and, as the sole managing member, have decision making authority that significantly affects the economic performance of the entity, while the limited partners have no substantive kick-out or participating rights. As a result, we consolidate SSE Holdings. The assets and liabilities of SSE Holdings represent substantially all of our consolidated assets and liabilities with the exception of certain deferred taxes and liabilities under the Tax Receivable Agreement. As of June 27, 2018 and December 27, 2017, the net assets of SSE Holdings were $217,822 and $197,301, respectively. The assets of SSE Holdings are subject to certain restrictions in SSE Holdings' revolving credit agreements. See Note 8 for more information.

Fiscal Year

We operate on a 52/53 week fiscal year ending on the last Wednesday in December. Fiscal 2018 contains 52 weeks and ends on December 26, 2018. Fiscal 2017 contained 52 weeks and ended on December 27, 2017. Unless otherwise stated, references to years in this report relate to fiscal years.

Use of Estimates

The preparation of these condensed consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of sales and expenses during the reporting period. Actual results could differ from those estimates.

Recently Adopted Accounting Pronouncements

We adopted the Accounting Standards Updates (“ASUs”) summarized below in fiscal 2018.



Accounting Standards Update (“ASU”)	Description	Date Adopted
Revenue from Contracts with Customers and related standards (ASU’s 2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20)	This standard supersedes the existing revenue recognition guidance and provides a new framework for recognizing revenue. The core principle of the standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new standard also requires significantly more comprehensive disclosures than the existing standard. Guidance subsequent to ASU 2014-09 has been issued to clarify various provisions in the standard, including principal versus agent considerations, identifying performance obligations, licensing transactions, as well as various technical corrections and improvements. See Note 3 for more information.	December 28, 2017
Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01)	For public business entities, this standard requires: (i) certain equity investments to be measured at fair value with changes in fair value recognized in net income; (ii) a qualitative assessment to identify impairment of equity investments without readily determinable fair values; (iii) elimination of the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet; (iv) use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) separate presentation of financial assets and liabilities by measurement category and form of financial asset in the financial statements; and (vii) an entity to evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The adoption of this standard did not have a material impact to our consolidated financial statements.	December 28, 2017
Statement of Cash Flows: Classification of Certain Cash Receipts and Payments (ASU 2016-15)	This standard provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The adoption of this standard did not have a material impact to our consolidated financial statements.	December 28, 2017

Recently Issued Accounting Pronouncements



Accounting Standards Update (“ASU”)	Description	Expected Impact	Effective Date
Leases (ASU's 2016-02, 2018-01, 2018-10, 2018-11)	This standard establishes a new lease accounting model, which introduces the recognition of lease assets and liabilities for those leases classified as operating leases under previous GAAP. It should be applied using a modified retrospective approach applied either at the beginning of the earliest period presented, or at the adoption date, with the option to elect various practical expedients. Early adoption is permitted.	We are currently evaluating the provisions of the standard, including optional practical expedients. We are assessing the impact to our accounting policies, processes, disclosures and internal control over financial reporting. We plan to adopt the standard on December 27, 2018. It is likely that the adoption will have a significant impact to our consolidated balance sheet given the number of real estate leases we have. We are still evaluating the expected impact to our consolidated statements of income and cash flows.	December 27, 2018

REVENUE

6 Months Ended

Jun. 27, 2018

Revenue from Contract with Customer [Abstract]

REVENUE

On December 28, 2017 we adopted ASU 2014-09, Revenue from Contracts with Customers (Topic 606), using the modified retrospective method applied to those contracts which were not completed as of December 28, 2017. We elected a practical expedient to aggregate the effect of all contract modifications that occurred before the adoption date, which did not have a material impact to our consolidated financial statements. Results for reporting periods beginning on or after December 28, 2017 are presented under Accounting Standards Codification Topic 606 ("ASC 606"). Prior period amounts were not revised and continue to be reported in accordance with ASC Topic 605 ("ASC 605"), the accounting standard then in effect.

Upon transition, on December 28, 2017, we recorded a decrease to opening equity of $1,574, net of tax, of which $1,135 was recognized in retained earnings and $439 in non-controlling interest, with a corresponding increase of $1,769 in other long-term liabilities, a decrease of $68 in other current liabilities, and an increase of $100 to accounts receivable.

Revenue Recognition

Revenue consists of Shack sales and licensing revenue. Generally, revenue is recognized as promised goods or services transfer to the guest or customer in an amount that reflects the consideration we expect to be entitled in exchange for those goods or services.

Revenue from Shack sales is presented net of discounts and recognized when food, beverage and retail products are sold. Sales tax collected from customers is excluded from Shack sales and the obligation is included in sales tax payable until the taxes are remitted to the appropriate taxing authorities. Revenue from our gift cards is deferred and recognized upon redemption.

Licensing revenues include initial territory fees, Shack opening fees, and ongoing sales-based royalty fees from licensed Shacks. Generally, the licenses granted to develop, open, and operate each Shack in a specified territory are the predominant goods or services transferred to the licensee in our contracts, and represent distinct performance obligations. Ancillary promised services, such as training and assistance during the initial opening of a Shack, are typically combined with the licenses and considered as one performance obligation per Shack. We determine the transaction price for each contract, which is comprised of the initial territory fee, and an estimate of the total Shack opening fees we expect to be entitled to. The calculation of total Shack opening fees included in the transaction price requires judgment, as it is based on an estimate of the number of Shacks we expect the licensee to open. The transaction price is then allocated equally to each Shack expected to open. The performance obligations are satisfied over time, starting when a Shack opens, through the end of the term of the license granted to the Shack. Because we are transferring licenses to access our intellectual property during a contractual term, revenue is recognized on a straight-line basis over the license term. Generally, payment for the initial territory fee is received upon execution of the licensing agreement, and payment for the restaurant opening fees are received either in advance of or upon opening the related restaurant. These payments are initially deferred and recognized as revenue as the performance obligations are satisfied, which occurs over a long-term period.

Revenue from sales-based royalties is recognized as the related sales occur.

Prior to the adoption of ASC 606, Shack opening fees were recorded as deferred revenue when received and proportionate amounts were recognized as revenue when a licensed Shack opened and all material services and conditions related to the fee were substantially performed. Territory fees were recorded as deferred revenue when received and recognized as revenue on a straight-line basis over the term of the license agreement, which generally began upon execution of the contract.

Revenue recognized for the thirteen and twenty-six weeks ended June 27, 2018 under ASC 606 and revenue that would have been recognized for the thirteen and twenty-six weeks ended June 27, 2018 had ASC 605 been applied is as follows:



	Thirteen Weeks Ended June 27, 2018							Twenty-Six Weeks Ended June 27, 2018
	As reported under ASC 606		If reported under ASC 605		Increase (decrease)			As reported under ASC 606		If reported under ASC 605		Increase (decrease)
Shack sales	$	112,898	$	112,898	$	—		$	208,987	$	208,987	$	—
Licensing revenue	3,384		3,524		(140		)	6,411		6,672		(261		)
Total revenue	$	116,282	$	116,422	$	(140	)	$	215,398	$	215,659	$	(261	)

Revenue recognized during the thirteen and twenty-six weeks ended June 27, 2018 (under ASC 606) and thirteen and twenty-six weeks ended June 28, 2017 (under ASC 605) disaggregated by type is as follows:



	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	June 27 2018		June 28 2017		June 27 2018		June 28 2017
Shack sales	$	112,898	$	88,003	$	208,987	$	162,158
Licensing revenue:
Sales-based royalties	3,319		3,200		6,291		5,600
Initial territory and opening fees	65		113		120		307
Total revenue	$	116,282	$	91,316	$	215,398	$	168,065

The aggregate amount of the transaction price allocated to performance obligations that are unsatisfied (or partially unsatisfied) as of June 27, 2018 is $10,557. We expect to recognize this amount as revenue over a long-term period, as the license term for each Shack ranges from 10 to 20 years with renewals. This amount excludes any variable consideration related to sales-based royalties.

Contract Balances

Opening and closing balances of contract liabilities and receivables from contracts with customers is as follows:



	June 27 2018		December 28 2017
Shack sales receivables	$	2,496	$	2,184
Licensing receivables	2,933		1,522
Gift card liability	1,334		1,472
Deferred revenue, current	305		265
Deferred revenue, long-term	6,653		3,742

Revenue recognized during the thirteen and twenty-six weeks ended June 27, 2018 that was included in their respective liability balances at the beginning of the period is as follows:



	Thirteen Weeks Ended June 27 2018		Twenty-Six Weeks Ended June 27 2018
Gift card liability	$	102	$	408
Deferred revenue, current	63		118

FAIR VALUE MEASUREMENTS

6 Months Ended

Jun. 27, 2018

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present information about our financial assets and liabilities measured at fair value on a recurring basis as of June 27, 2018 and December 27, 2017, and indicate the classification within the fair value hierarchy.

Cash, Cash Equivalents and Marketable Securities

The following tables summarize our cash, cash equivalents and marketable securities by significant investment categories as of June 27, 2018 and December 27, 2017:



		June 27, 2018
		Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash		$	25,875	$	—	$	—		$	25,875	$	25,875	$	—
Level 1:
	Money market funds	5,004		—		—			5,004		5,004		—
	Mutual funds	61,521		—		(122		)	61,399		—		61,399
Level 2:
	Corporate debt securities⁽¹⁾	—		—		—			—		—		—
Total		$	92,400	$	—	$	(122	)	$	92,278	$	30,879	$	61,399



		December 27, 2017
		Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash		$	16,138	$	—	$	—		$	16,138	$	16,138	$	—
Level 1:
	Money market funds	5,369		—		—			5,369		5,369		—
	Mutual funds	60,985		—		(61		)	60,924		—		60,924
Level 2:
	Corporate debt securities⁽¹⁾	2,125		2		(15		)	2,112		—		2,112
Total		$	84,617	$	2	$	(76	)	$	84,543	$	21,507	$	63,036


(1)	Corporate debt securities were measured at fair value using a market approach utilizing observable prices for identical securities or securities with similar characteristics and inputs that are observable or can be corroborated by observable market data.

On December 28, 2017, we adopted ASU 2016-01, which requires certain equity investments to be measured at fair value with changes in fair value recognized in net income. Net unrealized losses on available-for-sale equity securities totaling $23 and $61 were included on the Condensed Consolidated Statements of Income during the thirteen and twenty-six weeks ended June 27, 2018, respectively. Net unrealized losses on available-for-sale securities totaling $74 were included in accumulated other comprehensive income (loss) on the Condensed Consolidated Balance Sheet as of December 27, 2017.

The following tables summarize the gross unrealized losses and fair values for those investments that were in an unrealized loss position as of June 27, 2018 and December 27, 2017, aggregated by investment category and the length of time that individual securities have been in a continuous loss position:



		June 27, 2018
		Less than 12 Months					12 Months or Greater				Total
		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
	Money market funds	$	—	$	—		$	—	$	—	$	—	$	—
	Mutual funds	61,399		(122		)	—		—		61,399		(122		)
	Corporate debt securities	—		—			—		—		—		—
Total		$	61,399	$	(122	)	$	—	$	—	$	61,399	$	(122	)



		December 27, 2017
		Less than 12 Months					12 Months or Greater					Total
		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
	Money market funds	$	—	$	—		$	—	$	—		$	—	$	—
	Mutual funds	60,924		(61		)	—		—			60,924		(61		)
	Corporate debt securities	1,675		(12		)	162		(3		)	1,837		(15		)
Total		$	62,599	$	(73	)	$	162	$	(3	)	$	62,761	$	(76	)

A summary of other income from available-for-sale securities recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



		Thirteen Weeks Ended						Twenty-Six Weeks Ended
		June 27 2018			June 28 2017			June 27 2018			June 28 2017
Available-for-sale securities:
	Dividend income	$	329		$	191		$	604		$	369
	Interest income	—			19			7			39
	Realized gain (loss) on sale of investments	—			(12		)	(16		)	(15		)
	Unrealized gain (loss) on available-for-sale equity securities	(23		)	—			(61		)	—
Total other income, net		$	306		$	198		$	534		$	393

A summary of available-for-sale securities sold and gross realized gains and losses recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



		Thirteen Weeks Ended					Twenty-Six Weeks Ended
		June 27 2018		June 28 2017			June 27 2018			June 28 2017
Available-for-sale securities:
	Gross proceeds from sales and redemptions	$	—	$	473		$	2,144		$	628
	Cost basis of sales and redemptions	—		484			2,160			642
	Gross realized gains included in net income	—		—			2			—
	Gross realized losses included in net income	—		(12		)	(18		)	(15		)
	Amounts reclassified out of accumulated other comprehensive loss	—		11			16			14

Realized gains and losses are determined on a specific identification method and are included in other income, net on the Condensed Consolidated Statements of Income.

We periodically review our marketable securities for other-than-temporary impairment. We consider factors such as the duration, severity and the reason for the decline in value, the potential recovery period and our intent to sell. As of June 27, 2018 and December 27, 2017, the declines in the market value of our marketable securities investment portfolio were considered to be temporary in nature.

Other Financial Instruments

The carrying value of our other financial instruments, including accounts receivable, accounts payable, and accrued expenses as of June 27, 2018 and December 27, 2017 approximated their fair value due to the short-term nature of these financial instruments.

Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis

Assets and liabilities that are measured at fair value on a non-recurring basis include our long-lived assets and indefinite-lived intangible assets. There were no impairments recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

INVENTORIES

6 Months Ended

Jun. 27, 2018

Inventory Disclosure [Abstract]

INVENTORIES

Inventories as of June 27, 2018 and December 27, 2017 consisted of the following:



	June 27 2018		December 27 2017
Food	$	873	$	874
Wine	66		69
Beer	82		85
Beverages	134		111
Retail merchandise	83		119
Inventories	$	1,238	$	1,258

PROPERTY AND EQUIPMENT

6 Months Ended

Jun. 27, 2018

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT

Property and equipment as of June 27, 2018 and December 27, 2017 consisted of the following:



	June 27 2018		December 27 2017
Leasehold improvements	$	186,349	$	166,963
Landlord funded assets	12,117		7,472
Equipment	34,709		31,608
Furniture and fixtures	11,779		10,128
Computer equipment and software	14,504		12,721
Construction in progress (includes landlord funded assets under construction)	27,836		16,458
Property and equipment, gross	287,294		245,350
Less: accumulated depreciation	70,531		58,255
Property and equipment, net	$	216,763	$	187,095

SUPPLEMENTAL BALANCE SHEET INFORMATION

6 Months Ended

Jun. 27, 2018

Supplemental Balance Sheet Disclosures [Abstract]

SUPPLEMENTAL BALANCE SHEET INFORMATION

The components of other current liabilities as of June 27, 2018 and December 27, 2017 are as follows:



	June 27 2018		December 27 2017
Sales tax payable	$	3,139	$	1,813
Current portion of liabilities under tax receivable agreement	943		937
Gift card liability	1,334		1,472
Other	2,239		3,715
Other current liabilities	$	7,655	$	7,937

DEBT

6 Months Ended

Jun. 27, 2018

Debt Disclosure [Abstract]

DEBT

In January 2015, we executed a Third Amended and Restated Credit Agreement, which became effective on February 4, 2015 (together with the prior agreements and amendments, and as further amended, the "Revolving Credit Facility"), which provides for a revolving total commitment amount of $50,000, of which $20,000 is available immediately. The Revolving Credit Facility will mature and all amounts outstanding will be due and payable five years from the effective date. The Revolving Credit Facility permits the issuance of letters of credit upon our request of up to $10,000. Borrowings under the Revolving Credit Facility bear interest at either: (i) LIBOR plus a percentage ranging from 2.3% to 3.3% or (ii) the prime rate plus a percentage ranging from 0.0% to 0.8%, depending on the type of borrowing made under the Revolving Credit Facility. As of June 27, 2018 and December 27, 2017, there were no amounts outstanding under the Revolving Credit Facility. As of June 27, 2018, we had $19,317 of availability under the Revolving Credit Facility, after giving effect to $683 in outstanding letters of credit.

The Revolving Credit Facility is secured by a first-priority security interest in substantially all of the assets of SSE Holdings and the guarantors. The obligations under the Revolving Credit Facility are guaranteed by each of SSE Holdings' wholly-owned domestic subsidiaries (with certain exceptions).

The Revolving Credit Facility contains a number of covenants that, among other things, limit our ability to, subject to specified exceptions, incur additional debt; incur additional liens and contingent liabilities; sell or dispose of assets; merge with or acquire other companies; liquidate or dissolve ourselves; pay dividends or make distributions; engage in businesses that are not in a related line of business; make loans, advances or guarantees; engage in transactions with affiliates; and make investments. In addition, the Revolving Credit Facility contains certain cross-default provisions. We are required to maintain a specified consolidated fixed-charge coverage ratio and a specified funded net debt to adjusted EBITDA ratio, both as defined under the Revolving Credit Facility. As of June 27, 2018, we were in compliance with all covenants.

As of June 27, 2018 and December 27, 2017 we had deemed landlord financing liabilities of $18,340 and $14,518, respectively, for certain leases where we are involved in the construction of leased assets and are considered the accounting owner of the construction project.

Total interest costs incurred were $655 and $1,264 for the thirteen and twenty-six weeks ended June 27, 2018, respectively, and $409 and $733 for the thirteen and twenty-six weeks ended June 28, 2017, respectively. Total amounts capitalized into property and equipment were $42 and $86 for the thirteen and twenty-six weeks ended June 27, 2018, respectively, and $43 and $64 for the thirteen and twenty-six weeks ended June 28, 2017, respectively.

NON-CONTROLLING INTERESTS

6 Months Ended

Jun. 27, 2018

Noncontrolling Interest [Abstract]

NON-CONTROLLING INTERESTS

We are the sole managing member of SSE Holdings and, as a result, consolidate the financial results of SSE Holdings. We report a non-controlling interest representing the economic interest in SSE Holdings held by the other members of SSE Holdings. The Third Amended and Restated Limited Liability Company Agreement, as further amended, (the "LLC Agreement") of SSE Holdings provides that holders of LLC Interests may, from time to time, require SSE Holdings to redeem all or a portion of their LLC Interests for newly-issued shares of Class A common stock on a one-for-one basis. In connection with any redemption or exchange, we will receive a corresponding number of LLC Interests, increasing our total ownership interest in SSE Holdings. Changes in our ownership interest in SSE Holdings while we retain our controlling interest in SSE Holdings will be accounted for as equity transactions. As such, future redemptions or direct exchanges of LLC Interests in SSE Holdings by the other members of SSE Holdings will result in a change in ownership and reduce the amount recorded as non-controlling interest and increase additional paid-in capital.

The following table summarizes the ownership interest in SSE Holdings as of June 27, 2018 and December 27, 2017.



	June 27, 2018			December 27, 2017
	LLC Interests	Ownership%		LLC Interests	Ownership %
Number of LLC Interests held by Shake Shack Inc.	28,106,331	75.9	%	26,527,477	72.1	%
Number of LLC Interests held by non-controlling interest holders	8,924,592	24.1	%	10,250,007	27.9	%
Total LLC Interests outstanding	37,030,923	100.0	%	36,777,484	100.0	%

The weighted average ownership percentages for the applicable reporting periods are used to attribute net income and other comprehensive income to Shake Shack Inc. and the non-controlling interest holders. The non-controlling interest holders' weighted average ownership percentage for the thirteen and twenty-six weeks ended June 27, 2018 was 24.8% and 25.6%, respectively. The non-controlling interest holders' weighted average ownership percentage for the thirteen and twenty-six weeks ended June 28, 2017 was 29.6% and 30.0%, respectively.

The following table summarizes the effects of changes in ownership of SSE Holdings on our equity during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.



		Thirteen Weeks Ended				Twenty-Six Weeks Ended
		June 27 2018		June 28 2017		June 27 2018		June 28 2017
Net income attributable to Shake Shack Inc.		$	7,604	$	4,879	$	11,112	$	7,146
Other comprehensive income (loss):
	Net change related to available-for-sale securities	—		2		10		(2		)
Transfers (to) from non-controlling interests:
	Increase in additional paid-in capital as a result of the redemption of LLC Interests	1,801		720		7,359		2,042
	Increase in additional paid-in capital as a result of activity under stock compensation plans	1,237		632		2,103		3,502
Total effect of changes in ownership interest on equity attributable to Shake Shack Inc.		$	10,642	$	6,233	$	20,584	$	12,688

During the twenty-six weeks ended June 27, 2018 and June 28, 2017, an aggregate of 1,325,415 and 482,600 LLC Interests, respectively, were redeemed by non-controlling interest holders for newly-issued shares of Class A common stock, and we received 1,325,415 and 482,600 LLC Interests in connection with these redemptions for the twenty-six weeks ended June 27, 2018 and June 28, 2017, respectively, increasing our total ownership interest in SSE Holdings.

During the twenty-six weeks ended June 27, 2018 and June 28, 2017, we received an aggregate of 253,439 and 305,882 LLC Interests, respectively, in connection with the activity under our stock compensation plan.

EQUITY-BASED COMPENSATION

6 Months Ended

Jun. 27, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

EQUITY-BASED COMPENSATION

A summary of equity-based compensation expense recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	June 27 2018		June 28 2017		June 27 2018		June 28 2017
Stock options	$	773	$	863	$	1,600	$	1,827
Performance stock units	464		399		918		684
Restricted stock units	160		23		316		23
Equity-based compensation expense	$	1,397	$	1,285	$	2,834	$	2,534
Total income tax benefit recognized related to equity-based compensation	$	42	$	44	$	80	$	95

Amounts are included in general and administrative expense and labor and related expenses on the Condensed Consolidated Statements of Income.

INCOME TAXES

6 Months Ended

Jun. 27, 2018

Income Tax Disclosure [Abstract]

INCOME TAXES

We are the sole managing member of SSE Holdings and, as a result, consolidate the financial results of SSE Holdings. SSE Holdings is treated as a partnership for U.S. federal and most applicable state and local income tax purposes. As a partnership, SSE Holdings is not subject to U.S. federal and certain state and local income taxes. Any taxable income or loss generated by SSE Holdings is passed through to and included in the taxable income or loss of its members, including us, on a pro rata basis. We are subject to U.S. federal income taxes, in addition to state and local income taxes with respect to our allocable share of any taxable income or loss of SSE Holdings, as well as any stand-alone income or loss generated by Shake Shack Inc. We are also subject to withholding taxes in foreign jurisdictions.

Income Tax Expense

A reconciliation of income tax expense computed at the U.S. federal statutory income tax rate to the recognized income tax expense is as follows:



	Thirteen Weeks Ended										Twenty-Six Weeks Ended
	June 27 2018					June 28 2017					June 27 2018					June 28 2017
Expected U.S. federal income taxes at statutory rate	$	2,690		21.0	%	$	4,050		35.0	%	$	3,987		21.0	%	$	5,982		35.0	%
State and local income taxes, net of federal benefit	830			6.5	%	659			5.7	%	1,242			6.5	%	1,008			5.9	%
Foreign withholding taxes	271			2.1	%	227			2.0	%	802			4.2	%	413			2.4	%
Tax credits	(920		)	(7.2	)%	(248		)	(2.1	)%	(1,197		)	(6.3	)%	(378		)	(2.2	)%
Non-controlling interest	(731		)	(5.7	)%	(1,303		)	(11.3	)%	(1,185		)	(6.2	)%	(1,982		)	(11.6	)%
Other	100			0.8	%	—			—	%	(211		)	(1.1	)%	—			—	%
Income tax expense	$	2,240		17.5	%	$	3,385		29.3	%	$	3,438		18.1	%	$	5,043		29.5	%

Our effective income tax rates for the thirteen weeks ended June 27, 2018 and June 28, 2017 were 17.5% and 29.3%, respectively. The decrease was primarily driven by the reduction of the U.S. federal corporate income tax rate from 35% to 21% due to the enactment of the Tax Cuts and Jobs Act of 2017 (the "TCJA"), partially offset by the increase in our ownership interest in SSE Holdings, which increases our share of the taxable income of SSE Holdings, and higher foreign withholding taxes. Our weighted-average ownership interest in SSE Holdings was 75.2% and 70.4% for the thirteen weeks ended June 27, 2018 and June 28, 2017, respectively.

Our effective income tax rates for twenty-six weeks ended June 27, 2018 and June 28, 2017 were 18.1% and 29.5%, respectively. The decrease was primarily driven by the reduction of the U.S. federal corporate income tax rate from 35% to 21% due to the enactment of the TCJA, partially offset by the increase in our ownership interest in SSE Holdings, which increases our share of the taxable income of SSE Holdings, and higher foreign withholding taxes. Our weighted-average ownership interest in SSE Holdings was 74.4% and 70.0% for the twenty-six weeks ended June 27, 2018 and June 28, 2017, respectively.

Deferred Tax Assets and Liabilities

During the twenty-six weeks ended June 27, 2018, we acquired an aggregate of 1,578,854 LLC Interests in connection with the redemption of LLC Interests and activity relating to our stock compensation plan. We recognized a deferred tax asset in the amount of $16,831 associated with the basis difference in our investment in SSE Holdings upon acquisition of these LLC Interests. As of June 27, 2018, the total deferred tax asset related to the basis difference in our investment in SSE Holdings was $160,314. However, a portion of the total basis difference will only reverse upon the eventual sale of our interest in SSE Holdings, which we expect would result in a capital loss. As of June 27, 2018, the total valuation allowance established against the deferred tax asset to which this portion relates was $10,649.

During the twenty-six weeks ended June 27, 2018, we also recognized $4,972 of deferred tax assets related to additional tax basis increases generated from expected future payments under the Tax Receivable Agreement and related deductions for imputed interest on such payments. See "—Tax Receivable Agreement" for more information.

We evaluate the realizability of our deferred tax assets on a quarterly basis and establish valuation allowances when it is more likely than not that all or a portion of a deferred tax asset may not be realized. As of June 27, 2018, we concluded, based on the weight of all available positive and negative evidence, that all of our deferred tax assets (except for those deferred tax assets described above relating to basis differences that are expected to result in a capital loss upon the eventual sale of our interest in SSE Holdings) are more likely than not to be realized. As such, no additional valuation allowance was recognized.

Uncertain Tax Positions

No uncertain tax positions existed as of June 27, 2018. Shake Shack Inc. was formed in September 2014 and did not engage in any operations prior to the IPO and related organizational transactions. Shake Shack Inc. first filed tax returns for tax year 2014, which is the first tax year subject to examination by taxing authorities for U.S. federal and state income tax purposes. Additionally, although SSE Holdings is treated as a partnership for U.S. federal and state income taxes purposes, it is still required to file an annual U.S. Return of Partnership Income, which is subject to examination by the Internal Revenue Service ("IRS"). The statute of limitations has expired for tax years through 2013 for SSE Holdings.

Tax Receivable Agreement

Pursuant to our election under Section 754 of the Internal Revenue Code (the "Code"), we expect to obtain an increase in our share of the tax basis in the net assets of SSE Holdings when LLC Interests are redeemed or exchanged by the other members of SSE Holdings. We plan to make an election under Section 754 of the Code for each taxable year in which a redemption or exchange of LLC Interest occurs. We intend to treat any redemptions and exchanges of LLC Interests as direct purchases of LLC Interests for U.S. federal income tax purposes. These increases in tax basis may reduce the amounts that we would otherwise pay in the future to various tax authorities. They may also decrease gains (or increase losses) on future dispositions of certain capital assets to the extent tax basis is allocated to those capital assets.

On February 4, 2015, we entered into a tax receivable agreement with certain of the then-existing members of SSE Holdings (the "Tax Receivable Agreement") that provides for the payment by us of 85% of the amount of any tax benefits that we actually realize, or in some cases are deemed to realize, as a result of (i) increases in our share of the tax basis in the net assets of SSE Holdings resulting from any redemptions or exchanges of LLC Interests, (ii) tax basis increases attributable to payments made under the Tax Receivable Agreement, and (iii) deductions attributable to imputed interest pursuant to the Tax Receivable Agreement (the "TRA Payments"). We expect to benefit from the remaining 15% of any tax benefits that we may actually realize. The TRA Payments are not conditioned upon any continued ownership interest in SSE Holdings or us. The rights of each member of SSE Holdings, that is a party to the Tax Receivable Agreement, are assignable to transferees of their respective LLC Interests.

During the twenty-six weeks ended June 27, 2018, we acquired an aggregate of 1,325,415 LLC Interests in connection with the redemption of LLC Interests, which resulted in an increase in the tax basis of our investment in SSE Holdings subject to the provisions of the Tax Receivable Agreement. We recognized an additional liability in the amount of $17,992 for the TRA Payments due to the

redeeming members, representing 85% of the aggregate tax benefits we expect to realize from the tax basis increases related to the redemption of LLC Interests, after concluding it was probable that such TRA Payments would be paid based on our estimates of future taxable income. No payments were made to the members of SSE Holdings pursuant to the Tax Receivable Agreement during the twenty-six weeks ended June 27, 2018. During the twenty-six weeks ended June 28, 2017, payments of $1,471, inclusive of interest, were made to the members of SSE Holdings pursuant to the Tax Receivable Agreement. As of June 27, 2018, the total amount of TRA Payments due under the Tax Receivable Agreement, was $177,370, of which $943 was included in other current liabilities on the Condensed Consolidated Balance Sheet. See Note 14 for more information relating to our liabilities under the Tax Receivable Agreement.

EARNINGS PER SHARE

6 Months Ended

Jun. 27, 2018

Earnings Per Share [Abstract]

EARNINGS PER SHARE

Basic earnings per share of Class A common stock is computed by dividing net income attributable to Shake Shack Inc. by the weighted-average number of shares of Class A common stock outstanding during the period. Diluted earnings per share of Class A common stock is computed by dividing net income attributable to Shake Shack Inc. by the weighted-average number of shares of Class A common stock outstanding adjusted to give effect to potentially dilutive securities.

The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.



			Thirteen Weeks Ended				Twenty-Six Weeks Ended
			June 27 2018		June 28 2017		June 27 2018		June 28 2017
Numerator:
	Net income		$	10,571	$	8,184	$	15,550	$	12,046
	Less: net income attributable to non-controlling interests		2,967		3,305		4,438		4,900
	Net income attributable to Shake Shack Inc.		$	7,604	$	4,879	$	11,112	$	7,146
Denominator:
	Weighted-average shares of Class A common stock outstanding—basic		27,796		25,798		27,418		25,587
	Effect of dilutive securities:
		Stock options	867		494		785		523
		Performance stock units	68		20		68		23
		Restricted stock units	23		—		17		—
	Weighted-average shares of Class A common stock outstanding—diluted		28,754		26,312		28,288		26,133

Earnings per share of Class A common stock—basic			$	0.27	$	0.19	$	0.41	$	0.28
Earnings per share of Class A common stock—diluted			$	0.26	$	0.19	$	0.39	$	0.27

Shares of our Class B common stock do not share in the earnings or losses of Shake Shack and are therefore not participating securities. As such, separate presentation of basic and diluted earnings per share of Class B common stock under the two-class method has not been presented.

The following table presents potentially dilutive securities excluded from the computations of diluted earnings per share of Class A common stock for the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.



	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	June 27 2018		June 28 2017		June 27 2018		June 28 2017
Stock options	—		6,258	(1)	—		6,258	(1)
Performance stock units	60,437	(2)	84,755	(2)	60,437	(2)	84,755	(2)
Shares of Class B common stock	8,924,592	(3)	10,770,992	(3)	8,924,592	(3)	10,770,992	(3)

(1) Excluded from the computation of diluted earnings per share of Class A common stock because the exercise price of the stock options exceeded the average market price of our Class A common stock during the period ("out-of-the-money").

(2) Excluded from the computation of diluted earnings per share of Class A common stock because the performance conditions associated with these awards were not met assuming the end of the reporting period was the end of the performance period.

(3) Shares of our Class B common stock are considered potentially dilutive shares of Class A common stock. Amounts have been excluded from the computations of diluted earnings per share of Class A common stock because the effect would have been anti-dilutive under the if-converted and two-class methods.

SUPPLEMENTAL CASH FLOW INFORMATION

6 Months Ended

Jun. 27, 2018

Supplemental Cash Flow Elements [Abstract]

SUPPLEMENTAL CASH FLOW INFORMATION

The following table sets forth supplemental cash flow information for the twenty-six weeks ended June 27, 2018 and June 28, 2017:



		Twenty-Six Weeks Ended
		June 27 2018			June 28 2017
Cash paid for:
	Income taxes, net of refunds	$	1,436		$	1,595
	Interest, net of amounts capitalized	1,067			357
Non-cash investing activities:
	Accrued purchases of property and equipment	10,692			7,690
	Capitalized landlord assets for leases where we are deemed the accounting owner	3,307			7,634
	Accrued purchases of marketable securities	—			80
	Capitalized equity-based compensation	39			78
Non-cash financing activities:
	Class A common stock issued in connection with the redemption of LLC Interests	1			—
	Cancellation of Class B common stock in connection with the redemption of LLC Interests	(1		)	—
	Establishment of liabilities under tax receivable agreement	17,992			9,413

COMMITMENTS AND CONTINGENCIES

6 Months Ended

Jun. 27, 2018

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Lease Commitments

We are obligated under various operating leases for Shacks and our home office space, expiring in various years through 2035. Under certain of these leases, we are liable for contingent rent based on a percentage of sales in excess of specified thresholds and are typically responsible for our proportionate share of real estate taxes, common area maintenance charges and utilities.

As security under the terms of several of our leases, we are obligated under letters of credit totaling $160 as of June 27, 2018. The letters of credit expire in April 2019 and February 2026. In addition, in December 2013, we entered into an irrevocable standby letter of credit in conjunction with our home office lease in the amount of $80. The letter of credit expires in September 2018 and renews automatically for one-year periods through September 2019. In September 2017, we entered into an irrevocable standby letter of credit in conjunction with our new home office lease in the amount of $603. The letter of credit expires in August 2018 and renews automatically for one-year periods through January 2034.

Purchase Commitments

Purchase obligations include legally binding contracts, including commitments for the purchase, construction or remodeling of real estate and facilities, firm minimum commitments for inventory purchases, equipment purchases, marketing-related contracts, software acquisition/license commitments and service contracts. These obligations are generally short-term in nature and are recorded as liabilities when the related goods are received or services rendered. We also enter into long-term, exclusive contracts with certain vendors to supply us with food, beverages and paper goods, obligating us to purchase specified quantities.

Legal Contingencies

We are subject to various legal and regulatory proceedings, claims and liabilities, such as employment-related claims and slip and fall cases, which arise in the ordinary course of business and are generally covered by insurance. As of June 27, 2018, the amount of ultimate liability with respect to these matters was not material.

Liabilities under Tax Receivable Agreement

As described in Note 11, we are a party to the Tax Receivable Agreement under which we are contractually committed to pay certain of the members of SSE Holdings 85% of the amount of any tax benefits that we actually realize, or in some cases are deemed to realize, as a result of certain transactions. We are not obligated to make any payments under the Tax Receivable Agreement until the tax benefits associated with the transactions that gave rise to the payments are realized. Amounts payable under the Tax Receivable Agreement are contingent upon, among other things, (i) generation of future taxable income over the term of the Tax Receivable Agreement and (ii) future changes in tax laws. If we do not generate sufficient taxable income in the aggregate over the term of the Tax Receivable Agreement to utilize the tax benefits, then we would not be required to make the related TRA Payments. During the twenty-six weeks ended June 27, 2018 and June 28, 2017, we recognized liabilities totaling $17,992 and $9,413, respectively, relating to our obligations under the Tax Receivable Agreement, after concluding that it was probable that we would have sufficient future taxable income over the term of the Tax Receivable Agreement to utilize the related tax benefits. As of June 27, 2018 and December 27, 2017, our total obligations under the Tax Receivable Agreement, including accrued interest, were $177,370 and $159,373, respectively. There were no transactions subject to the Tax Receivable Agreement for which we did not recognize the related liability, as we concluded that we would have sufficient future taxable income to utilize all of the related tax benefits.

RELATED PARTY TRANSACTIONS

6 Months Ended

Jun. 27, 2018

RELATED PARTY TRANSACTIONS

Union Square Hospitality Group

The Chairman of our Board of Directors serves as the Chief Executive Officer of Union Square Hospitality Group, LLC. As a result, Union Square Hospitality Group, LLC and its subsidiaries, set forth below, are considered related parties.

USHG, LLC

Effective January 2015, we entered into an Amended and Restated Management Services Agreement with USHG, LLC ("USHG"), in which USHG provides reduced management services to SSE Holdings comprised of executive leadership from members of its senior management, advisory and development services and limited leadership development and human resources services. The initial term of the Amended and Restated Management Services Agreement is through December 31, 2019, with renewal periods.

No amounts were paid to USHG for general corporate expenses for the thirteen weeks ended June 27, 2018. Amounts paid to USHG for general corporate expenses were $2 for the twenty-six weeks ended June 27, 2018. Amounts paid to USHG for general corporate expenses were $1 and $6 for the thirteen and twenty-six weeks ended June 28, 2017, respectively. These amounts are included in general and administrative expenses on the Condensed Consolidated Statements of Income.

No amounts were payable to USHG as of June 27, 2018 and December 27, 2017. No amounts were due from USHG as of June 27, 2018 and December 27, 2017.

Hudson Yards Sports and Entertainment

In fiscal 2011, we entered into a Master License Agreement (as amended, "MLA") with Hudson Yards Sports and Entertainment LLC ("HYSE") to operate Shake Shack branded limited menu concession stands in sports and entertainment venues within the United States. The agreement expires in January 2027 and includes five consecutive five-year renewal options at HYSE's option. As consideration for these rights, HYSE pays us a license fee based on a percentage of net food sales, as defined in the MLA. HYSE also pays us a percentage of profits on sales of branded beverages, as defined in the MLA. Amount paid to us by the HYSE for the thirteen and twenty-six weeks ended June 27, 2018 were $64 and $111, respectively. Amounts paid to us by HYSE for the thirteen and twenty-six weeks ended June 28, 2017 were $115 and $135, respectively. These amounts are included in licensing revenue on the Condensed Consolidated Statements of Income. Total amounts due from HYSE as of June 27, 2018 and December 27, 2017 were $114 and $18, respectively, which are included in prepaid expenses and other current assets on the Condensed Consolidated Balance Sheets.

Madison Square Park Conservancy

The Chairman of our Board of Directors serves as a director of the Madison Square Park Conservancy ("MSP Conservancy"), with which we have a license agreement and pay license fees to operate our Madison Square Park Shack. Amounts paid to MSP Conservancy as rent amounted to $203 and $470 for the thirteen and twenty-six weeks ended June 27, 2018, respectively. Amounts paid to MSP Conservancy as rent amounted to $133 and $332 for the thirteen and twenty-six weeks ended June 28, 2017, respectively. These amounts are included in occupancy and related expenses on the Condensed Consolidated Statements of Income. No amounts were due to MSP Conservancy as of June 27, 2018 and December 27, 2017.

No amounts were paid to us from MSP Conservancy during the thirteen and twenty-six weeks ended June 27, 2018. No amounts were paid to us from MSP Conservancy during the thirteen weeks ended June 28, 2017. Amounts paid to us during the twenty-six weeks ended June 28, 2017 totaled $200. No amounts were due to us from MSP Conservancy as of June 27, 2018 and December 27, 2017.

Share Our Strength

The Chairman of our Board of Directors serves as a director of Share Our Strength, for which Shake Shack holds the "Great American Shake Sale" every year during the month of May to raise money and awareness for childhood hunger. During the Great American Shake Sale, we encourage guests to donate money to Share Our Strength's No Kid Hungry campaign in exchange for a coupon for a free cake-themed shake. All of the guest donations we collect go directly to Share Our Strength.

During the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 the Great American Shake Sale raised $343 and $631, respectively, for Share Our Strength. All proceeds were remitted to Share Our Strength in the respective years. We incurred costs of approximately $53 for both the thirteen and twenty-six weeks ended June 27, 2018 and $119 for both the thirteen and twenty-six weeks ended June 28, 2017. These costs represents the cost of the free shakes redeemed and are included in general and administrative expenses on the Condensed Consolidated Statements of Income.

Mobo Systems, Inc.

The Chairman of our Board of Directors serves as a director of Mobo Systems, Inc. (also known as "Olo"), a platform we use in connection with our mobile ordering application. Amounts paid to Olo during the thirteen and twenty-six weeks ended June 27, 2018 were $27 and $52, respectively. Amounts paid to Olo during the thirteen and twenty-six weeks ended June 28, 2017 were $20 and

$38, respectively. These amounts are included in other operating expenses on the Condensed Consolidated Statements of Income. No amounts were payable to Olo as of June 27, 2018 and December 27, 2017.

Square, Inc.

In July 2017, our Chief Executive Officer joined the Board of Directors of Square, Inc. ("Square"). We currently use certain point-of-sale applications, payment processing services, hardware and other enterprise platform services in connection with the processing of a limited amount of sales at certain of our Shacks, sales for certain off-site events and in connection with our kiosk technology. Additionally, we partnered with Caviar, Square’s food ordering service for delivery services, in a number of cities for limited-time delivery promotions.

Tax Receivable Agreement

As described in Note 11, we entered into a tax receivable agreement with certain members of SSE Holdings that provides for the payment by us of 85% of the amount of tax benefits, if any, that Shake Shack actually realizes or in some cases is deemed to realize as a result of certain transactions. No payments were made to the members of SSE Holdings pursuant to the Tax Receivable Agreement during the thirteen and twenty-six weeks ended June 27, 2018. No payments were paid to the members during the thirteen weeks ended June 28, 2017. During the twenty-six weeks ended June 28, 2017, payments totaling $1,471, inclusive of interest, were made to the members of SSE Holdings pursuant to the Tax Receivable Agreement. As of June 27, 2018 and December 27, 2017, total amounts due under the Tax Receivable Agreement were $177,370 and $159,373, respectively.

Distributions to Members of SSE Holdings

Under the terms of the SSE Holdings LLC Agreement, SSE Holdings is obligated to make tax distributions to its members. During the thirteen and twenty-six weeks ended June 27, 2018 distributions paid to non-controlling interest holders were $587 and $670, respectively. During the thirteen and twenty-six weeks ended June 28, 2017 distributions paid non-controlling interest holder were $2,024 and $2,379, respectively. No tax distributions were payable to non-controlling interest holders as of June 27, 2018 and December 27, 2017.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

6 Months Ended

Jun. 27, 2018

Accounting Policies [Abstract]

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of Shake Shack Inc. and its subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. These interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") and on a basis consistent in all material respects with the accounting policies described in our Annual Report on Form 10-K for the fiscal year ended December 27, 2017 ("2017 Form 10-K"). In our opinion, all adjustments, which are normal and recurring in nature, necessary for a fair presentation of our financial position and results of operation have been included. Certain reclassifications have been made to prior period amounts to conform to the current year presentation. Operating results for interim periods are not necessarily indicative of the results that may be expected for a full fiscal year.

The accompanying Condensed Consolidated Balance Sheet as of December 27, 2017 has been derived from the audited financial statements at that date but does not include all of the disclosures required by GAAP. These interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes thereto included in our 2017 Form 10-K.

SSE Holdings is considered a variable interest entity. Shake Shack Inc. is the primary beneficiary as we have the majority economic interest in SSE Holdings and, as the sole managing member, have decision making authority that significantly affects the economic performance of the entity, while the limited partners have no substantive kick-out or participating rights. As a result, we consolidate SSE Holdings. The assets and liabilities of SSE Holdings represent substantially all of our consolidated assets and liabilities with the exception of certain deferred taxes and liabilities under the Tax Receivable Agreement. As of June 27, 2018 and December 27, 2017, the net assets of SSE Holdings were $217,822 and $197,301, respectively. The assets of SSE Holdings are subject to certain restrictions in SSE Holdings' revolving credit agreements. See Note 8 for more information.

Fiscal Year

Fiscal YearWe operate on a 52/53 week fiscal year ending on the last Wednesday in December. Fiscal 2018 contains 52 weeks and ends on December 26, 2018. Fiscal 2017 contained 52 weeks and ended on December 27, 2017. Unless otherwise stated, references to years in this report relate to fiscal years.

Use of Estimates

Use of EstimatesThe preparation of these condensed consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of sales and expenses during the reporting period. Actual results could differ from those estimates.

Recently Adopted and Issued Accounting Pronouncements

Recently Adopted Accounting Pronouncements

We adopted the Accounting Standards Updates (“ASUs”) summarized below in fiscal 2018.



Accounting Standards Update (“ASU”)	Description	Date Adopted
Revenue from Contracts with Customers and related standards (ASU’s 2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20)	This standard supersedes the existing revenue recognition guidance and provides a new framework for recognizing revenue. The core principle of the standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The new standard also requires significantly more comprehensive disclosures than the existing standard. Guidance subsequent to ASU 2014-09 has been issued to clarify various provisions in the standard, including principal versus agent considerations, identifying performance obligations, licensing transactions, as well as various technical corrections and improvements. See Note 3 for more information.	December 28, 2017
Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01)	For public business entities, this standard requires: (i) certain equity investments to be measured at fair value with changes in fair value recognized in net income; (ii) a qualitative assessment to identify impairment of equity investments without readily determinable fair values; (iii) elimination of the requirement to disclose the method(s) and significant assumptions used to estimate the fair value for financial instruments measured at amortized cost on the balance sheet; (iv) use of the exit price notion when measuring the fair value of financial instruments for disclosure purposes; (v) separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; (vi) separate presentation of financial assets and liabilities by measurement category and form of financial asset in the financial statements; and (vii) an entity to evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The adoption of this standard did not have a material impact to our consolidated financial statements.	December 28, 2017
Statement of Cash Flows: Classification of Certain Cash Receipts and Payments (ASU 2016-15)	This standard provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice. The adoption of this standard did not have a material impact to our consolidated financial statements.	December 28, 2017

Recently Issued Accounting Pronouncements



Accounting Standards Update (“ASU”)	Description	Expected Impact	Effective Date
Leases (ASU's 2016-02, 2018-01, 2018-10, 2018-11)	This standard establishes a new lease accounting model, which introduces the recognition of lease assets and liabilities for those leases classified as operating leases under previous GAAP. It should be applied using a modified retrospective approach applied either at the beginning of the earliest period presented, or at the adoption date, with the option to elect various practical expedients. Early adoption is permitted.	We are currently evaluating the provisions of the standard, including optional practical expedients. We are assessing the impact to our accounting policies, processes, disclosures and internal control over financial reporting. We plan to adopt the standard on December 27, 2018. It is likely that the adoption will have a significant impact to our consolidated balance sheet given the number of real estate leases we have. We are still evaluating the expected impact to our consolidated statements of income and cash flows.	December 27, 2018

REVENUE (Tables)

6 Months Ended

Jun. 27, 2018

Revenue from Contract with Customer [Abstract]

Schedule of Disaggregation of Revenue

Revenue recognized for the thirteen and twenty-six weeks ended June 27, 2018 under ASC 606 and revenue that would have been recognized for the thirteen and twenty-six weeks ended June 27, 2018 had ASC 605 been applied is as follows:



	Thirteen Weeks Ended June 27, 2018							Twenty-Six Weeks Ended June 27, 2018
	As reported under ASC 606		If reported under ASC 605		Increase (decrease)			As reported under ASC 606		If reported under ASC 605		Increase (decrease)
Shack sales	$	112,898	$	112,898	$	—		$	208,987	$	208,987	$	—
Licensing revenue	3,384		3,524		(140		)	6,411		6,672		(261		)
Total revenue	$	116,282	$	116,422	$	(140	)	$	215,398	$	215,659	$	(261	)

Revenue recognized during the thirteen and twenty-six weeks ended June 27, 2018 (under ASC 606) and thirteen and twenty-six weeks ended June 28, 2017 (under ASC 605) disaggregated by type is as follows:



	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	June 27 2018		June 28 2017		June 27 2018		June 28 2017
Shack sales	$	112,898	$	88,003	$	208,987	$	162,158
Licensing revenue:
Sales-based royalties	3,319		3,200		6,291		5,600
Initial territory and opening fees	65		113		120		307
Total revenue	$	116,282	$	91,316	$	215,398	$	168,065

Schedule of Contract with Customer, Asset and Liability

Opening and closing balances of contract liabilities and receivables from contracts with customers is as follows:



	June 27 2018		December 28 2017
Shack sales receivables	$	2,496	$	2,184
Licensing receivables	2,933		1,522
Gift card liability	1,334		1,472
Deferred revenue, current	305		265
Deferred revenue, long-term	6,653		3,742

Revenue recognized during the thirteen and twenty-six weeks ended June 27, 2018 that was included in their respective liability balances at the beginning of the period is as follows:



	Thirteen Weeks Ended June 27 2018		Twenty-Six Weeks Ended June 27 2018
Gift card liability	$	102	$	408
Deferred revenue, current	63		118

FAIR VALUE MEASUREMENTS (Tables)

6 Months Ended

Jun. 27, 2018

Fair Value Disclosures [Abstract]

Schedule of Cash and Cash Equivalents

The following tables summarize our cash, cash equivalents and marketable securities by significant investment categories as of June 27, 2018 and December 27, 2017:



		June 27, 2018
		Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash		$	25,875	$	—	$	—		$	25,875	$	25,875	$	—
Level 1:
	Money market funds	5,004		—		—			5,004		5,004		—
	Mutual funds	61,521		—		(122		)	61,399		—		61,399
Level 2:
	Corporate debt securities⁽¹⁾	—		—		—			—		—		—
Total		$	92,400	$	—	$	(122	)	$	92,278	$	30,879	$	61,399



		December 27, 2017
		Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Cash and Cash Equivalents		Marketable Securities
Cash		$	16,138	$	—	$	—		$	16,138	$	16,138	$	—
Level 1:
	Money market funds	5,369		—		—			5,369		5,369		—
	Mutual funds	60,985		—		(61		)	60,924		—		60,924
Level 2:
	Corporate debt securities⁽¹⁾	2,125		2		(15		)	2,112		—		2,112
Total		$	84,617	$	2	$	(76	)	$	84,543	$	21,507	$	63,036

(1)

Corporate debt securities were measured at fair value using a market approach utilizing observable prices for identical securities or securities with similar characteristics and inputs that are observable or can be corroborated by observable market data.

Schedule of Unrealized Loss on Investments

The following tables summarize the gross unrealized losses and fair values for those investments that were in an unrealized loss position as of June 27, 2018 and December 27, 2017, aggregated by investment category and the length of time that individual securities have been in a continuous loss position:



		June 27, 2018
		Less than 12 Months					12 Months or Greater				Total
		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
	Money market funds	$	—	$	—		$	—	$	—	$	—	$	—
	Mutual funds	61,399		(122		)	—		—		61,399		(122		)
	Corporate debt securities	—		—			—		—		—		—
Total		$	61,399	$	(122	)	$	—	$	—	$	61,399	$	(122	)



		December 27, 2017
		Less than 12 Months					12 Months or Greater					Total
		Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
	Money market funds	$	—	$	—		$	—	$	—		$	—	$	—
	Mutual funds	60,924		(61		)	—		—			60,924		(61		)
	Corporate debt securities	1,675		(12		)	162		(3		)	1,837		(15		)
Total		$	62,599	$	(73	)	$	162	$	(3	)	$	62,761	$	(76	)

Schedule of Other Income From Available for Sale Securities

A summary of other income from available-for-sale securities recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



		Thirteen Weeks Ended						Twenty-Six Weeks Ended
		June 27 2018			June 28 2017			June 27 2018			June 28 2017
Available-for-sale securities:
	Dividend income	$	329		$	191		$	604		$	369
	Interest income	—			19			7			39
	Realized gain (loss) on sale of investments	—			(12		)	(16		)	(15		)
	Unrealized gain (loss) on available-for-sale equity securities	(23		)	—			(61		)	—
Total other income, net		$	306		$	198		$	534		$	393

Schedule of Available-for-sale Securities and Gross Realized Gains and Losses

A summary of available-for-sale securities sold and gross realized gains and losses recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



		Thirteen Weeks Ended					Twenty-Six Weeks Ended
		June 27 2018		June 28 2017			June 27 2018			June 28 2017
Available-for-sale securities:
	Gross proceeds from sales and redemptions	$	—	$	473		$	2,144		$	628
	Cost basis of sales and redemptions	—		484			2,160			642
	Gross realized gains included in net income	—		—			2			—
	Gross realized losses included in net income	—		(12		)	(18		)	(15		)
	Amounts reclassified out of accumulated other comprehensive loss	—		11			16			14

- Definition

Tabular disclosure of the realized and unrealized gains and losses reported in the statement of income which have resulted from the sale and holding of marketable securities, respectively, as well as the sale or disposal of cost method investments. Such amounts would include realized gains and losses on the sale or disposal of trading, available-for-sale, and held-to-maturity securities, unrealized gains and losses on trading securities, unrealized gains and losses on available-for-sale and held-to-maturity securities transferred to the trading securities category, realized gains and losses on the sale or disposal of cost method investments, and losses recognized for other than temporary impairments (OTTI) of such investments.

+ References + Details

INVENTORIES (Tables)

6 Months Ended

Jun. 27, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories as of June 27, 2018 and December 27, 2017 consisted of the following:



	June 27 2018		December 27 2017
Food	$	873	$	874
Wine	66		69
Beer	82		85
Beverages	134		111
Retail merchandise	83		119
Inventories	$	1,238	$	1,258

PROPERTY AND EQUIPMENT (Tables)

6 Months Ended

Jun. 27, 2018

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Property and equipment as of June 27, 2018 and December 27, 2017 consisted of the following:



	June 27 2018		December 27 2017
Leasehold improvements	$	186,349	$	166,963
Landlord funded assets	12,117		7,472
Equipment	34,709		31,608
Furniture and fixtures	11,779		10,128
Computer equipment and software	14,504		12,721
Construction in progress (includes landlord funded assets under construction)	27,836		16,458
Property and equipment, gross	287,294		245,350
Less: accumulated depreciation	70,531		58,255
Property and equipment, net	$	216,763	$	187,095

SUPPLEMENTAL BALANCE SHEET INFORMATION (Tables)

6 Months Ended

Jun. 27, 2018

Supplemental Balance Sheet Disclosures [Abstract]

Supplemental Balance Sheet Information

The components of other current liabilities as of June 27, 2018 and December 27, 2017 are as follows:



	June 27 2018		December 27 2017
Sales tax payable	$	3,139	$	1,813
Current portion of liabilities under tax receivable agreement	943		937
Gift card liability	1,334		1,472
Other	2,239		3,715
Other current liabilities	$	7,655	$	7,937

NON-CONTROLLING INTERESTS (Tables)

6 Months Ended

Jun. 27, 2018

Noncontrolling Interest [Abstract]

Schedule of Ownership Interests in SSE Holdings

The following table summarizes the ownership interest in SSE Holdings as of June 27, 2018 and December 27, 2017.



	June 27, 2018			December 27, 2017
	LLC Interests	Ownership%		LLC Interests	Ownership %
Number of LLC Interests held by Shake Shack Inc.	28,106,331	75.9	%	26,527,477	72.1	%
Number of LLC Interests held by non-controlling interest holders	8,924,592	24.1	%	10,250,007	27.9	%
Total LLC Interests outstanding	37,030,923	100.0	%	36,777,484	100.0	%

Schedule of Non-Controlling Interest

The following table summarizes the effects of changes in ownership of SSE Holdings on our equity during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.



		Thirteen Weeks Ended				Twenty-Six Weeks Ended
		June 27 2018		June 28 2017		June 27 2018		June 28 2017
Net income attributable to Shake Shack Inc.		$	7,604	$	4,879	$	11,112	$	7,146
Other comprehensive income (loss):
	Net change related to available-for-sale securities	—		2		10		(2		)
Transfers (to) from non-controlling interests:
	Increase in additional paid-in capital as a result of the redemption of LLC Interests	1,801		720		7,359		2,042
	Increase in additional paid-in capital as a result of activity under stock compensation plans	1,237		632		2,103		3,502
Total effect of changes in ownership interest on equity attributable to Shake Shack Inc.		$	10,642	$	6,233	$	20,584	$	12,688

EQUITY-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 27, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Equity-Based Compensation Expense Recognized

A summary of equity-based compensation expense recognized during the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017 is as follows:



	Thirteen Weeks Ended				Twenty-Six Weeks Ended
	June 27 2018		June 28 2017		June 27 2018		June 28 2017
Stock options	$	773	$	863	$	1,600	$	1,827
Performance stock units	464		399		918		684
Restricted stock units	160		23		316		23
Equity-based compensation expense	$	1,397	$	1,285	$	2,834	$	2,534
Total income tax benefit recognized related to equity-based compensation	$	42	$	44	$	80	$	95

INCOME TAXES (Tables)

6 Months Ended

Jun. 27, 2018

Income Tax Disclosure [Abstract]

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of income tax expense computed at the U.S. federal statutory income tax rate to the recognized income tax expense is as follows:



	Thirteen Weeks Ended										Twenty-Six Weeks Ended
	June 27 2018					June 28 2017					June 27 2018					June 28 2017
Expected U.S. federal income taxes at statutory rate	$	2,690		21.0	%	$	4,050		35.0	%	$	3,987		21.0	%	$	5,982		35.0	%
State and local income taxes, net of federal benefit	830			6.5	%	659			5.7	%	1,242			6.5	%	1,008			5.9	%
Foreign withholding taxes	271			2.1	%	227			2.0	%	802			4.2	%	413			2.4	%
Tax credits	(920		)	(7.2	)%	(248		)	(2.1	)%	(1,197		)	(6.3	)%	(378		)	(2.2	)%
Non-controlling interest	(731		)	(5.7	)%	(1,303		)	(11.3	)%	(1,185		)	(6.2	)%	(1,982		)	(11.6	)%
Other	100			0.8	%	—			—	%	(211		)	(1.1	)%	—			—	%
Income tax expense	$	2,240		17.5	%	$	3,385		29.3	%	$	3,438		18.1	%	$	5,043		29.5	%

EARNINGS PER SHARE (Tables)

6 Months Ended

Jun. 27, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share

The following table sets forth reconciliations of the numerators and denominators used to compute basic and diluted earnings per share of Class A common stock for the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.



			Thirteen Weeks Ended				Twenty-Six Weeks Ended
			June 27 2018		June 28 2017		June 27 2018		June 28 2017
Numerator:
	Net income		$	10,571	$	8,184	$	15,550	$	12,046
	Less: net income attributable to non-controlling interests		2,967		3,305		4,438		4,900
	Net income attributable to Shake Shack Inc.		$	7,604	$	4,879	$	11,112	$	7,146
Denominator:
	Weighted-average shares of Class A common stock outstanding—basic		27,796		25,798		27,418		25,587
	Effect of dilutive securities:
		Stock options	867		494		785		523
		Performance stock units	68		20		68		23
		Restricted stock units	23		—		17		—
	Weighted-average shares of Class A common stock outstanding—diluted		28,754		26,312		28,288		26,133

Earnings per share of Class A common stock—basic			$	0.27	$	0.19	$	0.41	$	0.28
Earnings per share of Class A common stock—diluted			$	0.26	$	0.19	$	0.39	$	0.27

SUPPLEMENTAL CASH FLOW INFORMATION (Tables)

6 Months Ended

Jun. 27, 2018

Supplemental Cash Flow Elements [Abstract]

Schedule of Cash Flow Information

The following table sets forth supplemental cash flow information for the twenty-six weeks ended June 27, 2018 and June 28, 2017:



		Twenty-Six Weeks Ended
		June 27 2018			June 28 2017
Cash paid for:
	Income taxes, net of refunds	$	1,436		$	1,595
	Interest, net of amounts capitalized	1,067			357
Non-cash investing activities:
	Accrued purchases of property and equipment	10,692			7,690
	Capitalized landlord assets for leases where we are deemed the accounting owner	3,307			7,634
	Accrued purchases of marketable securities	—			80
	Capitalized equity-based compensation	39			78
Non-cash financing activities:
	Class A common stock issued in connection with the redemption of LLC Interests	1			—
	Cancellation of Class B common stock in connection with the redemption of LLC Interests	(1		)	—
	Establishment of liabilities under tax receivable agreement	17,992			9,413

NATURE OF OPERATIONS (Details) - Restaurant	Jun. 27, 2018	Dec. 27, 2017
Class of Stock [Line Items]
Ownership percent of noncontrolling interest	75.90%	72.10%
Number of restaurants	179
United States \| Company-operated
Class of Stock [Line Items]
Number of restaurants	100
United States \| Licensed
Class of Stock [Line Items]
Number of restaurants	10
Non-United States \| Licensed
Class of Stock [Line Items]
Number of restaurants	69

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Net assets held by SSE holders	$ 217,822	$ 197,301

REVENUE - Narrative (Details) - USD ($) $ in Thousands	Dec. 28, 2017	Jun. 27, 2018	Dec. 27, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term liabilities		$ 7,256	$ 2,553
Other current liabilities		7,655	$ 7,937
Revenue, remaining performance obligation		$ 10,557
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Opening equity	$ 1,574
Other long-term liabilities	1,769
Other current liabilities	68
Accounts receivable	100
Retained Earnings \| Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Opening equity	1,135
Noncontrolling Interest \| Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Opening equity	$ 439

REVENUE - Schedule of Revenue Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 116,282	$ 91,316	$ 215,398	$ 168,065
If reported under ASC 605
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	116,422		215,659
Accounting Standards Update 2014-09 \| Increase (decrease)
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(140)		(261)
Shack sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	112,898	$ 88,003	208,987	$ 162,158
Shack sales \| If reported under ASC 605
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	112,898		208,987
Shack sales \| Accounting Standards Update 2014-09 \| Increase (decrease)
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0		0
Licensing revenue
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3,384		6,411
Licensing revenue \| If reported under ASC 605
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3,524		6,672
Licensing revenue \| Accounting Standards Update 2014-09 \| Increase (decrease)
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ (140)		$ (261)

REVENUE - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Disaggregation of Revenue [Line Items]
Document Period End Date			Jun. 27, 2018
Revenue from contract with customer	$ 116,282	$ 91,316	$ 215,398	$ 168,065
Shack sales
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	112,898	88,003	208,987	162,158
Sales-based royalties
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3,319	3,200	6,291	5,600
Initial territory and opening fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 65	$ 113	$ 120	$ 307

REVENUE - Schedule of Respective Liability Balances (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2018	Dec. 28, 2017	Dec. 27, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Document Period End Date	Jun. 27, 2018
Gift card liability	$ 1,334	$ 1,472	$ 1,472
Deferred revenue, current	305	265
Deferred revenue, long-term	6,653	3,742
Shack sales
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	2,496	2,184
Licensing receivables
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer, asset, net	$ 2,933	$ 1,522

REVENUE - Liability Balance (Details) - Accounting Standards Update 2014-09 - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 27, 2018	Jun. 27, 2018
Disaggregation of Revenue [Line Items]
Gift card liability	$ 102	$ 408
Deferred revenue, current	$ 63	$ 118

FAIR VALUE MEASUREMENTS - Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017	Jun. 28, 2017	Dec. 28, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost Basis	$ 30,879	$ 21,507	$ 22,436	$ 11,607
Total cost basis including Mutual Funds	92,400	84,617
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(122)	(76)
Cash and cash equivalents fair value	30,879	21,507
Fair value of marketable securities	61,399	63,036
Fair Value	92,278	84,543
Level 1 \| Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Mutual funds	61,521	60,985
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(122)	(61)
Fair value of marketable securities	61,399	60,924
Level 2 \| Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Corporate debt securities	0	2,125
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	(15)
Fair value of marketable securities	0	2,112
Cash
Schedule of Available-for-sale Securities [Line Items]
Cost Basis	25,875	16,138
Cash and cash equivalents fair value	25,875	16,138
Money market funds \| Level 1
Schedule of Available-for-sale Securities [Line Items]
Cost Basis	5,004	5,369
Cash and cash equivalents fair value	$ 5,004	$ 5,369

FAIR VALUE MEASUREMENTS - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017	Dec. 27, 2017
Fair Value Disclosures [Abstract]
Net unrealized gain (loss)					$ (74,000)
Unrealized gain (loss) on available-for-sale equity securities	$ (23,000)		$ (61,000)
Asset impairment charges	$ 0	$ 0	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017
Gain (Loss) on Investments [Line Items]
Fair Value (less than 12 months)	$ 61,399	$ 62,599
Unrealized Loss (less than 12 months)	(122)	(73)
Fair Value (12 months or greater)	0	162
Unrealized Loss (12 months or greater)	0	(3)
Fair Value	61,399	62,761
Unrealized Loss	(122)	(76)
Mutual funds
Gain (Loss) on Investments [Line Items]
Fair Value (less than 12 months)	61,399	60,924
Unrealized Loss (less than 12 months)	(122)	(61)
Fair Value (12 months or greater)	0	0
Unrealized Loss (12 months or greater)	0	0
Fair Value	61,399	60,924
Unrealized Loss	(122)	(61)
Corporate debt securities
Gain (Loss) on Investments [Line Items]
Fair Value (less than 12 months)	0	1,675
Unrealized Loss (less than 12 months)	0	(12)
Fair Value (12 months or greater)	0	162
Unrealized Loss (12 months or greater)	0	(3)
Fair Value	0	1,837
Unrealized Loss	$ 0	$ (15)

FAIR VALUE MEASUREMENTS - Other Income From Available For Sale Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Available-for-sale securities
Unrealized gain (loss) on available-for-sale equity securities	$ (23)		$ (61)
Total other income, net	406	$ 198	634	$ 393
Available-for-sale Securities
Available-for-sale securities
Dividend income	329	191	604	369
Interest income	0	19	7	39
Realized gain (loss) on sale of investments	0	(12)	(16)	(15)
Unrealized gain (loss) on available-for-sale equity securities	(23)	0	(61)	0
Total other income, net	$ 306	$ 198	$ 534	$ 393

- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

+ References + Details

FAIR VALUE MEASUREMENTS - Available for Sale Securities and Gross Realized Gains and Losses (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 27, 2018

Jun. 28, 2017

Jun. 27, 2018

Jun. 28, 2017

Available-for-sale securities:

Gross proceeds from sales and redemptions

$ 0

$ 473

$ 2,144

$ 628

Cost basis of sales and redemptions

0

484

2,160

642

Gross realized gains included in net income

0

2

0

Gross realized losses included in net income

0

(12)

(18)

(15)

Amounts reclassified out of accumulated other comprehensive loss

^[1]

$ 0

$ 11

$ 16

$ 14

[1]	Net of tax benefit (expense) of $0 for the thirteen and twenty-six weeks ended June 27, 2018 and June 28, 2017.

INVENTORIES (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017
Inventory [Line Items]
Inventories	$ 1,238	$ 1,258
Food
Inventory [Line Items]
Inventories	873	874
Wine
Inventory [Line Items]
Inventories	66	69
Beer
Inventory [Line Items]
Inventories	82	85
Beverages
Inventory [Line Items]
Inventories	134	111
Retail merchandise
Inventory [Line Items]
Inventories	$ 83	$ 119

PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 27, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 287,294	$ 245,350
Less: accumulated depreciation	70,531	58,255
Property and equipment, net	216,763	187,095
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	186,349	166,963
Landlord funded assets
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,117	7,472
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	34,709	31,608
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	11,779	10,128
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	14,504	12,721
Construction in progress (includes landlord funded assets under construction)
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 27,836	$ 16,458

SUPPLEMENTAL BALANCE SHEET INFORMATION (Details) - USD ($) $ in Thousands	Jun. 27, 2018	Dec. 28, 2017	Dec. 27, 2017
Other Liabilities, Current
Sales tax payable	$ 3,139		$ 1,813
Current portion of liabilities under tax receivable agreement	943		937
Gift card liability	1,334	$ 1,472	1,472
Other	2,239		3,715
Other current liabilities	$ 7,655		$ 7,937

DEBT (Details) - USD ($)			3 Months Ended		6 Months Ended
DEBT (Details) - USD ($)	Sep. 27, 2017	Feb. 04, 2015	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017	Dec. 27, 2017
Debt Instrument [Line Items]
Deemed landlord financing			$ 18,340,000		$ 18,340,000		$ 14,518,000
Interest costs incurred			655,000	$ 409,000	1,264,000	$ 733,000
Interest costs capitalized			42,000	$ 43,000	86,000	$ 64,000
Notes payable
Debt Instrument [Line Items]
Notes payable			0		0
Third Amendment and Restated Credit Arrangement \| Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 50,000,000
Current borrowing capacity		$ 20,000,000
Term to maturity		5 years
Amount available under revolving credit facility			19,317,000		19,317,000
Third Amendment and Restated Credit Arrangement \| Letter of credit \| Line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000
Current borrowing capacity			$ 683,000		$ 683,000
Third Amendment and Restated Credit Arrangement \| Minimum \| Line of credit \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.30%
Third Amendment and Restated Credit Arrangement \| Minimum \| Line of credit \| Prime rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.00%
Third Amendment and Restated Credit Arrangement \| Maximum \| Line of credit \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	3.30%
Third Amendment and Restated Credit Arrangement \| Maximum \| Line of credit \| Prime rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.80%

NON-CONTROLLING INTERESTS - Ownership Interest in SSE Holdings (Details) - shares	Jun. 27, 2018	Dec. 27, 2017
Noncontrolling Interest [Abstract]
Number of LLC Interests held by Shake Shack Inc. (in shares)	28,106,331	26,527,477
Number of LLC Interests held by non-controlling interest holders (in shares)	8,924,592	10,250,007
Total LLC Interests outstanding (in shares)	37,030,923	36,777,484
Number of LLC Interests held by Shake Shack Inc. (as a percentage)	75.90%	72.10%
Number of LLC Interests held by non-controlling interest holders (as a percentage)	24.10%	27.90%
Total LLC Interests outstanding (as a percentage)	100.00%	100.00%

NON-CONTROLLING INTERESTS - Narrative (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Noncontrolling Interest [Line Items]
Non-controlling interest holders' weighted average ownership percentage	24.80%	29.60%	25.60%	30.00%
Number of units redeemed (in shares)			1,325,415	482,600
Units acquired during the period (in shares)			1,578,854
Redemption or Exchange of Units
Noncontrolling Interest [Line Items]
Units acquired during the period (in shares)			1,325,415	482,600
Employee Stock Option
Noncontrolling Interest [Line Items]
Units acquired during the period (in shares)			253,439	305,882

NON-CONTROLLING INTERESTS - Changes in Ownership Interests in SSE Holdings (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Noncontrolling Interest [Line Items]
Net income attributable to Shake Shack Inc.	$ 7,604	$ 4,879	$ 11,112	$ 7,146
Other comprehensive income (loss):
Net change related to available-for-sale securities	0	3	13	(3)
Transfers (to) from non-controlling interests:
Total effect of changes in ownership interest on equity attributable to Shake Shack Inc.	10,642	6,233	20,584	12,688
Redemption or Exchange of Units
Transfers (to) from non-controlling interests:
Increase (decrease) in additional paid-in capital	1,801	720	7,359	2,042
Employee Stock Option
Transfers (to) from non-controlling interests:
Increase (decrease) in additional paid-in capital	1,237	632	2,103	3,502
Net change related to available-for-sale securities
Other comprehensive income (loss):
Net change related to available-for-sale securities	$ 0	$ 2	$ 10	$ (2)

EQUITY-BASED COMPENSATION - Schedule of compensation expense recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$ 1,397	$ 1,285	$ 2,834	$ 2,534
Total income tax benefit recognized related to equity-based compensation	42	44	80	95
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	773	863	1,600	1,827
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	464	399	918	684
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity-based compensation expense	$ 160	$ 23	$ 316	$ 23

INCOME TAXES - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Income Tax Disclosure [Abstract]
Expected U.S. federal income taxes at statutory rate	$ 2,690	$ 4,050	$ 3,987	$ 5,982
Expected U.S. federal income taxes at statutory rate, percentage	21.00%	35.00%	21.00%	35.00%
State and local income taxes, net of federal benefit	$ 830	$ 659	$ 1,242	$ 1,008
State and local income taxes, net of federal benefit, percentage	6.50%	5.70%	6.50%	5.90%
Foreign withholding taxes	$ 271	$ 227	$ 802	$ 413
Foreign withholding taxes, percentage	2.10%	2.00%	4.20%	2.40%
Tax credits	$ (920)	$ (248)	$ (1,197)	$ (378)
Tax credits, percentage	(7.20%)	(2.10%)	(6.30%)	(2.20%)
Non-controlling interest	$ (731)	$ (1,303)	$ (1,185)	$ (1,982)
Non-controlling interest, percentage	(5.70%)	(11.30%)	(6.20%)	(11.60%)
Other	$ 100	$ 0	$ (211)	$ 0
Other, percentage	0.80%	0.00%	(1.10%)	0.00%
Income tax expense	$ 2,240	$ 3,385	$ 3,438	$ 5,043
Income tax expense, percentage	17.50%	29.30%	18.10%	29.50%

INCOME TAXES - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
INCOME TAXES - Narrative (Details) - USD ($)	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017	Dec. 27, 2017
Income Tax Contingency [Line Items]
Effective income tax rate reconciliation (in percentage)	17.50%	29.30%	18.10%	29.50%
Ownership percentage, weighted average	75.20%	70.40%	74.40%	70.00%
Units acquired during the period (in shares)			1,578,854
Deferred tax asset recognized as a result of investment in partnership			$ 16,831,000
Deferred tax asset, investment in partnership	$ 160,314,000		160,314,000
Valuation allowance, deferred tax asset	10,649,000		10,649,000
Deferred tax asset related to additional tax basis			4,972,000
Uncertain tax positions	$ 0		$ 0
Percentage of tax benefits due to equity owners	85.00%		85.00%
Percentage of tax benefits expected to be realized	15.00%		15.00%
Establishment of liabilities under tax receivable agreement			$ 17,992,000	$ 9,413,000
Tax receivable agreement payments to related parties		$ 0	0	$ 1,471,000
Liabilities under tax receivable agreement	$ 177,370,000		177,370,000		$ 159,373,000
Current portion of liabilities under tax receivable agreement	$ 943,000		$ 943,000		$ 937,000
Redemption or Exchange of Units
Income Tax Contingency [Line Items]
Units acquired during the period (in shares)			1,325,415	482,600

EARNINGS PER SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Numerator:
Net income	$ 10,571	$ 8,184	$ 15,550	$ 12,046
Less: net income attributable to non-controlling interests	2,967	3,305	4,438	4,900
NET INCOME ATTRIBUTABLE TO SHAKE SHACK INC.	$ 7,604	$ 4,879	$ 11,112	$ 7,146
Denominator:
Weighted-average shares of Class A common stock outstanding—basic (in shares)	27,796	25,798	27,418	25,587
Effect of dilutive securities:
Weighted-average shares of Class A common stock outstanding—diluted (in shares)	28,754	26,312	28,288	26,133
Earnings per share of Class A common stock—basic (in dollars per share)	$ 0.27	$ 0.19	$ 0.41	$ 0.28
Earnings per share of Class A common stock—diluted (in dollars per share)	$ 0.26	$ 0.19	$ 0.39	$ 0.27
Performance stock units
Effect of dilutive securities:
Stock options (in shares)	68	20	68	23
Restricted stock units
Effect of dilutive securities:
Stock options (in shares)	23	0	17	0
Stock options
Effect of dilutive securities:
Stock options (in shares)	867	494	785	523

EARNINGS PER SHARE - Antidilutive Securities (Details) - Common Stock [Member] - shares	3 Months Ended		6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017	Jun. 27, 2018	Jun. 28, 2017
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	0	6,258	0	6,258
Performance stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	60,437	84,755	60,437	84,755
Shares of Class B common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	8,924,592	10,770,992	8,924,592	10,770,992

SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 27, 2018	Jun. 28, 2017
Cash paid for:
Income taxes, net of refunds	$ 1,436	$ 1,595
Interest, net of amounts capitalized	1,067	357
Non-cash investing activities:
Accrued purchases of property and equipment	10,692	7,690
Capitalized landlord assets for leases where we are deemed the accounting owner	3,307	7,634
Accrued purchases of marketable securities	0	80
Capitalized equity-based compensation	39	78
Non-cash financing activities:
Establishment of liabilities under tax receivable agreement	17,992	9,413
Redemption or Exchange of Units \| Class A Common Stock
Non-cash financing activities:
Class A common stock issued in connection with the redemption of LLC Interests	1	0
Redemption or Exchange of Units \| Class B Common Stock
Non-cash financing activities:
Cancellation of Class B common stock in connection with the redemption of LLC Interests	$ (1)	$ 0

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 28, 2018	Jun. 27, 2018	Jun. 28, 2017	Dec. 27, 2017	Sep. 30, 2017	Dec. 31, 2013
Loss Contingencies [Line Items]
Percentage of tax benefits due to equity owners		85.00%
Establishment of liabilities under tax receivable agreement		$ 17,992	$ 9,413
Tax receivable agreement liability		177,370		$ 159,373
Retail site
Loss Contingencies [Line Items]
Letters of credit outstanding		$ 160
Office building
Loss Contingencies [Line Items]
Letters of credit outstanding					$ 603	$ 80
Renewal term	1 year

RELATED PARTY TRANSACTIONS (Details)	3 Months Ended			6 Months Ended
RELATED PARTY TRANSACTIONS (Details)	Jun. 27, 2018 USD ($)	Mar. 28, 2018	Jun. 28, 2017 USD ($)	Jun. 27, 2018 USD ($) renewal_option	Jun. 28, 2017 USD ($)	Dec. 27, 2017 USD ($)
Related Party Transaction [Line Items]
Percentage of tax benefits due to equity owners	85.00%			85.00%
Tax receivable agreement payments to related parties			$ 0	$ 0	$ 1,471,000
Tax receivable agreement liability	$ 177,370,000			177,370,000		$ 159,373,000
Distributions paid to non-controlling interest holders	587,000		2,024,000	670,000	2,379,000
Tax distributions payable to non-controlling interest holders	0			0		0
Affiliated Entity
Related Party Transaction [Line Items]
Amount paid to USHG for general corporate expenses	0		1,000	2,000	6,000
Amounts due to related parties, current	0			0		0
Due from related parties, current	0			$ 0		0
Subsidiary to Affiliated Entity
Related Party Transaction [Line Items]
Number of renewal terms \| renewal_option				5
Renewal option period		5 years
Share Our Strength
Related Party Transaction [Line Items]
Charitable campaign flow through	343,000		631,000	$ 343,000	631,000
Expenses from transactions with related party	53,000		119,000	53,000	119,000
Concession Income \| Subsidiary to Affiliated Entity
Related Party Transaction [Line Items]
Due from related parties, current	114,000			114,000		18,000
Revenue from related parties	64,000		115,000	111,000	135,000
Rent Expense \| Madison Square Park Conservancy
Related Party Transaction [Line Items]
Amounts due to related parties, current	0			0		0
Revenues from transactions with related party			0	0	200,000
Expenses from transactions with related party	203,000		133,000	470,000	332,000
Tenant Improvement Allowance \| Madison Square Park Conservancy
Related Party Transaction [Line Items]
Amount due from MSP conservancy	0			0		0
Mobo Systems, Inc. \| Board of Directors Chairman
Related Party Transaction [Line Items]
Amounts due to related parties, current	0			0		$ 0
Expenses from transactions with related party	$ 27,000		$ 20,000	$ 52,000	$ 38,000