Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]

NOTE

1

— GENERAL AND BASIS OF PRESENTATION

These unaudited condensed consolidated interim financial statements of Ormat Technologies, Inc. and its subsidiaries (collectively, the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. Accordingly, they do

not

contain all information and notes required by U.S. GAAP for annual financial statements. In the opinion of management, these unaudited condensed consolidated interim financial statements reflect all adjustments, which include normal recurring adjustments, necessary for a fair statement of the Company’s consolidated financial position as of

June 30, 2018,

the consolidated results of operations and comprehensive income (loss) for the

three

and

six

-month periods ended

June 30, 2018

and

2017

and the consolidated cash flows for the

six

-month periods ended

June 30, 2018

and

2017.

The financial data and other information disclosed in the notes to the condensed consolidated financial statements related to these periods are unaudited. The results for the

three

and

six

-month period ended

June 30, 2018

are

not

necessarily indicative of the results to be expected for the year ending

December

31,

2018.

These condensed unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form

10

-K/A for the year ended

December

31,

2017.

The condensed consolidated balance sheet data as of

December

31,

2017

was derived from the Company’s audited consolidated financial statements for the year ended

December

31,

2017,

but does

not

include all disclosures required by U.S. GAAP.

Dollar amounts, except per share data, in the notes to these financial statements are rounded to the closest

$1,000.

Tungsten Mountain partnership transaction

On

May 17, 2018,

one

of the Company’s wholly-owned subsidiaries that indirectly owns the

26

MW Tungsten Mountain Geothermal power plant entered into a partnership agreement with a private investor. Under the transaction documents, the private investor acquired membership interests in the Tungsten Mountain Geothermal power plant project for an initial purchase price of approximately

$33.4

million and for which it will pay additional installments that are expected to amount to approximately

$13

million. The Company will continue to operate and maintain the power plant and will receive substantially all the distributable cash flow generated by the power plant.

Under the agreements, prior to the

December 31, 2026 (

“Target Flip Date”), the Company’s fully owned subsidiary, Ormat Nevada Inc.("Ormat Nevada"), receives substantially all of the distributable cash flow generated by the project, while the private investor receives substantially all of the tax attributes of the project. Following the later of the Target Flip Date and the date in which the private investor reaches its target return, Ormat Nevada will receive

97.5%

of the distributable cash and

95.0%

of the taxable income, on a going forward basis.

On the Target Flip Date, Ormat Nevada has the option to purchase the private investor’s interests at the then-current fair market value, plus an amount that

may

be needed to cause the private investor to reach its target return, if needed. If Ormat Nevada exercises this purchase option, it will become the sole owner of the project again.

Puna

On

May 3, 2018,

the Kilauea volcano located in close proximity to the Company’s

38

MW Puna geothermal power plant in the Puna district of Hawaii's Big Island erupted following a significant increase in seismic activity in the area. While the Company has taken steps to secure and protect the Puna facilities, including, among others, taking electricity generation offline and placing physical barriers around, and protective coverings over, the geothermal wells, and has evacuated non-essential personnel at the power plant and removed all pentane from the site, it is still assessing the impact of the volcanic eruption and seismic activity on the Puna facilities. The approaching lava covered the wellheads of

three

geothermal wells and the substation of the Puna complex and an adjacent warehouse that stored a drilling rig were burned due to the approaching lava, all of which had a carrying value of approximately

$4.9

million that was written-off during the

second

quarter of

2018.

These property damages are expected to be covered by the Company’s insurance policies and therefore the Company recorded a provision for such recoveries out of which approximately

$7.2

million was included in “Other income” as excess recoveries over the carrying value of the rig which was destroyed by the lava. The write-off and related insurance recoveries, excluding the excess portion, were recorded under “Electricity cost of revenues” in the condensed consolidated statements of operations and comprehensive income. The Company is in discussions with the insurance companies on the reimbursement for profit and loss and property damages. The total net book value of the Puna property, plant and equipment is approximately

$102.2

million. The Company cannot currently estimate when the lava flow will stop nor when it will be able to assess all of the damages. Any significant physical damage to, or extended shut-down of, the Puna facilities could have an adverse impact on the power plant's electricity generation and availability, which in turn could have a material adverse impact on the Company’s business and results of operations. The Company continues to monitor the condition of the Puna facilities, coordinate with Hawaii Electric Light Company (“HELCO”) and local authorities, and is taking steps to both further secure the power plant and restore its operations as soon as it is safe to do so. In addition, the Company will continue to assess the accounting implications of this event on the assets and liabilities on its balance sheet and whether an impairment will be required.

U.S. Geothermal (“USG”) transaction

On

April 24, 2018,

the Company completed its previously announced acquisition of USG. The total cash consideration (exclusive of transaction expenses) was approximately

$110

million, comprised of approximately

$106

million funded from available cash of Ormat Nevada Inc. (to acquire the outstanding shares of common stock of USG) and approximately

$4

million funded from available cash of USG (to cash-settle outstanding in-the-money options for common stock of USG). As a result of the acquisition, USG became an indirect wholly owned subsidiary of Ormat, and Ormat indirectly acquired, among other things, interests held by USG and its subsidiaries in:

•

three

operating power plants at Neal Hot Springs, Oregon, San Emidio, Nevada and Raft River, Idaho with a total net generating capacity of approximately

38

MW; and

• development assets which include a project at the Geysers, California; a

second

phase project at San Emidio, Nevada; a greenfield project in Crescent Valley, Nevada; and the El Ceibillo project located near Guatemala City, Guatemala.

As a result of the acquisition, the Company expanded its overall generation capacity and expects to improve the profitability of the purchased assets through cost reduction and synergies. The Company accounted for the transaction in accordance with Accounting Standard Codification ASC

805,

Business Combinations and following the transaction, the Company consolidates USG, in accordance with Accounting Standard Codification ASC

810,

Consolidation. Accounting guidance provides that the allocation of the purchase price

may

be modified for up to

one

year from the date of the acquisition to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. The Company deemed that the adoption of ASU

2017

-

01,

Business Combinations, as further described under Note

2

to the condensed consolidated financial statements, did

not

have an effect on the USG transaction.

The Company deemed the transaction to

not

meet the significant subsidiary threshold and as a result did

not

provide additional pro-forma and other related information, that otherwise would have been required.

The following table summarizes the fair value amounts of identified assets and liabilities assumed as of the transaction date (in millions):

Cash and cash equivalents and restricted cash	$	37.9
Working capital		(8.2	)
Property, plant and equipment and construction-in-process		77.3
Intangible assets (1)		127.0
Deferred tax liability		(4.9	)
Long-term term debt, net of deferred transaction costs		(98.3	)
Asset retirement obligation		(9.0	)
Total identifiable assets and liabilities acquired	$	121.8
Goodwill (2)	$	19.3

(

1

)

Intangible assets are primarily related to long-term electricity power purchase agreements and depreciated over an average of

19

years.

(

2

)

Goodwill is primarily related to the expected synergies in operation as a result of the purchase transaction and is allocated to the Electricity segment.

The fair value of the noncontrolling interest of

$34.9

million reflects the

40%

minority interests in the Neal Hot Springs project that was evaluated using the income approach. The fair value of the noncontrolling interest is based on the following significant inputs: (i) forecasted cash flows assumed to be generated in correspondence with the remaining life of the related power purchase agreement which is approximately

20

years; (ii) revenues were estimated in accordance with the price and generation capacity of the related power purchase agreement; (iii) assumed terminal value based on the realizable value of the project at the end of the power purchase agreement term; and (iv) assumed discount rate range of

9%.

Total Electricity segment revenues and operating losses related to the

three

USG power plants of approximately

$3.4

million and

$4.2

million, respectively, were included in the Company’s consolidated statements of operations and comprehensive income for the

three

and

six

months ended

June 30, 2018.

The following unaudited pro forma summary presents consolidated information of the Company as if the business combination had occurred on

January 1, 2017:

	Pro forma for the six months ended June 30, 2018		Pro forma for the six months ended June 30, 2017		Pro forma for the three months ended June 30, 2018		Pro forma for the three months ended June 30, 2017
	(Dollars in thousands)
Electricity revenues	$	265,965	$	241,420	$	125,003	$	117,207
Total revenues		373,619		384,010		181,123		185,675
Operating profit		89,219		114,753		36,200		53,238

Migdal Senior Unsecured Loan

On

March 22, 2018

the Company entered into a definitive loan agreement (the "Migdal Loan Agreement") with Migdal Insurance Company Ltd., Migdal Makefet Pension and Provident Funds Ltd. and Yozma Pension Fund of Self Employed Ltd., all entities within the Migdal Group, a leading insurance company and institutional investor in Israel. The Migdal Loan Agreement provides for a loan by the lenders to the Company in an aggregate principal amount of

$100

million (the “Migdal Loan”). The Migdal Loan will be repaid in

15

semi-annual payments of

$4.2

million each, commencing on

September 15, 2021,

with a final payment of

$37

million on

March 15, 2029.

The Migdal Loan bears interest at a fixed rate of

4.8%

per annum, payable semi-annually, subject to adjustment in certain circumstances as described below.

The Migdal Loan is subject to early redemption by the Company prior to maturity from time to time (but

not

more frequently than once per quarter) and at any time in whole or in part, at a redemption price set forth in the Migdal Loan Agreement. If the rating of the Company is downgraded to "ilA-", by Standard and Poor’s Global Ratings Maalot Ltd. (“Maalot”), the interest rate applicable to the Migdal Loan will be increased by

0.50%.

If the rating of the Company is further downgraded to a lower level, the interest rate applicable to the Migdal Loan will be increased by

0.25%

for each additional downgrade. In

no

event will the cumulative increase in the interest rate applicable to the Migdal Loan exceed

1%

regardless of the cumulative rating downgrade. A subsequent upgrade or reinstatement of a rating by Maalot will reduce the interest rate applicable to the Migdal Loan by

0.25%

for each upgrade (but in

no

event will the interest rate applicable the Migdal Loan fall below the base interest rate of

4.8%

). Additionally, if the ratio between short-term and long-term debt to financial institutions and bondholders, deducting cash and cash equivalents to EBITDA is equal to or higher than

4.5,

the interest rate on all amounts then outstanding under the Migdal Loan shall be increased by

0.5%

per annum over the interest rate then-applicable to the Migdal Loan.

The Migdal Loan constitutes senior unsecured indebtedness of the Company and will rank equally in right of payment with any existing and future senior unsecured indebtedness of the Company, and effectively junior to any existing and future secured indebtedness, to the extent of the security therefore.

The Migdal Loan Agreement includes various affirmative and negative covenants, including a covenant that the Company maintain (i) a debt to adjusted EBITDA ratio below

6,

(ii) a minimum equity amount (as shown on its consolidated financial statements, excluding noncontrolling interests) of

not

less than

$650

million, and (iii) an equity attributable to Company's stockholders to total assets ratio of

not

less than

25%.

In addition, the Migdal Loan Agreement restricts the Company from making dividend payments if its equity falls below

$800

million and otherwise restricts dividend payments in any

one

year to

not

more than

50%

of the net income of the Company of such year as shown on the Company’s consolidated annual financial statements as long as any of the Company's bonds issued in Israel prior to

March 27, 2018

remain outstanding. The Migdal Loan Agreement includes other customary affirmative and negative covenants and events of default. As of

June 30, 2018

the Company was in compliance with all such covenants.

Other comprehensive income

For the

six

months ended

June 30, 2018

and

2017,

the Company classified

$10,000

and

$54,000,

respectively, related to derivative instruments designated as cash flow hedges, from accumulated other comprehensive income, of which

$15,000

and

$30,000,

respectively, were recorded to reduce interest expense and

$5,000

and $(

24,000

), respectively, were recorded against the income tax provision, in the condensed consolidated statements of operations and comprehensive income. For the

three

months ended

June 30, 2018

and

2017,

the Company classified

$5,000

and

$30,000,

respectively, related to derivative instruments designated as cash flow hedges, from accumulated other comprehensive income, of which

$6,000

and

$20,000,

respectively, were recorded to reduce interest expense and

$1,000

and $(

10,000

), respectively, were recorded against the income tax provision, in the condensed consolidated statements of operations and comprehensive income. The accumulated net loss included in Other comprehensive income as of

June 30, 2018

is

$1.0

million

Write-offs of unsuccessful exploration activities

Write-offs of unsuccessful exploration activities for the

three

and

six

months ended

June 30, 2018

were

$0

and

$0.1

million. There were

no

write-offs of unsuccessful exploration activities for the

three

and

six

months ended

June 30, 2017.

Reconciliation of Cash and cash equivalents and Restricted cash and cash equivalents

The following table provides a reconciliation of Cash and cash equivalents and Restricted cash and cash equivalents reported on the balance sheet that sum to the total of the same amounts shown on the statement of cash flows:

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Cash and cash equivalents	$	66,696	$	47,818
Restricted cash and cash equivalents		76,041		48,825
Total Cash and cash equivalents and restricted cash and cash equivalents	$	142,737	$	96,643

Concentration of credit risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of temporary cash investments and accounts receivable.

The Company places its temporary cash investments with high credit quality financial institutions located in the United States (“U.S.”) and in foreign countries. At

June 30, 2018

and

December 31, 2017,

the Company had deposits totaling

$21.6

million and

$21.2

million, respectively, in

eight

U.S. financial institutions that were federally insured up to

$250,000

per account. At

June 30, 2018

and

December 31, 2017,

the Company’s deposits in foreign countries amounted to approximately

$59.8

million and

$32.8

million, respectively.

At

June 30, 2018

and

December 31, 2017,

accounts receivable related to operations in foreign countries amounted to approximately

$83.2

million and

$78.1

million, respectively. At

June 30, 2018

and

December 31, 2017,

accounts receivable from the Company’s primary customers amounted to approximately

55%

and

57%

of the Company’s accounts receivable, respectively.

Sierra Pacific Power Company and Nevada Power Company (subsidiaries of NV Energy, Inc.) accounted for

17.0%

and

16.7%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

16.7%

and

17.8%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017,

respectively.

Southern California Public Power Authority (“SCPPA”) accounted for

14.9%

and

8.7%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

15.6%

and

8.9%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017.

Kenya Power and Lighting Co. Ltd. accounted for

16.6%

and

15.4%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

15.8%

and

14.8%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017,

respectively.

The Company has historically been able to collect on substantially all of its receivable balances, and believes it will continue to be able to collect all amounts due. Accordingly,

no

provision for doubtful accounts has been made.

Note 2 - New Accounting Pronouncements

6 Months Ended

Jun. 30, 2018

New Accounting Pronouncements and Changes in Accounting Principles [Text Block]

NOTE

2

— NEW ACCOUNTING PRONOUNCEMENTS

New accounting pronouncements effective in the

six

-month period ended

June 30, 2018

Income Taxes

In

March 2018,

the Financial Accounting Standards Board

("

FASB") issued ASU

2018

-

05,

Income Taxes (Topic

740

). The amendments in this update add several SEC paragraphs pursuant to the issuance of the SEC Staff Accounting Bulletin

No.

118,

Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB

118”

) in

December 2017.

The amendments in this update are effective immediately. For additional information, see Note

11

to the consolidated financial statements.

Revenues from Contracts with Customers

In

May 2014,

the FASB issued ASU

2014

-

09,

Revenues from Contracts with Customers, Topic

606,

which was a joint project of the FASB and the International Accounting Standards Board to clarify the principles for recognizing revenue and to develop a common revenue standard for U.S. GAAP and International Financial Reporting Standards. The update provides that an entity should recognize revenue in connection with the transfer of 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 or services. Specifically, an entity is required to apply each of the following steps: (

1

) identify the contract(s) with the customer; (

2

) identify the performance obligations in the contracts; (

3

) determine the transaction price; (

4

) allocate the transaction price to the performance obligation in the contract; and (

5

) recognize revenue when (or as) the entity satisfies a performance obligation. ASU

2014

-

09

also prescribes additional financial presentations and disclosures. In

March 2016,

the FASB issued ASU

2016

-

08,

Principal versus Agent Considerations. This update did

not

change the core principles of the guidance and was intended to clarify the implementation guidance on principal versus agent considerations. When another entity is involved in providing goods or services to a customer, an entity is required to determine if the nature of its promise is to provide the specific good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent). The guidance included indicators to assist an entity in determining whether it acts as a principal or agent in a specified transaction.

The Company adopted this update effectively as of

January 1, 2018

using the modified retrospective approach with

one

-time cumulative adjustment to the opening balance of retained earnings as further described below and applied the

five

-step model described above on identified outstanding contracts at the date of adoption, under which revenues are generated. Under ASC

606,

an entity must identify the performance obligations in a contract, determine the transaction price and allocate the price to specific performance obligations and recognize the revenue when the obligation is completed. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The standard also requires disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flow arising from contracts.

The adoption of ASC

606,

Revenues from Contracts with Customers, as described above, did

not

have an impact on our Electricity, Product and Other segment revenues in

2018,

however, the adoption did have an impact on our accounting for investment in an unconsolidated company as further described in the following table and in the disclosure under the heading "Investment in an unconsolidated company" within this note below. Additionally, the following table below summarizes the impact of the adoption of ASC

606

on the Company’s consolidated financial statements as of

January 1, 2018,

followed by further information for each of the line items in the table:

	(Dollars in millions)
Electricity segment revenues	$	–
Product segment revenues		–
Other segment revenues		–
Investment in an unconsolidated company		24.0

Electricity segment revenues

: Electricity revenues are primarily related to sale of electricity from geothermal and recovered energy-based power plants owned and operated by the Company. Revenues related to the sale of electricity from geothermal and recovered energy-based power plants and capacity payments are recorded based upon output delivered and capacity provided at rates specified under relevant contract terms. For power purchase agreements (“PPAs”) agreed to, modified, or acquired in business combinations on or after

July 1, 2003,

the Company determines whether such PPAs contain a lease element requiring lease accounting. Revenue from such PPAs is accounted for in electricity revenues. The lease element of the PPAs is also assessed in accordance with the revenue arrangements with multiple deliverables guidance, which requires that revenues be allocated to the separate earnings processes based on their relative fair value. PPAs with minimum lease rentals which vary over time are generally recognized on the straight-line basis over the term of the PPAs. PPAs with contingent rentals are recognized when earned. In the Electricity segment, revenues for all but

three

power plants are accounted for under ASC

840

(Leases) as operating leases, and therefore equipment related to geothermal and recovered energy generation power plants is considered held for leasing. For power plants in the scope of ASC

606,

the Company identified electricity as a separate performance obligation. Performance obligations identified were evaluated and determined to be satisfied over time and qualified for the invoicing practical expedient since the invoiced amounts reasonably represented the value to customers of performance obligations fulfilled to date. The transaction price is determined based on the price per actual mega-watt output or available capacity as agreed to in the respective PPA. Customers are generally billed on a monthly basis and payment is typically due within

30

to

60

days after the issuance of the invoice.

Product segment revenues

: Product segment revenues are primarily related to sale of geothermal and recovered energy-based power plants, including equipment, engineering, construction and installation and operating services. Revenues from the supply and/or construction of geothermal and recovered energy-based power plant equipment and other equipment to

third

parties are recognized over time since control is transferred continuously to our customers. The majority of our contracts include a single performance obligation which is essentially the promise to transfer the individual goods or services that are

not

separately identifiable from other promises in the contracts and therefore deemed as

not

distinct. Performance obligations are satisfied over-time if the customer receives the benefits as we perform work, if the customer controls the asset as it is being constructed, or if the product being produced for the customer has

no

alternative use and we have a contractual right to payment. In our Product segment, revenues are spread over a period of

one

to

two

years and are recognized over time based on the cost incurred to date in ratio to total estimated costs which represents the input method that best depicts the transfer of control over the performance obligation to the customer. Costs include direct material, labor, and indirect costs. Selling, marketing, general, and administrative costs are expensed as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined.

In contracts for which we determine that control is

not

transferred continuously to the customer, we recognized revenues at the point in time when the customer obtains control of the asset. Revenues for such contracts are recorded upon delivery and acceptance by the customer. This generally is the case for the sale of spare parts, generators or similar products.

Accounting for product contracts that are satisfied over time includes use of several estimates such as variable consideration related to bonuses and penalties and total estimated cost for completing the contract. The estimated amount of variable consideration will be included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will

not

occur when the uncertainty associated with the variable consideration is subsequently resolved. These estimates are based on historical experience, anticipated performance and our best judgment at the time.

The nature of our product contracts give rise to several modifications or change requests by our customers. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are

not

distinct from those already provided. We include the additional revenues related to the modifications in our transaction price when both parties to the contract approved the modification. As a significant change in

one

or more of these estimates could affect the profitability of our contracts, we review and update our contract-related estimates regularly. We recognize adjustments in Product revenues on contracts under the cumulative catch-up method. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, we recognize the total loss in the period in which it is identified.

The Company generally provides a

one

-year warranty against defects in workmanship and materials related to the sale of products for electricity generation. The Company considered the warranty as an assurance type warranty since the warranty provides the customer the assurance that the product complies with agreed-upon specifications. Estimated future warranty obligations are included in operating expenses in the period in which the related revenue is recognized. Such charges are immaterial for the

three

and

six

months ended

June 30, 2018

and

2017.

Contract Assets and Liabilities related to our Product segment: Contract assets reflect revenue recognized and performance obligations satisfied in advance of customer billing. Contract liabilities relate to payments received in advance of the satisfaction of performance under the contract. We receive payments from customers based on the terms established in our contracts. Total contract assets and contract liabilities as of

June 30, 2018

and

December 31, 2017

are as follows:

	June 30,			December 31,
	2018			2017
	(Dollars in thousands)
Contract assets (*)	$	46,573		$	40,945
Contract liabilities (*)		(16,136	)		(20,241	)
Contract assets, net	$	30,437		$	20,704

(*) Contract assets and contract liabilities are presented as "Costs and estimated earnings in excess of billings on uncompleted contracts" and "Billings in excess of costs and estimated earnings on uncompleted contracts", respectively, on the consolidated balance sheet.

The following table presents the significant changes in the contract assets and contract liabilities for the

six

months ended

June 30, 2018:

	Contract assets			Contract liabilities
	(Dollars in thousands)
Recognition of contract liabilities as revenue as a result of performance obligations satisfied	$	-		$	11,094
Cash received in advance for which revenues have not yet recognized, net expenditures made		-			(12,901	)
Reduction of contract assets as a result of rights to consideration becoming unconditional		(59,634	)		-
Contract assets recognized, net of recognized receivables		71,174			-
Net change in contract assets and contract liabilities		11,540			(1,807	)

The timing of revenue recognition, billings and cash collections results in accounts receivable, contract assets and contract liabilities on the condensed consolidated balance sheet. In our Products segment, amounts are billed as work progresses in accordance with agreed-upon contractual terms, or upon achievement of contractual milestones. Generally, billing occurs subsequent to the recognition of revenue, resulting in contract assets. However, we sometimes receive advances or deposits from our customers before revenue can be recognized, resulting in contract liabilities. These assets and liabilities are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. The timing of billing our customers and receiving advance payments vary from contract to contract. We typically receive a down payment of between

10%

and

20%

of total contract consideration upon signing, followed by additional milestone payments for which timing varies from contract to contract. The majority of payments are received

no

later than the completion of the project and satisfaction of our performance obligation.

On

June 30, 2018,

we had approximately

$229.0

million of remaining performance obligations

not

yet satisfied or partly satisfied related to our Product segment. We expect to recognize approximately

96%

of this amount as Product revenues during the next

24

months and the rest will be recognized thereafter.

The following schedule reconciles revenues accounted for under ASC

840,

Leases, and ASC

606,

Revenues from Contracts with Customers, to total consolidated revenues for the

three

and

six

months ended

June 30, 2018:

	Three Months Ended June 30, 2018		Six Months Ended June 30, 2018
	(Dollars in thousands)		(Dollars in thousands)
Electricity revenues accounted under ASC 840, Leases	$	116,914	$	242,745
Electricity, Product and Other revenues accounted under ASC 606		61,385		119,577
Total consolidated revenues	$	178,299	$	362,322

Disaggregated revenues from contracts with customers for the

three

and

six

months ended

June 30, 2018

are shown under Note

9

– Business Segments, to the condensed consolidated financial statements.

Investment in an unconsolidated company

: The Company also reviewed the impact of the adoption of ASC

606

on its investment in an unconsolidated company. As a result of the adoption, the Company recorded

one

-time cumulative credit adjustment to the opening balance of retained earnings of approximately

$24.0

million as of

January 1, 2018.

This impact is a result of the unconsolidated company’s variable consideration related to the construction of its power plant for which, under the new guidance, is probable that a significant reversal in the amount of cumulative revenue recognized will

not

occur when the uncertainty is resolved. As such, the comparative information will

not

be restated and shall continue to be reported under the accounting standards in effect for those periods.

The following schedule quantifies the impact of adopting ASC

606

on the statement of operations for the

three

and

six

months ended

June 30, 2018:

	Three months ended June 30, 2018 under previous standard			Effect of the New Revenue Standard		As reported for the three months ended June 30, 2018
	(Dollars in thousands)
Equity in earnings (losses) of investees, net	$	(3,237	)	$	3,625	$	388
Income from continuing operations		(966	)		3,625		2,659
Net income attributable to the Company’s stockholders		(3,968	)		3,625		(343	)
Retained earnings		401,728			3,625		405,353

	Six months ended June 30, 2018 under previous standard			Effect of the New Revenue Standard		As reported for the six months ended June 30, 2018
	(Dollars in thousands)
Equity in earnings (losses) of investees, net	$	(1,293	)	$	2,891	$	1,598
Income from continuing operations		74,024			2,891		76,915
Net income attributable to the Company’s stockholders		66,274			2,891		69,165
Retained earnings		402,462			2,891		405,353

Other segment revenues

: Other segment revenues are primarily related to energy storage, demand-response and energy management related services. Revenues are recorded based on energy management of load curtailment capacity delivered or service provided at rates specified under the relevant contract terms. The Company determined that the Other segment revenues are in the scope of ASC

606

and identified energy management as a separate performance obligation. Performance obligations are satisfied once the Company provides verification to the electric power grid operator or utility of its ability to meet the committed capacity or power curtailment requirements and thus entitled to cash proceeds. Such verification

may

be provided by the Company bi-weekly, monthly or under any other frequency as set by the related program and are typically followed by a payment shortly after. Performance obligations identified were evaluated and determined to be satisfied over time and qualified for the invoicing practical expedient since the amounts included in the verification document reasonably represent the value of performance obligations fulfilled to date. The transaction price is determined based on mechanisms specified in the contract with the customer.

Compensation - Stock Compensation

In

May 2017,

the FASB issued ASU

2017

-

09,

Compensation—Stock Compensation (Topic

718

). The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic

718.

The amendments in this update require that an entity should account for the effects of a modification unless all of the following are met: (

1

) The fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified; (

2

) The vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; (

3

) The classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements under Topic

718

apply regardless of whether an entity is required to apply modification accounting under the amendments in this update. The amendments in this update are effective for all entities for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The amendments in this update should be applied prospectively to an award modified on or after the adoption date. The adoption of this guidance did

not

have a material impact on the Company’s consolidated financial statements.

Business Combinations

In

January 2017,

the FASB issued ASU

2017

-

01,

Business Combinations (Topic

805

). The update clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update primarily provide a screen to determine when a set of assets and activities is

not

a business and by that reduces the number of transactions that need to be further evaluated. The amendments in this update should be applied prospectively and are effective for financial statements issued for fiscal years beginning after

December 15, 2017,

and interim periods within those fiscal years. The adoption of this guidance did

not

have an impact on the Company’s condensed consolidated financial statements.

Statement of Cash Flow

In

November 2016,

the FASB issued ASU

2016

-

18,

Statement of Cash Flows (Topic

230

) – Restricted Cash. The amendments in this update require that a statement of cash flows explain the changes during the period in total cash, cash equivalents, and the amounts generally described as restricted cash or cash equivalents. Therefore, amounts of restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this update should be applied retrospectively for each period presented and are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The Company adopted this guidance retrospectively in its consolidated financial statements for the

three

month period ending

March 31, 2018

and adjusted its disclosure accordingly.

Intra-Entity Transfers of Assets Other than Inventory

In

October 2016,

the FASB issued ASU

2016

-

16,

Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory. The amendments in this update require that the entity would recognize the tax expense from the sale of the asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buyer’s jurisdiction would also be recognized at the time of the transfer. The new guidance does

not

apply to intra-entity transfers on inventory. The amendments in this update should be applied for each period presented and are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The modified retrospective approach is required for transition to the new guidance, with cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption. The Company adopted this guidance in its consolidated financial statements for the

three

months ending

March 31, 2018

using the modified retrospective approach and recorded a net cumulative-effect adjustment to retained earnings of approximately

$1.8

million with a corresponding adjustment to deferred charges and deferred income taxes on the condensed consolidated balance sheet of approximately

$49.8

million and

$51.6

million, respectively.

Statement of Cash Flows: Classification of Certain Cash Receipts and Cash payments (Topic

230

)

In

August 2016,

the FASB issued ASU

2016

-

15,

Statement of Cash-Flows (Topic

230

). This update addresses

eight

specific cash flow classification issues with the objective of reducing diversity in practice. One of the issues addressed in this update is debt prepayment or debt extinguishment costs which under the new guidance should be classified as cash outflows for financing activities. Additionally, the update addressed contingent consideration payments made after a business combination. Such cash payments made soon after the acquisition date to settle a contingent consideration liability should be classified as cash outflows for investing activities. Payments made thereafter should be classified as cash outflows for financing activities up to the amount of the original contingent consideration liability. Payments made in excess of the amount of the original contingent consideration liability should be classified as cash outflows for operating activities. The amendments in this update are effective for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The amendments in this update should be applied using a retrospective transition method to each period presented. The Company adopted this guidance and expects that the impact from the adoption of the update will result in a reclassification of approximately

$8.0

million of cash paid for achievement of production threshold in Guadeloupe during the

fourth

quarter of

2017

from cash outflows from investing activities to cash outflows from financing activities as required by this update.

Recognition and Measurement of Financial Assets and Financial Liabilities

In

January 2016,

the FASB issued ASU

2016

-

01,

Recognition and Measurement of Financial Assets and Financial Liabilities. The update primarily requires that an entity present separately, in other comprehensive income, the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk if the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The application of this update should be by means of cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The amendments in this update are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The adoption of this update did

not

have a material impact on the Company’s consolidated financial statements.

New accounting pronouncements effective in future periods

Derivatives and Hedging

In

August 2017,

the FASB issued ASU

2017

-

12,

Targeted Improvements to Accounting for Hedging Activities. The amendments in this update better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. To meet that objective, the amendments expand and refine hedge accounting for both nonfinancial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. The amendments in this update are effective for fiscal years beginning after

December 15, 2018,

and interim periods within those fiscal years. Early application is permitted in any interim period after issuance of the update. The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Intangibles –Goodwill and Other

In

January 2017,

the FASB issued ASU

2017

-

04,

Intangibles – Goodwill and Other (Topic

350

). The amendments in this update require the entity to perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. However, the loss recognized should

not

exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider the income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. This update eliminated Step

2

from the goodwill impairment test under the current guidance. Step

2

measures a goodwill impairment loss by comparing the implied fair value of reporting unit’s goodwill with the carrying amount of that goodwill. The amendments in this update should be applied on a prospective basis. An entity is also required to disclose the nature of and the reason for the change in accounting principle upon transition. That disclosure should be provided in the

first

annual period and the interim period within the

first

annual period when the entity initially adopts the amendments in this update. The amendments in this update are effective for the annual or any interim goodwill impairment tests in fiscal years beginning after

December 15, 2019.

Early adoption is permitted for interim or annual impairment tests performed on testing dates after

January 1, 2017.

The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Leases

In

February 2016,

the FASB issued ASU

2016

-

02,

Leases (Topic

842

). This update introduces a number of changes and simplifies previous guidance, primarily the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases. The update retains the distinction between finance leases and operating leases and the classification criteria between the

two

types remains substantially similar. Also, lessor accounting remains largely unchanged from previous guidance. However, key aspects of the update were aligned with the revenue recognition guidance in Topic

606.

Additionally, the update defines a lease as a contract, or part of a contract, that conveys the right to control the use of an identified asset for a period of time in exchange for consideration. Control over the use of the identified asset means that the customer has both (a) the right to obtain substantially all of the economic benefits from the use of the asset and (b) the right to direct the use of the asset. This update requires the modified retrospective transition approach, which requires lessees and lessors to recognize and measure leases at the beginning of the earliest period presented. The modified retrospective approach includes a number of optional practical expedients related to identification and classification of leases that commenced before the effective date, initial direct costs for leases that commenced before the effective date and the ability to use hindsight in evaluating lessee options to extend or terminate a lease or to purchase the underlying asset. An entity that elects to apply the practical expedients will, in effect, continue to account for leases that commenced before the effective date in accordance with the previous generally accepted accounting principles in the United States unless the lease is modified, except that lessees are required to recognize a right-of-use asset and a lease liability for all operating leases at each reporting date based on the present value of the remaining minimum rental payments that were tracked and disclosed under previous generally accepted accounting principles in the United States. The amendments in this update are effective for annual reporting periods beginning after

December 15, 2018,

including interim periods within those reporting periods. Early adoption is permitted. The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income

In

February 2018,

the FASB issued ASU

2018

-

02,

Income Statement – Reporting Comprehensive Income (Topic

220

). The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting for the Tax Cuts and Jobs Act of

2017

(the “Tax Act”). The guidance is effective for the fiscal years beginning after

December 15, 2018,

and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the potential impact of the adoption of these amendments on its consolidated financial statements, however, such impact, if any, is

not

expected to be material.

Note 3 - Inventories

6 Months Ended

Jun. 30, 2018

Inventory Disclosure [Text Block]

NOTE

3

— INVENTORIES

Inventories consist of the following:

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Raw materials and purchased parts for assembly	$	26,919	$	12,007
Self-manufactured assembly parts and finished products		9,777		7,544
Total	$	36,696	$	19,551

Note 4 - Investment in an Unconsolidated Company

6 Months Ended

Jun. 30, 2018

Equity Method Investments and Joint Ventures Disclosure [Text Block]

NOTE

4

—

INVESTMENT IN AN

UNCONSOLIDATED

COMPANY

Unconsolidated investments consist of the following:

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Sarulla	$	66,551	$	34,084

The Sarulla Project

The Company holds a

12.75%

equity interest in a consortium that developed the

330

MW Sarulla geothermal power plant project in Tapanuli Utara, North Sumatra, Indonesia. The Sarulla project is comprised of

three

separately constructed

110

MW units, the most recent of which,

NIL

2,

was completed in

April 2018.

The Sarulla project is owned and operated by the consortium members under the framework of a joint operating contract and energy sales contract that were both executed on

April 4, 2013

.

Under the joint operating contract, PT Pertamina Geothermal Energy, the concession holder for the project, provided the consortium with the right to use the geothermal field, and under the energy sales contract, PT PLN, the state electric utility, is the off-taker at Sarulla for a period of

30

years.

On

May 16, 2014,

the consortium closed

$1.17

billion in financing for the development of the Sarulla project with a consortium of lenders comprised of Japan Bank for International Cooperation (“JBIC”), the Asian Development Bank and

six

commercial banks and obtained construction and term loans on a limited recourse basis backed by a political risk guarantee from JBIC. Of the

$1.17

billion,

$0.1

billion bears interest at a fixed rate and

$1.07

billion bears interest at a rate linked to LIBOR. The total interest expenses, net incurred by the consortium for the

six

months ended

June 30, 2018,

totaled approximately

$23.1

million.

The Sarulla consortium entered into interest rate swap agreements with various international banks, effective as of

June 4, 2014,

in order to fix the interest rate linked to LIBOR on up to

$0.96

billion of the

$1.07

billion portion of the financing arrangement subject to such interest rate at

3.4565%.

The Sarulla project company accounted for the interest rate swap as a cash flow hedge upon which changes in the fair value of the hedging instrument, relative to the effective portion, are recorded in other comprehensive income. During the

three

and

six

months ended

June 30, 2018

the Sarulla project company recorded a gain of

$4.2

million and

$24.8

million, respectively, net of deferred tax, of which the Company’s share was

$0.5

million and

$3.2

million, respectively. The Company’s share of such gains was recorded in other comprehensive income. During the

three

and

six

months ended

June 30, 2017

the Sarulla project company recorded losses of

$7.2

million and

$2.7

million, respectively, net of deferred tax, of which the Company’s share was

$0.9

million and

$0.3

million, respectively. The Company’s share of such losses was recorded in other comprehensive income. The related accumulated loss recorded by the Company in other comprehensive income (loss) as of

June 30, 2018

is

$1.9

million.

During the

three

and

six

months ended

June 30, 2018,

the Company made additional cash equity investments in the Sarulla project of approximately

$2.5

and

$3.8

million, respectively, for a total of

$62.0

million since inception.

As further described above under the heading “New accounting pronouncement effective in the

six

-month period ended

June 30, 2018”

in Note

2

to the condensed consolidated financial statements, the Company adopted ASC

606,

Revenue from Contracts with Customers, on

January 1, 2018.

The impact of the adoption of this standard on its investment in an unconsolidated company amounted to

$24.0

million at

January 1, 2018.

This impact was a result of the unconsolidated company’s variable consideration related to the construction of its power plant for which, under the new guidance, is probable that a significant reversal in the amount of cumulative revenue recognized will

not

occur when the uncertainty is resolved. The Company adopted the new standard using the modified retrospective approach with a

one

-time cumulative adjustment to the opening balance of retained earnings of approximately

$24.0

million at

January 1, 2018,

the date of initial application.

Note 5 - Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Text Block]

NOTE

5—

FAIR VALUE OF FINANCIAL INSTRUMENTS

The fair value measurement guidance clarifies that fair value is an exit price, representing the amount that would be received upon selling an asset or paid upon transferring a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level

1

measurements) and the lowest priority to unobservable inputs (Level

3

measurements). The

three

levels of the fair value hierarchy under the fair value measurement guidance are described below:

Level

1

— Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets or liabilities.

Level

2

— Quoted prices in markets that are

not

active, or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability.

Level

3

— Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (supported by little or

no

market activity).

The following table sets forth certain fair value information at

June 30, 2018

and

December 31, 2017

for financial assets and liabilities measured at fair value by level within the fair value hierarchy, as well as cost or amortized cost. As required by the fair value measurement guidance, assets and liabilities are classified in their entirety based on the lowest level of inputs that is significant to the fair value measurement.

				June 30, 2018
				Fair Value
	Carrying Value at June 30, 2018			Total			Level 1		Level 2			Level 3
	(Dollars in thousands)
Assets:
Current assets:
Cash equivalents (including restricted cash accounts)	$	19,069		$	19,069		$	19,069	$	—		$	—
Derivatives:
Contingent receivable (1)		106			106			—		—			106
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(13,808	)		(13,808	)		—		—			(13,808	)
Currency forward contracts (2)		(507	)		(507	)		—		(507	)		—
	$	4,860		$	4,860		$	19,069	$	(507	)	$	(13,702	)

				December 31, 2017
				Fair Value
	Carrying Value at December 31, 2017			Total			Level 1		Level 2		Level 3
	(Dollars in thousands)
Assets
Current assets:
Cash equivalents (including restricted cash accounts)	$	18,359		$	18,359		$	18,359	$	—	$	—
Derivatives:
Contingent receivable (1)		108			108			—		—		108
Currency forward contracts (2)		992			992			—		992		—
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(13,904	)		(13,904	)		—		—		(13,904	)
Warrants (1)		(3,967	)		(3,967	)		—		—		(3,967	)
	$	1,588		$	1,588		$	18,359	$	992	$	(17,763	)

(

1

)

These amounts relate to contingent receivables and payables and warrants relating to acquisition of substantially all of the assets of Viridity Energy, Inc. and to the Guadeloupe power plant purchase transaction, valued primarily based on unobservable inputs and are included within “Prepaid expenses and other”, “Accounts payable and accrued expenses” and “Other long-term liabilities” on

June 30, 2018

and

December 31, 2017

in the consolidated balance sheets with the corresponding gain or loss being recognized within Derivatives and foreign currency transaction gains (losses) in the consolidated statement of operations and comprehensive income. The warrants were executed during the

second

quarter of

2018

in accordance with the purchase agreements.

(

2

)

These amounts relate to currency forward contracts valued primarily based on observable inputs, including forward and spot prices for currencies, net of contracted rates and then multiplied by notional amounts, and are included within “Prepaid expenses and other” and “Accounts payable and accrued expenses”, as applicable, on

June 30, 2018

and

December 31, 2017,

in the consolidated balance sheet with the corresponding gain or loss being recognized within “Derivatives and foreign currency transaction gains (losses)” in the consolidated statement of operations and comprehensive income.

The amounts set forth in the tables above include investments in debt instruments and money market funds (which are included in cash equivalents). Those securities and deposits are classified within Level

1

of the fair value hierarchy because they are valued using quoted market prices in an active market.

The following table presents the amounts of gain (loss) recognized in the consolidated statements of operations and comprehensive income on derivative instruments

not

designated as hedges:

		Amount of recognized gain (loss)
Derivatives not designated as hedging instruments	Location of recognized gain (loss)	Three Months Ended June 30,						Six Months Ended June 30,
		2018			2017			2018			2017

Put options on natural gas price	Derivatives and foreign transaction gains (losses)		—			(48	)		—			(241	)
Contingent considerations	Derivative and foreign transaction gains (losses)		—			(45	)		—			(95	)
Currency forward contracts	Derivative and foreign and transaction gains (losses)		(911	)		1,457			(1,457	)		3,719
		$	(911	)	$	1,364		$	(1,457	)	$	3,383

In

January 2017,

the Company entered into Henry Hub Natural Gas Future contracts under which it bought a number of put options covering a notional quantity of approximately

4.1

million British Thermal Units with exercise prices of

$3

and expiration dates ranging from

January 26, 2017

until

November 27, 2017

in order to reduce its exposure to fluctuations in natural gas prices under its PPAs with Southern California Edison. The Company paid an aggregate amount of approximately

$0.7

million for these put options.

The foregoing future and forward transactions were

not

designated as hedge transactions and are marked to market with the corresponding gains or losses recognized within “Derivatives and foreign currency transaction gains (losses)”.

There were

no

transfers of assets or liabilities between Level

1,

Level

2

and Level

3

during the

six

months ended

June 30, 2018.

The fair value of the Company’s long-term debt approximates its carrying amount, except for the following:

	Fair Value				Carrying Amount
	June 30, 2018		December 31, 2017		June 30, 2018		December 31, 2017
	(Dollars in millions)				(Dollars in millions)
Olkaria III Loan - OPIC		219.6		234.6		219.6		228.6
Olkaria IV Loan - DEG 2		49.5		50.7		50.0		50.0
Amatitlan Loan		31.7		32.8		31.5		33.3
Senior Secured Notes:
OrCal Geothermal Inc. ("OrCal")		28.7		34.2		27.3		32.1
OFC 2 LLC ("OFC 2")		219.2		234.6		224.2		232.5
Don A. Campbell 1 ("DAC 1")		79.9		85.5		85.3		88.3
USG Prudential - NV		29.7		—		28.3		—
USG Prudential - ID		18.6		—		18.9		—
USG DOE		49.0		—		53.0		—
Senior Unsecured Bonds		198.1		200.3		204.3		204.3
Senior Unsecured Loan		101.3		—		100.0		—
Other long-term debt		5.4		7.0		6.4		7.9

The fair value of the long-term debt is determined by a valuation model, which is based on a conventional discounted cash flow methodology and utilizes assumptions of current borrowing rates. The fair value of revolving lines of credit is determined using a comparison of market-based price sources that are reflective of similar credit ratings to those of the Company.

The carrying value of financial instruments such as revolving lines of credit and deposits approximates fair value.

The following table presents the fair value of financial instruments as of

June 30, 2018:

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III - OPIC		—		—		219.6		219.6
Olkaria IV - DEG 2		—		—		49.5		49.5
Amatitlan Loan		—		31.7		—		31.7
Senior Secured Notes:
OrCal Senior Secured Notes		—		—		28.7		28.7
OFC 2 Senior Secured Notes		—		—		219.2		219.2
DAC 1 Senior Secured Notes		—		—		79.9		79.9
USG Prudential - NV		—		—		29.7		29.7
USG Prudential - ID		—		—		18.6		18.6
USG DOE		—		—		49.0		49.0
Senior Unsecured Bonds		—		—		198.1		198.1
Senior Unsecured Loan		—		—		101.3		101.3
Other long-term debt		—		—		5.4		5.4
Revolving lines of credit		—		158.6		—		158.6
Deposits	19.3			—		—		19.3

The following table presents the fair value of financial instruments as of

December

31,

2017:

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III Loan - OPIC	$	—	$	—	$	234.6	$	234.6
Olkaria IV - DEG 2						50.7		50.7
Amatitlan Loan		—		32.8		—		32.8
Senior Secured Notes:
OrCal Senior Secured Notes		—		—		34.2		34.2
OFC 2 Senior Secured Notes		—		—		234.6		234.6
DAC 1 Senior Secured Notes		—		—		85.5		85.5
Senior Unsecured Bonds		—		—		200.3		200.3
Other long-term debt		—		—		7.0		7.0
Revolving lines of credit		—		51.5		—		51.5
Deposits		15.6		—		—		15.6

- 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

Note 6 - Stock-based Compensation

6 Months Ended

Jun. 30, 2018

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

NOTE

6

— STOCK-BASED COMPENSATION

The

2012

Incentive Compensation Plan

In

May 2012,

the Company’s shareholders adopted the

2012

Incentive Plan, which provides for the grant of the following types of awards: incentive stock options, non-qualified stock options, restricted stock, stock appreciation rights “(SARs”), stock units, performance awards, phantom stock, incentive bonuses, and other possible related dividend equivalents to employees of the Company, directors and independent contractors. Under the

2012

Incentive Plan, a total of

4,000,000

shares of the Company’s common stock were reserved for issuance, all of which could be issued as options or as other forms of awards. Options and SARs granted to employees under the

2012

Incentive Plan typically vest and become exercisable as follows:

25%

vest

24

months after the grant date, an additional

25%

vest

36

months after the grant date, and the remaining

50%

vest

48

months after the grant date. Options granted to non-employee directors under the

2012

Incentive Plan will vest and become exercisable

one

year after the grant date. Restricted stock units granted to directors and members of senior management vest according to a vesting schedule as follows: for the directors,

100%

on the

first

anniversary of the grant date and for members of senior management,

25%

on each of the first, second,

third

and

fourth

anniversaries of the grant date. The term of stock-based awards typically ranges from

six

to

ten

years from the grant date. The shares of common stock issued in respect of awards under the

2012

Incentive Plan are issued from the Company’s authorized share capital upon exercise of options or SARs. The

2012

Incentive Plan expired in

May 2018

upon adoption of the

2018

Incentive Compensation Plan (

“2018

Incentive Plan”), except as to stock-based awards outstanding under the

2012

Incentive Plan on that date.

The

201

8

Incentive Compensation Plan

On

May

7,

2018,

the Company held its

2018

Annual Meeting of Stockholders at which the Company's stockholders approved the

2018

Incentive Plan. The

2018

Incentive Plan provides for the grant of the following types of awards: incentive stock options, restricted stock units (“RSUs”), SARs, stock units, performance awards, phantom stock, incentive bonuses and other possible related dividend equivalents to employees of the Company, directors and independent contractors. Under the

2018

Incentive Plan, a total of

5,000,000

shares of the Company’s common stock were authorized and reserved for issuance, all of which could be issued as options or as other forms of awards. SARs and RSUs granted to employees under the

2018

Incentive Plan typically vest and become exercisable as follows:

50%

on the

second

anniversary of the grant date and

25%

on each of the

third

and

fourth

anniversaries of the grant date. SARs and Restricted stock units granted to directors under the

2018

Incentive Plan typically vest and become exercisable (

100%

) on the

first

anniversary of the grant date. The term of stock-based awards typically ranges from

six

to

ten

years from the grant date. The shares of common stock issued in respect of awards under the

2018

Incentive Plan are issued from the Company’s authorized share capital upon exercise of options or SARs.

On

May 8, 2018,

the Company granted an aggregate of

295,671

SARs and

40,489

RSUs to the CEO and

one

of the directors under the Company’s

2018

Incentive Plan. The exercise price of each SAR is

$55.16,

which represented the fair market value of the Company’s common stock on the grant date. The SARs and RSUs will expire in

five

and a half years from the date of grant and will vest according to a vesting schedule as follows: for the directors,

100%

after a half year from the grant date and for the CEO,

22%

on each of the

first

and

second

anniversaries of the grant date and

28%

on the

third

and

fourth

anniversaries of the grant date.

The fair value of each SAR for the director and the CEO on the grant date was

$14.56

and

$14.57,

respectively. The fair value of each RSU for the director and the CEO on the grant date was

$54.92

and

$54.23,

respectively. The Company calculated the fair value of each SAR and RSU on the grant date using the Exercise Multiple-Based Lattice Pricing model based on the following assumptions:

Risk-free interest rate	2.84	%
Expected life (in years)	5.5
Dividend yield	0.79	%
Expected volatility	25.24	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

On

June 25, 2018,

the Company granted its employees and members of its senior management an aggregate of

838,117

SARs and

19,848

RSUs under the Company’s

2018

Incentive Plan. The exercise price of each SAR is

$53.44,

which represented the fair market value of the Company’s common stock on the grant date. The SARs and RSUs will expire in

six

years from the date of grant and will vest according to a vesting schedule as follows:

50%

on the

second

anniversary of the grant date and

25%

on each of the

third

and

fourth

anniversaries of the grant date.

The fair value of each SAR for the employees and members of senior management on the grant date was

$13.82

and

$14.64,

respectively. The fair value of each RSU for the employees and members of senior management on the grant date was

$52.03

and

$52.09,

respectively. The Company calculated the fair value of each SAR and RSU on the grant date using the Exercise Multiple-Based Lattice Pricing model based on the following assumptions:

Risk-free interest rate	2.79	%
Expected life (in years)	6
Dividend yield	0.92	%
Expected volatility	25.64	%
Forfeiture rate for employees	2.78	%
Forfeiture rate for members of the senior management	0.0	%
Sub-Optimal Exercise Factor for employees	2.0
Sub-Optimal Exercise Factor for members of the senior management	2.8

Note 7 - Interest Expense, Net

6 Months Ended

Jun. 30, 2018

Interest Expense Disclosure [Text Block]

NOTE

7

— INTEREST EXPENSE, NET

The components of interest expense are as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017

Interest related to sale of tax benefits	$	1,761		$	1,849		$	3,170		$	3,861
Interest expense		15,421			14,146			28,727			28,321
Less — amount capitalized		(1,336	)		(1,455	)		(1,707	)		(2,719	)
	$	15,846		$	14,540		$	30,190		$	29,463

Note 8 - Earnings Per Share

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Text Block]

NOTE

8

— EARNINGS PER SHARE

Basic earnings per share attributable to the Company’s stockholders is computed by dividing net income or loss attributable to the Company’s stockholders by the weighted average number of shares of common stock outstanding for the period. The Company does

not

have any equity instruments that are dilutive, except for employee stock-based awards.

The table below shows the reconciliation of the number of shares used in the computation of basic and diluted earnings per share:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017

Weighted average number of shares used in computation of basic earnings per share		50,623		49,771		50,618		49,726
Add:
Additional shares from the assumed exercise of employee stock options		335		853		383		833

Weighted average number of shares used in computation of diluted earnings per share		50,958		50,624		51,001		50,559

The number of stock-based awards that could potentially dilute future earnings per share and that were

not

included in the computation of diluted earnings per share because to do so would have been anti-dilutive was

232,925

and

2,363

for the

three

months ended

June 30, 2018

and

2017,

respectively, and

223,708

and

2,430

for the

six

months ended

June 30, 2018

and

2017,

respectively.

Note 9 - Business Segments

6 Months Ended

Jun. 30, 2018

Segment Reporting Disclosure [Text Block]

NOTE

9

— BUSINESS SEGMENTS

In

2018,

the Company started disclosing its energy storage and power load management business activity under the Other segment as such operations met the reportable segment criteria of ASC

280,

Segment Reporting. As such, starting in

2018

the Company has

three

reporting segments: the Electricity segment, the Product segment and the Other segment. These segments are managed and reported separately as each offers different products and serves different markets. The Electricity segment is engaged in the sale of electricity from the Company’s power plants pursuant to PPAs. The Product segment is engaged in the manufacture, including design and development, of turbines and power units for the supply of electrical energy and in the associated construction of power plants utilizing the power units manufactured by the Company to supply energy from geothermal fields and other alternative energy sources. The Other segment is engaged in management of curtailable customer loads under contracts with U.S. retail energy providers and directly with large commercial and industrial customers as well as battery storage as a service.

Transfer prices between the operating segments are determined based on current market values or cost plus markup of the seller’s business segment.

Summarized financial information concerning the Company’s reportable segments is shown in the following tables, including, as further described under Note

1

to the consolidated financial statements, the Company's disaggregated revenues from contracts with customers as required by ASC

606:

	Electricity		Product		Other			Consolidated
	(Dollars in thousands)
Three Months Ended June 30, 2018:
Revenues from external customers:
United States (1)	$	73,139	$	27	$	1,205		$	74,371
Foreign (2)		49,040		54,888		—			103,928
Net revenue from external customers		122,179		54,915		1,205			178,299
Intersegment revenue		—		11,453		—			11,453
Operating income		27,462		10,761		(1,590	)		36,633
Segment assets at period end (3) (*)		2,805,182		125,572		63,395			2,994,149
* Including unconsolidated investments		66,551		—		—			66,551

Three Months Ended June 30, 2017:
Net revenue from external customers	$	110,896	$	67,587		881			179,364
Intersegment revenue		—		16,565		—			16,565
Operating income		38,014		17,035		(1,897	)		53,152
Segment assets at period end (3) (*)		2,273,503		187,015		50,115			2,510,633
* Including unconsolidated investments		13,957		—		—			13,957

Six Months Ended June 30, 2018:
Revenues from external customers:
United States (1)	$	156,822	$	221	$	4,067		$	161,110
Foreign (2)		97,846		103,366		—			201,212
Net revenues from external customers		254,668		103,587		4,067			362,322
Intersegment revenues		—		36,280		—			36,280
Operating income		73,874		20,314		(2,962	)		91,226
Segment assets at period end (3) (*)		2,805,182		125,572		63,395			2,994,149
* Including unconsolidated investments		66,551		—		—			66,551

Six Months Ended June 30, 2017:
Net revenues from external customers	$	226,672	$	141,709	$	881		$	369,262
Intersegment revenues		—		32,778		—			32,778
Operating income		78,912		35,633		(1,897	)		112,648
Segment assets at period end (3) (*)		2,273,503		187,015		50,115			2,510,633
* Including unconsolidated investments		13,957		—		—			13,957

	( 1 )	Electricity segment revenues in the United States are all accounted under ASC 840, Leases, except for $5.3 million and $11.9 million in the three and six months ended June 30, 2018 that are accounted under ASC 606 starting in 2018. Product and Other segment revenues in the United States are accounted under ASC 606, as further described under Note 2 to the consolidated financial statements.
	( 2 )	Electricity segment revenues in foreign countries are all accounted under ASC 840, Leases, and Product revenues in foreign countries are accounted under ASC 606 as further described under Note 2 to the consolidated financial statements.

(

3

)

Electricity segment assets include goodwill in the amount of

$26.7

million and

$6.6

million as of

June 30, 2018

and

2017,

respectively. Other segment assets include goodwill in the amount of

$13.5

million as of

June 30, 2018

and

2017.

Reconciling information between reportable segments and the Company’s consolidated totals is shown in the following table:

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017

Revenue:
Total segment revenue	$	178,299		$	179,364		$	362,322		$	369,262
Intersegment revenue		11,453			16,565			36,280			32,778
Elimination of intersegment revenue		(11,453	)		(16,565	)		(36,280	)		(32,778	)
Total consolidated revenue	$	178,299		$	179,364		$	362,322		$	369,262

Operating income:
Operating income	$	36,633		$	53,152		$	91,226		$	112,648
Interest income		189			362			302			606
Interest expense, net		(15,846	)		(14,540	)		(30,190	)		(29,463	)
Derivatives and foreign currency transaction gains (losses)		(529	)		1,703			(2,128	)		3,041
Income attributable to sale of tax benefits		3,556			4,356			10,917			10,513
Other non-operating income (expense), net		7,373			6			7,353			(86	)
Total consolidated income before income taxes and equity in income of investees	$	31,376		$	45,039		$	77,480		$	97,259

Note 10 - Commitments and Contingencies

6 Months Ended

Jun. 30, 2018

Commitments and Contingencies Disclosure [Text Block]

NOTE

10

— COMMITMENTS AND CONTINGENCIES

●

Following the announcement of the Company’s acquisition of USG, a number of putative shareholder class action complaints were initially filed on behalf of USG shareholders between

March 8, 2018

and

March 30, 2018

against USG and the individual members of the USG board of directors. All of the purported class action suits filed in Federal Court in Idaho have been voluntarily dismissed. The single remaining class action complaint is a purported class action filed in the Delaware Chancery Court, entitled Riche v. Pappas, et al., Case

No.

2018

-

0177

(Del. Ch.,

Mar. 12, 2018).

An amended complaint was filed on

May 24, 2018

under seal, under a confidentiality agreement that was executed by the plaintiff (the “Amended Complaint”). The Amended Complaint alleges state law claims for breach of fiduciary duty against former USG directors and seeks post-closing damages.

●

On

February 18, 2018,

Western Watersheds Project (“WWP”) filed a notice of appeal and petition with the U.S. Department of the Interior Board of Land Appeals for standing with respect to the

January 16, 2018

Bureau of Land Management (“BLM”) decision approving Addendum

2

to Operation Plan & Utilization Plan for the McGinness Hills Geothermal Project. The appeal alleges that the

January 2018

BLM decision authorizing construction and operation of Phase

3

of the McGinness Hills Geothermal Project causes harm to WWP and its members by allowing degradation of the wildlife habitat of the greater sage-grouse in that area. The Company has filed a motion to intervene as an interested party in support of the BLM decision. The litigation was resolved and the settlement was approved by the Interior Board of Land appeals.

●

On

August 5, 2016,

George Douvris, Stephanie Douvris, Michael Hale, Cheryl Cacocci, Hillary E. Wilt and Christina Bryan, acting for themselves and on behalf of all other similarly situated residents of the lower Puna District, filed a complaint in the Third Circuit Court for the State of Hawaii (the “Third Circuit Court”) seeking certification of a class action for preliminary and permanent injunctive relief, consequential and punitive damages, attorney’s fees and statutory interest against Puna Geothermal Venture (“PGV”) and other presently unknown defendants. On

December 12, 2016,

the District Court granted plaintiffs motion for joinder of HELCO as a co-defendant. The amended complaint purports that injuries and other damages in an undisclosed amount were caused to the plaintiffs as a result of an alleged toxic release by PGV in the wake of Hurricane Iselle in

August 2014.

On

June 14, 2017,

the Third Circuit Court denied HELCO’s motion to discuss the complaint against itself which it had filed On

March 25, 2017.

Discovery is underway. The Company believes that it has valid defenses under law and intends to defend itself vigorously. On

June 19, 2018,

PGV filed a motion for leave to serve a

third

-party complaint for damages against

third

party defendants Valve Service & Supply Inc. and Curtiss-Wright Flow Control Corporation, who are, respectively, the distributor and manufacturer of the pressure release valve that failed to reseat during the Hurricane Iselle. The claim is for recovery of damages to PGV due to the supply of a defective pressure valve to PGV, which defect was the cause for any alleged toxic or unpermitted release of Hydrogen Sulfide. HELCO subsequently filed a motion of

no

objection to the PGV filing.

	●	On March 29, 2016, a former local sales representative in Chile, Aquavant, S.A. (“Aquavant”), filed a claim on the basis of unjust enrichment against Ormat’s subsidiaries in the 27th Civil Court of Santiago, Chile. The claim requests that the court order Ormat to pay Aquavant $4.6 million in connection with its activities in Chile, including the EPC contract for the Cerro Pabellon project and various geothermal concessions, plus 3.75% of Ormat geothermal products sales in Chile over the next 10 years. Pursuant to various motions submitted by the defendants and the plaintiffs to various courts, including the Court of Appeals of Santiago, Chile, the case was removed from the original court and then refiled before the 11th Civil Court of Santiago (the “Civil Court”). Preliminary defenses have been filed by the Company, which are under consideration by the Civil Court. The Company believes that it has valid defenses under law and intends to defend itself vigorously.

	●	Jon Olson and Hilary Wilt, together with Puna Pono Alliance filed a complaint on February 17, 2015 in the Third Circuit Court, requesting declaratory and injunctive relief requiring that PGV comply with an ordinance that the plaintiffs allege will prohibit PGV from engaging in night drilling operations at its KS- 16 well site. On May 17, 2015, the original complaint was amended to add the county of Hawaii and the State of Hawaii Department of Land and Natural Resources as defendants to the case. On October 10, 2016, the Third Circuit Court issued its decision in response to each of the plaintiffs’ and defendants’ motions for summary judgment, denying plaintiffs’ motion and granting defendant PGV's and the County of Hawaii’s cross motions for summary judgment, effectively rendering the plaintiffs’ action moot. On January 23, 2017, the plaintiffs filed motion requesting the Intermediate Court of Appeals for the State of Hawaii to address appellate jurisdiction, which was denied by the court on April 20, 2017 as premature.

●

On

May 21, 2018,

a motion to certify a class action was filed in Tel Aviv District Court against the Company and

11

of its officers and directors. The alleged class is defined as "All persons who purchased Ormat shares on the Tel Aviv Stock Exchange between

August 3, 2017

and

May 13, 2018.

The motion alleges that the Company violated Sections

31

(a)(

1

) and

38C

of the Israeli Securities Law because it allegedly: (

1

) misled investors by stating in its financial statements that it maintains effective internal controls over its accounting policies and procedures, however the Company's internal controls had material weaknesses which led to erroneous accounting in its

2017

unaudited quarterly reports that had to be restated, including adjustments to the Company’s net income and shareholders’ equity; and (

2

) failed to issue an immediate report in Israel until

May 16, 2018,

analogous to the report that was released in the United States on

May 11, 2018

stating, inter alia, that the errors in its financial reports affected its balance sheet and would be remedied in its

2017

annual report. The proceedings in Israel were stayed by the district court until a final decision in the U.S. case described below (Mac Costas) is adjudicated.

●

On

June 11, 2018,

a putative class action on behalf of alleged shareholders that purchased or acquired the Company's ordinary shares between

August 8, 2017

and

May 15, 2018

was commenced in the United States District Court for the District of Nevada against the Company and its Chief Executive Officer and Chief Financial Officer. The complaint asserts claims against all defendants pursuant to Section

10

(b) of the Exchange Act, as amended, and Rule

10b

-

5

thereunder and against its officers pursuant to Section

20

(a) of the Exchange Act. The complaint alleges that the Company's Form

10

-K for the years ended

December 31, 2016

and

2017,

and Form

10

-Qs for each of the quarters in the

nine

months ended

September 30, 2017

contained material misstatements or omissions, among other things, with respect to the Company’s tax provisions and the effectiveness of its internal control over financial reporting, and that, as a result of such alleged misstatements and omissions, the plaintiffs suffered damages. The Company has

not

yet responded to the complaints. The Company believes that it has valid defenses under law and intends to defend itself vigorously.

In addition, from time to time, the Company is named as a party to various other lawsuits, claims and other legal and regulatory proceedings that arise in the ordinary course of our business. These actions typically seek, among other things, compensation for alleged personal injury, breach of contract, property damage, punitive damages, civil penalties or other losses, or injunctive or declaratory relief. With respect to such lawsuits, claims and proceedings, the Company accrues reserves when a loss is probable, and the amount of such loss can be reasonably estimated. It is the opinion of the Company’s management that the outcome of these proceedings, individually and collectively, will

not

be material to the Company’s consolidated financial statements as a whole.

Note 11 - Income Taxes	6 Months Ended
Note 11 - Income Taxes	Jun. 30, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	NOTE 11 — INCOME TAXES The Company’s effective tax rate expense (benefit) for the three months ended June 30, 2018 and 2017 was 92.8% and 72.7%, respectively, and 2.8% and 45.0% for the six months ended June 30, 2018 and 2017, respectively. The effective rate differs from the federal statutory rate of 21% for the six months ended June 30, 2018 due to: (i) the impact of the newly enacted global intangible low tax income (“GILTI”); (ii) a partial valuation allowance release against the Company’s U.S. deferred tax assets; (iii) forecasted generation of production tax credits; (iv) impact of U.S. permanent tax adjustments; (v) higher tax rate in Kenya of 37.5% partially offset by a lower tax rate in Israel of 16% and (vi) a tax credit and tax exemption related to the Company’s subsidiaries in Guatemala and Honduras. The Tax Cuts and Jobs Act (the “Tax Act”) was enacted on December 22, 2017. The Tax Act ( 1 ) reduced the U.S. federal corporate income tax rate from 35 percent to 21 percent; ( 2 ) required companies to include in taxable income an amount on certain unrepatriated earnings of foreign subsidiaries; ( 3 ) generally eliminated U.S. federal income taxes on dividends from foreign subsidiaries; ( 4 ) required a current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations; ( 5 ) eliminated the corporate alternative minimum tax (“AMT”) and changed how existing AMT credits can be realized; ( 6 ) created the base erosion anti-abuse tax (“BEAT”), a new minimum tax; ( 7 ) created a new limitation on deductible interest expense; and ( 8 ) changed rules related to uses and limitations of net operating loss carryforwards created in tax years beginning after December 31, 2017. The SEC staff issued SAB 118, which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provision of the tax laws that were in effect immediately before the enactment of the Tax Act. The Company is applying the guidance in SAB 118 when accounting for the enactment date effects of the Act. As of December 31, 2017, the Company made provisional estimates related to ( 1 ) deemed repatriation transition tax; ( 2 ) GILTI; ( 3 ) valuation allowance; and ( 4 ) uncertain tax positions. As of June 30, 2018, the Company made updates to its provisional estimates related to GILTI and valuation allowance. The Company will continue to refine the estimates as it continues its analysis of the statutory provisions and related interpretations. Any changes to a provisional estimate of the tax effect of the Tax Act, that were recorded as of December 31, 2017, will be recorded as a discrete item in the interim period. The Company continues to analyze specific provisions of the Act, including the newly created requirement that GILTI earned by controlled foreign corporations (CFCs) must be included currently in gross income of the CFC’s U.S. shareholder. In the second quarter of 2018, certain officials from the Treasury and the IRS made public comments about a plan to propose regulations related to GILTI that will confirm how to allocate certain income in the GILTI calculation. The method of allocation is different than the analysis of the law at March 31, 2018 and resulted in a year to date tax benefit of $27.5 million for the decrease of the valuation allowance related to foreign tax credits and production tax credits compared to tax benefit of $44.4 million at March 31, 2018. This change has been reflected as a discrete item in the quarter. The U.S. Department of the Treasury and the IRS recently published proposed regulations under IRC Section 965 (Transition Tax). These highly anticipated rules are complex and affect a broad range of taxpayers. The company is still evaluating the impact of this guidance on its preliminary accrual for transition tax as of December 31, 2017. The company will continue to evaluate this and other guidance as it completes its accounting related to the Tax Cuts and Jobs Act of 2017, which was enacted on December 22, 2017.

Note 12 - Subsequent Events	6 Months Ended
Note 12 - Subsequent Events	Jun. 30, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	NOTE 12 — SUBSEQUENT EVENTS Cash dividend On August 7, 2018 , the Board of Directors of the Company declared, approved and authorized payment of a quarterly dividend of $5.1 million ( $0.10 per share) to all holders of the Company’s issued and outstanding shares of common stock on August 21, 2018 , payable on August 29, 2018 .

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2018

Accounting Policies [Abstract]

Debt, Policy [Policy Text Block]

Migdal Senior Unsecured Loan

On

March 22, 2018

the Company entered into a definitive loan agreement (the "Migdal Loan Agreement") with Migdal Insurance Company Ltd., Migdal Makefet Pension and Provident Funds Ltd. and Yozma Pension Fund of Self Employed Ltd., all entities within the Migdal Group, a leading insurance company and institutional investor in Israel. The Migdal Loan Agreement provides for a loan by the lenders to the Company in an aggregate principal amount of

$100

million (the “Migdal Loan”). The Migdal Loan will be repaid in

15

semi-annual payments of

$4.2

million each, commencing on

September 15, 2021,

with a final payment of

$37

million on

March 15, 2029.

The Migdal Loan bears interest at a fixed rate of

4.8%

per annum, payable semi-annually, subject to adjustment in certain circumstances as described below.

The Migdal Loan is subject to early redemption by the Company prior to maturity from time to time (but

not

more frequently than once per quarter) and at any time in whole or in part, at a redemption price set forth in the Migdal Loan Agreement. If the rating of the Company is downgraded to "ilA-", by Standard and Poor’s Global Ratings Maalot Ltd. (“Maalot”), the interest rate applicable to the Migdal Loan will be increased by

0.50%.

If the rating of the Company is further downgraded to a lower level, the interest rate applicable to the Migdal Loan will be increased by

0.25%

for each additional downgrade. In

no

event will the cumulative increase in the interest rate applicable to the Migdal Loan exceed

1%

regardless of the cumulative rating downgrade. A subsequent upgrade or reinstatement of a rating by Maalot will reduce the interest rate applicable to the Migdal Loan by

0.25%

for each upgrade (but in

no

event will the interest rate applicable the Migdal Loan fall below the base interest rate of

4.8%

). Additionally, if the ratio between short-term and long-term debt to financial institutions and bondholders, deducting cash and cash equivalents to EBITDA is equal to or higher than

4.5,

the interest rate on all amounts then outstanding under the Migdal Loan shall be increased by

0.5%

per annum over the interest rate then-applicable to the Migdal Loan.

The Migdal Loan constitutes senior unsecured indebtedness of the Company and will rank equally in right of payment with any existing and future senior unsecured indebtedness of the Company, and effectively junior to any existing and future secured indebtedness, to the extent of the security therefore.

The Migdal Loan Agreement includes various affirmative and negative covenants, including a covenant that the Company maintain (i) a debt to adjusted EBITDA ratio below

6,

(ii) a minimum equity amount (as shown on its consolidated financial statements, excluding noncontrolling interests) of

not

less than

$650

million, and (iii) an equity attributable to Company's stockholders to total assets ratio of

not

less than

25%.

In addition, the Migdal Loan Agreement restricts the Company from making dividend payments if its equity falls below

$800

million and otherwise restricts dividend payments in any

one

year to

not

more than

50%

of the net income of the Company of such year as shown on the Company’s consolidated annual financial statements as long as any of the Company's bonds issued in Israel prior to

March 27, 2018

remain outstanding. The Migdal Loan Agreement includes other customary affirmative and negative covenants and events of default. As of

June 30, 2018

the Company was in compliance with all such covenants.

Comprehensive Income, Policy [Policy Text Block]

Other comprehensive income

For the

six

months ended

June 30, 2018

and

2017,

the Company classified

$10,000

and

$54,000,

respectively, related to derivative instruments designated as cash flow hedges, from accumulated other comprehensive income, of which

$15,000

and

$30,000,

respectively, were recorded to reduce interest expense and

$5,000

and $(

24,000

), respectively, were recorded against the income tax provision, in the condensed consolidated statements of operations and comprehensive income. For the

three

months ended

June 30, 2018

and

2017,

the Company classified

$5,000

and

$30,000,

respectively, related to derivative instruments designated as cash flow hedges, from accumulated other comprehensive income, of which

$6,000

and

$20,000,

respectively, were recorded to reduce interest expense and

$1,000

and $(

10,000

), respectively, were recorded against the income tax provision, in the condensed consolidated statements of operations and comprehensive income. The accumulated net loss included in Other comprehensive income as of

June 30, 2018,

is

$1.0

million

Exploratory Drilling Costs Capitalization and Impairment, Policy [Policy Text Block]

Write-offs of unsuccessful exploration activities

Write-offs of unsuccessful exploration activities for the

three

and

six

months ended

June 30, 2018

were

$0

and

$0.1

million. There were

no

write-offs of unsuccessful exploration activities for the

three

and

six

months ended

June 30, 2017.

Cash and Cash Equivalents, Policy [Policy Text Block]

Reconciliation of Cash and cash equivalents and Restricted cash and cash equivalents

The following table provides a reconciliation of Cash and cash equivalents and Restricted cash and cash equivalents reported on the balance sheet that sum to the total of the same amounts shown on the statement of cash flows:

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Cash and cash equivalents	$	66,696	$	47,818
Restricted cash and cash equivalents		76,041		48,825
Total Cash and cash equivalents and restricted cash and cash equivalents	$	142,737	$	96,643

Concentration Risk, Credit Risk, Policy [Policy Text Block]

Concentration of credit risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of temporary cash investments and accounts receivable.

The Company places its temporary cash investments with high credit quality financial institutions located in the United States (“U.S.”) and in foreign countries. At

June 30, 2018

and

December 31, 2017,

the Company had deposits totaling

$21.6

million and

$21.2

million, respectively, in

eight

U.S. financial institutions that were federally insured up to

$250,000

per account. At

June 30, 2018

and

December 31, 2017,

the Company’s deposits in foreign countries amounted to approximately

$59.8

million and

$32.8

million, respectively.

At

June 30, 2018

and

December 31, 2017,

accounts receivable related to operations in foreign countries amounted to approximately

$83.2

million and

$78.1

million, respectively. At

June 30, 2018

and

December 31, 2017,

accounts receivable from the Company’s primary customers amounted to approximately

55%

and

57%

of the Company’s accounts receivable, respectively.

Sierra Pacific Power Company and Nevada Power Company (subsidiaries of NV Energy, Inc.) accounted for

17.0%

and

16.7%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

16.7%

and

17.8%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017,

respectively.

Southern California Public Power Authority (“SCPPA”) accounted for

14.9%

and

8.7%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

15.6%

and

8.9%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017.

Kenya Power and Lighting Co. Ltd. accounted for

16.6%

and

15.4%

of the Company’s total revenues for the

three

months ended

June 30, 2018

and

2017,

respectively, and

15.8%

and

14.8%

of the Company’s total revenues for the

six

months ended

June 30, 2018

and

2017,

respectively.

The Company has historically been able to collect on substantially all of its receivable balances, and believes it will continue to be able to collect all amounts due. Accordingly,

no

provision for doubtful accounts has been made.

New Accounting Pronouncements, Policy [Policy Text Block]

New accounting pronouncements effective in the

six

-month period ended

June 30, 2018

Income Taxes

In

March 2018,

the Financial Accounting Standards Board

("

FASB") issued ASU

2018

-

05,

Income Taxes (Topic

740

). The amendments in this update add several SEC paragraphs pursuant to the issuance of the SEC Staff Accounting Bulletin

No.

118,

Income Tax Accounting Implications of the Tax Cuts and Jobs Act (“SAB

118”

) in

December 2017.

The amendments in this update are effective immediately. For additional information, see Note

11

to the consolidated financial statements.

Revenues from Contracts with Customers

In

May 2014,

the FASB issued ASU

2014

-

09,

Revenues from Contracts with Customers, Topic

606,

which was a joint project of the FASB and the International Accounting Standards Board to clarify the principles for recognizing revenue and to develop a common revenue standard for U.S. GAAP and International Financial Reporting Standards. The update provides that an entity should recognize revenue in connection with the transfer of 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 or services. Specifically, an entity is required to apply each of the following steps: (

1

) identify the contract(s) with the customer; (

2

) identify the performance obligations in the contracts; (

3

) determine the transaction price; (

4

) allocate the transaction price to the performance obligation in the contract; and (

5

) recognize revenue when (or as) the entity satisfies a performance obligation. ASU

2014

-

09

also prescribes additional financial presentations and disclosures. In

March 2016,

the FASB issued ASU

2016

-

08,

Principal versus Agent Considerations. This update did

not

change the core principles of the guidance and was intended to clarify the implementation guidance on principal versus agent considerations. When another entity is involved in providing goods or services to a customer, an entity is required to determine if the nature of its promise is to provide the specific good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent). The guidance included indicators to assist an entity in determining whether it acts as a principal or agent in a specified transaction.

The Company adopted this update effectively as of

January 1, 2018

using the modified retrospective approach with

one

-time cumulative adjustment to the opening balance of retained earnings as further described below and applied the

five

-step model described above on identified outstanding contracts at the date of adoption, under which revenues are generated. Under ASC

606,

an entity must identify the performance obligations in a contract, determine the transaction price and allocate the price to specific performance obligations recognize the revenue when the obligation is completed. A performance obligation is a promise in a contract to transfer a distinct good or service to the customer. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The standard also requires disclosure of sufficient information to allow users to understand the nature, amount, timing and uncertainty of revenue and cash flow arising from contracts.

The adoption of ASC

606,

Revenues from Contracts with Customers, as described above, did

not

have an impact on our Electricity, Product and Other segment revenues in

2018,

however, the adoption did have an impact on our accounting for investment in an unconsolidated company as further described in the following table and in the disclosure under the heading "Investment in an unconsolidated company" within this note below. Additionally, the following table below summarizes the impact of the adoption of ASC

606

on the Company’s consolidated financial statements as of

January 1, 2018,

followed by further information for each of the line items in the table:

	(Dollars in millions)
Electricity segment revenues	$	–
Product segment revenues		–
Other segment revenues		–
Investment in an unconsolidated company		24.0

Electricity segment revenues

: Electricity revenues are primarily related to sale of electricity from geothermal and recovered energy-based power plants owned and operated by the Company. Revenues related to the sale of electricity from geothermal and recovered energy-based power plants and capacity payments are recorded based upon output delivered and capacity provided at rates specified under relevant contract terms. For power purchase agreements (“PPAs”) agreed to, modified, or acquired in business combinations on or after

July 1, 2003,

the Company determines whether such PPAs contain a lease element requiring lease accounting. Revenue from such PPAs is accounted for in electricity revenues. The lease element of the PPAs is also assessed in accordance with the revenue arrangements with multiple deliverables guidance, which requires that revenues be allocated to the separate earnings processes based on their relative fair value. PPAs with minimum lease rentals which vary over time are generally recognized on the straight-line basis over the term of the PPAs. PPAs with contingent rentals are recognized when earned. In the Electricity segment, revenues for all but

three

power plants are accounted for under ASC

840

(Leases) as operating leases, and therefore equipment related to geothermal and recovered energy generation power plants is considered held for leasing. For power plants in the scope of ASC

606,

the Company identified electricity as a separate performance obligation. Performance obligations identified were evaluated and determined to be satisfied over time and qualified for the invoicing practical expedient since the invoiced amounts reasonably represented the value to customers of performance obligations fulfilled to date. The transaction price is determined based on the price per actual mega-watt output or available capacity as agreed to in the respective PPA. Customers are generally billed on a monthly basis and payment is typically due within

30

to

60

days after the issuance of the invoice.

Product segment revenues

: Product segment revenues are primarily related to sale of geothermal and recovered energy-based power plants, including equipment, engineering, construction and installation and operating services. Revenues from the supply and/or construction of geothermal and recovered energy-based power plant equipment and other equipment to

third

parties are recognized over time since control is transferred continuously to our customers. The majority of our contracts include a single performance obligation which is essentially the promise to transfer the individual goods or services that are

not

separately identifiable from other promises in the contracts and therefore deemed as

not

distinct. Performance obligations are satisfied over-time if the customer receives the benefits as we perform work, if the customer controls the asset as it is being constructed, or if the product being produced for the customer has

no

alternative use and we have a contractual right to payment. In our Product segment, revenues are spread over a period of

one

to

two

years and are recognized over time based on the cost incurred to date in ratio to total estimated costs which represents the input method that best depicts the transfer of control over the performance obligation to the customer. Costs include direct material, labor, and indirect costs. Selling, marketing, general, and administrative costs are expensed as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined.

In contracts for which we determine that control is

not

transferred continuously to the customer, we recognized revenues at the point in time when the customer obtains control of the asset. Revenues for such contracts are recorded upon delivery and acceptance by the customer. This generally is the case for the sale of spare parts, generators or similar products.

Accounting for product contracts that are satisfied over time includes use of several estimates such as variable consideration related to bonuses and penalties and total estimated cost for completing the contract. The estimated amount of variable consideration will be included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will

not

occur when the uncertainty associated with the variable consideration is subsequently resolved. These estimates are based on historical experience, anticipated performance and our best judgment at the time.

The nature of our product contracts give rise to several modifications or change requests by our customers. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are

not

distinct from those already provided. We include the additional revenues related to the modifications in our transaction price when both parties to the contract approved the modification. As a significant change in

one

or more of these estimates could affect the profitability of our contracts, we review and update our contract-related estimates regularly. We recognize adjustments in Product revenues on contracts under the cumulative catch-up method. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, we recognize the total loss in the period in which it is identified.

The Company generally provides a

one

-year warranty against defects in workmanship and materials related to the sale of products for electricity generation. The Company considered the warranty as an assurance type warranty since the warranty provides the customer the assurance that the product complies with agreed-upon specifications. Estimated future warranty obligations are included in operating expenses in the period in which the related revenue is recognized. Such charges are immaterial for the

three

and

six

months ended

June 30, 2018

and

2017.

Contract Assets and Liabilities related to our Product segment: Contract assets reflect revenue recognized and performance obligations satisfied in advance of customer billing. Contract liabilities relate to payments received in advance of the satisfaction of performance under the contract. We receive payments from customers based on the terms established in our contracts. Total contract assets and contract liabilities as of

June 30, 2018

and

December 31, 2017

are as follows:

	June 30,			December 31,
	2018			2017
	(Dollars in thousands)
Contract assets (*)	$	46,573		$	40,945
Contract liabilities (*)		(16,136	)		(20,241	)
Contract assets, net	$	30,437		$	20,704

(*) Contract assets and contract liabilities are presented as "Costs and estimated earnings in excess of billings on uncompleted contracts" and "Billings in excess of costs and estimated earnings on uncompleted contracts", respectively, on the consolidated balance sheet.

The following table presents the significant changes in the contract assets and contract liabilities for the

six

months ended

June 30, 2018:

	Contract assets			Contract liabilities
	(Dollars in thousands)
Recognition of contract liabilities as revenue as a result of performance obligations satisfied	$	-		$	11,094
Cash received in advance for which revenues have not yet recognized, net expenditures made		-			(12,901	)
Reduction of contract assets as a result of rights to consideration becoming unconditional		(59,634	)		-
Contract assets recognized, net of recognized receivables		71,174			-
Net change in contract assets and contract liabilities		11,540			(1,807	)

The timing of revenue recognition, billings and cash collections results in accounts receivable, contract assets and contract liabilities on the condensed consolidated balance sheet. In our Products segment, amounts are billed as work progresses in accordance with agreed-upon contractual terms, or upon achievement of contractual milestones. Generally, billing occurs subsequent to the recognition of revenue, resulting in contract assets. However, we sometimes receive advances or deposits from our customers before revenue can be recognized, resulting in contract liabilities. These assets and liabilities are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. The timing of billing our customers and receiving advance payments vary from contract to contract. We typically receive a down payment of between

10%

and

20%

of total contract consideration upon signing, followed by additional milestone payments for which timing varies from contract to contract. The majority of payments are received

no

later than the completion of the project and satisfaction of our performance obligation.

On

June 30, 2018,

we had approximately

$229.0

million of remaining performance obligations

not

yet satisfied or partly satisfied related to our Product segment. We expect to recognize approximately

91%

of this amount as Product revenues during the next

24

months and the rest will be recognized thereafter.

The following schedule reconciles revenues accounted for under ASC

840,

Leases, and ASC

606,

Revenues from Contracts with Customers, to total consolidated revenues for the

three

and

six

months ended

June 30, 2018:

	Three Months Ended June 30, 2018		Six Months Ended June 30, 2018
	(Dollars in thousands)		(Dollars in thousands)
Electricity Revenues accounted under ASC 840, Leases	$	118,984	$	246,812
Electricity, Product and Other revenues accounted under ASC 606		59,315		115,510
Total consolidated revenues	$	178,299	$	362,322

Disaggregated revenues from contracts with customers for the

three

and

six

months ended

June 30, 2018

are shown under Note

9

– Business Segments, to the condensed consolidated financial statements.

Investment in an unconsolidated company

: The Company also reviewed the impact of the adoption of ASC

606

on its investment in an unconsolidated company. As a result of the adoption, the Company recorded

one

-time cumulative credit adjustment to the opening balance of retained earnings of approximately

$24.0

million as of

January 1, 2018.

This impact is a result of the unconsolidated company’s variable consideration related to the construction of its power plant for which, under the new guidance, is probable that a significant reversal in the amount of cumulative revenue recognized will

not

occur when the uncertainty is resolved. As such, the comparative information will

not

be restated and shall continue to be reported under the accounting standards in effect for those periods.

The following schedule quantifies the impact of adopting ASC

606

on the statement of operations for the

three

months ended

June 30, 2018:

	2018, under previous standard		Effect of the New Revenue Standard			2018, as reported
	(Dollars in thousands)
Equity in earnings of investees, net	$	2,332	$	(734	)	$	1,598
Income from continuing operations		74,990		(734	)		94,356
Net income attributable to the Company’s stockholders		70,242		(734	)		86,606
Retained earnings		411,492		(734	)		422,794

Other segment revenues

: Other segment revenues are primarily related to energy storage, demand-response and energy management related services. Revenues are recorded based on energy management of load curtailment capacity delivered or service provided at rates specified under the relevant contract terms. The Company determined that the Other segment revenues are in the scope of ASC

606

and identified energy management as a separate performance obligation. Performance obligations are satisfied once the Company provides verification to the electric power grid operator or utility of its ability to meet the committed capacity or power curtailment requirements and thus entitled to cash proceeds. Such verification

may

be provided by the Company bi-weekly, monthly or under any other frequency as set by the related program and are typically followed by a payment shortly after. Performance obligations identified were evaluated and determined to be satisfied over time and qualified for the invoicing practical expedient since the amounts included in the verification document reasonably represent the value of performance obligations fulfilled to date. The transaction price is determined based on mechanisms specified in the contract with the customer.

Compensation - Stock Compensation

In

May 2017,

the FASB issued ASU

2017

-

09,

Compensation—Stock Compensation (Topic

718

). The amendments in this update provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic

718.

The amendments in this update require that an entity should account for the effects of a modification unless all of the following are met: (

1

) The fair value of the modified award is the same as the fair value of the original award immediately before the original award is modified; (

2

) The vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; (

3

) The classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The current disclosure requirements under Topic

718

apply regardless of whether an entity is required to apply modification accounting under the amendments in this update. The amendments in this update are effective for all entities for annual periods, and interim periods within those annual periods, beginning after

December 15, 2017.

The amendments in this update should be applied prospectively to an award modified on or after the adoption date. The adoption of this guidance did

not

have a material impact on the Company’s consolidated financial statements.

Business Combinations

In

January 2017,

the FASB issued ASU

2017

-

01,

Business Combinations (Topic

805

). The update clarifies the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The amendments in this update primarily provide a screen to determine when a set of assets and activities is

not

a business and by that reduces the number of transactions that need to be further evaluated. The amendments in this update should be applied prospectively and are effective for financial statements issued for fiscal years beginning after

December 15, 2017,

and interim periods within those fiscal years. The adoption of this guidance did

not

have an impact on the Company’s condensed consolidated financial statements.

Statement of Cash Flow

In

November 2016,

the FASB issued ASU

2016

-

18,

Statement of Cash Flows (Topic

230

) – Restricted Cash. The amendments in this update require that a statement of cash flows explain the changes during the period in total cash, cash equivalents, and the amounts generally described as restricted cash or cash equivalents. Therefore, amounts of restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in this update should be applied retrospectively for each period presented and are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The Company adopted this guidance retrospectively in its consolidated financial statements for the

three

month period ending

March 31, 2018

and adjusted its disclosure accordingly.

Intra-Entity Transfers of Assets Other than Inventory

In

October 2016,

the FASB issued ASU

2016

-

16,

Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory. The amendments in this update require that the entity would recognize the tax expense from the sale of the asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buyer’s jurisdiction would also be recognized at the time of the transfer. The new guidance does

not

apply to intra-entity transfers on inventory. The amendments in this update should be applied for each period presented and are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The modified retrospective approach is required for transition to the new guidance, with cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption. The Company adopted this guidance in its consolidated financial statements for the

three

months ending

March 31, 2018

using the modified retrospective approach and recorded a net cumulative-effect adjustment to retained earnings of approximately

$1.8

million with a corresponding adjustment to deferred charges and deferred income taxes on the condensed consolidated balance sheet of approximately

$49.8

million and

$51.6

million, respectively.

Statement of Cash Flows: Classification of Certain Cash Receipts and Cash payments (Topic

230

)

In

August 2016,

the FASB issued ASU

2016

-

15,

Statement of Cash-Flows (Topic

230

). This update addresses

eight

specific cash flow classification issues with the objective of reducing diversity in practice. One of the issues addressed in this update is debt prepayment or debt extinguishment costs which under the new guidance should be classified as cash outflows for financing activities. Additionally, the update addressed contingent consideration payments made after a business combination. Such cash payments made soon after the acquisition date to settle a contingent consideration liability should be classified as cash outflows for investing activities. Payments made thereafter should be classified as cash outflows for financing activities up to the amount of the original contingent consideration liability. Payments made in excess of the amount of the original contingent consideration liability should be classified as cash outflows for operating activities. The amendments in this update are effective for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The amendments in this update should be applied using a retrospective transition method to each period presented. The Company adopted this guidance and expects that the impact from the adoption of the update will result in a reclassification of approximately

$8.0

million of cash paid for achievement of production threshold in Guadeloupe during the

fourth

quarter of

2017

from cash outflows from investing activities to cash outflows from financing activities as required by this update.

Recognition and Measurement of Financial Assets and Financial Liabilities

In

January 2016,

the FASB issued ASU

2016

-

01,

Recognition and Measurement of Financial Assets and Financial Liabilities. The update primarily requires that an entity present separately, in other comprehensive income, the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk if the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The application of this update should be by means of cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The amendments in this update are effective for financial statements issued for fiscal years beginning after

December 15, 2017

and interim periods within those fiscal years. The adoption of this update did

not

have a material impact on the Company’s consolidated financial statements.

New accounting pronouncements effective in future periods

Derivatives and Hedging

In

August 2017,

the FASB issued ASU

2017

-

12,

Targeted Improvements to Accounting for Hedging Activities. The amendments in this update better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. To meet that objective, the amendments expand and refine hedge accounting for both nonfinancial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. The amendments in this update are effective for fiscal years beginning after

December 15, 2018,

and interim periods within those fiscal years. Early application is permitted in any interim period after issuance of the update. The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Intangibles –Goodwill and Other

In

January 2017,

the FASB issued ASU

2017

-

04,

Intangibles – Goodwill and Other (Topic

350

). The amendments in this update require the entity to perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. However, the loss recognized should

not

exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider the income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. This update eliminated Step

2

from the goodwill impairment test under the current guidance. Step

2

measures a goodwill impairment loss by comparing the implied fair value of reporting unit’s goodwill with the carrying amount of that goodwill. The amendments in this update should be applied on a prospective basis. An entity is also required to disclose the nature of and the reason for the change in accounting principle upon transition. That disclosure should be provided in the

first

annual period and the interim period within the

first

annual period when the entity initially adopts the amendments in this update. The amendments in this update are effective for the annual or any interim goodwill impairment tests in fiscal years beginning after

December 15, 2019.

Early adoption is permitted for interim or annual impairment tests performed on testing dates after

January 1, 2017.

The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Leases

In

February 2016,

the FASB issued ASU

2016

-

02,

Leases (Topic

842

). This update introduces a number of changes and simplifies previous guidance, primarily the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases. The update retains the distinction between finance leases and operating leases and the classification criteria between the

two

types remains substantially similar. Also, lessor accounting remains largely unchanged from previous guidance. However, key aspects of the update were aligned with the revenue recognition guidance in Topic

606.

Additionally, the update defines a lease as a contract, or part of a contract, that conveys the right to control the use of an identified asset for a period of time in exchange for consideration. Control over the use of the identified asset means that the customer has both (a) the right to obtain substantially all of the economic benefits from the use of the asset and (b) the right to direct the use of the asset. This update requires the modified retrospective transition approach, which requires lessees and lessors to recognize and measure leases at the beginning of the earliest period presented. The modified retrospective approach includes a number of optional practical expedients related to identification and classification of leases that commenced before the effective date, initial direct costs for leases that commenced before the effective date and the ability to use hindsight in evaluating lessee options to extend or terminate a lease or to purchase the underlying asset. An entity that elects to apply the practical expedients will, in effect, continue to account for leases that commenced before the effective date in accordance with the previous generally accepted accounting principles in the United States unless the lease is modified, except that lessees are required to recognize a right-of-use asset and a lease liability for all operating leases at each reporting date based on the present value of the remaining minimum rental payments that were tracked and disclosed under previous generally accepted accounting principles in the United States. The amendments in this update are effective for annual reporting periods beginning after

December 15, 2018,

including interim periods within those reporting periods. Early adoption is permitted. The Company is currently evaluating the potential impact, if any, of the adoption of these amendments on its consolidated financial statements.

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income

In

February 2018,

the FASB issued ASU

2018

-

02,

Income Statement – Reporting Comprehensive Income (Topic

220

). The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting for the Tax Cuts and Jobs Act of

2017

(the “Tax Act”). The guidance is effective for the fiscal years beginning after

December 15, 2018,

and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the potential impact of the adoption of these amendments on its consolidated financial statements, however, such impact, if any, is

not

expected to be material.

Note 1 - General and Basis of Presentation (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

Cash and cash equivalents and restricted cash	$	37.9
Working capital		(8.2	)
Property, plant and equipment and construction-in-process		77.3
Intangible assets (1)		127.0
Deferred tax liability		(4.9	)
Long-term term debt, net of deferred transaction costs		(98.3	)
Asset retirement obligation		(9.0	)
Total identifiable assets and liabilities acquired	$	121.8
Goodwill (2)	$	19.3

Business Acquisition, Pro Forma Information [Table Text Block]

	Pro forma for the six months ended June 30, 2018		Pro forma for the six months ended June 30, 2017		Pro forma for the three months ended June 30, 2018		Pro forma for the three months ended June 30, 2017
	(Dollars in thousands)
Electricity revenues	$	265,965	$	241,420	$	125,003	$	117,207
Total revenues		373,619		384,010		181,123		185,675
Operating profit		89,219		114,753		36,200		53,238

Schedule of Cash and Cash Equivalents [Table Text Block]

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Cash and cash equivalents	$	66,696	$	47,818
Restricted cash and cash equivalents		76,041		48,825
Total Cash and cash equivalents and restricted cash and cash equivalents	$	142,737	$	96,643

Note 2 - New Accounting Pronouncements (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	(Dollars in millions)
Electricity segment revenues	$	–
Product segment revenues		–
Other segment revenues		–
Investment in an unconsolidated company		24.0

	Three Months Ended June 30, 2018		Six Months Ended June 30, 2018
	(Dollars in thousands)		(Dollars in thousands)
Electricity revenues accounted under ASC 840, Leases	$	116,914	$	242,745
Electricity, Product and Other revenues accounted under ASC 606		61,385		119,577
Total consolidated revenues	$	178,299	$	362,322

	Three months ended June 30, 2018 under previous standard			Effect of the New Revenue Standard		As reported for the three months ended June 30, 2018
	(Dollars in thousands)
Equity in earnings (losses) of investees, net	$	(3,237	)	$	3,625	$	388
Income from continuing operations		(966	)		3,625		2,659
Net income attributable to the Company’s stockholders		(3,968	)		3,625		(343	)
Retained earnings		401,728			3,625		405,353

	Six months ended June 30, 2018 under previous standard			Effect of the New Revenue Standard		As reported for the six months ended June 30, 2018
	(Dollars in thousands)
Equity in earnings (losses) of investees, net	$	(1,293	)	$	2,891	$	1,598
Income from continuing operations		74,024			2,891		76,915
Net income attributable to the Company’s stockholders		66,274			2,891		69,165
Retained earnings		402,462			2,891		405,353

Contract with Customer, Asset and Liability [Table Text Block]

	June 30,			December 31,
	2018			2017
	(Dollars in thousands)
Contract assets (*)	$	46,573		$	40,945
Contract liabilities (*)		(16,136	)		(20,241	)
Contract assets, net	$	30,437		$	20,704

	Contract assets			Contract liabilities
	(Dollars in thousands)
Recognition of contract liabilities as revenue as a result of performance obligations satisfied	$	-		$	11,094
Cash received in advance for which revenues have not yet recognized, net expenditures made		-			(12,901	)
Reduction of contract assets as a result of rights to consideration becoming unconditional		(59,634	)		-
Contract assets recognized, net of recognized receivables		71,174			-
Net change in contract assets and contract liabilities		11,540			(1,807	)

Note 3 - Inventories (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Inventory, Current [Table Text Block]

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Raw materials and purchased parts for assembly	$	26,919	$	12,007
Self-manufactured assembly parts and finished products		9,777		7,544
Total	$	36,696	$	19,551

Note 4 - Investment in an Unconsolidated Company (Tables)

6 Months Ended

Jun. 30, 2018

Equity Method Investments [Table Text Block]

	June 30,		December 31,
	2018		2017
	(Dollars in thousands)
Sarulla	$	66,551	$	34,084

Note 5 - Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value, by Balance Sheet Grouping [Table Text Block]

				June 30, 2018
				Fair Value
	Carrying Value at June 30, 2018			Total			Level 1		Level 2			Level 3
	(Dollars in thousands)
Assets:
Current assets:
Cash equivalents (including restricted cash accounts)	$	19,069		$	19,069		$	19,069	$	—		$	—
Derivatives:
Contingent receivable (1)		106			106			—		—			106
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(13,808	)		(13,808	)		—		—			(13,808	)
Currency forward contracts (2)		(507	)		(507	)		—		(507	)		—
	$	4,860		$	4,860		$	19,069	$	(507	)	$	(13,702	)

				December 31, 2017
				Fair Value
	Carrying Value at December 31, 2017			Total			Level 1		Level 2		Level 3
	(Dollars in thousands)
Assets
Current assets:
Cash equivalents (including restricted cash accounts)	$	18,359		$	18,359		$	18,359	$	—	$	—
Derivatives:
Contingent receivable (1)		108			108			—		—		108
Currency forward contracts (2)		992			992			—		992		—
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(13,904	)		(13,904	)		—		—		(13,904	)
Warrants (1)		(3,967	)		(3,967	)		—		—		(3,967	)
	$	1,588		$	1,588		$	18,359	$	992	$	(17,763	)

Derivative Instruments, Gain (Loss) [Table Text Block]

		Amount of recognized gain (loss)
Derivatives not designated as hedging instruments	Location of recognized gain (loss)	Three Months Ended June 30,						Six Months Ended June 30,
		2018			2017			2018			2017

Put options on natural gas price	Derivatives and foreign transaction gains (losses)		—			(48	)		—			(241	)
Contingent considerations	Derivative and foreign transaction gains (losses)		—			(45	)		—			(95	)
Currency forward contracts	Derivative and foreign and transaction gains (losses)		(911	)		1,457			(1,457	)		3,719
		$	(911	)	$	1,364		$	(1,457	)	$	3,383

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]

	Fair Value				Carrying Amount
	June 30, 2018		December 31, 2017		June 30, 2018		December 31, 2017
	(Dollars in millions)				(Dollars in millions)
Olkaria III Loan - OPIC		219.6		234.6		219.6		228.6
Olkaria IV Loan - DEG 2		49.5		50.7		50.0		50.0
Amatitlan Loan		31.7		32.8		31.5		33.3
Senior Secured Notes:
OrCal Geothermal Inc. ("OrCal")		28.7		34.2		27.3		32.1
OFC 2 LLC ("OFC 2")		219.2		234.6		224.2		232.5
Don A. Campbell 1 ("DAC 1")		79.9		85.5		85.3		88.3
USG Prudential - NV		29.7		—		28.3		—
USG Prudential - ID		18.6		—		18.9		—
USG DOE		49.0		—		53.0		—
Senior Unsecured Bonds		198.1		200.3		204.3		204.3
Senior Unsecured Loan		101.3		—		100.0		—
Other long-term debt		5.4		7.0		6.4		7.9

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III - OPIC		—		—		219.6		219.6
Olkaria IV - DEG 2		—		—		49.5		49.5
Amatitlan Loan		—		31.7		—		31.7
Senior Secured Notes:
OrCal Senior Secured Notes		—		—		28.7		28.7
OFC 2 Senior Secured Notes		—		—		219.2		219.2
DAC 1 Senior Secured Notes		—		—		79.9		79.9
USG Prudential - NV		—		—		29.7		29.7
USG Prudential - ID		—		—		18.6		18.6
USG DOE		—		—		49.0		49.0
Senior Unsecured Bonds		—		—		198.1		198.1
Senior Unsecured Loan		—		—		101.3		101.3
Other long-term debt		—		—		5.4		5.4
Revolving lines of credit		—		158.6		—		158.6
Deposits	19.3			—		—		19.3

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III Loan - OPIC	$	—	$	—	$	234.6	$	234.6
Olkaria IV - DEG 2						50.7		50.7
Amatitlan Loan		—		32.8		—		32.8
Senior Secured Notes:
OrCal Senior Secured Notes		—		—		34.2		34.2
OFC 2 Senior Secured Notes		—		—		234.6		234.6
DAC 1 Senior Secured Notes		—		—		85.5		85.5
Senior Unsecured Bonds		—		—		200.3		200.3
Other long-term debt		—		—		7.0		7.0
Revolving lines of credit		—		51.5		—		51.5
Deposits		15.6		—		—		15.6

Note 6 - Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Share-based Payment Award, Equity Awards Other than Options, Valuation Assumptions [Table Text Block]

Risk-free interest rate	2.84	%
Expected life (in years)	5.5
Dividend yield	0.79	%
Expected volatility	25.24	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

Risk-free interest rate	2.79	%
Expected life (in years)	6
Dividend yield	0.92	%
Expected volatility	25.64	%
Forfeiture rate for employees	2.78	%
Forfeiture rate for members of the senior management	0.0	%
Sub-Optimal Exercise Factor for employees	2.0
Sub-Optimal Exercise Factor for members of the senior management	2.8

Note 7 - Interest Expense, Net (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Other Nonoperating Expense, by Component [Table Text Block]

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017

Interest related to sale of tax benefits	$	1,761		$	1,849		$	3,170		$	3,861
Interest expense		15,421			14,146			28,727			28,321
Less — amount capitalized		(1,336	)		(1,455	)		(1,707	)		(2,719	)
	$	15,846		$	14,540		$	30,190		$	29,463

Note 8 - Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Weighted Average Number of Shares [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017

Weighted average number of shares used in computation of basic earnings per share		50,623		49,771		50,618		49,726
Add:
Additional shares from the assumed exercise of employee stock options		335		853		383		833

Weighted average number of shares used in computation of diluted earnings per share		50,958		50,624		51,001		50,559

Note 9 - Business Segments (Tables)

6 Months Ended

Jun. 30, 2018

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	Electricity		Product		Other			Consolidated
	(Dollars in thousands)
Three Months Ended June 30, 2018:
Revenues from external customers:
United States (1)	$	73,139	$	27	$	1,205		$	74,371
Foreign (2)		49,040		54,888		—			103,928
Net revenue from external customers		122,179		54,915		1,205			178,299
Intersegment revenue		—		11,453		—			11,453
Operating income		27,462		10,761		(1,590	)		36,633
Segment assets at period end (3) (*)		2,805,182		125,572		63,395			2,994,149
* Including unconsolidated investments		66,551		—		—			66,551

Three Months Ended June 30, 2017:
Net revenue from external customers	$	110,896	$	67,587		881			179,364
Intersegment revenue		—		16,565		—			16,565
Operating income		38,014		17,035		(1,897	)		53,152
Segment assets at period end (3) (*)		2,273,503		187,015		50,115			2,510,633
* Including unconsolidated investments		13,957		—		—			13,957

Six Months Ended June 30, 2018:
Revenues from external customers:
United States (1)	$	156,822	$	221	$	4,067		$	161,110
Foreign (2)		97,846		103,366		—			201,212
Net revenues from external customers		254,668		103,587		4,067			362,322
Intersegment revenues		—		36,280		—			36,280
Operating income		73,874		20,314		(2,962	)		91,226
Segment assets at period end (3) (*)		2,805,182		125,572		63,395			2,994,149
* Including unconsolidated investments		66,551		—		—			66,551

Six Months Ended June 30, 2017:
Net revenues from external customers	$	226,672	$	141,709	$	881		$	369,262
Intersegment revenues		—		32,778		—			32,778
Operating income		78,912		35,633		(1,897	)		112,648
Segment assets at period end (3) (*)		2,273,503		187,015		50,115			2,510,633
* Including unconsolidated investments		13,957		—		—			13,957

Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017

Revenue:
Total segment revenue	$	178,299		$	179,364		$	362,322		$	369,262
Intersegment revenue		11,453			16,565			36,280			32,778
Elimination of intersegment revenue		(11,453	)		(16,565	)		(36,280	)		(32,778	)
Total consolidated revenue	$	178,299		$	179,364		$	362,322		$	369,262

Operating income:
Operating income	$	36,633		$	53,152		$	91,226		$	112,648
Interest income		189			362			302			606
Interest expense, net		(15,846	)		(14,540	)		(30,190	)		(29,463	)
Derivatives and foreign currency transaction gains (losses)		(529	)		1,703			(2,128	)		3,041
Income attributable to sale of tax benefits		3,556			4,356			10,917			10,513
Other non-operating income (expense), net		7,373			6			7,353			(86	)
Total consolidated income before income taxes and equity in income of investees	$	31,376		$	45,039		$	77,480		$	97,259

Note 1 - General and Basis of Presentation (Details Textual)				3 Months Ended		6 Months Ended		12 Months Ended
	May 17, 2018 USD ($)	Apr. 24, 2018 USD ($) MWh	Mar. 22, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	May 03, 2018 USD ($)
Insured Event, Gain (Loss)						$ 7,150,000
Property, Plant and Equipment, Net, Ending Balance				$ 1,840,558,000		1,840,558,000		$ 1,734,691,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax				5,000,000	$ 30,000,000	10,000,000	54,000,000
Interest Expense, Total				15,846,000	14,540,000	30,190,000	29,463,000
Income Tax Expense (Benefit), Total				29,105,000	32,765,000	2,163,000	43,769,000
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total				(2,297,000)		(2,297,000)		(4,706,000)
Exploration Abandonment and Impairment Expense				0	$ 0	119,000	$ 0
Accounts Receivable, Net, Current, Total				$ 109,061,000		109,061,000		$ 110,410,000
Provision for Doubtful Accounts						$ 0
Accounts Receivable [Member] \| Customer Concentration Risk [Member] \| Primary Customers [Member]
Concentration Risk, Percentage						55.00%		57.00%
Sales Revenue, Net [Member] \| Customer Concentration Risk [Member] \| Sierra Pacific Power Company And Nevada Power Company [Member]
Concentration Risk, Percentage				17.00%	16.70%	16.70%	17.80%
Sales Revenue, Net [Member] \| Customer Concentration Risk [Member] \| Southern California Public Power Authority [Member]
Concentration Risk, Percentage				14.90%	8.70%	15.60%	8.90%
Sales Revenue, Net [Member] \| Customer Concentration Risk [Member] \| Kenya Power and Lighting Co LTD [Member]
Concentration Risk, Percentage				16.60%	15.40%	15.80%	14.80%
UNITED STATES
Cash, Cash Equivalents, and Short-term Investments, Total				$ 21,600,000		$ 21,600,000		$ 21,200,000
Foreign Countries [Member]
Cash, Cash Equivalents, and Short-term Investments, Total				59,800,000		59,800,000		32,800,000
Accounts Receivable, Net, Current, Total				83,200,000		83,200,000		$ 78,100,000
Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total				1,000,000		1,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest Expense, Total				6,000,000	$ 20,000,000	(15,000,000)	$ (30,000,000)
Income Tax Expense (Benefit), Total				(1,000,000)	$ 10,000,000	5,000,000	$ 24,000,000
Migdal Loan [Member]
Debt Instrument, Face Amount			$ 100,000,000
Debt Instrument, Periodic Payment, Total			4,200,000
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid			$ 37,000,000
Debt Instrument, Interest Rate, Stated Percentage			4.80%
Debt Instrument Increase in Stated Interest Rate if Rating is Downgraded to ILA Negative			0.50%
Debt Instrument Increase in Stated Interest Rate Each Additional Downgrade			0.25%
Debt Instrument Decrease in Stated Interest Rate for Each Rating Upgrade			0.25%
Debt to EBITDA Ratio Threshold for Rate Increase			4.5
Debt Instrument Increase in Stated Interest Rate if Debt to EBITDA Ratio Exceeds Threshold			0.50%
Debt to EBITDA Ratio Requirement			6
Stockholders Equity, Debt Covenant, Minimum Threshold			$ 650,000,000
Stockholders Equity to Total Assets, Ratio			25.00%
Stockholders Equity, Debt Covenant, Minimum Threshold to Pay Dividends			$ 800,000,000
Dividends to Net Income, Ratio			50.00%
Migdal Loan [Member] \| Maximum [Member]
Debt Instrument, Increase in Stated Interest Rate			1.00%
Migdal Loan [Member] \| Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage			4.80%
U.S. Geothermal [Member]
Payments to Acquire Businesses, Gross		$ 110,000,000
Current Power Generation \| MWh		38
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				3,400,000		3,400,000
Business Acquisition, Pro Forma Operating Income (Loss) since Acquisition Date, Actual				(4,200,000)		$ (4,200,000)
U.S. Geothermal [Member] \| Neal Hot Springs [Member]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		$ 34,900,000
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Percent		40.00%
U.S. Geothermal [Member] \| Neal Hot Springs [Member] \| Measurement Input, Expected Term [Member]
Noncontrolling Interest, Measurement Input		20
U.S. Geothermal [Member] \| Neal Hot Springs [Member] \| Measurement Input, Discount Rate [Member]
Noncontrolling Interest, Measurement Input		9
U.S. Geothermal [Member] \| Long-term Electricity Power Purchase Agreements [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		19 years
U.S. Geothermal [Member] \| Ormat Nevada Inc. [Member]
Payments to Acquire Businesses, Gross		$ 106,000,000
U.S. Geothermal [Member] \| Ormat Technologies, Inc. [Member]
Payments to Acquire Businesses, Gross		$ 4,000,000
Puna Geothermal Power Plant [Member]
Impairment of Long-Lived Assets Held-for-use				4,900,000
Property, Plant and Equipment, Net, Ending Balance									$ 102,200,000
Puna Geothermal Power Plant [Member] \| Other Income [Member]
Insured Event, Gain (Loss)				$ 7,200,000
Tungsten Mountain [Member]
Parternship Agreement, Initial Purchase Price	$ 33,400,000
Partnership Agreement, Expected Additional Installments	$ 13,000,000
Partnership Agreement, Percentage of Distributable Cash Flow Generated	97.50%
Partnership Agreement, Percentage of Taxable Income	95.00%

Note 1 - General and Basis of Presentation - Fair Value of Amounts of Identified Assets and Liabilities Assumed in a Business Combination (Details) - USD ($)
$ in Thousands

Jun. 30, 2018

Apr. 24, 2018

Dec. 31, 2017

Goodwill (2)

$ 40,133

$ 21,037

U.S. Geothermal [Member]

Cash and cash equivalents and restricted cash

$ 37,900

Working capital

(8,200)

Property, plant and equipment and construction-in-process

77,300

Intangible assets (1)

^[1]

127,000

Deferred tax liability

(4,900)

Long-term term debt, net of deferred transaction costs

(98,300)

Asset retirement obligation

(9,000)

Total identifiable assets and liabilities acquired

121,800

Goodwill (2)

^[2]

$ 19,300

[1]	Intangible assets are primarily related to long-term electricity power purchase agreements and depreciated over an average of 19 years.
[2]	Goodwill is primarily related to the expected synergies in operation as a result of the purchase transaction and is allocated to the Electricity segment.

Note 1 - General and Basis of Presentation - Summary of Unaudited Pro Forma Information Related to a Business Combination (Details) - U.S. Geothermal [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues	$ 181,123	$ 185,675	$ 373,619	$ 384,010
Operating profit	36,200	53,238	89,219	114,753
Electricity Segment [Member]
Revenues	$ 125,003	$ 117,207	$ 265,965	$ 241,420

Note 1 - General and Basis of Presentation - Cash and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 66,696	$ 47,818
Restricted cash and cash equivalents	76,041	48,825
Total Cash and cash equivalents and restricted cash and cash equivalents	$ 142,737	$ 96,643	$ 167,900	$ 264,476

Note 2 - New Accounting Pronouncements 1 (Details Textual) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period				2 years
Deferred Costs, Total			$ 49,834
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000
Accounting Standards Update 2016-16 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total		$ 1,800
Deferred Costs, Total		49,800
Deferred Tax Assets, Net, Noncurrent		$ 51,600
Accounting Standards Update 2016-15 [Member] \| Reclassifcation of Cash Paid From Investing Activities to Financing Activities [Member]
Prior Period Reclassification Adjustment			$ 8,000
Product Segment [Member]
Revenue, Remaining Performance Obligation, Amount				$ 229,000

Note 2 - New Accounting Pronouncements 2 (Details Textual)	Jun. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Percentage	96.00%

Note 2 - New Accounting Pronouncements - Impact of Adoption (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Investment in an unconsolidated company		$ 66,551		$ 66,551		$ 34,084
Total consolidated revenues		178,299	$ 179,364	362,322	$ 369,262
Equity in earnings (losses) of investees, net		388	(428)	1,598	(2,027)
Income from continuing operations		2,659	11,846	76,915	51,463
Net income attributable to the Company’s stockholders		(343)	8,640	69,165	43,834
Retained earnings		405,353		405,353		$ 327,255
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity in earnings (losses) of investees, net		(3,237)		(1,293)
Income from continuing operations		(966)		74,024
Net income attributable to the Company’s stockholders		(3,968)		66,274
Retained earnings		401,728		401,728
Electricity [Member]
Revenues		122,179	110,896	254,668	226,672
Electricity, Product and Other revenues accounted under ASC 606		122,179	110,896	254,668	226,672
Product [Member]
Revenues		54,915	67,587	103,587	141,709
Electricity, Product and Other revenues accounted under ASC 606		54,915	67,587	103,587	141,709
Other Revenue [Member]
Revenues		1,205	881	4,067	881
Electricity, Product and Other revenues accounted under ASC 606		1,205	$ 881	4,067	$ 881
Accounting Standards Update 2014-09 [Member]
Investment in an unconsolidated company	$ 24,000
Accounting Standards Update 2014-09 [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Equity in earnings (losses) of investees, net		3,625		2,891
Income from continuing operations		3,625		2,891
Net income attributable to the Company’s stockholders		3,625		2,891
Retained earnings		3,625		3,625
Accounting Standards Update 2014-09 [Member] \| Electricity [Member]
Revenues
Electricity revenues accounted under ASC 840, Leases		116,914		242,745
Electricity, Product and Other revenues accounted under ASC 606
Accounting Standards Update 2014-09 [Member] \| Product [Member]
Revenues
Electricity, Product and Other revenues accounted under ASC 606
Accounting Standards Update 2014-09 [Member] \| Electricity and Product Revenue [Member]
Revenues		61,385		119,577
Electricity, Product and Other revenues accounted under ASC 606		$ 61,385		$ 119,577
Accounting Standards Update 2014-09 [Member] \| Other Revenue [Member]
Revenues
Electricity, Product and Other revenues accounted under ASC 606

Note 2 - New Accounting Pronouncements - Contract Assets (Liabilities) (Details) - USD ($)
$ in Thousands

6 Months Ended

Jun. 30, 2018

Dec. 31, 2017

Contract assets (*)

^[1]

$ 46,573

$ 40,945

Contract liabilities (*)

^[1]

(16,136)

(20,241)

Contract assets, net

30,437

$ 20,704

Recognition of contract liabilities as revenue as a result of performance obligations satisfied, liabilities

11,094

Cash received in advance for which revenues have not yet recognized, net expenditures made, liabilities

(12,901)

Reduction of contract assets as a result of rights to consideration becoming unconditional, assets

(59,634)

Contract assets recognized, net of recognized receivables, assets

71,174

Net change in contract assets and contract liabilities, assets

11,540

Net change in contract assets and contract liabilities, liabilities

$ (1,807)

[1]	Contract assets and contract liabilities are presented as "Costs and estimated earnings in excess of billings on uncompleted contracts" and "Billings in excess of costs and estimated earnings on uncompleted contracts", respectively, on the consolidated balance sheet.

Note 3 - Inventories - Inventories, Current (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Raw materials and purchased parts for assembly	$ 26,919	$ 12,007
Self-manufactured assembly parts and finished products	9,777	7,544
Total	$ 36,696	$ 19,551

Note 4 - Investment in an Unconsolidated Company (Details Textual) $ in Thousands			3 Months Ended		6 Months Ended
	Jan. 01, 2018 USD ($)	Jun. 04, 2014 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) MWh	Jun. 30, 2017 USD ($)	May 16, 2014 USD ($)
Number of Commercial Lenders in Funding Consortium							6
Interest Expense, Total			$ 15,846	$ 14,540	$ 30,190	$ 29,463
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			$ 529	(916)	$ 3,163	(347)
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000
Sarulla [Member] \| Lenders Consortium [Member]
Senior Notes, Total							$ 1,170,000
Sarulla [Member]
Jointly Owned Utility Plant, Proportionate Ownership Share			12.75%		12.75%
Expected Power Generating Capacity \| MWh					330
Number of Phases of Construction					3
Power Utilization \| MWh					110
Power Plant Usage Agreement Term					30 years
Payments to Acquire Projects			$ 2,500		$ 3,800
Accumulated Cash Contributions to Acquire Projects			62,000		$ 62,000
Contract Effective Date					April 4, 2013
Sarulla [Member] \| Accounting Standards Update 2014-09 [Member]
Equity Method Investments	24,000
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000
Sarulla [Member] \| Interest Rate Swap [Member]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			500	(900)	$ 3,200	(300)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance			1,900		1,900
Sarulla [Member] \| Interest Rate Swap [Member] \| Sarulla Project Company [Member]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			$ 4,200	$ (7,200)	24,800	$ (2,700)
Sarulla [Member] \| Lenders Consortium [Member] \| Interest Rate Swap [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate		3.4565%
Sarulla [Member] \| Lenders Consortium [Member] \| Subject to Fixed Interest Rate [Member]
Senior Notes, Total							100,000
Sarulla [Member] \| Lenders Consortium [Member] \| Subject to Fixed LIBOR Interest Rate [Member]
Senior Notes, Total							$ 1,070,000
Interest Expense, Total					$ 23,100
Sarulla [Member] \| Lenders Consortium [Member] \| Subject to Fixed LIBOR Interest Rate [Member] \| Interest Rate Swap [Member]
Senior Notes, Total		$ 960,000

Note 4 - Investment in an Unconsolidated Company - Unconsolidated Investments Mainly in Power Plants (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Sarulla	$ (8,268)	$ (6,416)
Sarulla [Member]
Sarulla	$ 66,551	$ 34,084

Note 5 - Fair Value of Financial Instruments (Details Textual) - Henry Hub Natural Gas Future ("NG") Contracts [Member] - Put Option [Member] BTU in Millions, $ in Millions	Jan. 12, 2017 USD ($) BTU $ / BTU
Derivative, Nonmonetary Notional Amount, Energy Measure \| BTU	4.1
Derivative, Price Risk Option Strike Price \| $ / BTU	3
Payments for Derivative Instrument, Investing Activities \| $	$ 0.7

Note 5 - Fair Value of Financial Instruments - Financial Assets and Liabilities at Fair Value (Details) - USD ($)
$ in Thousands

Jun. 30, 2018

Dec. 31, 2017

Reported Value Measurement [Member]

Cash equivalents (including restricted cash accounts)

$ 19,069

$ 18,359

4,860

1,588

Reported Value Measurement [Member] | Contingent Receivable [Member]

Reported Value Measurement [Member] | Currency Forward Contracts [Member]

^[1]

106

108

Reported Value Measurement [Member] | Contingent Payable [Member]

^[2]

(507)

992

Reported Value Measurement [Member] | Warrant [Member]

^[1]

(13,808)

(13,904)

Estimate of Fair Value Measurement [Member]

^[1]

(3,967)

Cash equivalents (including restricted cash accounts)

19,069

18,359

4,860

1,588

Estimate of Fair Value Measurement [Member] | Contingent Receivable [Member]

Estimate of Fair Value Measurement [Member] | Currency Forward Contracts [Member]

^[1]

106

108

Estimate of Fair Value Measurement [Member] | Contingent Payable [Member]

^[2]

(507)

992

Estimate of Fair Value Measurement [Member] | Warrant [Member]

^[1]

(13,808)

(13,904)

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]

^[1]

(3,967)

Cash equivalents (including restricted cash accounts)

19,069

18,359

19,069

18,359

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Receivable [Member]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Currency Forward Contracts [Member]

^[1]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Payable [Member]

^[2]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Warrant [Member]

^[1]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]

^[1]

Cash equivalents (including restricted cash accounts)

(507)

992

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Receivable [Member]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Currency Forward Contracts [Member]

^[1]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Payable [Member]

^[2]

(507)

992

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Warrant [Member]

^[1]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]

^[1]

Cash equivalents (including restricted cash accounts)

(13,702)

(17,763)

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Receivable [Member]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Currency Forward Contracts [Member]

^[1]

106

108

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Payable [Member]

^[2]

Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Warrant [Member]

^[1]

$ (13,808)

(13,904)

^[1]

$ (3,967)

[1]

These amounts relate to contingent receivables and payables and warrants relating to acquisition of substantially all of the assets of Viridity Energy, Inc. and to the Guadeloupe power plant purchase transaction, valued primarily based on unobservable inputs and are included within "Prepaid expenses and other", "Accounts payable and accrued expenses" and "Other long-term liabilities" on June 30, 2018 and December 31, 2017 in the consolidated balance sheets with the corresponding gain or loss being recognized within Derivatives and foreign currency transaction gains (losses) in the consolidated statement of operations and comprehensive income. The warrants were executed during the second quarter of 2018 in accordance with the purchase agreements.

[2]

These amounts relate to currency forward contracts valued primarily based on observable inputs, including forward and spot prices for currencies, net of contracted rates and then multiplied by notional amounts, and are included within "Prepaid expenses and other" and "Accounts payable and accrued expenses", as applicable, on June 30, 2018 and December 31, 2017, in the consolidated balance sheet with the corresponding gain or loss being recognized within "Derivatives and foreign currency transaction gains (losses)" in the consolidated statement of operations and comprehensive income.

Note 5 - Fair Value of Financial Instruments - Amounts of Gain (Loss) Recognized in Condensed Consolidated Statements on Derivative Instruments Not Designated as Hedges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Amount of gain (loss) recognized	$ (911)	$ 1,364	$ (1,457)	$ 3,383
Foreign Currency Gain (Loss) [Member] \| Put Options on Natural Gas Price [Member]
Amount of gain (loss) recognized		(48)		(241)
Foreign Currency Gain (Loss) [Member] \| Contingent Considerations [Member]
Amount of gain (loss) recognized		(45)		(95)
Foreign Currency Gain (Loss) [Member] \| Currency Forward Contracts [Member]
Amount of gain (loss) recognized	$ (911)	$ 1,457	$ (1,457)	$ 3,719

Note 5 - Fair Value of Financial Instruments - Fair Value of Long-term Debt Approximates Its Carrying Amount, Exceptions (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Estimate of Fair Value Measurement [Member]
Other long-term debt	$ 5.4	$ 7.0
Reported Value Measurement [Member]
Other long-term debt	6.4	7.9
Olkaria III OPIC [Member]
Loans	219.6	234.6
Olkaria III OPIC [Member] \| Estimate of Fair Value Measurement [Member]
Loans	219.6	234.6
Olkaria III OPIC [Member] \| Reported Value Measurement [Member]
Loans	219.6	228.6
Olkaria IV Loan - DEG 2 [Member]
Loans	49.5
Olkaria IV Loan - DEG 2 [Member] \| Estimate of Fair Value Measurement [Member]
Loans	49.5	50.7
Olkaria IV Loan - DEG 2 [Member] \| Reported Value Measurement [Member]
Loans	50.0	50.0
Amatitlan Loan [Member]
Loans	31.7	32.8
Amatitlan Loan [Member] \| Estimate of Fair Value Measurement [Member]
Loans	31.7	32.8
Amatitlan Loan [Member] \| Reported Value Measurement [Member]
Loans	31.5	33.3
OrCal Geothermal Inc [Member]
Notes	28.7	34.2
OrCal Geothermal Inc [Member] \| Estimate of Fair Value Measurement [Member]
Notes	28.7	34.2
OrCal Geothermal Inc [Member] \| Reported Value Measurement [Member]
Notes	27.3	32.1
OFC Two Senior Secured Notes [Member]
Notes	219.2	234.6
OFC Two Senior Secured Notes [Member] \| Estimate of Fair Value Measurement [Member]
Notes	219.2	234.6
OFC Two Senior Secured Notes [Member] \| Reported Value Measurement [Member]
Notes	224.2	232.5
Don A. Campbell 1 ("DAC1") [Member]
Notes	79.9	85.5
Don A. Campbell 1 ("DAC1") [Member] \| Estimate of Fair Value Measurement [Member]
Notes	79.9	85.5
Don A. Campbell 1 ("DAC1") [Member] \| Reported Value Measurement [Member]
Notes	85.3	88.3
USG Prudential - NV [Member]
Notes	29.7
USG Prudential - NV [Member] \| Estimate of Fair Value Measurement [Member]
Notes	29.7
USG Prudential - NV [Member] \| Reported Value Measurement [Member]
Notes	28.3
USG Prudential - ID [Member]
Notes	18.6
USG Prudential - ID [Member] \| Estimate of Fair Value Measurement [Member]
Notes	18.6
USG Prudential - ID [Member] \| Reported Value Measurement [Member]
Notes	18.9
USG DOE [Member]
Notes	49.0
USG DOE [Member] \| Estimate of Fair Value Measurement [Member]
Notes	49.0
USG DOE [Member] \| Reported Value Measurement [Member]
Notes	53.0
Senior Unsecured Bonds [Member]
Senior secured debt	198.1	200.3
Senior Unsecured Bonds [Member] \| Estimate of Fair Value Measurement [Member]
Senior secured debt	198.1	200.3
Senior Unsecured Bonds [Member] \| Reported Value Measurement [Member]
Senior secured debt	204.3	204.3
Senior Unsecured Loan [Member]
Senior secured debt	101.3
Senior Unsecured Loan [Member] \| Estimate of Fair Value Measurement [Member]
Senior secured debt	101.3
Senior Unsecured Loan [Member] \| Reported Value Measurement [Member]
Senior secured debt	$ 100.0

Note 5 - Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Revolving lines of credit	$ 158.6	$ 51.5
Deposits	19.3	15.6
Fair Value, Inputs, Level 1 [Member]
Revolving lines of credit
Deposits	19.3	15.6
Fair Value, Inputs, Level 2 [Member]
Revolving lines of credit	158.6	51.5
Deposits
Fair Value, Inputs, Level 3 [Member]
Revolving lines of credit
Deposits
Olkaria III OPIC [Member]
Loans	219.6	234.6
Olkaria III OPIC [Member] \| Fair Value, Inputs, Level 1 [Member]
Loans
Olkaria III OPIC [Member] \| Fair Value, Inputs, Level 2 [Member]
Loans
Olkaria III OPIC [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans	219.6	234.6
Olkaria IV Loan - DEG 2 [Member]
Loans	49.5
Olkaria IV Loan - DEG 2 [Member] \| Fair Value, Inputs, Level 1 [Member]
Loans
Olkaria IV Loan - DEG 2 [Member] \| Fair Value, Inputs, Level 2 [Member]
Loans
Olkaria IV Loan - DEG 2 [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans	49.5	50.7
Amatitlan Loan [Member]
Loans	31.7	32.8
Amatitlan Loan [Member] \| Fair Value, Inputs, Level 1 [Member]
Loans
Amatitlan Loan [Member] \| Fair Value, Inputs, Level 2 [Member]
Loans	31.7	32.8
Amatitlan Loan [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans
OrCal Geothermal Inc [Member]
Notes	28.7	34.2
OrCal Geothermal Inc [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
OrCal Geothermal Inc [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
OrCal Geothermal Inc [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	28.7	34.2
OFC Two Senior Secured Notes [Member]
Notes	219.2	234.6
OFC Two Senior Secured Notes [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
OFC Two Senior Secured Notes [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
OFC Two Senior Secured Notes [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	219.2	234.6
Don A. Campbell 1 ("DAC1") [Member]
Notes	79.9	85.5
Don A. Campbell 1 ("DAC1") [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
Don A. Campbell 1 ("DAC1") [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
Don A. Campbell 1 ("DAC1") [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	79.9	85.5
USG Prudential - NV [Member]
Notes	29.7
USG Prudential - NV [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
USG Prudential - NV [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
USG Prudential - NV [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	29.7
Senior Unsecured Bonds [Member]
Senior secured debt	198.1	200.3
Senior Unsecured Bonds [Member] \| Fair Value, Inputs, Level 1 [Member]
Senior secured debt
Senior Unsecured Bonds [Member] \| Fair Value, Inputs, Level 2 [Member]
Senior secured debt
Senior Unsecured Bonds [Member] \| Fair Value, Inputs, Level 3 [Member]
Senior secured debt	198.1	200.3
USG Prudential - ID [Member]
Notes	18.6
USG Prudential - ID [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
USG Prudential - ID [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
USG Prudential - ID [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	18.6
Other Long-term Debt [Member]
Senior secured debt		7.0
Other long-term debt	5.4
Other Long-term Debt [Member] \| Fair Value, Inputs, Level 1 [Member]
Senior secured debt
Other long-term debt
Other Long-term Debt [Member] \| Fair Value, Inputs, Level 2 [Member]
Senior secured debt
Other long-term debt
Other Long-term Debt [Member] \| Fair Value, Inputs, Level 3 [Member]
Senior secured debt		$ 7.0
Other long-term debt	5.4
USG DOE [Member]
Notes	49.0
USG DOE [Member] \| Fair Value, Inputs, Level 1 [Member]
Notes
USG DOE [Member] \| Fair Value, Inputs, Level 2 [Member]
Notes
USG DOE [Member] \| Fair Value, Inputs, Level 3 [Member]
Notes	49.0
Senior Unsecured Loan [Member]
Senior secured debt	101.3
Senior Unsecured Loan [Member] \| Fair Value, Inputs, Level 1 [Member]
Senior secured debt
Senior Unsecured Loan [Member] \| Fair Value, Inputs, Level 2 [Member]
Senior secured debt
Senior Unsecured Loan [Member] \| Fair Value, Inputs, Level 3 [Member]
Senior secured debt	$ 101.3

Note 6 - Stock-based Compensation (Details Textual) - $ / shares				1 Months Ended
	Jun. 25, 2018	May 08, 2018	May 07, 2018	May 31, 2012
2012 Stock Incentive Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period				6 years
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized				4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				1 year
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				2 years
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member] \| Share-based Compensation Award, Tranche One [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				100.00%
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				25.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				3 years
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member] \| Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				50.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				4 years
2012 Stock Incentive Plan [Member] \| Stock Options And Stock Appreciation Rights [Member] \| Share-based Compensation Award, Tranche Four [Member] \| Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage				25.00%
2012 Stock Incentive Plan [Member] \| Employee Stock Option [Member] \| Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				1 year
The 2018 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized			5,000,000
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			6 years
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period			10 years
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		100.00%	100.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			50.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		22.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche One [Member] \| Employees and Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	50.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			25.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		22.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Employees and Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage			25.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		28.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Three [Member] \| Employees and Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights and Restricted Stock Units [Member] \| Share-based Compensation Award, Tranche Four [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage		28.00%
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		295,671
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 14.56
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 14.64
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	838,117
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 13.82
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Director and Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		5 years 182 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Exercise Price		$ 55.16
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		295,671
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 14.57
The 2018 Incentive Plan [Member] \| Stock Appreciation Rights (SARs) [Member] \| Employees and Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	6 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 53.44
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		40,489
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 54.92
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 52.09
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	19,848
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 52.03
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Director and Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		5 years 182 days
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Chief Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		40,489
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 54.23
The 2018 Incentive Plan [Member] \| Restricted Stock Units (RSUs) [Member] \| Employees and Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	6 years

Note 6 - Stock-based Compensation - Fair Value of Stock-based Award Using Exercise Multiple-based Lattice SAR and RSU Pricing Model Assumptions (Details) - Stock Appreciation Rights and Restricted Stock Units [Member] - The 2018 Incentive Plan [Member]	Jun. 25, 2018	May 08, 2018
Director and Chief Executive Officer [Member]
Risk-free interest rate		2.84%
Expected life (in years) (Year)		5 years 182 days
Dividend yield		0.79%
Expected volatility		25.24%
Forfeiture rate		0.00%
Sub-Optimal Exercise Factor		2.5
Employees and Senior Management [Member]
Risk-free interest rate	2.79%
Expected life (in years) (Year)	6 years
Dividend yield	0.92%
Expected volatility	25.64%
Employees [Member]
Forfeiture rate	2.78%
Sub-Optimal Exercise Factor	2
Senior Management [Member]
Forfeiture rate	0.00%
Sub-Optimal Exercise Factor	2.8

Note 7 - Interest Expense, Net - Components of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest related to sale of tax benefits	$ 1,761	$ 1,849	$ 3,170	$ 3,861
Interest expense	15,421	14,146	28,727	28,321
Less — amount capitalized	(1,336)	(1,455)	(1,707)	(2,719)
Interest Expense, Total	$ 15,846	$ 14,540	$ 30,190	$ 29,463

Note 8 - Earnings Per Share (Details Textual) - shares	3 Months Ended		6 Months Ended
Note 8 - Earnings Per Share (Details Textual) - shares	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	232,925	2,363	223,708	2,430

Note 8 - Earnings Per Share - Shares Used to Calculate Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Weighted average number of shares used in computation of basic earnings per share (in shares)	50,623	49,771	50,618	49,726
Additional shares from the assumed exercise of employee stock options (in shares)	335	853	383	833
Weighted average number of shares used in computation of diluted earnings per share (in shares)	50,958	50,624	51,001	50,559

Note 9 - Business Segments (Details Textual) $ in Thousands	3 Months Ended	6 Months Ended
Note 9 - Business Segments (Details Textual) $ in Thousands	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)
Number of Reportable Segments		3
Goodwill, Ending Balance	$ 40,133	$ 40,133	$ 21,037
Electricity Segment [Member]
Goodwill, Ending Balance	26,700	26,700		$ 6,600
Other Segments [Member]
Goodwill, Ending Balance	13,500	13,500		$ 13,500
Accounting Standards Update 2014-09 [Member] \| Electricity Revenues [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 5,300	$ 11,900

Note 9 - Business Segments - Summarized Financial Information Concerning Reportable Segments (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Jun. 30, 2018

Jun. 30, 2017

Dec. 31, 2017

$ 178,299

$ 179,364

$ 362,322

$ 369,262

36,633

53,152

91,226

112,648

2,994,149

^[1]

2,510,633

^[1]

2,994,149

^[1]

2,510,633

^[1]

$ 2,623,864

66,551

13,957

66,551

13,957

Intersegment Eliminations [Member]

36,633

53,152

91,226

112,648

Electricity Segment [Member]

11,453

16,565

36,280

32,778

122,179

110,896

254,668

226,672

27,462

38,014

73,874

78,912

^[1]

2,805,182

2,273,503

2,805,182

2,273,503

66,551

13,957

66,551

13,957

Electricity Segment [Member] | Intersegment Eliminations [Member]

27,462

38,014

73,874

78,912

Product Segment [Member]

54,915

67,587

103,587

141,709

10,761

17,035

20,314

35,633

^[1]

125,572

187,015

125,572

187,015

Product Segment [Member] | Intersegment Eliminations [Member]

10,761

17,035

20,314

35,633

11,453

16,565

36,280

32,778

Other Segments [Member]

1,205

881

4,067

881

(1,590)

(1,897)

(2,962)

(1,897)

^[1]

63,395

50,115

63,395

50,115

Other Segments [Member] | Intersegment Eliminations [Member]

(1,590)

(1,897)

(2,962)

(1,897)

UNITED STATES

UNITED STATES | Electricity Segment [Member]

^[2]

74,371

161,110

UNITED STATES | Product Segment [Member]

^[2]

73,139

156,822

UNITED STATES | Other Segments [Member]

^[2]

27

221

Foreign Countries [Member]

^[2]

1,205

4,067

Foreign Countries [Member] | Electricity Segment [Member]

^[3]

103,928

201,212

Foreign Countries [Member] | Product Segment [Member]

^[3]

49,040

97,846

Foreign Countries [Member] | Other Segments [Member]

^[3]

54,888

103,366