Ormat (ORA) 10-Q 19 Jun 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Jun. 17, 2018
Document Information [Line Items]
Entity Registrant Name	ORMAT TECHNOLOGIES, INC.
Entity Central Index Key	1,296,445
Trading Symbol	ora
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		50,617,209
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018		Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 54,723		$ 47,818
Restricted cash and cash equivalents (primarily related to VIEs)	50,332		48,825
Receivables:
Trade	103,580		110,410
Other	10,018		13,828
Inventories	20,069		19,551
Costs and estimated earnings in excess of billings on uncompleted contracts	41,134		40,945
Prepaid expenses and other	42,274		40,269
Total current assets	322,130		321,646
Investment in an unconsolidated company	63,109		34,084
Deposits and other	21,205		21,599
Deferred income taxes	124,304		57,337
Deferred charges			49,834
Property, plant and equipment, net	1,723,560		1,734,691
Construction-in-process	345,563		293,542
Deferred financing and lease costs, net	4,922		4,674
Intangible assets, net	84,771		85,420
Goodwill	21,253		21,037
Total assets	2,710,817	[1]	2,623,864
Current liabilities:
Accounts payable and accrued expenses	103,551		153,796
Short term revolving credit lines with banks (full recourse)	38,500		51,500
Billings in excess of costs and estimated earnings on uncompleted contracts	10,458		20,241
Current portion of long-term debt:
Senior secured notes	28,398		33,226
Other loans	21,495		21,495
Full recourse	2,809		3,087
Total current liabilities	205,211		283,345
Long-term debt, net of current portion:
Senior secured notes (less deferred financing costs of $7,693 and $8,113, respectively)	305,905		311,668
Other loans (less deferred financing costs of $5,231 and $5,258, respectively)	237,245		242,385
Senior unsecured bonds (less deferred financing costs of $863 and $580, respectively)	303,469		203,752
Other loans (less deferred financing costs of $994 and $1,011, respectively)	46,506		46,489
Liability associated with sale of tax benefits	42,622		44,634
Deferred lease income	50,745		51,520
Deferred income taxes	48,074		61,961
Liability for unrecognized tax benefits	9,074		8,890
Liabilities for severance pay	20,874		21,141
Asset retirement obligation	27,639		27,110
Other long-term liabilities	21,625		18,853
Total liabilities	1,318,989		1,321,748
Commitments and contingencies (Note 10)
Redeemable noncontrolling interest	6,943		6,416
Equity:
Common stock, par value $0.001 per share; 200,000,000 shares authorized; 50,617,209 and 50,609,051 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	51		51
Additional paid-in capital	890,485		888,778
Retained earnings	410,758		327,255
Accumulated other comprehensive loss	(909)		(4,706)
Total equity attributable to the Company's stockholders	1,300,385		1,211,378
Noncontrolling interest	84,500		84,322
Total equity	1,384,885		1,295,700
Total liabilities, redeemable noncontrolling interest and equity	$ 2,710,817		$ 2,623,864
[1]	Electricity segment assets include goodwill in the amount of $7.8 million and $6.2 million as of March, 31, 2018 and 2017, respectively. Other segment assets include goodwill in the amount of $13.5 million as of March 31, 2018 and 2017.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, plant and equipment, net	$ 1,723,560	$ 1,734,691
Construction-in-process	$ 345,563	$ 293,542
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	50,617,209	50,609,051
Common stock, shares outstanding (in shares)	50,617,209	50,609,051
Senior Secured Notes [Member]
Deferred financing costs	$ 7,693	$ 8,113
Other Loans, Limited and Non-recourse [Member]
Deferred financing costs	5,231	5,258
Senior Unsecured Bonds [Member]
Deferred financing costs	863	580
Other Loans, Full Recourse [Member]
Deferred financing costs	994	1,011
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net	1,655,365	1,631,900
Construction-in-process	$ 149,872	$ 142,717

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Total consolidated revenues	$ 184,023	$ 189,898	[1]
Cost of revenues:
Cost of revenues	110,651	115,488
Gross profit	73,372	74,410
Operating expenses:
Research and development expenses	1,108	602
Selling and marketing expenses	3,699	4,363
General and administrative expenses	13,849	9,949
Write-off of unsuccessful exploration activities	123	0
Operating income	54,593	59,496	[1]
Other income (expense):
Interest income	113	244
Interest expense, net	(14,344)	(14,923)
Derivatives and foreign currency transaction gains (losses)	(1,599)	1,338
Income attributable to sale of tax benefits	7,361	6,157
Other non-operating expense, net	(20)	(92)
Income from continuing operations before income taxes and equity in earnings (losses) of investees	46,104	52,220
Income tax (provision) benefit	26,942	(11,004)
Equity in earnings (losses) of investees, net	1,210	(1,599)
Income from continuing operations	74,256	39,617
Net income attributable to noncontrolling interest	(4,748)	(4,423)
Net income attributable to the Company's stockholders	69,508	35,194
Comprehensive income:
Net income	74,256	39,617
Other comprehensive income (loss), net of related taxes:
Change in foreign currency translation adjustments	1,528
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment	2,634	569
Loss in respect of derivative instruments designated for cash flow hedge	20	48
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge	(15)	(24)
Comprehensive income	78,423	40,210
Comprehensive income attributable to noncontrolling interest	(5,118)	(4,412)
Comprehensive income attributable to the Company's stockholders	$ 73,305	$ 35,798
Basic:
Net income (in dollars per share)	$ 1.37	$ 0.71
Diluted:
Net income (in dollars per share)	$ 1.36	$ 0.70
Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders:
Basic (in shares)	50,614	49,680
Diluted (in shares)	51,051	50,491
Dividend per share declared (in dollars per share)	$ 0.23	$ 0.17
Electricity [Member]
Revenues:
Total consolidated revenues	$ 132,489	$ 115,776
Cost of revenues:
Cost of revenues	73,482	66,036
Product [Member]
Revenues:
Revenues	48,672	74,122
Cost of revenues:
Cost of revenues	33,726	49,452
Other Revenue [Member]
Revenues:
Revenues	2,862
Cost of revenues:
Cost of revenues	$ 3,443
[1]	The amounts related to the Other segment are immaterial.

Consolidated Statements of Equi

Consolidated Statements of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Dec. 31, 2016	49,667
Balance at Dec. 31, 2016	$ 50	$ 869,463	$ 215,352	$ (8,175)	$ 1,076,690	$ 91,582	$ 1,168,272
Stock-based compensation		1,713			1,713		1,713
Exercise of options by employees and directors (in shares)	39
Exercise of options by employees and directors
Cash paid to noncontrolling interest						(6,807)	(6,807)
Cash dividend declared			(8,448)		(8,448)		(8,448)
Net income			35,194		35,194	4,079	39,273
Other comprehensive income (loss), net of related taxes:
Currency translation adjustment				89	89	(11)
Loss in respect of derivative instruments designated for cash flow hedge				48	48		48
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment				569	569		569
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge				(24)	(24)		(24)
Balance (in shares) at Dec. 31, 2016	49,667
Balance at Dec. 31, 2016	$ 50	869,463	215,352	(8,175)	1,076,690	91,582	1,168,272
Other comprehensive income (loss), net of related taxes:
Stock-based compensation		1,713			1,713		1,713
Exercise of options by employees and directors (in shares)	39
Exercise of options by employees and directors
Cash paid to noncontrolling interest						(6,807)	(6,807)
Cash dividend declared			(8,448)		(8,448)		(8,448)
Net income			35,194		35,194	4,079	39,273
Balance (in shares) at Mar. 31, 2017	49,706
Balance at Mar. 31, 2017	$ 50	871,176	242,098	(7,493)	1,105,831	88,843	1,194,674
Balance (in shares) at Dec. 31, 2017	50,609
Balance at Dec. 31, 2017	$ 51	888,778	327,255	(4,706)	1,211,378	84,322	1,295,700
Stock-based compensation		1,707			1,707		1,707
Exercise of options by employees and directors (in shares)	8
Exercise of options by employees and directors
Cash paid to noncontrolling interest						(4,674)	(4,674)
Cash dividend declared			(11,640)		(11,640)		(11,640)
Net income			69,508		69,508	4,482	73,990
Other comprehensive income (loss), net of related taxes:
Currency translation adjustment				1,158	1,158	370	1,528
Loss in respect of derivative instruments designated for cash flow hedge				20	20		20
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment				2,634	2,634		2,634
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge				(15)	(15)		(15)
Balance (in shares) at Dec. 31, 2017	50,609
Balance at Dec. 31, 2017	$ 51	888,778	327,255	(4,706)	1,211,378	84,322	1,295,700
Other comprehensive income (loss), net of related taxes:
Stock-based compensation		1,707			1,707		1,707
Exercise of options by employees and directors (in shares)	8
Exercise of options by employees and directors
Cash paid to noncontrolling interest						(4,674)	(4,674)
Cash dividend declared			(11,640)		(11,640)		(11,640)
Net income			69,508		69,508	4,482	73,990
Balance (in shares) at Mar. 31, 2018	50,617
Balance at Mar. 31, 2018	$ 51	890,485	410,758	(909)	1,300,385	84,500	1,384,885
Other comprehensive income (loss), net of related taxes:
Cumulative effect of changes in accounting principles			$ 25,635		$ 25,635		$ 25,635

Consolidated Statements of Equ6

Consolidated Statements of Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Retained Earnings [Member]
Cash dividend declared, per share (in dollars per share)	$ 0.23	$ 0.17
Amortization of unrealized gains, tax	$ 9	$ 14
Loss in respect of derivative instruments designated for cash flow hedge, related tax	$ 13
Cash dividend declared, per share (in dollars per share)	$ 0.23	$ 0.17

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 74,256	$ 39,617
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30,553	27,059
Accretion of asset retirement obligation	529	455
Stock-based compensation	1,707	1,713
Amortization of deferred lease income	(671)	(671)
Income attributable to sale of tax benefits, net of interest expense	(6,295)	(4,335)
Equity in losses (earnings) of investees	(1,210)	1,600
Mark-to-market of derivative instruments	962	(1,519)
Write-off of unsuccessful exploration activities	123	0
Gain on severance pay fund asset	129	(947)
Deferred income tax provision and deferred charges	(29,467)	6,612
Liability for unrecognized tax benefits	184	692
Deferred lease revenues	(104)	(92)
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	9,777	19,092
Costs and estimated earnings in excess of billings on uncompleted contracts	(189)	(4,352)
Inventories	(503)	(5,800)
Prepaid expenses and other	(2,005)	6,873
Deposits and other	62	(557)
Accounts payable and accrued expenses	(49,027)	681
Billings in excess of costs and estimated earnings on uncompleted contracts	9,783	14,035
Liabilities for severance pay	(267)	930
Other long-term liabilities	1,008	(1,553)
Net cash provided by operating activities	19,769	71,463
Cash flows from investing activities:
Capital expenditures	(66,962)	(52,885)
Investment in unconsolidated companies	(1,275)	(14,918)
Cash paid for acquisition of controlling interest in a subsidiary, net of cash acquired		(35,300)
Decrease (increase) in severance pay fund asset, net of payments made to retired employees	203	(18)
Net cash used in investing activities	(68,034)	(103,121)
Cash flows from financing activities:
Proceeds from long-term loans, net of transaction costs	100,000
Proceeds from revolving credit lines with banks	860,800	50,000
Repayment of revolving credit lines with banks	(873,800)	(20,000)
Cash received from noncontrolling interest	4,134	1,411
Repayments of long-term debt	(16,687)	(13,405)
Cash paid to noncontrolling interest	(4,674)	(6,807)
Payments of capital leases	(436)	(408)
Deferred debt issuance costs	(1,020)	(1,144)
Cash dividends paid	(11,640)	(8,448)
Net cash provided by financing activities	56,677	1,199
Net change in cash and cash equivalents and restricted cash and cash equivalents	8,412	(30,459)
Cash and cash equivalents and restricted cash and cash equivalentsat beginning of period	96,643	264,476
Cash and cash equivalents and restricted cash and cash equivalents at end of period	105,055	234,017
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	$ (1,673)	$ 1,801

Note 1 - General and Basis of P

Note 1 - General and Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	NOTE 1 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 March 31, 2018, three March 31, 2018 2017 three March 31, 2018 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 March 31, 2018 not 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 December 31, 2017. December 31, 2017 December 31, 2017, not Dollar amounts, except per share data, in the notes to these financial statements are rounded to the closest $1,000. Revision of previously issued condensed consolidated financial statements As previously disclosed in the Company’s Form 10 December 31 2017, June 19, 2018, 2017 The Company also identified other tax errors in the previously issued unaudited condensed consolidated financial statements as of and for the three March 31, 2017, 1.Materiality, 250, 250” not 2017 three March 31, 2017 $0.1 $1.7 January 1, 2017 2017. The effects of the revision on the line items within the Company's condensed consolidated statements of operations and comprehensive income for the three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Income tax provision $ (10,886 ) $ (118 ) $ (11,004 ) Income from continuing operations 39,735 (118 ) 39,617 Net income attributable to the Company’s Stockholders 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge 22 26 48 Comprehensive income 40,302 (92 ) 40,210 Comprehensive income attributable to the Company’s stockholders 35,890 (92 ) 35,798 Earnings per share Basic: $ 0.71 $ - $ 0.71 Diluted: $ 0.70 $ - $ 0.70 The effects of the revision on the line items within the Company’s condensed consolidated statements of equity for the three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Balances as of December 31, 2016: Retained earnings $ 216,644 $ (1,292 ) $ 215,352 Accumulated other comprehensive loss (7,732 ) (443 ) (8,175 ) Total stockholders’ equity attributable to the Company’s stockholders 1,078,425 (1,735 ) 1,076,690 Total equity 1,170,007 (1,735 ) 1,168,272 Net income for the three months ended March 31, 2017 39,391 (118 ) 39,273 Net income attributable to the Company’s stockholders for the three months ended March 31, 2017 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge for the three months ended March 31, 2017 22 26 48 Balances as of March 31, 2017: Retained earnings 243,508 (1,410 ) 242,098 Accumulated other comprehensive loss (7,076 ) (417 ) (7,493 ) Total stockholders’ equity attributable to the Company’s stockholders 1,107,658 (1,827 ) 1,105,831 Total equity 1,196,501 (1,827 ) 1,194,674 Although there was no three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Cash flows from operating activities: Net income $ 39,735 $ (118 ) $ 39,617 Liability for unrecognized tax benefits 574 118 692 Net cash provided by operating activities 71,463 - 71,463 Migdal Senior Unsecured Loan On March 22, 2018 $100 15 $4.2 September 15, 2021, $37 March 15, 2029. 4.8% The Migdal Loan is subject to early redemption by the Company prior to maturity from time to time (but not 0.50%. 0.25% no 1% 0.25% no 4.8% 4.5, 0.5% 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, not $650 not 25%. $800 one not 50% March 27, 2018 Other comprehensive income For the three March 31, 2018 2017, $5,000 $2,000, $9,000 $3,000, $4,000 $1,000, March 31, 2018, $0.6 Write-offs of unsuccessful exploration activities Write-offs of unsuccessful exploration activities for the three March 31, 2018 $0.1 no three March 31, 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: March 31, December 31, 2018 2017 Cash and cash equivalents $ 54,723 $ 47,818 Restricted cash and cash equivalents 50,332 48,825 Total Cash and cash equivalents and Restricted cash and cash equivalents $ 105,055 $ 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 and in foreign countries. At March 31, 2018 December 31, 2017, $20.3 $21.2 eight $250,000 March 31, 2018 December 31, 2017, $47.3 $32.8 At March 31, 2018 December 31, 2017, $73.3 $78.1 March 31, 2018 December 31, 2017, 59% 57% Sierra Pacific Power Company and Nevada Power Company (subsidiaries of NV Energy, Inc.) accounted for 17.4% 18.8% three March 31, 2018 2017, Southern California Public Power Authority (“SCPPA”) accounted for 16.3% 9.0% three March 31, 2018 2017, Kenya Power and Lighting Co. Ltd. accounted for 15.1% 14.3% three March 31, 2018 2017, 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

Note 2 - New Accounting Pronoun

Note 2 - New Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	NOTE 2 New accounting pronouncements effective in the three March 31, 2018 Income Taxes In March 2018, 2018 05, 740 No. 118, 118” December 2017. 11 Revenues from Contracts with Customers In May 2014, 2014 09, 606, 1 2 3 4 5 2014 09 March 2016, 2016 08, not The Company adopted this update effectively as of January 1, 2018 one five 606, The adoption of ASC 606, not 2018, 606 January 1, 2018, (Dollars in millions) Electricity segment revenues $ – Product segment revenues – Other segment revenues – Investment in an unconsolidated company 24.0 Electricity segment revenues July 1, 2003, three 840 606, 30 60 Product segment revenues third not not no one two In contracts for which we determine that control is not 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 The nature of our product contracts give rise to several modifications or change requests by our customer. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are not one The Company generally provides a one December 31, 2017, 2016, 2015. Contract Assets and Liabilities related to our Product segment March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 (Dollars in thousands) Contract assets (*) $ 41,134 $ 40,945 Contract liabilities (*) (10,458 ) (20,241 ) Contract assets, net $ 30,676 $ 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 three March 31, 2018: Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ – $ 8,353 Cash received in advance for which revenues have not yet recognized – (4,451 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (22,144 ) – Contract assets recognized, net of recognized receivables 28,214 – Net change in contract assets and contract liabilities $ 6,070 $ 3,902 The timing of revenue recognition, billings and cash collections results in accounts receivable, contract assets and contract liabilities on the 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% 20% no On March 31, 2018, $211.0 not 91% 24 The following schedule reconciles revenues accounted under ASC 840, 606, three March 31, 2018: Three Months Ended March 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 125,832 Electricity and Product revenues accounted under ASC 606 58,191 Total consolidated revenues $ 184,023 Disaggregated revenues from contracts with customers for the three March 31, 2018 9 Investment in an unconsolidated company 606 one $24.0 January 1, 2018. not not The following schedule quantifies the impact of adopting ASC 606 three March 31, 2018: 2018, under previous standard Effect of the New Revenue Standard 2018, as reported (Dollars in thousands) Equity in earnings of investees, net $ 1,944 $ (734 ) $ 1,210 Income from continuing operations 74,990 (734 ) 74,256 Net income attributable to the Company’s stockholders 70,242 (734 ) 69,508 Retained earnings 411,492 (734 ) 410,758 Other segment revenues 606 may Compensation - Stock Compensation In May 2017, 2017 09, 718 718. 1 2 3 718 December 15, 2017. not Business Combinations In January 2017, 2017 01, 805 not December 15, 2017, not Statement of Cash Flow In November 2016, 2016 18, 230 December 15, 2017 three March 31, 2018 Intra-Entity Transfers of Assets Other than Inventory In October 2016, 2016 16, not December 15, 2017 three March 31, 2018 $1.8 $49.8 $51.6 Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (Topic 230 In August 2016, 2016 15, 230 eight December 15, 2017 $8.0 fourth 2017 Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, 2016 01, December 15, 2017 not New accounting pronouncements effective in future periods Derivatives and Hedging In August 2017, 2017 12, December 15, 2018, Intangibles –Goodwill and Other In January 2017, 2017 04, 350 not 2 2 first first December 15, 2019. January 1, 2017. Leases In February 2016, 2016 02, 842 two 606. December 15, 2018, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income In February 2018, 2018 02, 220 2017. December 15, 2018, not

Note 3 - Inventories

Note 3 - Inventories	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Inventory Disclosure [Text Block]	NOTE 3 Inventories consist of the following: March 31, December 31, 2018 2017 (Dollars in thousands) Raw materials and purchased parts for assembly $ 12,019 $ 12,007 Self-manufactured assembly parts and finished products 8,050 7,544 Total $ 20,069 $ 19,551

Note 4 - Investment in an Uncon

Note 4 - Investment in an Unconsolidated Company	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Equity Method Investments and Joint Ventures Disclosure [Text Block]	NOTE 4 Unconsolidated investments consist of the following: March 31, December 31, 2018 2017 (Dollars in thousands) Sarulla $ 63,109 $ 34,084 The Sarulla Project The Company holds a 12.75% 330 three 110 NIL 2, April 2018. April 4, 2013 30 On May 16, 2014, $1.17 six $1.17 $0.1 $1.07 three March 31, 2018, $16.9 The Sarulla consortium entered into interest rate swap agreements with various international banks, effective as of June 4, 2014, $0.96 $1.07 3.4565%. three March 31, 2018 2017, $20.7 $4.5 $2.6 $0.6 March 31, 2018 $2.5 During the three March 31, 2018, $1.3 $59.5 As further described above under the heading “New accounting pronouncement effective in the three March 31, 2018” 2 606, January 1, 2018. $24.0 January 1, 2018. not one $24.0 January 1, 2018,

Note 5 - Fair Value of Financia

Note 5 - Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Fair Value Disclosures [Text Block]	NOTE 5— 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 3 three Level 1 Level 2 not Level 3 no The following table sets forth certain fair value information at March 31, 2018 December 31, 2017 March 31, 2018 Fair Value Carrying Value at March 31, 2018 Total Level 1 Level 2 Level 3 (Dollars in thousands) Assets: Current assets: Cash equivalents (including restricted cash accounts) $ 20,658 $ 20,658 $ 20,658 $ — $ — Derivatives: Contingent receivable (1) 111 111 — — 111 Currency forward contracts (2) 30 30 — 30 — Liabilities: Current liabilities: Derivatives: Contingent payables (1) (14,006 ) (14,006 ) — — (14,006 ) Warrants (1) (4,080 ) (4,080 ) — — (4,080 ) $ 2,713 $ 2,713 $ 20,658 $ 30 $ (17,975 ) 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 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 March 31, 2018 December 31, 2017 ( 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 March 31, 2018 December 31, 2017, 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 The following table presents the amounts of gain (loss) recognized in the consolidated statements of operations and comprehensive income on derivative instruments not Amount of recognized gain (loss) Derivatives not designated Location of recognized Three Months Ended March 31, as hedging instruments gain (loss) 2018 2017 Put options on natural gas price Derivatives and foreign currency transaction gains (losses) $ — $ (193 ) Contingent considerations Derivative and foreign currency transaction gains (losses) — (50 ) Currency forward contracts Derivative and foreign currency and transaction gains (losses) (546 ) 2,262 $ (546 ) $ 2,019 In January 2017, 4.1 $3 January 26, 2017 November 27, 2017 $0.7 The foregoing future and forward transactions were not There were no 1, 2 3 three March 31, 2018. The fair value of the Company’s long-term debt approximates its carrying amount, except for the following: Fair Value Carrying Amount March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 (Dollars in millions) (Dollars in millions) Olkaria III Loan - OPIC $ 225.2 $ 234.6 $ 224.1 $ 228.6 Olkaria IV Loan - DEG 2 50.6 50.7 50.0 50.0 Amatitlan Loan 31.2 32.8 32.4 33.3 Senior Secured Notes: OrCal Geothermal Inc. ("OrCal") 28.5 34.2 27.3 32.1 OFC 2 LLC ("OFC 2") 223.9 234.6 228.0 232.5 Don A. Campbell 1 ("DAC 1") 81.6 85.5 86.7 88.3 Senior Unsecured Bonds 196.5 200.3 204.3 204.3 Senior Unsecured Loan 100.7 — 100.0 — Other long-term debt 6.6 7.0 7.8 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 March 31, 2018: Level 1 Level 2 Level 3 Total (Dollars in millions) Olkaria III - OPIC $ — $ — $ 225.2 $ 225.2 Olkaria IV - DEG 2 — — 50.6 50.6 Amatitlan Loan — 31.2 — 31.2 Senior Secured Notes: OrCal Senior Secured Notes — — 28.5 28.5 OFC 2 Senior Secured Notes — — 223.9 223.9 DAC 1 Senior Secured Notes — — 81.6 81.6 Senior Unsecured Bonds — — 196.5 196.5 Senior Unsecured Loan — — 100.7 100.7 Other long-term debt — — 6.6 6.6 Revolving lines of credit — 38.5 — 38.5 Deposits 15.2 — — 15.2 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

Note 6 - Stock-based Compensati

Note 6 - Stock-based Compensation	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	NOTE 6 The 2004 In 2004, 2004 “2004 2004 3,750,000 2004 25% 24 25% 36 50% 48 2004 one may ten 2004 2004 May 2012 2012 “2012 2004 The 2012 In May 2012, 2012 2012 4,000,000 2012 25% 24 25% 36 50% 48 2012 one 100% first 25% third fourth six ten 2012 2012 2018 2018 “2018 2012 The 2018 On May 7, 2018, 2018 2018 2018 2018 5,000,000

Note 7 - Interest Expense, Net

Note 7 - Interest Expense, Net	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Interest Expense Disclosure [Text Block]	NOTE 7 The components of interest expense are as follows: Three Months Ended March 31, 2018 2017 Interest related to sale of tax benefits $ 1,409 $ 2,012 Interest expense 13,306 14,175 Less — amount capitalized (371 ) (1,264 ) $ 14,344 $ 14,923

Note 8 - Earnings Per Share

Note 8 - Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Earnings Per Share [Text Block]	NOTE 8 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 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 March 31, 2018 2017 Weighted average number of shares used in computation of basic earnings per share 50,614 49,680 Add: Additional shares from the assumed exercise of employee stock options 437 811 Weighted average number of shares used in computation of diluted earnings per share 51,051 50,491 The number of stock-based awards that could potentially dilute future earnings per share and that were not 62,409 11,491 three March 31, 2018 2017,

Note 9 - Business Segments

Note 9 - Business Segments	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	NOTE 9 In 2018, 280, 2018 three three March 31, 2017 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 1 606: Electricity Product Other Consolidated (Dollars in thousands) Three Months Ended March 31, 2018: Revenues from external customers: United States (1) 83,683 194 2,862 86,739 Foreign (2) 48,806 48,478 — 97,284 Total net revenues from external customers $ 132,489 $ 48,672 2,862 184,023 Intersegment revenues — 24,827 — 24,827 Operating income 46,412 9,553 (1,372 ) 54,593 Segment assets at period end (3) (*) 2,542,154 114,815 53,848 2,710,817 (*) Including unconsolidated investments 63,109 — — 63,109 Three Months Ended March 31, 2017: Net revenues from external customers (4) $ 115,776 $ 74,122 — 189,898 Intersegment revenues (4) — 16,213 — 16,213 Operating income (4) 40,898 18,598 — 59,496 Segment assets at period end (3) 2,233,237 217,051 49,600 2,499,888 ( 1 Electricity revenues in the United States are all accounted under ASC 840, $6.7 606 2018. 606, 2 ( 2 Electricity revenues in foreign countries are all accounted under ASC 840, 606 2 ( 3 Electricity segment assets include goodwill in the amount of $7.8 $6.2 March, 31, 2018 2017, $13.5 March 31, 2018 2017. ( 4 The amounts related to the Other segment are immaterial. Reconciling information between reportable segments and the Company’s consolidated totals is shown in the following table: Three Months Ended March 31, 2018 2017 Revenue: Total segment revenue $ 184,023 $ 189,898 Intersegment revenue 24,827 16,213 Elimination of intersegment revenue (24,827 ) (16,213 ) Total consolidated revenue $ 184,023 $ 189,898 Operating income: Operating income $ 54,593 $ 59,496 Interest income 113 244 Interest expense, net (14,344 ) (14,923 ) Derivatives and foreign currency transaction gains (losses) (1,599 ) 1,338 Income attributable to sale of tax benefits 7,361 6,157 Other non-operating income (expense), net (20 ) (92 ) Total consolidated income before income taxes and equity in earnings of investees $ 46,104 $ 52,220

Note 10 - Commitments and Conti

Note 10 - Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	NOTE 10 ● Following the announcement of the Company’s acquisition of U.S. Geothermal Inc. (“USG”), a number of putative shareholder class action complaints were initially filed on behalf of USG shareholders between March 8, 2018 March 30, 2018 No. 2018 0177 Mar. 12, 2018). ● On February 18, 2018, January 16, 2018 2 January 2018 3 ● On August 5, 2016, December 12, 2016, August 2014. June 14, 2017, ● On March 29, 2016, 27th $4.8 3.75% 10 11th February 2018 ● Jon Olson and Hilary Wilt, together with Puna Pono Alliance filed a complaint on February 17, 2015 16 May 17, 2015, October 10, 2016, January 23, 2017, April 20, 2017 ● On May 21, 2018, 44366 05 18 eleven 93 $26 August 3, 2017 May 13, 2018. ● On June 11, 2018, August 8, 2017 May 15, 2018 10 10b 5 20 10 December 31, 2016 2017, 10 nine September 30, 2017 not 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

Note 11 - Income Taxes

Note 11 - Income Taxes	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	NOTE 11 The Company’s effective tax rate expense (benefit) for the three March 31, 2018 2017 58.4 21.1%, 21% three March 31, 2018 16% The Tax Cuts and Jobs Act (the Tax Act) was enacted on December 22, 2017. 1 35 21 2 3 4 5 6 7 8 December 31, 2017. The SEC staff issued SAB 118, 118 not one 740. 118, 740 740 The Company is applying the guidance in SAB 118 December 31, 2017, 1 2 3 4 March 31, 2018, December 31, 2017, During the first 2018, not 118, first 2018, $44.4 96% first 2018. 740. 2018 2018, In May 2018 Q1 not $44.4 first 2018. second 740 second three June 30, 2018. may 2018.

Note 12 - Subsequent Events

Note 12 - Subsequent Events	3 Months Ended
	Mar. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	NOTE 12 Cash dividend On May 7, 2018, $5.1 $0.10 May 21, 2018, May 30, 2018. Compliance with financial covenants In relation to covenants in certain debt facilities, which require timely filing of quarterly financial statements, the Company received waivers from each of its and its subsidiaries’ lenders as follows: ● The Company received waivers extending the period required to file the quarterly condensed consolidated financial statements for the three March 31, 2018 May 30, 2018 ● The deeds of trust governing the Company’s Series 2 3 June 14, 2018 three March 31, 2018. not not 10 March 31, 2018. may Following the filing of such condensed consolidated financial statements and the filing of the restated consolidated financial statements for the fiscal year ended December 31, 2017 second third 2017, Tungsten Mountain partnership transaction On May 17, 2018, one 26 $33.4 $13 Puna On May 3, 2018, 38 three $109 Platanares loan On April 30, 2018 $124.7 35 may three 14 second 2018. 6.75% 7.25% U.S. Geothermal transaction On April 24, 2018, $110 $106 $4 ● three 38 ● development assets which include a project at the Geysers, California; a second The Company accounted for the transaction in accordance with ASC 805, 810, may one 2017 01, 2 not The Company deemed the transaction to not not

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Reclassification, Policy [Policy Text Block]	Revision of previously issued condensed consolidated financial statements As previously disclosed in the Company’s Form 10 December 31 2017, June 19, 2018, 2017 The Company also identified other tax errors in the previously issued unaudited condensed consolidated financial statements as of and for the three March 31, 2017, 1.Materiality, 250, 250” not 2017 three March 31, 2017 $0.1 $1.7 January 1, 2017 2017. The effects of the revision on the line items within the Company's condensed consolidated statements of operations and comprehensive income for the three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Income tax provision $ (10,886 ) $ (118 ) $ (11,004 ) Income from continuing operations 39,735 (118 ) 39,617 Net income attributable to the Company’s Stockholders 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge 22 26 48 Comprehensive income 40,302 (92 ) 40,210 Comprehensive income attributable to the Company’s stockholders 35,890 (92 ) 35,798 Earnings per share Basic: $ 0.71 $ - $ 0.71 Diluted: $ 0.70 $ - $ 0.70 The effects of the revision on the line items within the Company’s condensed consolidated statements of equity for the three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Balances as of December 31, 2016: Retained earnings $ 216,644 $ (1,292 ) $ 215,352 Accumulated other comprehensive loss (7,732 ) (443 ) (8,175 ) Total stockholders’ equity attributable to the Company’s stockholders 1,078,425 (1,735 ) 1,076,690 Total equity 1,170,007 (1,735 ) 1,168,272 Net income for the three months ended March 31, 2017 39,391 (118 ) 39,273 Net income attributable to the Company’s stockholders for the three months ended March 31, 2017 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge for the three months ended March 31, 2017 22 26 48 Balances as of March 31, 2017: Retained earnings 243,508 (1,410 ) 242,098 Accumulated other comprehensive loss (7,076 ) (417 ) (7,493 ) Total stockholders’ equity attributable to the Company’s stockholders 1,107,658 (1,827 ) 1,105,831 Total equity 1,196,501 (1,827 ) 1,194,674 Although there was no three March 31, 2017 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Cash flows from operating activities: Net income $ 39,735 $ (118 ) $ 39,617 Liability for unrecognized tax benefits 574 118 692 Net cash provided by operating activities 71,463 - 71,463
Debt, Policy [Policy Text Block]	Migdal Senior Unsecured Loan On March 22, 2018 $100 15 $4.2 September 15, 2021, $37 March 15, 2029. 4.8% The Migdal Loan is subject to early redemption by the Company prior to maturity from time to time (but not 0.50%. 0.25% no 1% 0.25% no 4.8% 4.5, 0.5% 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, not $650 not 25%. $800 one not 50% March 27, 2018
Comprehensive Income, Policy [Policy Text Block]	Other comprehensive income For the three March 31, 2018 2017, $5,000 $2,000, $9,000 $3,000, $4,000 $1,000, March 31, 2018, $0.6
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 March 31, 2018 $0.1 no three March 31, 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: March 31, December 31, 2018 2017 Cash and cash equivalents $ 54,723 $ 47,818 Restricted cash and cash equivalents 50,332 48,825 Total Cash and cash equivalents and Restricted cash and cash equivalents $ 105,055 $ 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 and in foreign countries. At March 31, 2018 December 31, 2017, $20.3 $21.2 eight $250,000 March 31, 2018 December 31, 2017, $47.3 $32.8 At March 31, 2018 December 31, 2017, $73.3 $78.1 March 31, 2018 December 31, 2017, 59% 57% Sierra Pacific Power Company and Nevada Power Company (subsidiaries of NV Energy, Inc.) accounted for 17.4% 18.8% three March 31, 2018 2017, Southern California Public Power Authority (“SCPPA”) accounted for 16.3% 9.0% three March 31, 2018 2017, Kenya Power and Lighting Co. Ltd. accounted for 15.1% 14.3% three March 31, 2018 2017, 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
New Accounting Pronouncements, Policy [Policy Text Block]	New accounting pronouncements effective in the three March 31, 2018 Income Taxes In March 2018, 2018 05, 740 No. 118, 118” December 2017. 11 Revenues from Contracts with Customers In May 2014, 2014 09, 606, 1 2 3 4 5 2014 09 March 2016, 2016 08, not The Company adopted this update effectively as of January 1, 2018 one five 606, The adoption of ASC 606, not 2018, 606 January 1, 2018, (Dollars in millions) Electricity segment revenues $ – Product segment revenues – Other segment revenues – Investment in an unconsolidated company 24.0 Electricity segment revenues July 1, 2003, three 840 606, 30 60 Product segment revenues third not not no one two In contracts for which we determine that control is not 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 The nature of our product contracts give rise to several modifications or change requests by our customer. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are not one The Company generally provides a one December 31, 2017, 2016, 2015. Contract Assets and Liabilities related to our Product segment March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 (Dollars in thousands) Contract assets (*) $ 41,134 $ 40,945 Contract liabilities (*) (10,458 ) (20,241 ) Contract assets, net $ 30,676 $ 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 three March 31, 2018: Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ – $ 8,353 Cash received in advance for which revenues have not yet recognized – (4,451 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (22,144 ) – Contract assets recognized, net of recognized receivables 28,214 – Net change in contract assets and contract liabilities $ 6,070 $ 3,902 The timing of revenue recognition, billings and cash collections results in accounts receivable, contract assets and contract liabilities on the 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% 20% no On March 31, 2018, $211.0 not 91% 24 The following schedule reconciles revenues accounted under ASC 840, 606, three March 31, 2018: Three Months Ended March 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 125,832 Electricity and Product revenues accounted under ASC 606 58,191 Total consolidated revenues $ 184,023 Disaggregated revenues from contracts with customers for the three March 31, 2018 9 Investment in an unconsolidated company 606 one $24.0 January 1, 2018. not not The following schedule quantifies the impact of adopting ASC 606 three March 31, 2018: 2018, under previous standard Effect of the New Revenue Standard 2018, as reported (Dollars in thousands) Equity in earnings of investees, net $ 1,944 $ (734 ) $ 1,210 Income from continuing operations 74,990 (734 ) 74,256 Net income attributable to the Company’s stockholders 70,242 (734 ) 69,508 Retained earnings 411,492 (734 ) 410,758 Other segment revenues 606 may Compensation - Stock Compensation In May 2017, 2017 09, 718 718. 1 2 3 718 December 15, 2017. not Business Combinations In January 2017, 2017 01, 805 not December 15, 2017, not Statement of Cash Flow In November 2016, 2016 18, 230 December 15, 2017 three March 31, 2018 Intra-Entity Transfers of Assets Other than Inventory In October 2016, 2016 16, not December 15, 2017 three March 31, 2018 $1.8 $49.8 $51.6 Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments (Topic 230 In August 2016, 2016 15, 230 eight December 15, 2017 $8.0 fourth 2017 Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, 2016 01, December 15, 2017 not New accounting pronouncements effective in future periods Derivatives and Hedging In August 2017, 2017 12, December 15, 2018, Intangibles –Goodwill and Other In January 2017, 2017 04, 350 not 2 2 first first December 15, 2019. January 1, 2017. Leases In February 2016, 2016 02, 842 two 606. December 15, 2018, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income In February 2018, 2018 02, 220 2017. December 15, 2018, not

Note 1 - General and Basis of21

Note 1 - General and Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Income tax provision $ (10,886 ) $ (118 ) $ (11,004 ) Income from continuing operations 39,735 (118 ) 39,617 Net income attributable to the Company’s Stockholders 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge 22 26 48 Comprehensive income 40,302 (92 ) 40,210 Comprehensive income attributable to the Company’s stockholders 35,890 (92 ) 35,798 Earnings per share Basic: $ 0.71 $ - $ 0.71 Diluted: $ 0.70 $ - $ 0.70 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Balances as of December 31, 2016: Retained earnings $ 216,644 $ (1,292 ) $ 215,352 Accumulated other comprehensive loss (7,732 ) (443 ) (8,175 ) Total stockholders’ equity attributable to the Company’s stockholders 1,078,425 (1,735 ) 1,076,690 Total equity 1,170,007 (1,735 ) 1,168,272 Net income for the three months ended March 31, 2017 39,391 (118 ) 39,273 Net income attributable to the Company’s stockholders for the three months ended March 31, 2017 35,312 (118 ) 35,194 Loss in respect of derivative instruments designated for cash flow hedge for the three months ended March 31, 2017 22 26 48 Balances as of March 31, 2017: Retained earnings 243,508 (1,410 ) 242,098 Accumulated other comprehensive loss (7,076 ) (417 ) (7,493 ) Total stockholders’ equity attributable to the Company’s stockholders 1,107,658 (1,827 ) 1,105,831 Total equity 1,196,501 (1,827 ) 1,194,674 Three months ended March 31, 2017 As originally reported Adjustments As revised (Dollars in thousands) Cash flows from operating activities: Net income $ 39,735 $ (118 ) $ 39,617 Liability for unrecognized tax benefits 574 118 692 Net cash provided by operating activities 71,463 - 71,463
Schedule of Cash and Cash Equivalents [Table Text Block]	March 31, December 31, 2018 2017 Cash and cash equivalents $ 54,723 $ 47,818 Restricted cash and cash equivalents 50,332 48,825 Total Cash and cash equivalents and Restricted cash and cash equivalents $ 105,055 $ 96,643

Note 2 - New Accounting Prono22

Note 2 - New Accounting Pronouncements (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
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 March 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 125,832 Electricity and Product revenues accounted under ASC 606 58,191 Total consolidated revenues $ 184,023 2018, under previous standard Effect of the New Revenue Standard 2018, as reported (Dollars in thousands) Equity in earnings of investees, net $ 1,944 $ (734 ) $ 1,210 Income from continuing operations 74,990 (734 ) 74,256 Net income attributable to the Company’s stockholders 70,242 (734 ) 69,508 Retained earnings 411,492 (734 ) 410,758
Contract with Customer, Asset and Liability [Table Text Block]	March 31, 2018 December 31, 2017 (Dollars in thousands) Contract assets (*) $ 41,134 $ 40,945 Contract liabilities (*) (10,458 ) (20,241 ) Contract assets, net $ 30,676 $ 20,704 Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ – $ 8,353 Cash received in advance for which revenues have not yet recognized – (4,451 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (22,144 ) – Contract assets recognized, net of recognized receivables 28,214 – Net change in contract assets and contract liabilities $ 6,070 $ 3,902

Note 3 - Inventories (Tables)

Note 3 - Inventories (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Schedule of Inventory, Current [Table Text Block]	March 31, December 31, 2018 2017 (Dollars in thousands) Raw materials and purchased parts for assembly $ 12,019 $ 12,007 Self-manufactured assembly parts and finished products 8,050 7,544 Total $ 20,069 $ 19,551

Note 4 - Investment in an Unc24

Note 4 - Investment in an Unconsolidated Company (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Equity Method Investments [Table Text Block]	March 31, December 31, 2018 2017 (Dollars in thousands) Sarulla $ 63,109 $ 34,084

Note 5 - Fair Value of Financ25

Note 5 - Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Fair Value, by Balance Sheet Grouping [Table Text Block]	March 31, 2018 Fair Value Carrying Value at March 31, 2018 Total Level 1 Level 2 Level 3 (Dollars in thousands) Assets: Current assets: Cash equivalents (including restricted cash accounts) $ 20,658 $ 20,658 $ 20,658 $ — $ — Derivatives: Contingent receivable (1) 111 111 — — 111 Currency forward contracts (2) 30 30 — 30 — Liabilities: Current liabilities: Derivatives: Contingent payables (1) (14,006 ) (14,006 ) — — (14,006 ) Warrants (1) (4,080 ) (4,080 ) — — (4,080 ) $ 2,713 $ 2,713 $ 20,658 $ 30 $ (17,975 ) 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 Location of recognized Three Months Ended March 31, as hedging instruments gain (loss) 2018 2017 Put options on natural gas price Derivatives and foreign currency transaction gains (losses) $ — $ (193 ) Contingent considerations Derivative and foreign currency transaction gains (losses) — (50 ) Currency forward contracts Derivative and foreign currency and transaction gains (losses) (546 ) 2,262 $ (546 ) $ 2,019
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	Fair Value Carrying Amount March 31, 2018 December 31, 2017 March 31, 2018 December 31, 2017 (Dollars in millions) (Dollars in millions) Olkaria III Loan - OPIC $ 225.2 $ 234.6 $ 224.1 $ 228.6 Olkaria IV Loan - DEG 2 50.6 50.7 50.0 50.0 Amatitlan Loan 31.2 32.8 32.4 33.3 Senior Secured Notes: OrCal Geothermal Inc. ("OrCal") 28.5 34.2 27.3 32.1 OFC 2 LLC ("OFC 2") 223.9 234.6 228.0 232.5 Don A. Campbell 1 ("DAC 1") 81.6 85.5 86.7 88.3 Senior Unsecured Bonds 196.5 200.3 204.3 204.3 Senior Unsecured Loan 100.7 — 100.0 — Other long-term debt 6.6 7.0 7.8 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 $ — $ — $ 225.2 $ 225.2 Olkaria IV - DEG 2 — — 50.6 50.6 Amatitlan Loan — 31.2 — 31.2 Senior Secured Notes: OrCal Senior Secured Notes — — 28.5 28.5 OFC 2 Senior Secured Notes — — 223.9 223.9 DAC 1 Senior Secured Notes — — 81.6 81.6 Senior Unsecured Bonds — — 196.5 196.5 Senior Unsecured Loan — — 100.7 100.7 Other long-term debt — — 6.6 6.6 Revolving lines of credit — 38.5 — 38.5 Deposits 15.2 — — 15.2 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 7 - Interest Expense, Net

Note 7 - Interest Expense, Net (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Schedule of Other Nonoperating Expense, by Component [Table Text Block]	Three Months Ended March 31, 2018 2017 Interest related to sale of tax benefits $ 1,409 $ 2,012 Interest expense 13,306 14,175 Less — amount capitalized (371 ) (1,264 ) $ 14,344 $ 14,923

Note 8 - Earnings Per Share (Ta

Note 8 - Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Schedule of Weighted Average Number of Shares [Table Text Block]	Three Months Ended March 31, 2018 2017 Weighted average number of shares used in computation of basic earnings per share 50,614 49,680 Add: Additional shares from the assumed exercise of employee stock options 437 811 Weighted average number of shares used in computation of diluted earnings per share 51,051 50,491

Note 9 - Business Segments (Tab

Note 9 - Business Segments (Tables)	3 Months Ended
	Mar. 31, 2018
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Electricity Product Other Consolidated (Dollars in thousands) Three Months Ended March 31, 2018: Revenues from external customers: United States (1) 83,683 194 2,862 86,739 Foreign (2) 48,806 48,478 — 97,284 Total net revenues from external customers $ 132,489 $ 48,672 2,862 184,023 Intersegment revenues — 24,827 — 24,827 Operating income 46,412 9,553 (1,372 ) 54,593 Segment assets at period end (3) (*) 2,542,154 114,815 53,848 2,710,817 (*) Including unconsolidated investments 63,109 — — 63,109 Three Months Ended March 31, 2017: Net revenues from external customers (4) $ 115,776 $ 74,122 — 189,898 Intersegment revenues (4) — 16,213 — 16,213 Operating income (4) 40,898 18,598 — 59,496 Segment assets at period end (3) 2,233,237 217,051 49,600 2,499,888
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]	Three Months Ended March 31, 2018 2017 Revenue: Total segment revenue $ 184,023 $ 189,898 Intersegment revenue 24,827 16,213 Elimination of intersegment revenue (24,827 ) (16,213 ) Total consolidated revenue $ 184,023 $ 189,898 Operating income: Operating income $ 54,593 $ 59,496 Interest income 113 244 Interest expense, net (14,344 ) (14,923 ) Derivatives and foreign currency transaction gains (losses) (1,599 ) 1,338 Income attributable to sale of tax benefits 7,361 6,157 Other non-operating income (expense), net (20 ) (92 ) Total consolidated income before income taxes and equity in earnings of investees $ 46,104 $ 52,220

Note 1 - General and Basis of29

Note 1 - General and Basis of Presentation (Details Textual) $ in Thousands	Mar. 22, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Jan. 01, 2017USD ($)	Dec. 31, 2016USD ($)
Income Tax Expense (Benefit), Total		$ (26,942)		$ 11,004
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance		1,384,885	$ 1,295,700	1,194,674	$ 1,295,700				$ 1,168,272
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		5,000		2,000
Interest Expense, Total		14,344		14,923
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		(909)	(4,706)	(7,493)	(4,706)				(8,175)
Exploration Abandonment and Impairment Expense		123		$ 0
Accounts Receivable, Net, Current, Total		103,580	110,410		110,410
Provision for Doubtful Accounts		0
Deferred Tax Liabilities, Gross, Noncurrent		$ 48,074	61,961		$ 61,961
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Primary Customers [Member]
Concentration Risk, Percentage		59.00%			57.00%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Sierra Pacific Power Company And Nevada Power Company [Member]
Concentration Risk, Percentage		17.40%		18.80%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Southern California Public Power Authority [Member]
Concentration Risk, Percentage		16.30%		9.00%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Kenya Power and Lighting Co LTD [Member]
Concentration Risk, Percentage		15.10%		14.30%
UNITED STATES
Cash, Cash Equivalents, and Short-term Investments, Total		$ 20,300	21,200		$ 21,200
Foreign Countries [Member]
Cash, Cash Equivalents, and Short-term Investments, Total		47,300	32,800		32,800
Accounts Receivable, Net, Current, Total		73,300	78,100		$ 78,100
Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total		600
Reclassification out of Accumulated Other Comprehensive Income [Member]
Income Tax Expense (Benefit), Total		(4,000)		$ (1,000)
Interest Expense, Total		$ (9,000)		(3,000)
Migdal Loan [Member]
Debt Instrument, Face Amount	$ 100,000
Debt Instrument, Periodic Payment, Total	4,200
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	$ 37,000
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
Stockholders Equity to Total Assets, Ratio	25.00%
Stockholders Equity, Debt Covenant, Minimum Threshold to Pay Dividends	$ 800,000
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%
Restatement Adjustment [Member]
Income Tax Expense (Benefit), Total			$ 100	118
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance				(1,827)				$ 1,700	(1,735)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total				$ (417)					$ (443)
Deferred Tax Liabilities, Gross, Noncurrent						$ 1,100	$ 6,100

Note 1 - General and Basis of30

Note 1 - General and Basis of Presentation - Effect of Revision on Balance Sheet Line Items (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Jan. 01, 2017	Dec. 31, 2016
Income tax provision	$ 26,942		$ (11,004)
Income from continuing operations	74,256		39,617
Net income attributable to the Company’s Stockholders	69,508		35,194
Loss in respect of derivative instruments designated for cash flow hedge	20		48
Comprehensive income	78,423		40,210
Comprehensive income attributable to the Company’s stockholders	$ 73,305		$ 35,798
Net income (in dollars per share)	$ 1.37		$ 0.71
Diluted: (in dollars per share)	$ 1.36		$ 0.70
Retained earnings	$ 410,758	$ 327,255	$ 242,098		$ 215,352
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total	(909)	(4,706)	(7,493)		(8,175)
Total stockholders’ equity attributable to the Company’s stockholders	1,300,385	1,211,378	1,105,831		1,076,690
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance	1,384,885	1,295,700	1,194,674		1,168,272
Net income for the three months ended March 31, 2017	73,990		39,273
Net income	74,256		39,617
Liability for unrecognized tax benefits	(29,467)		6,612
Net cash provided by operating activities	$ 19,769		71,463
Previously Reported [Member]
Income tax provision			(10,886)
Income from continuing operations			39,735
Net income attributable to the Company’s Stockholders			35,312
Loss in respect of derivative instruments designated for cash flow hedge			22
Comprehensive income			40,302
Comprehensive income attributable to the Company’s stockholders			$ 35,890
Net income (in dollars per share)			$ 0.71
Diluted: (in dollars per share)			$ 0.70
Retained earnings			$ 243,508		216,644
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total			(7,076)		(7,732)
Total stockholders’ equity attributable to the Company’s stockholders			1,107,658		1,078,425
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance			1,196,501		1,170,007
Net income for the three months ended March 31, 2017			39,391
Net income			39,735
Liability for unrecognized tax benefits			574
Net cash provided by operating activities			71,463
Restatement Adjustment [Member]
Income tax provision		$ (100)	(118)
Income from continuing operations			(118)
Net income attributable to the Company’s Stockholders			(118)
Loss in respect of derivative instruments designated for cash flow hedge			26
Comprehensive income			(92)
Comprehensive income attributable to the Company’s stockholders			$ (92)
Net income (in dollars per share)
Diluted: (in dollars per share)
Retained earnings			$ (1,410)		(1,292)
Accumulated Other Comprehensive Income (Loss), Net of Tax, Total			(417)		(443)
Total stockholders’ equity attributable to the Company’s stockholders			(1,827)		(1,735)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance			(1,827)	$ 1,700	$ (1,735)
Net income for the three months ended March 31, 2017			(118)
Net income			(118)
Liability for unrecognized tax benefits			118
Net cash provided by operating activities

Note 1 - General and Basis of31

Note 1 - General and Basis of Presentation - Cash and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 54,723	$ 47,818
Restricted cash and cash equivalents	50,332	48,825
Total Cash and cash equivalents and Restricted cash and cash equivalents	$ 105,055	$ 96,643	$ 234,017	$ 264,476

Note 2 - New Accounting Prono32

Note 2 - New Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017
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		$ 211,000

Note 2 - New Accounting Prono33

Note 2 - New Accounting Pronouncements - Remaining Performance Obligation Percentage (Details Textual)	Mar. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Revenue, Remaining Performance Obligation, Percentage	91.00%

Note 2 - New Accounting Prono34

Note 2 - New Accounting Pronouncements - Impact of Adoption (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017		Dec. 31, 2017	Dec. 31, 2016
Investment in an unconsolidated company		$ 63,109			$ 34,084
Total consolidated revenues		184,023	$ 189,898	[1]
Equity in earnings of investees, net		1,210	(1,599)
Income from continuing operations		74,256	39,617
Net income attributable to the Company’s stockholders		69,508	35,194
Retained earnings		410,758	242,098		$ 327,255	$ 215,352
Electricity [Member]
Total consolidated revenues		132,489	115,776
Product [Member]
Revenues		48,672	74,122
Other Revenue [Member]
Revenues		2,862
Accounting Standards Update 2014-09 [Member]
Investment in an unconsolidated company	$ 24,000
Accounting Standards Update 2014-09 [Member] | Electricity [Member]
Revenues
Electricity Revenues accounted under ASC 840, Leases		125,832
Accounting Standards Update 2014-09 [Member] | Product [Member]
Revenues
Accounting Standards Update 2014-09 [Member] | Electricity and Product Revenue [Member]
Revenues		58,191
Accounting Standards Update 2014-09 [Member] | Other Revenue [Member]
Revenues
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity in earnings of investees, net		1,944
Income from continuing operations		74,990
Net income attributable to the Company’s stockholders		70,242
Retained earnings		411,492
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Equity in earnings of investees, net		(734)
Income from continuing operations		(734)
Net income attributable to the Company’s stockholders		(734)
Retained earnings		$ (734)
[1]	The amounts related to the Other segment are immaterial.

Note 2 - New Accounting Prono35

Note 2 - New Accounting Pronouncements - Contract Assets (Liabilities) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Contract assets (*)	[1]	$ 41,134	$ 40,945
Contract liabilities (*)	[1]	(10,458)	(20,241)
Contract assets, net		30,676	$ 20,704
Recognition of contract liabilities as revenue as a result of performance obligations satisfied, liabilities		8,353
Cash received in advance for which revenues have not yet recognized, liabilities		(4,451)
Reduction of contract assets as a result of rights to consideration becoming unconditional, assets		(22,144)
Contract assets recognized, net of recognized receivables, assets		28,214
Net change in contract assets and contract liabilities, assets		6,070
Net change in contract assets and contract liabilities, liabilities		$ 3,902
[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 - Inventor

Note 3 - Inventories - Inventories, Current (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Raw materials and purchased parts for assembly	$ 12,019	$ 12,007
Self-manufactured assembly parts and finished products	8,050	7,544
Total	$ 20,069	$ 19,551

Note 4 - Investment in an Unc37

Note 4 - Investment in an Unconsolidated Company (Details Textual) $ in Thousands	Jan. 01, 2018USD ($)	Jun. 04, 2014USD ($)	Mar. 31, 2018USD ($)MWh	Mar. 31, 2017USD ($)	May 16, 2014USD ($)
Number of Commercial Lenders in Funding Consortium					6
Interest Expense, Total			$ 14,344	$ 14,923
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			$ 2,634	569
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%
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			$ 1,300
Accumulated Cash Contributions to Acquire Projects			$ 59,500
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			$ 2,600	600
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance			2,500
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			20,700	$ 4,500
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			$ 16,900
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 Unc38

Note 4 - Investment in an Unconsolidated Company - Unconsolidated Investments Mainly in Power Plants (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Sarulla	$ (6,943)	$ (6,416)
Sarulla [Member]
Sarulla	$ 63,109	$ 34,084

Note 5 - Fair Value of Financ39

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, 2017USD ($)BTU$ / 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 Financ40

Note 5 - Fair Value of Financial Instruments - Financial Assets and Liabilities at Fair Value (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Reported Value Measurement [Member]
Cash equivalents (including restricted cash accounts)		$ 20,658	$ 18,359
		2,713	1,588
Reported Value Measurement [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	111	108
Reported Value Measurement [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]	30	992
Reported Value Measurement [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	(14,006)	(13,904)
Reported Value Measurement [Member] | Warrant [Member]
Derivative Liability, Current	[1]	(4,080)	(3,967)
Estimate of Fair Value Measurement [Member]
Cash equivalents (including restricted cash accounts)		20,658	18,359
		2,713	1,588
Estimate of Fair Value Measurement [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	111	108
Estimate of Fair Value Measurement [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]	30	992
Estimate of Fair Value Measurement [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	(14,006)	(13,904)
Estimate of Fair Value Measurement [Member] | Warrant [Member]
Derivative Liability, Current	[1]	(4,080)	(3,967)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents (including restricted cash accounts)		20,658	18,359
		20,658	18,359
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Warrant [Member]
Derivative Liability, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash equivalents (including restricted cash accounts)
		30	992
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]	30	992
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Warrant [Member]
Derivative Liability, Current	[1]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash equivalents (including restricted cash accounts)
		(17,975)	(17,763)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	111	108
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	(14,006)	(13,904)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Warrant [Member]
Derivative Liability, Current	[1]	$ (4,080)	$ (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 the and 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 March 31, 2018 and within "Prepaid expenses and other" and "Other long-term liabilities" on 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.
[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 March 31, 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 Financ41

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
	Mar. 31, 2018	Mar. 31, 2017
Amount of gain (loss) recognized	$ (546)	$ 2,019
Foreign Currency Gain (Loss) [Member] | Put Options on Natural Gas Price [Member]
Amount of gain (loss) recognized		(193)
Foreign Currency Gain (Loss) [Member] | Contingent Considerations [Member]
Amount of gain (loss) recognized		(50)
Foreign Currency Gain (Loss) [Member] | Currency Forward Contracts [Member]
Amount of gain (loss) recognized	$ (546)	$ 2,262

Note 5 - Fair Value of Financ42

Note 5 - Fair Value of Financial Instruments - Fair Value of Long-term Debt Approximates Its Carrying Amount, Exceptions (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Estimate of Fair Value Measurement [Member]
Other long-term debt	$ 6.6	$ 7
Reported Value Measurement [Member]
Other long-term debt	7.8	7.9
Olkaria III OPIC [Member]
Loans	225.2	234.6
Olkaria III OPIC [Member] | Estimate of Fair Value Measurement [Member]
Loans	225.2	234.6
Olkaria III OPIC [Member] | Reported Value Measurement [Member]
Loans	224.1	228.6
Olkaria IV Loan - DEG 2 [Member]
Loans	50.6
Olkaria IV Loan - DEG 2 [Member] | Estimate of Fair Value Measurement [Member]
Loans	50.6	50.7
Olkaria IV Loan - DEG 2 [Member] | Reported Value Measurement [Member]
Loans	50	50
Amatitlan Loan [Member]
Loans	31.2	32.8
Amatitlan Loan [Member] | Estimate of Fair Value Measurement [Member]
Loans	31.2	32.8
Amatitlan Loan [Member] | Reported Value Measurement [Member]
Loans	32.4	33.3
OrCal Geothermal Inc [Member]
Notes	28.5	34.2
OrCal Geothermal Inc [Member] | Estimate of Fair Value Measurement [Member]
Notes	28.5	34.2
OrCal Geothermal Inc [Member] | Reported Value Measurement [Member]
Notes	27.3	32.1
OFC Two Senior Secured Notes [Member]
Notes	223.9	234.6
OFC Two Senior Secured Notes [Member] | Estimate of Fair Value Measurement [Member]
Notes	223.9	234.6
OFC Two Senior Secured Notes [Member] | Reported Value Measurement [Member]
Notes	228	232.5
Don A. Campbell 1 ("DAC1") [Member]
Notes	81.6	85.5
Don A. Campbell 1 ("DAC1") [Member] | Estimate of Fair Value Measurement [Member]
Notes	81.6	85.5
Don A. Campbell 1 ("DAC1") [Member] | Reported Value Measurement [Member]
Notes	86.7	88.3
Senior Unsecured Bonds [Member]
Senior secured debt	196.5	200.3
Senior Unsecured Bonds [Member] | Estimate of Fair Value Measurement [Member]
Senior secured debt	196.5	200.3
Senior Unsecured Bonds [Member] | Reported Value Measurement [Member]
Senior secured debt	204.3	204.3
Senior Unsecured Loan [Member]
Senior secured debt	100.7
Senior Unsecured Loan [Member] | Estimate of Fair Value Measurement [Member]
Senior secured debt	100.7
Senior Unsecured Loan [Member] | Reported Value Measurement [Member]
Senior secured debt	$ 100

Note 5 - Fair Value of Financ43

Note 5 - Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Revolving lines of credit	$ 38.5	$ 51.5
Deposits	15.2	15.6
Fair Value, Inputs, Level 1 [Member]
Revolving lines of credit
Deposits	15.2	15.6
Fair Value, Inputs, Level 2 [Member]
Revolving lines of credit	38.5	51.5
Deposits
Fair Value, Inputs, Level 3 [Member]
Revolving lines of credit
Deposits
Olkaria III OPIC [Member]
Loans	225.2	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	225.2	234.6
Olkaria IV Loan - DEG 2 [Member]
Loans	50.6
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	50.6	50.7
Amatitlan Loan [Member]
Loans	31.2	32.8
Amatitlan Loan [Member] | Fair Value, Inputs, Level 1 [Member]
Loans
Amatitlan Loan [Member] | Fair Value, Inputs, Level 2 [Member]
Loans	31.2	32.8
Amatitlan Loan [Member] | Fair Value, Inputs, Level 3 [Member]
Loans
OrCal Geothermal Inc [Member]
Notes	28.5	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	28.5	34.2
OFC Two Senior Secured Notes [Member]
Notes	223.9	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	223.9	234.6
Don A. Campbell 1 ("DAC1") [Member]
Notes	81.6	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	81.6	85.5
Senior Unsecured Bonds [Member]
Senior secured debt	196.5	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	196.5	200.3
Senior Unsecured Loan [Member]
Senior secured debt	100.7
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	100.7
Other Long-term Debt [Member]
Senior secured debt		7
Other long-term debt	6.6
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
Other long-term debt	$ 6.6

Note 6 - Stock-based Compensa44

Note 6 - Stock-based Compensation (Details Textual) - shares	1 Months Ended	12 Months Ended
	May 31, 2012	Dec. 31, 2004	Mar. 31, 2018
2004 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized		3,750,000
2004 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
2004 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
2004 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
2004 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
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
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] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 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 One [Member] | Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
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 Two [Member] | Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
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 Three [Member] | Senior Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	25.00%
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

Note 7 - Interest Expense, Ne45

Note 7 - Interest Expense, Net - Components of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest related to sale of tax benefits	$ 1,409	$ 2,012
Interest expense	13,306	14,175
Less — amount capitalized	(371)	(1,264)
Interest Expense, Total	$ 14,344	$ 14,923

Note 8 - Earnings Per Share (De

Note 8 - Earnings Per Share (Details Textual) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	62,409	11,491

Note 8 - Earnings Per Share - S

Note 8 - Earnings Per Share - Shares Used to Calculate Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Weighted average number of shares used in computation of basic earnings per share (in shares)	50,614	49,680
Additional shares from the assumed exercise of employee stock options (in shares)	437	811
Weighted average number of shares used in computation of diluted earnings per share (in shares)	51,051	50,491

Note 9 - Business Segments (Det

Note 9 - Business Segments (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Number of Reportable Segments	3
Goodwill, Ending Balance	$ 21,253	$ 21,037
Electricity Segment [Member]
Goodwill, Ending Balance	7,800	6,200
Other Segments [Member]
Goodwill, Ending Balance	13,500	$ 13,500
Accounting Standards Update 2014-09 [Member] | Electricity Revenues [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 6,700

Note 9 - Business Segments - Su

Note 9 - Business Segments - Summarized Financial Information Concerning Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017		Dec. 31, 2017
Total consolidated revenues		$ 184,023		$ 189,898	[1]
Operating income		54,593		59,496	[1]
Segment assets at period end		2,710,817	[2]	2,499,888	[2]	$ 2,623,864
Including unconsolidated investments		63,109
Operating income		54,593		59,496	[1]
Intersegment Eliminations [Member]
Total consolidated revenues		24,827		16,213	[1]
Electricity Segment [Member]
Total consolidated revenues		132,489		115,776	[1]
Operating income		46,412		40,898	[1]
Segment assets at period end	[2]	2,542,154		2,233,237
Including unconsolidated investments		63,109
Operating income		46,412		40,898	[1]
Electricity Segment [Member] | Intersegment Eliminations [Member]
Total consolidated revenues					[1]
Product Segment [Member]
Total consolidated revenues		48,672		74,122	[1]
Operating income		9,553		18,598	[1]
Segment assets at period end	[2]	114,815		217,051
Including unconsolidated investments
Operating income		9,553		18,598	[1]
Product Segment [Member] | Intersegment Eliminations [Member]
Total consolidated revenues		24,827		16,213	[1]
Other Segments [Member]
Total consolidated revenues		2,862			[1]
Operating income		(1,372)			[1]
Segment assets at period end	[2]	53,848		49,600
Including unconsolidated investments
Operating income		(1,372)			[1]
Other Segments [Member] | Intersegment Eliminations [Member]
Total consolidated revenues					[1]
UNITED STATES
Total consolidated revenues	[3]	86,739
UNITED STATES | Electricity Segment [Member]
Total consolidated revenues	[3]	83,683
UNITED STATES | Product Segment [Member]
Total consolidated revenues	[3]	194
UNITED STATES | Other Segments [Member]
Total consolidated revenues	[3]	2,862
Foreign Countries [Member]
Total consolidated revenues	[4]	97,284
Foreign Countries [Member] | Electricity Segment [Member]
Total consolidated revenues	[4]	48,806
Foreign Countries [Member] | Product Segment [Member]
Total consolidated revenues	[4]	48,478
Foreign Countries [Member] | Other Segments [Member]
Total consolidated revenues	[4]
[1]	The amounts related to the Other segment are immaterial.
[2]	Electricity segment assets include goodwill in the amount of $7.8 million and $6.2 million as of March, 31, 2018 and 2017, respectively. Other segment assets include goodwill in the amount of $13.5 million as of March 31, 2018 and 2017.
[3]	Electricity revenues in the United States are all accounted under ASC 840, Leases, except for $6.7 million that are accounted under ASC 606 starting 2018. Product and Other revenues in the United States are accounted under ASC 606, as further described under Note 2 to the consolidated financial statements.
[4]	Electricity 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.

Note 9 - Business Segments - Re

Note 9 - Business Segments - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Total consolidated revenues	$ 184,023	$ 189,898	[1]
Operating income	54,593	59,496	[1]
Interest income	113	244
Interest expense, net	(14,344)	(14,923)
Derivatives and foreign currency transaction gains (losses)	(1,599)	1,338
Income attributable to sale of tax benefits	7,361	6,157
Other non-operating income (expense), net	(20)	(92)
Total consolidated income before income taxes and equity in earnings of investees	46,104	52,220
Intersegment Eliminations [Member]
Total consolidated revenues	24,827	16,213	[1]
Consolidation, Eliminations [Member]
Total consolidated revenues	$ (24,827)	$ (16,213)
[1]	The amounts related to the Other segment are immaterial.

Note 10 - Commitments and Con51

Note 10 - Commitments and Contingencies (Details Textual) ₪ in Millions, $ in Millions	May 21, 2018USD ($)	May 21, 2018ILS (₪)	Mar. 29, 2016USD ($)
Former Local Sales Representative vs. Ormat [Member] | Pending Litigation [Member]
Loss Contingency, Damages Sought, Value			$ 4.8
Loss Contingency, Additional Damages Sought for Ormat Geothermal Products Sales in Chile, Percent			3.75%
Loss Contingency, Damages Sought, Ormat Geothermal Products Sales in Chile, Period			10 years
Heit vs Ormat Technologies, Inc. et al (C.A. 44366-05-18) [Member] | Subsequent Event [Member]
Loss Contingency, Damages Sought, Value	$ 26	₪ 93

Note 11 - Income Taxes (Details

Note 11 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Percent, Total	(58.40%)	21.10%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%			35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	$ 44.4
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%
Foreign Tax Authority [Member] | Israel Tax Authority [Member]
National Corporate Tax Rate	16.00%

Note 12 - Subsequent Events (De

Note 12 - Subsequent Events (Details Textual) $ / shares in Units, $ in Thousands	May 07, 2018USD ($)$ / shares	Apr. 30, 2018USD ($)MWh	Apr. 24, 2018USD ($)MWh	Mar. 31, 2018USD ($)$ / shares	Mar. 31, 2017USD ($)$ / shares	May 17, 2018USD ($)	May 03, 2018USD ($)	Dec. 31, 2017USD ($)
Dividends, Common Stock, Total				$ 11,640	$ 8,448
Common Stock, Dividends, Per Share, Declared | $ / shares				$ 0.23	$ 0.17
Property, Plant and Equipment, Net, Ending Balance				$ 1,723,560				$ 1,734,691
Subsequent Event [Member]
Dividends, Common Stock, Total	$ 5,100
Common Stock, Dividends, Per Share, Declared | $ / shares	$ 0.10
Dividends Payable, Date of Record	May 21, 2018
Dividends Payable, Date to be Paid	May 30, 2018
Subsequent Event [Member] | U.S. Geothermal [Member]
Current Power Generation | MWh			38
Payments to Acquire Businesses, Gross			$ 110,000
Subsequent Event [Member] | U.S. Geothermal [Member] | Ormat Nevada Inc. [Member]
Payments to Acquire Businesses, Gross			106,000
Subsequent Event [Member] | U.S. Geothermal [Member] | Ormat Technologies, Inc. [Member]
Payments to Acquire Businesses, Gross			$ 4,000
Subsequent Event [Member] | Puna Geothermal Power Plant [Member]
Property, Plant and Equipment, Net, Ending Balance							$ 109,000
Subsequent Event [Member] | Platanares [Member]
Non-recourse Financing Agreement		$ 124,700
Current Power Generation | MWh		35
Non-recourse Finacing Agreement, Term		14 years
Subsequent Event [Member] | Platanares [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage		6.75%
Subsequent Event [Member] | Platanares [Member] | Maximum [Member]
Debt Instrument, Interest Rate, Stated Percentage		7.25%
Subsequent Event [Member] | Tungsten Mountain [Member]
Parternship Agreement, Initial Purchase Price						$ 33,400
Partnership Agreement, Expected Additional Installments						$ 13,000