Ormat (ORA) 10-K 1 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 26, 2019	Jun. 30, 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 Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding (in shares)		50,702,174
Entity Public Float			$ 2,108,534,590
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Shell Company	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents		$ 98,802	$ 47,818
Restricted cash and cash equivalents		78,693	48,825
Receivables:
Trade		137,581	110,410
Other		19,393	13,828
Inventories		45,024	19,551
Contract assets (*)	[1]	42,130	40,945
Prepaid expenses and other		51,441	40,269
Total current assets		473,064	321,646
Investment in an unconsolidated company		71,983	34,084
Deposits and other		18,209	21,599
Deferred income taxes		113,760	57,337
Deferred charges			49,834
Property, plant and equipment, net		1,959,578	1,734,691
Construction-in-process		261,690	293,542
Deferred financing and lease costs, net		3,242	4,674
Intangible assets, net		199,874	85,420
Goodwill		19,950	21,037
Total assets	[2]	3,121,350	2,623,864
Current liabilities:
Accounts payable and accrued expenses		116,362	153,796
Short term revolving credit lines with banks (full recourse)		159,000	51,500
Billings in excess of costs and estimated earnings on uncompleted contracts		18,402	20,241
Current portion of long-term debt:
Senior secured notes		33,493	33,226
Other loans		29,687	21,495
Full recourse		5,000	3,087
Total current liabilities		361,944	283,345
Long-term debt, net of current portion:
Senior secured notes (less deferred financing costs of $7,434 and $8,113, respectively)		375,337	311,668
Other loans (less deferred financing costs of $9,354 and $5,258, respectively)		320,242	242,385
Senior unsecured bonds (less deferred financing costs of $758 and $580, respectively)		303,575	203,752
Other loans (less deferred financing costs of $921 and $1,011, respectively)		41,579	46,489
Liability associated with sale of tax benefits		69,893	44,634
Deferred lease income		48,433	51,520
Deferred income taxes		61,323	61,961
Liability for unrecognized tax benefits		11,769	8,890
Liabilities for severance pay		17,994	21,141
Asset retirement obligation		39,475	27,110
Other long-term liabilities		16,087	18,853
Total liabilities		1,667,651	1,321,748
Commitments and contingencies (Note 22)
Redeemable noncontrolling interest		8,603	6,416
Equity:
Common stock, par value $0.001 per share; 200,000,000 shares authorized; 50,699,781 and 50,609,051 shares issued and outstanding as of December 31, 2018 and December 31, 2017, respectively		51	51
Additional paid-in capital		901,363	888,778
Retained earnings		422,222	327,255
Accumulated other comprehensive loss		(3,799)	(4,706)
Total stockholders' equity attributable to Company's stockholders		1,319,837	1,211,378
Noncontrolling interest		125,259	84,322
Total equity		1,445,096	1,295,700
Total liabilities, redeemable noncontrolling interest and equity		$ 3,121,350	$ 2,623,864
[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.
[2]	Electricity segment assets include goodwill in the amount of $20.0 million and $7.6 million as of December 31, 2018 and 2017, respectively. Other segment assets include goodwill in the amount of $0 million and $13.5 million as of December 31, 2018 and 2017, respectively. For further information on goodwill, see Note 9 – Intangible assets and goodwill to the consolidated financial statements.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment, net	$ 1,959,578	$ 1,734,691
Construction-in-process	$ 261,690	$ 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)	50,699,781	50,609,051
Common stock, shares outstanding (in shares)	50,699,781	50,609,051
Senior Secured Notes [Member]
Deferred financing costs	$ 7,434	$ 8,113
Other Loans, Limited and Non-recourse [Member]
Deferred financing costs	9,354	5,258
Senior Unsecured Bonds [Member]
Deferred financing costs	758	580
Other Loans, Full Recourse [Member]
Deferred financing costs	921	1,011
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net	1,859,228	1,631,900
Construction-in-process	$ 104,085	$ 142,717

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Revenue		$ 719,267	$ 692,812	$ 662,591
Revenues	[1]	719,267	692,812	662,591
Cost of revenues:
Cost of revenues		448,832	424,360	391,796
Gross profit		270,435	268,452	270,795
Operating expenses:
Research and development expenses		4,183	3,157	2,762
Selling and marketing expenses		19,802	15,600	16,424
General and administrative expenses		47,750	42,881	46,710
Impairment charge		13,464
Write-off of unsuccessful exploration activities		126	1,796	3,017
Operating income		185,110	205,018	201,882
Other income (expense):
Interest income		974	988	971
Interest expense, net		(70,924)	(54,142)	(67,389)
Derivatives and foreign currency transaction gains (losses)		(4,761)	2,654	(5,534)
Income attributable to sale of tax benefits		19,003	17,878	16,503
Other non-operating income (expense), net		7,779	(1,666)	(5,345)
Income from continuing operations before income taxes and equity in earnings (losses) of investees		137,181	170,730	141,088
Income tax (provision) benefit		(34,733)	(21,664)	(37,059)
Equity in earnings (losses) of investees, net		7,663	(1,957)	(7,735)
Income from continuing operations		110,111	147,109	96,294
Net income attributable to noncontrolling interest		(12,145)	(14,695)	(7,586)
Net income attributable to the Company's stockholders		97,966	132,414	88,708
Comprehensive income:
Net income		110,111	147,109	96,294
Other comprehensive income (loss), net of related taxes:
Currency translation adjustments		(1,831)	3,440	(1,648)
Change in unrealized gains or losses in respect of the Company's share in derivatives instruments of unconsolidated investment		2,235	804	1,185
Loss in respect of derivative instruments designated for cash flow hedge		81	135	141
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge		(57)	(73)	(96)
Comprehensive income		110,539	151,415	95,876
Comprehensive income attributable to noncontrolling interest		(11,666)	(15,532)	(7,179)
Comprehensive income attributable to the Company's stockholders		$ 98,873	$ 135,883	$ 88,697
Basic:
Net income (in dollars per share)		$ 1.93	$ 2.64	$ 1.79
Diluted:
Net income (in dollars per share)		$ 1.92	$ 2.61	$ 1.77
Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders:
Basic (in shares)		50,643	50,110	49,469
Diluted (in shares)		50,969	50,769	50,140
Electricity [Member]
Revenues:
Revenue		$ 509,879	$ 465,593	$ 436,292
Cost of revenues:
Cost of revenues		298,255	266,840	261,573
Product [Member]
Revenues:
Revenue		201,743	224,483	226,299
Cost of revenues:
Cost of revenues		140,697	152,094	130,223
Other Revenue [Member]
Revenues:
Revenue		7,645	2,736
Cost of revenues:
Cost of revenues		$ 9,880	$ 5,426
[1]	Revenues as reported in the geographic area in which they originate.

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Guadeloupe 1 [Member]Common Stock [Member]	Guadeloupe 1 [Member]Additional Paid-in Capital [Member]	Guadeloupe 1 [Member]Retained Earnings [Member]	Guadeloupe 1 [Member]AOCI Attributable to Parent [Member]	Guadeloupe 1 [Member]Parent [Member]	Guadeloupe 1 [Member]Noncontrolling Interest [Member]	Guadeloupe 1 [Member]	Tungsten [Member]Common Stock [Member]	Tungsten [Member]Additional Paid-in Capital [Member]	Tungsten [Member]Retained Earnings [Member]	Tungsten [Member]AOCI Attributable to Parent [Member]	Tungsten [Member]Parent [Member]	Tungsten [Member]Noncontrolling Interest [Member]	Tungsten [Member]	Ormat Nevada ORTP LLC [Member]Common Stock [Member]	Ormat Nevada ORTP LLC [Member]Additional Paid-in Capital [Member]	Ormat Nevada ORTP LLC [Member]Retained Earnings [Member]	Ormat Nevada ORTP LLC [Member]AOCI Attributable to Parent [Member]	Ormat Nevada ORTP LLC [Member]Parent [Member]	Ormat Nevada ORTP LLC [Member]Noncontrolling Interest [Member]	Ormat Nevada ORTP LLC [Member]	OPC LLC [Member]Common Stock [Member]	OPC LLC [Member]Additional Paid-in Capital [Member]	OPC LLC [Member]Retained Earnings [Member]	OPC LLC [Member]AOCI Attributable to Parent [Member]	OPC LLC [Member]Parent [Member]	OPC LLC [Member]Noncontrolling Interest [Member]	OPC LLC [Member]	U.S. Geothermal [Member]Common Stock [Member]	U.S. Geothermal [Member]Additional Paid-in Capital [Member]	U.S. Geothermal [Member]Retained Earnings [Member]	U.S. Geothermal [Member]AOCI Attributable to Parent [Member]	U.S. Geothermal [Member]Parent [Member]	U.S. Geothermal [Member]Noncontrolling Interest [Member]	U.S. Geothermal [Member]	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, 2015																																				49,107
Balance at Dec. 31, 2015																																				$ 49	$ 849,223	$ 152,326	$ (8,164)	$ 993,434	$ 93,873	$ 1,087,307
Stock-based compensation																																					5,157			5,157		5,157
Exercise of options by employees and directors (in shares)																																				560
Exercise of options by employees and directors																																				$ 1	7,249			7,250		7,250
Cash paid to non controlling interest																																									(57,391)	(57,391)
Cash dividend declared																																						(25,682)		(25,682)		(25,682)
Increase in noncontrolling interest						$ 8,240	$ 8,240																																		3,697	3,697
Issuance of shares to noncontrolling interest, net of transaction costs																																					7,834			7,834	36,268	44,102
Net income																																						88,708		88,708	7,302	96,010
Currency translation adjustment																																							(1,241)	(1,241)	(407)	(1,648)
Loss in respect of derivative instruments designated for cash flow hedge																																							141	141		141
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment																																							1,185	1,185		1,185
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																																							(96)	(96)		(96)
Currency translation adjustments																																							(1,241)	(1,241)	(407)	(1,648)
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																																					8,760			8,760		8,760
Exercise of options by employees and directors (in shares)																																				942
Exercise of options by employees and directors																																				$ 1	16,111			16,112		16,112
Cash paid to non controlling interest																																									(21,313)	(21,313)
Cash dividend declared																																						(20,511)		(20,511)		(20,511)
Net income																																						132,414		132,414	13,643	146,057
Currency translation adjustment																																							2,603	2,603	837	3,440
Loss in respect of derivative instruments designated for cash flow hedge																																							135	135		135
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment																																							804	804		804
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																																							(73)	(73)		(73)
Buyout of Class B membership																$ 2,913			$ 2,913	$ (6,964)	$ (4,051)		$ (8,469)			$ (8,469)	$ 6,537	$ (1,932)
Currency translation adjustments																																							2,603	2,603	837	3,440
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																																					10,218			10,218		10,218
Exercise of options by employees and directors (in shares)																																				91
Exercise of options by employees and directors
Cash paid to non controlling interest																																									(10,972)	(10,972)
Cash dividend declared																																						(26,834)		(26,834)		(26,834)
Increase in noncontrolling interest						$ 5,339	$ 5,339						$ 996	$ 996
Net income																																						97,966		97,966	11,155	109,121
Currency translation adjustment																																							(1,352)	(1,352)	(479)	(1,831)
Loss in respect of derivative instruments designated for cash flow hedge																																							81	81		81
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment																																							2,235	2,235		2,235
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge																																							(57)	(57)		(57)
Buyout of Class B membership																$ 2,900				$ (7,000)			(8,500)				6,500
Cumulative effect of changes in accounting principles at Dec. 31, 2017																																						23,835		23,835		23,835
Adjusted balance as of the beginning of the year at Dec. 31, 2017																																				51	888,778	351,090	(4,706)	1,235,213	84,322	1,319,535
Tax effect of partnership interest buyout																							$ 2,367			$ 2,367		$ 2,367
Purchase of USG																																		$ 34,898	$ 34,898
Currency translation adjustments																																							(1,352)	(1,352)	(479)	(1,831)
Balance (in shares) at Dec. 31, 2018																																				50,700
Balance at Dec. 31, 2018																																				$ 51	$ 901,363	$ 422,222	$ (3,799)	$ 1,319,837	$ 125,259	$ 1,445,096

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retained Earnings [Member]
Cash dividend declared, per share (in dollars per share)	$ 0.53	$ 0.41	$ 0.52
Amortization of unrealized gains, tax		$ 46	$ 57
AOCI Attributable to Parent [Member]
Amortization of unrealized gains, tax	$ 18
Loss in respect of derivative instruments designated for cash flow hedge, related tax	24
Change in unrealized gains or losses in respect of the Company's share in derivative instruments of unconsolidated investment, tax.	$ 0
Cash dividend declared, per share (in dollars per share)	$ 0.53	$ 0.41	$ 0.52

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Cash flows from operating activities:
Net income	$ 110,111	$ 147,109	$ 96,294
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	132,233	115,146	105,977
Amortization of premium from senior unsecured bonds			(513)
Accretion of asset retirement obligation	2,474	1,874	1,778
Stock-based compensation	10,218	8,760	5,157
Amortization of deferred lease income	(2,685)	(2,685)	(2,685)
Income attributable to sale of tax benefits, net of interest expense	(8,609)	(11,956)	(6,962)
Equity in losses (earnings) of investees	(7,663)	1,957	7,735
Mark-to-market of derivative instruments	2,032	(1,473)	319
Write-off of unsuccessful exploration activities	126	1,796	3,017
Impairment charge	13,464
Loss (gain) on severance pay fund asset	1,186	(1,746)	(304)
Deferred income tax provision and deferred charges	19,360	(41,147)	23,222
Liability for unrecognized tax benefits	2,879	3,270	(4,174)
Deferred lease revenues	(402)	(356)	(853)
Gain from insurance recoveries	(4,463)
Other	100	737
Changes in operating assets and liabilities, net of businesses acquired:
Receivables	(29,928)	(24,040)	(33,280)
Costs and estimated earnings in excess of billings on uncompleted contracts	(1,185)	11,253	(27,078)
Inventories	(9,318)	(1,070)	6,297
Prepaid expenses and other	(11,172)	208	(12,540)
Deposits and other	18	(2,570)	(1,009)
Accounts payable and accrued expenses	(56,724)	51,641	(1,375)
Billings in excess of costs and estimated earnings on uncompleted contracts	(1,839)	(11,389)	(2,262)
Liabilities for severance pay	(3,147)	2,541	(786)
Other long-term liabilities	(11,244)	(2,285)	3,310
Net cash provided by operating activities	145,822	245,575	159,285
Cash flows from investing activities:
Capital expenditures	(258,521)	(259,234)	(151,930)
Cash received from insurance recoveries related to destroyed equipment	10,427
Investment in unconsolidated companies	(3,800)	(46,318)	(3,569)
Cash paid for acquisition of controlling interest in a subsidiary, net of cash acquired	(95,093)	(35,300)	(20,135)
Intangible assets acquired		(868)
Decrease (increase) in severance pay fund asset, net of payments made to retired employees	2,186	526	1,862
Net cash used in investing activities	(342,434)	(345,526)	(173,772)
Cash flows from financing activities:
Proceeds from sale of membership interests to noncontrolling interest, net of transaction costs	3,174		44,102
Proceeds from long-term loans, net of transaction costs	214,700		142,500
Proceeds from exercise of options by employees		16,111	7,249
Proceeds from issuance of senior unsecured notes, net of transaction costs			203,483
Purchase of Senior unsecured notes			(249,468)
Proceeds from the sale of limited liability company interest in Tungsten, net of transaction costs	4,134	2,017	1,972
Purchase of OFC Senior Secured Notes		(14,270)	(6,815)
Proceeds from revolving credit lines with banks	4,097,000	1,097,500	309,400
Repayment of revolving credit lines with banks	(3,989,500)	(1,046,000)	(309,400)
Cash paid for achievement of production threshold in GB		(8,032)
Repayments of long-term debt	(62,774)	(66,223)	(62,052)
Cash paid to noncontrolling interest	(13,106)	(21,313)	(64,065)
Payments of capital leases	(2,551)	(1,871)	(1,178)
Deferred debt issuance costs	(5,287)	(5,290)	(6,402)
Cash dividends paid	(26,834)	(20,511)	(25,682)
Net cash provided by (used in) financing activities	251,131	(67,882)	43,541
Effect of exchange rate changes	(660)
Net change in cash and cash equivalents and restricted cash and cash equivalents	53,859	(167,833)	29,054
Restricted cash and cash equivalents acquired in a business combination	26,993
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	96,643	264,476	235,422
Cash and cash equivalents and restricted cash and cash equivalents at end of period	177,495	96,643	264,476
Supplemental disclosure of cash flow information:
Interest, net of interest capitalized	53,864	40,484	55,366
Income taxes, net	18,028	21,878	18,490
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	(6,878)	4,484	(2,219)
Accrued liabilities related to financing activities	8,584		6,291
Increase (decrease) in asset retirement cost and asset retirement obligation	881	1,888	714
Tungsten [Member]
Cash flows from financing activities:
Proceeds from the sale of limited liability company interest in Tungsten, net of transaction costs	32,175		59,897
Ormat Nevada ORTP LLC [Member]
Cash flows from investing activities:
Buyout of Class B membership in ORTP		(2,400)
OPC LLC [Member]
Cash flows from investing activities:
Buyout of Class B membership in OPC	$ 2,367	$ (1,932)

Note 1 - Business and Significa

Note 1 - Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	NOTE 1 Business The Company is primarily engaged in the geothermal and recovered energy business, including the supply of equipment that is manufactured by the Company and the design and construction of power plants for projects owned by the Company or for third Most of the Company’s domestic power plant facilities are Qualifying Facilities under the PURPA. The PPAs for certain of such facilities are dependent upon their maintaining Qualifying Facility status. Management believes that all of the facilities located in the U.S. were in compliance with Qualifying Facility status requirements as of December 31, 2018. Cash dividends During the years ended December 31, 2018, 2017, 2016, $26.8 $0.53 $20.5 $0.41 $25.7 $0.52 Rounding Dollar amounts, except per share data, in the notes to these financial statements are rounded to the closest $1,000, Basis of presentation The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of the Company and of all majority-owned subsidiaries in which the Company exercises control over operating and financial policies, and variable interest entities in which the Company has an interest and is the primary beneficiary. Intercompany accounts and transactions have been eliminated in consolidation. Investments in less-than-majority-owned entities or other entities in which the Company exercises significant influence over operating and financial policies are accounted for using the equity method of accounting or consolidated if they are a variable interest entity in which the Company has an interest and is the primary beneficiary. Under the equity method, original investments are recorded at cost and adjusted by the Company’s share of undistributed earnings or losses of such companies. The Company’s earnings or losses in investments accounted for under the equity method have been reflected as “equity in earnings (losses) of investees, net” on the Company’s consolidated statements of operations and comprehensive income (loss). Cash and cash equivalents The Company considers all highly liquid instruments, with an original maturity of three Restricted cash, cash equivalents, and marketable securities Under the terms of certain long-term debt agreements, the Company is required to maintain certain debt service reserves, cash collateral and operating fund accounts that have been classified as restricted cash and cash equivalents. Funds that will be used to satisfy obligations due during the next twelve 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: December 31, 2018 2017 2016 (Dollars in thousands) Cash and cash equivalents $ 98,802 $ 47,818 $ 230,214 Restricted cash and cash equivalents 78,693 48,825 34,262 Total Cash and cash equivalents and restricted cash and cash equivalents $ 177,495 $ 96,643 $ 264,476 Concentration of credit risk Financial instruments which potentially subject the Company to 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 U.S. and in foreign countries. At December 31, 2018 2017, $31.3 $21.2 ten seven $250,000 December 31, 2018 2017, $93.9 $32.8 not At December 31, 2018 2017, $102.0 $78.1 December 31, 2018, 2017, 19 56% 57%, 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 Additionally, one 1.9% 11 January 2019 may Inventories Inventories consist primarily of raw material parts and sub-assemblies for power units and are stated at the lower of cost or net realizable value, using the weighted-average cost method. Inventories are reduced by a provision for slow-moving and obsolete inventories. This provision was not December 31, 2018 2017. Deposits and other Deposits and other consist primarily of performance bonds for construction projects, long-term insurance contract and receivables, and derivative instruments. Deferred charges Deferred charges represent prepaid income taxes on intercompany sales. Such amounts were amortized using the straight-line method and included in income tax provision over the life of the related property, plant and equipment. The Company adopted Accounting Standards Update 2016 16, first 2018 $49.8 December 31, 2018" Property, plant and equipment, net Property, plant and equipment are stated at cost. All costs associated with the acquisition, development and construction of power plants operated by the Company are capitalized. Major improvements are capitalized and repairs and maintenance (including major maintenance) costs are expensed. Power plants operated by the Company, which include geothermal wells and exploration and resource development costs, are depreciated using the straight-line method over their estimated useful lives, which range from 15 30 Buildings (in years) 25 Leasehold improvements (in years) 15 - 20 Machinery and equipment — manufacturing and drilling (in years) 10 Machinery and equipment — computers (in years) 3 - 5 Office equipment — furniture and fixtures (in years) 5 - 15 Office equipment — other (in years) 5 - 10 Automobiles (in years) 5 - 7 The cost and accumulated depreciation of items sold or retired are removed from the accounts. Any resulting gain or loss is recognized currently and recorded in the accompanying statements of operations. The Company capitalizes interest costs as part of constructing power plant facilities. Such capitalized interest is recorded as part of the asset to which it relates and is amortized over the asset’s estimated useful life. Capitalized interest costs amounted to $3.7 $7.2 $3.3 December 31, 2018, 2017, 2016, Exploration and development costs The Company capitalizes costs incurred in connection with the exploration and development of geothermal resources once it acquires land rights to the potential geothermal resource. Prior to acquiring land rights, the Company makes an initial assessment that an economically feasible geothermal reservoir is probable on that land. The Company determines the economic feasibility of potential geothermal resources internally, with all available data and external assessments vetted through the exploration department and occasionally using outside service providers. Costs associated with the initial assessment are expensed and included in cost of electricity revenues in the consolidated statements of operations and comprehensive income (loss). Such costs were immaterial during the years ended December 31, 2018, 2017 2016. two three may In most cases, the Company obtains the right to conduct the geothermal development and operations on land owned by the BLM, various states or with private parties. In consideration for certain of these leases, the Company may Following the acquisition of land rights to the potential geothermal resource, the Company conducts further studies and surveys, including water and soil analyses among others, and augments its database with the results of these studies. The Company then initiates a suite of geophysical surveys to assess the resource and determine drilling locations. If the results of these activities support the initial assessment of the feasibility of the geothermal resource, the Company then proceeds to exploratory drilling and other related activities which may may not When deciding whether to continue holding lease rights and/or to pursue exploration activity, we diligently prioritize our prospective investments, taking into account resource and probability assessments in order to make informed decisions about whether a particular project will support commercial operation. As a result, write-off of unsuccessful activities for the year ended December 31, 2018, 2017 2016 $0.1 $1.8 $3.0 2017, 2016, no Grants received from the U.S. DOE are offset against the related exploration and development costs. There were no December 31, 2018 2017. December 31, 2016 $0.3 All exploration and development costs that are being capitalized, including the up-front bonus payments made to secure land leases, will be depreciated over their estimated useful lives when the related geothermal power plant is substantially complete and ready for use. A geothermal power plant is substantially complete and ready for use when electricity generation commences. Asset retirement obligation The Company records the fair value of a legal liability for an asset retirement obligation in the period in which it is incurred. The Company’s legal liabilities include plugging wells and post-closure costs of power producing sites. When a new liability for asset retirement obligations is recorded, the Company capitalizes the costs of the liability by increasing the carrying amount of the related long-lived asset. The liability is accreted to its present value each period, and the capitalized cost is depreciated over the useful life of the related asset. The Company periodically reassess the assumptions used to estimate the expected cash flows required to settle the asset retirement obligation, including changes in estimated probabilities, amounts, and timing of the settlement of the asset retirement obligation, as well as changes in the legal requirements of an obligation and revises the previously recorded asset retirement obligation accordingly. At retirement, the obligation is settled for its recorded amount at a gain or loss. Deferred financing and lease transaction costs Deferred financing costs are amortized over the term of the related obligation using the effective interest method. Amortization of deferred financing costs is presented as interest expense in the consolidated statements of operations and comprehensive income (loss). Accumulated amortization related to deferred financing costs amounted to $21.8 $31.0 December 31, 2018 2017, December 31, 2018, 2017, 2016 $4.6 $5.7 $6.9 December 31, 2018, 2017 2016, $0.0 $0.6 $0.1 Deferred transaction costs relating to the Puna operating lease (see Note 12 $4.2 23 $2.5 $2.3 December 31, 2018 2017, December 31, 2018, 2017, 2016 $0.2 Goodwill Goodwill represents the excess of the fair value of consideration transferred in the business combination transactions of Guadeloupe, Viridity and USG over the fair value of tangible and intangible assets acquired, net of the fair value of liabilities assumed and the fair value of any noncontrolling interest in the acquisitions. Goodwill is not December 31 not first not no one not first January 2017, 2017 04, 350 2018, two two December 31, 2018" 2017 04, one not 9 Intangible assets Intangible assets consist of allocated acquisition costs of PPAs, which are amortized using the straight-line method over the 13 25 9 19 may not no no not Impairment of long-lived assets and long-lived assets to be disposed of The Company evaluates long-lived assets, such as property, plant and equipment and construction-in-process for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not not not not The Company tests its operating plants that are operated together as a complex for impairment at the complex level because the cash flows of such plants result from significant shared operating activities. For example, the operating power plants in a complex are managed under a combined operation management generally with one one not not not Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated future net undiscounted cash flows expected to be generated by the asset. The significant assumptions that the Company uses in estimating its undiscounted future cash flows include: (i) projected generating capacity of the complex or power plant and rates to be received under the respective PPA(s) and expected market rates thereafter and (ii) projected operating expenses of the relevant complex or power plant. Estimates of future cash flows used to test recoverability of a long-lived asset under development also include cash flows associated with all future expenditures necessary to develop the asset. If the assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds their fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Management believes that no may may Derivative instruments Derivative instruments (including certain derivative instruments embedded in other contracts) are measured at their fair value and recorded as either assets or liabilities unless exempted from derivative treatment as a normal purchase and sale. All changes in the fair value of derivatives are recognized in earnings unless specific hedge criteria are met, which requires a company to formally document, designate and assess the effectiveness of transactions that receive hedge accounting. The Company maintains a risk management strategy that may not Foreign currency translation The U.S. dollar is the functional currency for all of the Company’s consolidated operations and those of its equity affiliates except for the Guadeloupe power plant. For those entities, all gains and losses from currency translations are included within the line item “Derivatives and foreign currency transaction gains (losses)” within the consolidated statements of operations and comprehensive income (loss). The Euro is the functional currency of the Guadeloupe power plant and thus gains and losses from currency translation adjustments related to Guadeloupe are included as currency translation adjustments in accumulated other comprehensive income in the consolidated statements of equity and in comprehensive income. The accumulated currency translation adjustments amounted to $0.0 $1.4 December 31, 2018 2017, Comprehensive income (loss) reporting Comprehensive income (loss) includes net income or loss plus other comprehensive income (loss), which for the Company consists of changes in unrealized gains or losses in respect of the Company’s share in derivatives instruments of unconsolidated investment, foreign currency translation adjustments and amortization of unrealized gains in respect of derivative instruments designated as a cash flow hedge. The changes in foreign currency translation adjustments, amortization of unrealized gains and loss in respect of derivative instruments designated as a cash flow hedge during the years ended December 31, 2018, 2017 2016 5 Revenues and cost of revenues Revenues are primarily related to: (i) sale of electricity from geothermal and recovered energy-based power plants owned and operated by the Company; (ii) geothermal and recovered energy-based power plant equipment engineering, sale, construction and installation, and operating services and (iii) energy storage, demand-response and energy management services. Electricity segment revenues July 1, 2003, four 840 8 606, 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 customers. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are not one Other segment revenues 606 may For additional information please see “Revenues from Contracts with Customers” under “New accounting pronouncement” section below. Our accounting policy for revenues included under the comparative periods were accounted under the previous accounting standard as follows: Revenues related to the sale of electricity from geothermal and recovered energy-based power plants and capacity payments are recorded based upon output delivered and capacity provided at rates specified under relevant contract terms. For PPAs agreed to, modified, or acquired in business combinations on or after July 1, 2003, two 840 8 Revenues from engineering, operating services, and parts and product sales are recorded upon providing the service or delivery of the products and parts and when collectability is reasonably assured. Revenues from the supply and/or construction of geothermal and recovered energy-based power plant equipment and other equipment to third may In specific instances where there is a lack of dependable estimates or inherent risks cause forecast to be doubtful, then the completed-contract method is followed. Revenue is recognized when the contract is substantially complete and when collectability is reasonably assured. Costs that are closely associated with the project are deferred as contract costs and recognized similarly to the associated revenues. Termination fee Fees to terminate PPAs are recognized in the period incurred as selling and marketing expenses. During 2018, 2 $5 2018. 2017 2016, no Warranty on products sold The Company generally provides a one two December 31, 2018, 2017, 2016. Research and development Research and development costs incurred by the Company for the development of existing and new geothermal, recovered energy and remote power technologies are expensed as incurred. Grants received from the DOE are offset against the related research and development expenses. There were no December 31, 2018, 2017, 2016. Stock-based compensation The Company accounts for stock-based compensation using the fair value method whereby compensation cost is measured at the grant date, based on the calculated fair value of the award, and is recognized as an expense over the requisite employee service period (generally the vesting period of the grant). Starting in 2016, 2016, Tax monetization Transactions The Company has two 13 2017 13. 470. 810. 835 7. Income taxes Income taxes are accounted for using the asset and liability approach, which requires the recognition of taxes payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in the Company’s financial statements or tax returns. The measurement of current and deferred tax assets and liabilities are based on provisions of the enacted tax law. On December 22, 2017, not 1 35 21 2 3 4 5 6 7 8 December 31, 2017. 18 not not Earnings per share Basic earnings per share attributable to the Company’s stockholders (“earnings per share”) 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: Year Ended December 31, 2018 2017 2016 (In thousands) Weighted average number of shares used in computation of basic earnings per share 50,643 50,110 49,469 Add: Additional shares from the assumed exercise of employee stock options 326 659 671 Weighted average number of shares used in computation of diluted earnings per share 50,969 50,769 50,140 The number of stock-based awards that could potentially dilute future earnings per share and were not 176.4 42.9 102.8 December 31, 2018, 2017, 2016. Use of estimates in preparation of financial statements The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of such financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. The most significant estimates with regard to the Company’s consolidated financial statements relate to the useful lives of property, plant and equipment, impairment of goodwill and long-lived assets, including intangible assets, revenue recognition of product sales using the percentage of completion method, asset retirement obligations, and the provision for income taxes. Puna Power Plant On May 3, 2018, 38 three December 31, 2018 $3.3 May 2018 December 31, 2018 $12.1 May 2018. New Accounting Pronouncements New accounting pronouncements effective in the year ended December 31, 2018 Income Taxes In March 2018, 2018 05, 740 No. 118, 118” December 2017. 18 8 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 as of January 1, 2018 24.0 For a detailed description of our Electricity, Products and Other revenues, please see “Revenues and cost of revenues” caption above. Contract Assets and Liabilities related to our Product segment: Contract assets reflect revenue recognized and performance obligations satisfied in advance of customer billing. Contract liabilities relate to payments received in advance of the satisfaction of performance under the contract. We receive payments from customers based on the terms established in our contracts. Total contract assets and contract liabilities as of December 31, 2018 December 31, 2017 December 31, December 31, 2018 2017 (Dollars in thousands) Contract assets (*) $ 42,130 $ 40,945 Contract liabilities (*) (18,402 ) (20,241 ) Contract assets, net $ 23,728 $ 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 year ended December 31, 2018: Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ - $ 33,349 Cash received in advance for which revenues have not yet recognized, net expenditures made - (38,162 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (128,659 ) - Contract assets recognized, net of recognized receivables 136,496 - Net change in contract assets and contract liabilities 7,837 (4,813 ) 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. The majority of payments are received no On December 31, 2018, $188.1 not 100% 24 The following schedule reconciles revenues accounted for under ASC 840, 606, December 31, 2018: Year Ended December 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 481,619 Electricity, Product and Other revenues accounted under ASC 606 237,648 Total consolidated revenues $ 719,267 Disaggregated revenues from contracts with customers for the year ended December 31, 2018 19 Investment in an unconsolidated company 606 one- $24.0 January 1, 2018. not not The following schedule quantifies the impact of adopting ASC 606 December 31, 2018: Year ended December 31, 2018 under previous standard Effect of the New Revenue Standard As reported for the year ended December 31, 2018 (Dollars in thousands) Equity in earnings (losses) of investees, net $ 5,615 $ 2,048 $ 7,663 Income from continuing operations 108,063 2,048 110,111 Net income attributable to the Company’s stockholders 95,918 2,048 97,966 Retained earnings as of the end of the period 420,174 2,048 422,222 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 December 31, 2018 Intra-Entity Transfers of Assets Other than Inventory In October 2016, 2016 16, not December 15, 2017 December 31, 2018 $49.8 Statement of Cash Flows: Classification of Certain Cash Receipts and Cash payments (Topic 230 In August 2016, 2016 15, 230 eight December 15, 2017 December 31, 2018 $8.0 fourth 2017 Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, 2016 01, December 15, 2017 not Intangibles –Goodwill and Other In January 2017, 2017 04, 350 not 2 2 first first December 15, 2019. January 1, 2017. 2018 New accounting pronouncements effective in future periods Derivatives and Hedging In August 2017, 2017 12, December 15, 2018, Leases In February 2016, 2016 02, 842 two 606. February 2016, 2018 11, July 2018 December 15, 2018, The Company performed an evaluation of the impact from adopting the standard on its financial statements which included, among others, utilization of internal resources to lead the implementation efforts and supplement them with external resources and accounting professionals, review of the Company’s existing lease portfolio and assess the impact to its business processes and internal control over financial reporting. The Company will adopt this update on January 1, 2019, no not one not The Company has substantially completed its assessment of the potential impact that the implementation of this update will have on its consolidated financial statements and continues to finalize its efforts relative to the adoption of this update as of January 1, 2019. not $27.0 $30.0 not Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income In February 2018, 2018 02, 220 December 15, 2018, not NOTE 1 Retrospective adjustments as a result of adoption of accounting policies and change in segments As described above in Note 1, 2016 15, 2016 18, December 31, 2017 2016 19, 2018, 280, December 31, 2017.

Note 2 - Business Acquisitions

Note 2 - Business Acquisitions and Others	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Business Combination Disclosure [Text Block]	NOTE 2 USG transaction On April 24, 2018, $110 $106 $4 • three 38 • development assets which include a project at the Geysers, California; a second As a result of the acquisition, the Company expanded its overall generation capacity and expects to improve the profitability of the purchased assets through cost reduction and synergies. The Company accounted for the transaction in accordance with Accounting Standard Codification ASC 805, 810, may one 2017 01, 1 not The following table summarizes the purchase price allocation to the fair value of the assets acquired and liabilities assumed (in millions): Cash and cash equivalents and restricted cash $ 37.9 Property, plant and equipment and construction-in-process 77.3 Intangible assets (1) 127.0 Goodwill (2) 12.7 Deferred taxes 1.7 Total assets acquired $ 256.6 Other working capital $ (8.2 ) Long-term term debt (98.3 ) Asset retirement obligation (9.0 ) Noncontrolling interest (34.9 ) Total liabilities assumed $ (150.4 ) Total assets acquired, and liabilities assumed, net $ 106.2 ( 1 Intangible assets are primarily related to long-term electricity power purchase agreements and depreciated over an average of 19 ( 2 Goodwill is primarily related to the expected synergies in operations as a result of the purchase transaction. The goodwill is allocated to the Electricity segment and not The fair value of the noncontrolling interest of $34.9 40% 20 9%. Total Electricity revenues and operating profit related to the three $21.4 $2.5 December 31, 2018 December 31, 2018. January 1, 2017: Pro forma for the year ended December 31, 2018 Pro forma for the year ended December 31, 2017 (Dollars in thousands) Electricity revenues $ 521,175 $ 497,650 Total revenues 730,563 724,869 Income from continuing operations before income taxes and equity in losses of investees 134,142 169,546 Viridity transaction On March 15, 2017, $35.3 $12.4 2017 2020. first 2017 not $0.6 December 31, 2018, second 2020 not $10.3 December 31, 2018. Using proprietary software and solutions, Viridity serves primarily retail energy providers, utilities, and large commercial and industrial customers. Viridity’s offerings enable its customers to optimize and monetize their energy management, demand response and storage facilities potential by interacting on their behalf with regional transmission organizations and independent system operators. The Company accounted for the transaction in accordance with Accounting Standard Codification 805, $34.7 19 $0.4 $13.5 810, During the fourth 2018, 9

Note 3 - Inventories

Note 3 - Inventories	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Inventory Disclosure [Text Block]	NOTE 3 Inventories consist of the following: December 31, 2018 2017 (Dollars in thousands) Raw materials and purchased parts for assembly $ 26,914 $ 12,007 Self-manufactured assembly parts and finished products 18,110 7,544 Total $ 45,024 $ 19,551

Note 4 - Cost and Estimated Ear

Note 4 - Cost and Estimated Earnings on Uncompleted Contracts	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Long-term Contracts or Programs Disclosure [Text Block]	NOTE 4 Cost and estimated earnings on uncompleted contracts consist of the following: December 31, 2018 2017 (Dollars in thousands) Costs and estimated earnings incurred on uncompleted contracts $ 278,797 $ 550,823 Less billings to date (255,069 ) (530,119 ) Total $ 23,728 $ 20,704 These amounts are included in the consolidated balance sheets under the following captions: December 31, 2018 2017 (Dollars in thousands) Costs and estimated earnings in excess of billings on uncompleted contracts $ 42,130 $ 40,945 Billings in excess of costs and estimated earnings on uncompleted contracts (18,402 ) (20,241 ) Total $ 23,728 $ 20,704 The completion costs of the Company’s construction contracts are subject to estimation. Due to uncertainties inherent in the estimation process, it is reasonably possible that estimated contract earnings will be further revised in the near term.

Note 5 - Investment in an Uncon

Note 5 - Investment in an Unconsolidated Company	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Equity Method Investments and Joint Ventures Disclosure [Text Block]	NOTE 5 Investment in an unconsolidated company Investment in an unconsolidated company mainly consist of the following: December 31, 2018 2017 (Dollars in thousands) Sarulla $ 71,983 $ 34,084 The Sarulla Project The Company holds a 12.75% 330 three 110 NIL 2, April 2018. April 4, 2013 30 During the years ended December 31, 2018 2017, $3.8 $46.3 $62.0 The Sarulla consortium entered into interest rate swap agreements with various international banks, effective as of June 4, 2014, Year Ended December 3 1 , 2018 2017 (Dollars in thousands) Change, net of deferred tax, in unrealized gains (losses) in respect of the Company’s share in derivative instruments of unconsolidated investment $ 2,235 $ 804 The related accumulated loss recorded by the Company in other comprehensive income (loss) as of December 31, 2018 $2.9 As further described above under Note 1 December 31, 2018”, 606, January 1, 2018. $24.0 January 1, 2018. not one $24.0 January 1, 2018,

Note 6 - Variable Interest Enti

Note 6 - Variable Interest Entities	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Disclosure Of Variable Interest Entities [Text Block]	NOTE 6 The Company’s overall methodology for evaluating transactions and relationships under the variable interest entity (“VIE”) accounting and disclosure requirements includes the following two In performing the first • The design of the entity, including the nature of its risks and the purpose for which the entity was created, to determine the variability that the entity was designed to create and distribute to its interest holders; • The nature of the Company’s involvement with the entity; • Whether control of the entity may not • Whether there is sufficient equity investment at risk to finance the activities of the entity; and • Whether parties other than the equity holders have the obligation to absorb expected losses or the right to receive residual returns. If the Company identifies a VIE based on the above considerations, it then performs the second • Whether the Company has the power to direct the activities of the VIE that most significantly impact the entity’s economic performance; and • Whether the Company has the obligation to absorb losses of the entity that could potentially be significant to the VIE or the right to receive benefits from the entity that could potentially be significant to the VIE. The Company’s VIEs include certain of its wholly owned subsidiaries that own one not may The tables below detail the assets and liabilities (excluding intercompany balances which are eliminated in consolidation) for the Company’s VIEs, combined by VIE classifications, that were included in the consolidated balance sheets as of December 31, 2018 2017: December 31, 2018 Project Debt PPAs (Dollars in thousands) Assets: Restricted cash and cash equivalents $ 76,019 $ 2,304 Other current assets 213,007 9,698 Property, plant and equipment, net 1,552,408 306,820 Construction-in-process 90,812 13,273 Other long-term assets 177,723 9,104 Total assets $ 2,109,969 $ 341,199 Liabilities: Accounts payable and accrued expenses $ 24,245 $ 2,651 Long-term debt 805,850 — Other long-term liabilities 125,769 12,483 Total liabilities $ 955,864 $ 15,134 December 31, 2017 Project Debt PPAs (Dollars in thousands) Assets: Restricted cash, cash equivalents and marketable securities $ 48,676 $ — Other current assets 124,322 18,010 Property, plant and equipment, net 1,252,623 379,277 Construction-in-process 129,832 12,885 Other long-term assets 63,667 276 Total assets $ 1,619,120 $ 410,448 Liabilities: Accounts payable and accrued expenses $ 24,887 $ 6,863 Long-term debt 658,726 — Other long-term liabilities 93,682 6,757 Total liabilities $ 777,295 $ 13,620

Note 7 - Fair Value of Financia

Note 7 - Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Fair Value Disclosures [Text Block]	NOTE 7— 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 December 31, 2018 2017 December 31, 2018 Fair Value Carrying Value at December 31, 2018 Total Level 1 Level 2 Level 3 (Dollars in thousands) Assets: Current assets: Cash equivalents (including restricted cash accounts) $ 18,787 $ 18,787 $ 18,787 $ — $ — Derivatives: Contingent receivable (1) 104 104 — — 104 Liabilities: Current liabilities: Derivatives: Contingent payables (1) (3,424 ) (3,424 ) — — (3,424 ) Currency forward contracts (2) (1,040 ) (1,040 ) — (1,040 ) — $ 14,427 $ 14,427 $ 18,787 $ (1,040 ) $ (3,320 ) 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 December 31, 2018 2017 ( 2 December 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 (loss) on derivative instruments not Derivatives not designated as hedging instruments Location of recognized gain (loss) Amount of recognized gain (loss) 2018 2017 2016 (Dollars in thousands) Put options on natural gas price Derivative and foreign currency transaction gains (losses) $ — $ (350 ) $ — Call options on natural gas price Derivative and foreign currency transaction gains (losses) — — (1,340 ) Call and put options on oil price Derivative and foreign currency transaction gains (losses) — — (1,313 ) Contingent considerations Derivative and foreign currency transaction gains (losses) 170 (129 ) (1,527 ) Contingent considerations General and administrative expenses 10,322 2,048 — Currency forward contracts Derivative and foreign currency transaction gains (losses) (3,081 ) 3,699 238 $ 7,411 $ 5,268 $ (3,942 ) In January 2017, 4.1 $3 January 26, 2017 November 27, 2017 $0.7 On February 2, 2016, 4.1 $2 February 24, 2016 December 27, 2016 $1.9 On February 24, 2016, 185,000 $32.80 $35.50 March 24, 2016 December 22, 2016 $1.1 March 2016, 2 31,800 $41 $42.50 $32.80 $33.50. 16,500 17,000 February 2016 $28.50 $37.50 $28 $38.50, The foregoing future, forward and swap transactions have not There were no 1, 2 3 December 31, 2018. The fair value of the Company’s long-term debt is as follows: Fair Value Carrying Amount 2018 2017 2018 2017 (Dollars in millions) (Dollars in millions) Olkaria III Loan - OPIC 211.8 234.6 210.6 228.6 Olkaria IV Loan - DEG 2 47.2 50.7 47.5 50.0 Platanares Loan - OPIC 119.1 — 112.7 — Amatitlan Loan 29.9 32.8 29.8 33.3 Senior Secured Notes: OrCal Geothermal Inc. ("OrCal") 19.0 34.2 18.7 32.1 OFC 2 LLC ("OFC 2") 214.5 234.6 217.8 232.5 Don A. Campbell 1 ("DAC 1") 78.8 85.5 83.3 88.3 USG Prudential - NV 29.4 — 27.8 — USG Prudential - ID 18.6 — 18.9 — USG DOE 48.3 — 51.4 — Senior Unsecured Bonds 199.4 200.3 204.3 204.3 Senior Unsecured Loan 102.2 — 100.0 — Other long-term debt 5.4 7.0 6.2 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 other 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 December 31, 2018: Level 1 Level 2 Level 3 Total (Dollars in millions) Olkaria III - OPIC — — 211.8 211.8 Olkaria IV - DEG 2 — — 47.2 47.2 Platanares Loan - OPIC — — 119.1 119.1 Amatitlan Loan — 29.9 — 29.9 Senior Secured Notes: OrCal Senior Secured Notes — — 19.0 19.0 OFC 2 Senior Secured Notes — — 214.5 214.5 DAC 1 Senior Secured Notes — — 78.8 78.8 USG Prudential - NV — — 29.4 29.4 USG Prudential - ID — — 18.6 18.6 USG DOE — — 48.3 48.3 Senior Unsecured Bonds — — 199.4 199.4 Senior Unsecured Loan — — 102.2 102.2 Other long-term debt — — 5.4 5.4 Revolving lines of credit — 159.0 — 159.0 Deposits 12.0 — — 12.0 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 8 - Property, Plant and Eq

Note 8 - Property, Plant and Equipment and Construction-in-process	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Property, Plant and Equipment Disclosure [Text Block]	NOTE 8 Property, plant and equipment Property, plant and equipment, net, consist of the following: December 31, 2018 2017 (Dollars in thousands) Land owned by the Company where the geothermal resource is located $ 38,060 $ 32,178 Leasehold improvements 5,718 3,984 Machinery and equipment 208,646 182,121 Land, buildings and office equipment 35,708 31,128 Automobiles 22,074 12,596 Geothermal and recovered energy generation power plants, including geothermal wells and exploration and resource development costs: United States of America, net of cash grants 2,065,377 1,744,728 Foreign countries 710,775 700,498 Asset retirement cost 11,448 10,563 3,097,806 2,717,797 Less accumulated depreciation (1,138,228 ) (983,106 ) Property, plant and equipment, net $ 1,959,578 $ 1,734,691 Depreciation expense for the years ended December 31, 2018, 2017, 2016 $114.4 $98.8 $94.8 December 31, 2018, 2017 2016 $6.4 $5.5 $5.5 U.S. Operations The net book value of the property, plant and equipment, including construction-in-process, located in the U.S. was approximately $1,696.4 $1,447.4 December 31, 2018 2017, December 31, 2018 2017 $179.7 $133.2 Foreign Operations The net book value of property, plant and equipment, including construction-in-process, located outside of the U.S. was approximately $524.8 $580.8 December 31, 2018 2017, The Company, through its wholly owned subsidiary, OrPower 4, 4” $302.0 $326.1 December 31, 2018 2017, 20 The Company, through its wholly owned subsidiary, Orzunil I de Electricidad, Limitada (“Orzunil”), owns a power plant in Guatemala. On January 22, 2014, 2019 2034. 3% $14.6 $9.9 December 31, 2018 2017, The Company, through its wholly owned subsidiary, Ortitlan, Limitada (“Ortitlan”), owns a power plant in Guatemala. The net book value of the assets related to the power plant was $43.5 $40.7 December 31, 2018 2017, The Company, through its wholly owned subsidiary, GeoPlatanares, signed a BOT contract for the Platanares geothermal project in Honduras with ELCOSA, a privately owned Honduran energy company, for 15 30 $105.7 $140.3 December 31, 2018 2017, The Company, through its subsidiary, GB, owns a power plant in Guadeloupe. The net book value of the assets related to the power plant was $23.9 $24.9 December 31, 2018 2017, 15 Construction-in-process Construction-in-process consists of the following: December 31, 2018 2017 (Dollars in thousands) Projects under exploration and development: Up-front bonus lease costs $ 17,018 $ 17,018 Exploration and development costs 53,237 46,154 Interest capitalized 703 703 70,958 63,875 Projects under construction: Up-front bonus lease costs 27,473 27,473 Drilling and construction costs 160,398 198,943 Interest capitalized 2,861 3,251 190,732 229,667 Total $ 261,690 $ 293,542 Projects under Exploration and Development Up-front Bonus Lease Costs Exploration and Development Costs Interest Capitalized Total (Dollars in thousands) Balance at December 31, 2015 $ 26,491 $ 35,726 $ 703 $ 62,920 Cost incurred during the year 1,514 25,165 — 26,679 Write off of unsuccessful exploration costs (380 ) (2,637 ) — (3,017 ) Transfer of projects under exploration and development to projects under construction (10,240 ) (21,895 ) — (32,135 ) Balance at December 31, 2016 17,385 36,359 703 54,447 Cost incurred during the year — 11,224 — 11,224 Write off of unsuccessful exploration costs (367 ) (1,429 ) — (1,796 ) Balance at December 31, 2017 17,018 46,154 703 63,875 Cost incurred during the year — 7,209 — 7,209 Write off of unsuccessful exploration costs — (126 ) — (126 ) Balance at December 31, 2018 $ 17,018 $ 53,237 $ 703 $ 70,958 Projects under Construction Up-front Bonus Lease Costs Drilling and Construction Costs Interest Capitalized Total (Dollars in thousands) Balance at December 31, 2015 $ 27,473 $ 150,467 $ 7,975 $ 185,915 Cost incurred during the year — 116,247 6,510 122,757 Transfer of projects under exploration and development to projects under construction 10,240 21,895 — 32,135 Transfer of completed projects to property, plant and equipment — (86,398 ) (2,147 ) (88,545 ) Balance at December 31, 2016 37,713 202,211 12,338 252,262 Cost incurred during the year — 231,926 7,300 239,226 Transfer of completed projects to property, plant and equipment (10,240 ) (235,194 ) (16,387 ) (261,821 ) Balance at December 31, 2017 27,473 198,943 3,251 229,667 Cost incurred during the year — 219,610 — 219,610 Cost write off — (1,380 ) — (1,380 ) Fair value of projects under construction acquired in a business combination — 4,668 — 4,668 Transfer of completed projects to property, plant and equipment — (261,443 ) (390 ) (261,833 ) Balance at December 31, 2018 $ 27,473 $ 160,398 $ 2,861 $ 190,732

Note 9 - Intangible Assets and

Note 9 - Intangible Assets and Goodwill	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Intangible Assets Disclosure [Text Block]	NOTE 9 Intangible assets amounting to $199.9 $85.4 $61.5 $50.0 December 31, 2018 2017, December 31, 2018 2017, $32.2 $33.8 $3.4 $1.7 December 31, 2018, 2017, 2016 $11.2 $6.9 $4.4 December 31, 2018, 2017 2016, $127.0 $35.6 $33.0 2018, 2017 2016 December 2018 2017 may not no 2018, 2017 2016. Estimated future amortization expense for the intangible assets as of December 31, 2018 (Dollars in thousands) Year ending December 31: 2019 $ 13,422 2020 13,105 2021 13,105 2022 12,850 2023 12,734 Thereafter 134,658 Total $ 199,874 Goodwill Goodwill amounting to $20.0 $21.0 December 31, 2018 2017, During the fourth 2018, one 1 fourth 2018. $13.5 December 31, 2018. zero 3 Except as noted above, for the years 2018 2017, no Changes in the carrying amount of the Company’s goodwill for the years ended December 31, 2018 2017 2018 2017 (Dollars in thousands) Goodwill as of January 1, $ 21,037 $ 6,650 Goodwill acquired 12,710 13,464 Goodwill impairment charge (13,464 ) - Translation differences (333 ) 923 Goodwill as of December 31, $ 19,950 $ 21,037

Note 10 - Accounts Payable and

Note 10 - Accounts Payable and Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Accounts Payable and Accrued Liabilities Disclosure [Text Block]	NOTE 10 Accounts payable and accrued expenses consist of the following: December 31, 2018 2017 (Dollars in thousands) Trade payable $ 56,299 $ 64,289 Salaries and other payroll costs 20,188 19,888 Customer advances 918 1,177 Accrued interest 5,914 4,462 Income tax payable 8,436 43,682 Property tax payable 2,999 1,860 Scheduling and transmission 595 531 Royalty accrual 4,610 2,909 Deferred revenues 2,300 858 Warranty accrual 4,552 3,619 Other 9,551 10,521 Total $ 116,362 $ 153,796

Note 11 - Long-term Debt and Cr

Note 11 - Long-term Debt and Credit Agreements	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Long-term Debt [Text Block]	NOTE 11 Long-term debt consists of notes payable under the following agreements: December 31, 2018 2017 (Dollars in thousands) Limited and non-recourse agreements: Loans: Non-recourse: Other loans $ 6,241 $ 7,252 Limited recourse: Loan agreement with OPIC (the Olkaria III power plant) 210,641 228,635 Loan agreement with OPIC (the Platanares power plant) 112,652 - Loan agreement with Banco Industrial S.A. and Westrust Bank (International) Limited 29,750 33,251 Senior Secured Notes: Non-recourse: OrCal Senior Secured Notes 18,652 32,142 DAC 1 Senior Secured Notes 83,319 88,339 Limited recourse: OFC 2 Senior Secured Notes 217,810 232,526 Other loans 96,482 - 775,547 622,145 Less current portion (63,180 ) (54,720 ) Non current portion $ 712,367 $ 567,425 Full recourse agreements: Senior Unsecured Bonds $ 204,332 $ 204,332 Senior Unsecured Loan (Migdal) 100,000 - Loan agreements with DEG (the Olkaria III and IV power plants) 47,500 50,000 Loan from a commercial bank - 587 Revolving credit lines with banks 159,000 51,500 510,832 306,419 Less current portion (164,000 ) (54,587 ) Non current portion $ 346,832 $ 251,832 Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited On July 31, 2015, 12 $42.0 20 The loan is payable in 48 September 30, 2015. per annum 1.25% 4.35% 4.75% March 30, June 30, September 30 December 30 not may 100 50 eighth There are various restrictive covenants under the Amatitlan credit agreement. These include, among others, (i) a financial covenant to maintain a Debt Service Coverage Ratio (as defined in the credit agreement) of not 1.15 1.00 not 1.25 1.00 four December 31, 2018, 12 1.58 1.59, The loan is collateralized by substantially all the assets of the borrower and a pledge of all of the membership interests of the borrower. The Company has guaranteed payment of all obligations under the credit agreement and related financing documents. The guaranty is limited in the sense that the Company is only required to pay the guaranteed obligations if a “trigger event” occurs. A trigger event is the occurrence and continuation of a default by INDE in its payment obligations under the PPA for the Amatitlàn power plant or a refusal by INDE to receive capacity and energy sold under that PPA. The Company’s obligations under the guaranty may As of December 31, 2018, $29.8 Finance Agreement with OPIC (the Olkaria III Complex) On August 23, 2012, 4, $310.0 November 9, 2012. The OPIC Loan is comprised of up to three • Tranche I in an aggregate principal amount of $85.0 November 2012, $20.5 $1.5 • Tranche II in an aggregate principal amount of $180.0 2” November 2012, $135.0 February 2013, $45.0 • Tranche III in an aggregate principal amount of $45.0 3 November 2013, $45.0 In July 2013, December 31, 2018 $56.6 December 15, 2030, December 31, 2018 $121.8 June 15, 2030, 6.31%. November 2013, December 31, 2018 $32.2 December 15, 2030, 6.12%. OrPower 4 2.0% first two 2 1% third 2 not 1.7. The OPIC Loan is collateralized by substantially all of OrPower 4’s 4. The finance agreement includes customary events of default, including failure to pay any principal, interest or other amounts when due, failure to comply with covenants, breach of representations and warranties, non-payment or acceleration of other debt of OrPower 4, 4 4, There are various restrictive covenants under the OPIC Loan, which include a required historical and projected 12 not 1.4 March 15, June 15, September 15 December 15 4 1.1, 4. December 15, 2014. December 31, 2018, 12 2.87 3.03, As of December 31, 2018, $210.6 Debt service reserve As required under the terms of the OPIC Loan, OrPower 4 may six December 31, 2018 2017, $2.6 $3.7 December 31, 2018, $16.1 22 Well drilling reserve As required under the terms of the OPIC Loan, OrPower 4 may may Finance Agreement with OPIC (the Platanares power plant) On April 30, 2018, $124.7 35 October 2018. Tranche I in an aggregate principal amount of $114.7 October 2018, 7.02% September 2032. $10 first 2019 Under the Finance Agreement, Platanares may, $5 2% first second 1% third no fourth The OPIC Loan is also subject to customary mandatory prepayment upon the occurrence of certain events, including, among others, (i) receipt by Platanares of compensation or damages following a dispute that results in a material adverse change to the primary power purchase agreement for the Project, (ii) receipt by Platanares of a termination or indemnity payment from a third The OPIC Loan will be secured by a first no 1.1 1; not 1.2 1. December 31, 2018, 12 1.50. The Finance Agreement also contains customary events of default, including, among others, failure to pay principal, interest or other amounts when due, non-payment or acceleration of other indebtedness of Platanares, the occurrence of a change of control of Platanares without the prior approval of OPIC, expropriation, judgments rendered against Platanares in excess of a certain threshold, failure to comply with covenants, a voluntary abandonment of the Project and the occurrence of certain bankruptcy events, subject to various exceptions and applicable notice, cure and grace periods. As of December 31, 2018, $112.7 Debt service reserve As required under the terms of the Platanares Loan, Platanares maintains an account which may six nine December 31, 2018, $13.4 no Well drilling reserve As required under the terms of the Finance Agreement, Platanares is required to maintain an account which may December 31, 2018, $2 no OFC Senior Secured Notes In February 2004, $190.0 1, 1A, 2 3 50% December 30, 2020, September 2017, $14.3 $1.3 OrCal Senior Secured Notes In December 2005, $165.0 6.21% $161.1 $3.9 December 30, 2020. 12 not 1.25 June 30 December 31 December 31, 2018, 12 1.18 12 1.41. $18.7 $32.1 December 31, 2018 December 31, 2017, OrCal may may 100% Debt service reserve As required under the terms of the OrCal Senior Secured Notes, OrCal maintains an account which may six December 31, 2018 2017, $0.0 $1.9 December 31, 2018 2017, $4.6 22 OFC 2 In September 2011, 2, 2’s 2 2 $350.0 2 2 December 31, 2034. Subject to the fulfillment of customary and other specified conditions precedent, the OFC 2 may six 2 2 2 not December 31, 2034. ten 80% 2 1705 2005, 2 2 On October 31, 2011, 2 $151.7 4.687% 2032 $141.1 March, June, September December On June 20, 2014, 1 $4.3 On August 29, 2014, 2 $140.0 2 second 1705 2005. December 2032, 4.61% In connection with the anticipated sale of the Series C Notes, on August 13, 2014, August 15, 2014. $140.0 10 one 2 August 15, 2014. 10 August 18, 2014, $1.5 The Company concluded that the cash flow hedge was fully effective with no no 2014, $0.9 $0.6 2 2016 2015, $0.1 The OFC 2 2 2. 2 2 2. 2 Among other things, the distribution restrictions include a historical debt service coverage ratio requirement of at least 1.2 2 two six 1.5 2 two six December 31, 2018, 2.55 2.21, two six 2.09 2.18, two six There were $217.8 $232.5 2 December 31, 2018 December 31, 2017, The Company provided a guaranty in connection with the issuance of the Series A Notes and Series C Notes. The guaranty may 2 2 may 2 2 2 2 2 not Debt service reserve; other restricted funds Under the terms of the OFC 2 2 (i) A debt service reserve account which may 2 six December 31, 2018, $20.0 22 (ii) A performance level reserve account, intended to provide additional security for the OFC 2 may $28.0 December 31, 2018, zero no (iii) Under the terms of the OFC 2 2 may (iv) A performance level reserve account for McGinness Hills Phase II, intended to provide additional security for the OFC 2 may December 31, 2018, no Don A. Campbell Senior Secured Notes — Non-Recourse On November 29, 2016, 47 47” 47 47 $92.5 4.03% September 27, 2033 ( 1 1933, 47 first 1” The net proceeds from the sale of the DAC 1 $87.1 47 1 ORNI 47 1 December 27, 2016 27th March, June, September December, 1 The DAC 1 47 47. 47 47 may 1 $2 may 1 100% 47 47 1 101% not 1 may 47 1 100% 47 47 47 47 47 not 1.20 four December 31, 2018, 1.35 1.69, As of December 31, 2018, $83.3 1 USG loans On April 24, 2018, Prudential Capital Group – Idaho non-recourse In May 2016, $20.0 $50.0 two $20.0 5.8% first seven $16.0 seven December 31, 2018, $18.9 U.S. Department of Energy – non-recourse On August 31, 2011, first $96.8 February 23, 2011. No 13 21.5 first 2.6%. December 31, 2018, $51.4 Prudential Capital Group – Nevada non-recourse On September 26, 2013, 24 6.75% December 31, 2018, $27.8 Senior Unsecured Bonds In September 2016, two $67 2 $137 3 2 2 3 September 29, 2016 $250 August 1, 2017. The Series 2 September 2020 3.7% 3 September 2022 4.45% 2 3 Senior Unsecured Loan On March 22, 2018 $100.0 15 $4.2 September 15, 2021, $37.0 March 15, 2029. 4.8% The 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 Loan Agreements with DEG (the Olkaria III Complex ) In March 2009, 4, $105.0 December 15, 2018, 19 6 4.0%. 6.90%. September 2017, $11.8 $0.1 On October 20, 2016, 4 $50 2 December 21, 2016, 4 $50 6.28% 2 2 20 December 21, 2018, June 21, 2028. 2 4 4 2 1 3 2 Under the DEG 2 4 may 2 $5 may 2 100% 4 2 100% 2 4 2 As of December 31, 2018, $47.5 2 Revolving credit lines with commercial banks As of December 31, 2018, eight $468.0 $60.0 $35.0 one $233.0 one $235.0 March 2019 September 2019. As of December 31, 2018, $159.0 $14.1 $229.6 Credit Agreements Credit agreement with Union Bank In February 2012, June 30, 2019. December 31, 2018, $60 may, There are various restrictive covenants under the credit agreement, which include a requirement to comply with the following financial ratios, which are measured quarterly: (i) a 12 not 4.5; 12 not 1.35; not 2.0. December 31, 2018: ( 12 2.91; 12 2.94; 1.10. As of December 31, 2018, $51.5 Credit agreement with HSBC In May 2013, one August 31, 2019. $10 $35 $10 may may, There are various restrictive covenants under the credit agreement, including a requirement to comply with the following financial ratios, which are measured quarterly: (i) a 12 not 4.5; 12 not 1.35; not 2.0. December 31, 2018: ( 12 2.91; 12 2.94; 1.10. As of December 31, 2018, $30.0 CHUBB Surety Bond In May 2017, may $200.0 may no may twenty not December 31, 2018, $141.1 Restrictive covenants The Company’s obligations under the credit agreements, the loan agreements, and the trust instrument governing the bonds, described above, are unsecured, but are subject to a negative pledge in favor of the banks and the other lenders and certain other restrictive covenants. These include, among other things, a prohibition on: (i) creating any floating charge or any permanent pledge, charge or lien over our assets without obtaining the prior written approval of the lender; (ii) guaranteeing the liabilities of any third third $600.0 no 25% 12 not 6; not 35% December 31, 2018: ( $1,445.1 46.3%, 12 3.21. December 31, 2018, $26.8 Future minimum payments Future minimum payments under long-term obligations, excluding revolving credit lines with commercial banks, as of December 31, 2018 (Dollars in thousands) Year ending December 31: 2019 $ 68,180 2020 136,018 2021 64,039 2022 205,908 2023 84,101 Thereafter 570,751 Total $ 1,128,997

Note 12 - Puna Power Plant Leas

Note 12 - Puna Power Plant Lease Transactions	12 Months Ended
	Dec. 31, 2018
Projected [Member]
Notes to Financial Statements
Leases of Lessee Disclosure [Text Block]	NOTE 12 In 2005, Pursuant to a 31 $83.0 December 31, 2018 2017 $19.7 $25.3 $33.1 $35.6 23 not The Head Lease and the Project Lease are being accounted for separately. Each was classified as an operating lease in accordance with the accounting standards for leases. The Deferred Lease Income is amortized into revenue, using the straight-line method, over the 31 $4.2 23 Future minimum lease payments under the Project Lease, as of December 31, 2018, (Dollars in thousands) Year ending December 31: 2019 $ 6,018 2020 2,450 2021 1,723 2022 824 2023 - Thereafter 1,917 Total $ 12,932 Depository accounts As required under the terms of the lease agreements, there are certain reserve funds that need to be managed by the indenture trustee in accordance with certain balance requirements. Such reserve funds amounted to $1.3 $7.9 December 31, 2018 2017, Distribution account PGV maintains an account to deposit its remaining cash, after making all of the necessary payments and transfers as provided for in the lease agreements, in order to make distributions to Ormat Nevada. The distributions are allowed only if PGV maintains various restrictive covenants under the lease agreements, which include limitations on additional indebtedness. As of December 31, 2018 2017, $ 0

Note 13 - Tax Monetization Tran

Note 13 - Tax Monetization Transactions	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Disclosure Of Investments In And Advances To Affiliates [Text Block]	NOTE 13 Opal Geo Transaction On December 16, 2016, December 16, 2016, five In connection with the transactions contemplated by the Equity Contribution Agreement and the LLC Agreement, Ormat Nevada transferred its indirect ownership interest in the McGinness Hills (Phase I and Phase II), Tuscarora, Jersey Valley and second 2” 63.25% 2 100% Pursuant to the Equity Contribution Agreement, JPM contributed approximately $62.1 100% 2 $21 December 31, 2022. Under the LLC Agreement, until December 31, 2022, 97.5% 2.5% December 31, 2022 100% 97.5%, 2.5%, Under the LLC Agreement, all items of Opal Geo income and loss, gain, deduction and credit (including the federal production tax credits relating to the operation of the two two 99% 1% 5% 95% no two 5% 95% Under the LLC Agreement, OrLeaf, which owns 100% five may five 2 five The LLC Agreement contains certain customary restrictions on transfer applicable to both OrLeaf and JPM with respect to their respective Membership Interests in Opal Geo, and also provides OrLeaf with a right of first may December 31, 2022 9 $3 Pursuant to the Equity Contribution Agreement, the Company has provided a guaranty for the benefit of JPM of certain of OrLeaf’s indemnification obligations to JPM under the LLC Agreement. In addition, Ormat Nevada also provided a guaranty for the benefit of JPM of all present and future payment and performance obligations of OrLeaf under the LLC Agreement and each ancillary document to which OrLeaf is a party. JPM’s approximately $62.1 $3.7 $58.5 1. 2 Tungsten Mountain partnership transaction On May 17, 2018, one 26 $33.4 $13 Under the agreements, prior to December 31, 2026 ( 97.5% 95.0% On the Target Flip Date, Ormat Nevada has the option to purchase the private investor’s interests at the then-current fair market value, plus an amount that may Other completed tax monetization transactions On May 31, 2017, October 31, 2017, $1.9 $6.5 $8.5 In March 2017, July 10, 2017, $2.4 $7.0 $2.9

Note 14 - Asset Retirement Obli

Note 14 - Asset Retirement Obligation	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Asset Retirement Obligation Disclosure [Text Block]	NOTE 14 The following table presents a reconciliation of the beginning and ending aggregate carrying amount of asset retirement obligation for the years presented below: Year Ended December 31, 2018 2017 (Dollars in thousands) Balance at beginning of year $ 27,110 $ 23,348 Revision in estimated cash flows (258 ) 1,888 Liabilities incurred and acquired 10,149 — Accretion expense 2,474 1,874 Balance at end of year $ 39,475 $ 27,110

Note 15 - Stock-based Compensat

Note 15 - Stock-based Compensation	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	NOTE 15 The Company makes an estimate of expected forfeitures and recognizes compensation costs only for those stock-based awards expected to vest. As of December 31, 2018, $17.0 1.3 During the years ended December 31, 2018, 2017 2016, Year Ended December 31, 2018 2017 2016 (Dollars in thousands, except per share data) Cost of revenues $ 3,488 $ 3,369 $ 2,400 Selling and marketing expenses 792 452 247 General and administrative expenses 5,938 4,939 2,510 Total stock-based compensation expense 10,218 8,760 5,157 Tax effect on stock-based compensation expense 668 604 617 Net effect of stock-based compensation expense $ 9,550 $ 8,156 $ 4,540 During the fourth 2018, 2017 2016, 5.3%, 1.1% 10.3%, 381.8%, 89.3%, 7%, Valuation assumptions Prior to 2016, 2016, 20% 0.9% December 31, 2018. The Company calculated the fair value of each stock-based award on the date of grant based on the following assumptions: Year Ended December 31, 2018 2017 2016 For stock options issued by the Company: Risk-free interest rates 2.8 % 1.9 % 1.3 % Expected lives (in weighted average years) 3.5 3.1 4.5 Dividend yield 0.90 % 0.62 % 1.10 % Expected volatility (weighted average) 25.5 % 27.2 % 30.7 % Forfeiture rate (weighted average) 3.1 % 0.0 % 8.4 % Stock-based awards 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 May 2018 2018 “2018 2012 The 2018 On May 7, 2018, 2018 2018 2018 2018 5,000,000 2018 50% second 25% third fourth 2018 100% first six ten 2018 On June 13, 2016, 1,080,000 2012 $42.87, six 4 50% two 25% three 25% four The fair value of each SAR on the grant date was $11.98 $11.42 Risk-free interest rate 1.29 % Expected life (in years) 6 Dividend yield 1.14 % Expected volatility 30.7 % Forfeiture rate: Senior management 0.0 % Other employees 10.5 % Sub-Optimal Exercise Factor: Senior management 2.5 Other employees 2.0 On November 8, 2016, 60,000 2012 $47.46, seven first The fair value of each SAR on the grant date was $14.51. Risk-free interest rate 1.65 % Expected life (in years) 7 Dividend yield 1.1 % Expected volatility 30.6 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 On June 7, 2017, 23,200 2012 $58.79, five 50% first 25% third fourth The fair value of each SAR on the grant date was $13.67. Risk-free interest rate 1.74 % Expected life (in years) 5 Dividend yield 0.66 % Expected volatility 26.3 % Forfeiture rate 10.3 % Sub-Optimal Exercise Factor 2 On August 4, 2017, 30,000 2012 $57.97, seven one The fair value of each option on the grant date was $18.42. Risk-free interest rate 2.08 % Expected life (in years) 7 Dividend yield 0.69 % Expected volatility 29.4 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 On November 8, 2017, 108,771 22,742 2012 $63.35, six 100% first 25% third fourth The fair value of each SAR for the directors and members of senior management on the grant date was $17.6 $17.7, $62.9 $62.3, Risk-free interest rate 2.1 % Expected life (in years) 6 Dividend yield 0.6 % Expected volatility 26.9 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 On May 8, 2018, 295,671 40,489 one 2018 $55.16, five 100% 22% one 28% two three The fair value of each SAR for the director and the CEO on the grant date was $14.56 $14.57, $54.92 $54.23, Risk-free interest rate 2.84 % Expected life (in years) 1.9 – 3.5 Dividend yield 0.79 % Expected volatility 25.24 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 On June 25, 2018, 841,117 19,848 2018 $53.44, six 50% second 25% third fourth The fair value of each SAR for the employees and members of senior management on the grant date was $13.82 $14.64, $52.09, Risk-free interest rate 2.79 % Expected life (in years) 3.5 – 3.7 Dividend yield 0.92 % Expected volatility 25.64 % Forfeiture rate for employees 2.78 % Forfeiture rate for members of the senior management 0.0 % Sub-Optimal Exercise Factor for employees 2.0 Sub-Optimal Exercise Factor for members of the senior management 2.8 On November 7, 2018, 35,395 13,688 2018 $53.16 six 100% first 50% second 25% third fourth The fair value of each SAR for the directors and employees on the grant date was $14.8 $14.0, $52.6. Risk-free interest rate 3.11 % Expected life (in years) 2.0 – 3.6 Dividend yield 1.03 % Expected volatility 25.87 % Forfeiture rate for directors 0.0 % Forfeiture rate for employees 2.78 % Sub-Optimal Exercise Factor for directors 2.8 Sub-Optimal Exercise Factor for employees 2.0 Year Ended December 31, 2018 2017 2016 Shares (In thousands) Weighted Average Exercise Price Shares (In thousands) Weighted Average Exercise Price Shares (In thousands) Weighted Average Exercise Price Outstanding at beginning of year 1,548 $ 41.35 2,565 $ 33.36 2,438 $ 25.38 Granted, at fair value: Stock Options — — 30 57.97 1,155 43.01 SARs* 1,172 53.87 132 62.55 — — RSUs** 74 — 23 — — — Exercised (203 ) 29.75 (1,181 ) 25.92 (967 ) 25.33 Forfeited (64 ) 45.73 (21 ) 46.15 (57 ) 24.12 Expired — — — — (4 ) 26.84 Outstanding at end of year 2,527 46.77 1,548 41.35 2,565 33.36 Options and SARs exercisable at end of year 846 42.06 431 32.61 557 25.22 Weighted-average fair value of options and SARs granted during the year $ 16.45 $ 22.82 $ 11.61 * Upon exercise, SARs entitle the recipient to receive shares of common stock equal to the increase in value of the award between the grant date and the exercise date. ** An RSU represents the right to receive one As of December 31, 2018, 3,605,740 2018 No 2012 2004 The following table summarizes information about stock-based awards outstanding at December 31, 2018 Options Outstanding Options Exercisable Exercise Price Number of Stock-based Awards Outstanding Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value Number of Stock-based Awards Exercisable Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value $ - 75 1.8 3,933 - - - 20.13 29 0.3 924 29 0.3 924 23.34 99 0.4 2,897 99 0.4 2,897 35.15 15 4.1 257 15 4.1 257 38.24 15 3.8 211 15 3.8 211 42.87 942 3.5 8,879 521 3.5 4,918 47.46 38 4.9 182 38 4.9 182 53.16 35 5.9 - - - - 53.44 828 5.5 - - - - 55.16 296 4.9 - 66 4.9 - 57.97 30 5.6 - 30 5.6 - 58.79 16 3.5 - - - - 63.35 109 4.9 - 33 4.9 - 2,527 4.3 $ 17,283 846 3.3 $ 9,389 The following table summarizes information about stock-based awards outstanding at December 31, 2017 Options Outstanding Options Exercisable Exercise Price Number of Stock-based Awards Outstanding Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value Number of Stock-based Awards Exercisable Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value $ - 23 3.9 1,455 - - - 20.13 35 1.3 1,533 35 1.3 1,533 23.34 176 1.4 7,150 176 1.4 7,150 25.65 10 0.3 398 10 0.3 398 35.15 15 5.1 432 15 5.1 432 38.24 15 4.8 386 15 4.8 386 42.87 1,074 4.5 22,651 143 4.5 3,005 47.46 38 5.9 619 38 5.9 619 57.97 30 6.6 180 - - - 58.79 23 4.5 120 - - - 63.35 109 5.9 66 - - - 1,548 4.2 $ 34,990 432 3.0 $ 13,523 The aggregate intrinsic value in the above tables represents the total pretax intrinsic value, based on the Company’s stock price of $52.30 $63.96 December 31, 2018 2017, December 31, 2018 2017 846,215 431,387, The total pretax intrinsic value of options exercised during the year ended December 31, 2018 2017 $5.2 $38.9 $55.58 $58.82 December 31, 2018 2017,

Note 16 - Power Purchase Agreem

Note 16 - Power Purchase Agreements	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Leases of Lessor Disclosure [Text Block]	NOTE 16 Substantially all of the Company’s electricity revenues are recognized pursuant to PPAs in the U.S. and in various foreign countries, including Kenya, Guatemala, Guadeloupe and Honduras. These PPAs generally provide for the payment of energy payments or both energy and capacity payments through their respective terms which expire in varying periods from 2019 2043. not first Pursuant to the terms of certain of the PPAs, the Company may not not may As discussed in Note 1, July 1, 2003, December 31, 2018 none

Note 17 - Interest Expense, Net

Note 17 - Interest Expense, Net	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Interest Expense Disclosure [Text Block]	NOTE 17 The components of interest expense are as follows: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Interest related to sale of tax benefits $ 11,284 $ 6,985 $ 9,349 Interest expense 63,368 54,381 61,327 Less — amount capitalized (3,728 ) (7,224 ) (3,287 ) $ 70,924 $ 54,142 $ 67,389

Note 18 - Income Taxes

Note 18 - Income Taxes	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Income Tax Disclosure [Text Block]	NOTE 18 U.S. and foreign components of income from continuing operations, before income taxes and equity in income (losses) of investees consisted of: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) U.S $ 14,097 $ 13,680 $ (7,109 ) Non-U.S. (foreign) 123,084 157,050 148,197 Total income from continuing operations, before income taxes and equity in losses $ 137,181 $ 170,730 $ 141,088 The components of the provision (benefit) for income taxes, net are as follows: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Current: Federal $ — $ 43,935 $ — State 381 43 (276 ) Foreign 14,992 11,186 13,554 Total current income tax expense $ 15,373 $ 55,164 $ 13,278 Deferred: Federal (6,886 ) (55,718 ) 57 State (2,595 ) (3,284 ) — Foreign 28,841 25,502 23,724 Total deferred tax benefit 19,360 (33,500 ) 23,781 Total Income tax provision $ 34,733 $ 21,664 $ 37,059 Reconciliation of the U.S. federal statutory tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2018 2017 2016 U.S. federal statutory tax rate 21.0 % 35.0 % 35.0 % Impact of federal tax reform 2.6 (12.4 ) - Transition tax inclusion (5.7 ) 42.1 - Foreign tax credits (4.2 ) (50.5 ) - Tax basis adjustment - - (4.9 ) Withholding tax 5.9 34.1 - Valuation allowance - U.S. (17.2 ) (22.6 ) 16.5 State income tax, net of federal benefit 1.0 1.1 (0.6 ) Uncertain Tax Positions 2.1 - - Effect of foreign income tax, net 5.6 (10.7 ) (10.3 ) Production tax credits (3.1 ) (1.2 ) (8.3 ) Subpart F income 0.5 1.7 0.3 Tax on global intangible low-tax income 18.6 - - Intra-entity transfers of assets other than inventory (2.1 ) - - Other, net 0.3 (3.9 ) (1.4 ) Effective tax rate 25.3 % 12.7 % 26.3 % The net deferred tax assets and liabilities consist of the following: December 31, 2018 2017 (Dollars in thousands) Deferred tax assets (liabilities): Net foreign deferred taxes, primarily depreciation $ (57,202 ) $ (61,961 ) Depreciation (30,500 ) (65,315 ) Intangible drilling costs 7,370 13,003 Net operating loss carryforward - U.S. 65,020 55,084 Tax monetization transaction (17,104 ) (13,134 ) State and Investment tax credits 813 813 Production tax credits 90,913 85,193 Foreign tax credits 58,072 86,206 Withholding tax (8,052 ) (14,400 ) Stock options amortization 1,440 1,166 Basis difference in partnership interest (36,516 ) (16,817 ) Accrued liabilities and other 624 3,109 74,878 72,947 Less - valuation allowance (22,441 ) (77,571 ) Total $ 52,437 $ (4,624 ) The following table presents a reconciliation of the beginning and ending valuation allowance: 2018 2017 2016 (Dollars in thousands) Balance at beginning of the year $ 77,571 $ 116,234 $ 92,898 Additions to valuation allowance 4,747 46,560 23,336 Release of valuation allowance (59,877 ) (85,223 ) - Balance at end of the year $ 22,441 $ 77,571 $ 116,234 At December 31, 2018, $230.5 $224.5 December 31, 2017 2027 2037, $6.0 $269.1 $264.7 2025 2038 $3.3 $0.8 December 31, 2018 $90.9 December 31, 2018 20 2026 2038. $58.1 December 31, 2018 10 2027. The Company has recorded deferred tax assets for net operating losses, foreign tax credits, and production tax credits. Realization of the deferred tax assets and tax credits is dependent on generating sufficient taxable income in appropriate jurisdictions prior to expiration of the NOL carryforwards and tax credits. Based upon available evidence of the Company’s ability to generate additional taxable income in the future and historical losses in prior years, a valuation allowance in the amount of $22.4 $77.6 December 31, 2018 2017, not not $55.1 965 $22.4 On April 24, 2018, 100% $110 $1.7 382, $115.2 $49.9 $2.1 not not On December 22, 2017, not 1 35 21 2 3 one December 31, 2017; ( 4 5 6 December 31, 2017. The Company applied the guidance of SAB 118 2017 2018. December 2018. 1986 $71.9 2018 $64.2 no $3.5 $22.6 2017. The FASB released guidance Staff Q&A, Topic 740, No. 5, The following table presents the deferred taxes on the balance sheet as of the dates indicated: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Non-current deferred tax assets $ 113,760 $ 57,337 $ — Non-current deferred tax liabilities (61,323 ) (61,961 ) (36,411 ) Non-current deferred tax assets, net 52,437 (4,624 ) (36,411 ) Uncertain tax benefit offset (1) (95 ) (95 ) — $ 52,342 $ (4,719 ) $ (36,411 ) ( 1 $0.1 2013 11, During 2017, $396.0 $300.0 December 2017 $96.0 December 2018. 2018 2017 15% $14.4 December 31, 2018, $8.1 $2.2 $53 $2.2 10 The total amount of undistributed earnings of foreign subsidiaries for income tax purposes was approximately $211.3 December 31, 2018. not not Uncertain tax positions We are subject to income taxes in the U.S. (federal and state) and numerous foreign jurisdictions. Significant judgment is required in evaluating our tax positions and determining our provision for income taxes. During the ordinary course of business, there are many transactions and calculations for which the ultimate tax determination is uncertain. We establish reserves for tax-related uncertainties based on estimates of whether, and the extent to which additional taxes will be due. These reserves are established when we believe that certain positions might be challenged despite evidence supporting the position. We adjust these reserves in light of changing facts and circumstances, such as the outcome of tax audits. The provision for income taxes includes the impact of reserve positions and changes to reserves that are considered probable. At December 31, 2018 2017, $11.8 $8.9 A reconciliation of our unrecognized tax benefits is as follows: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Balance at beginning of year $ 6,357 $ 4,609 $ 7,781 Additions based on tax positions taken in prior years 293 5 675 Additions based on tax positions taken in the current year 2,446 2,580 1,532 Reduction based on tax positions taken in prior years (276 ) (837 ) (5,379 ) Balance at end of year $ 8,820 $ 6,357 $ 4,609 The Company and its U.S. subsidiaries file consolidated income tax returns for federal and state purposes. As of December 31, 2018, not 2002 2017 2004 2017. may The reduction of $0.3 $0.8 $5.4 2018, 2017, 2016, The Company’s foreign subsidiaries remain open to examination by the local income tax authorities in the following countries for the years indicated: Israel 2015 - 2018 Kenya 2012 - 2018 Guatemala 2014 - 2018 Honduras 2014 - 2018 Guadeloupe 2016 - 2018 New Zealand 2012 - 2018 Management believes that the liability for unrecognized tax benefits is adequate for all open tax years based on its assessment of many factors, including among others, past experience and interpretations of local income tax regulations. This assessment relies on estimates and assumptions and may Tax benefits in the U.S . The U.S. government encourages production of electricity from geothermal resources through certain tax subsidies. On February 9, 2018 2018 2018. 2018 2.4 first 10 may 30% January 1, 2018, 1 20 If the Company claims the ITC, the Company’s “tax base” in the plant that it can recover through bonus or accelerated depreciation (if elected) must be reduced by half of the ITC. If the Company claims the PTC, there is no September 27, 2017, first ● 80% Dec. 31, 2022 Jan. 1, 2024. ● 60% Dec. 31, 2023 Jan. 1, 2025. ● 40% Dec. 31, 2024 Jan. 1, 2026. ● 20% Dec. 31, 2025 Jan. 1, 2027. The Company could also elect in lieu of bonus deprecation to depreciate most of the plant for tax purposes over five may first Income taxes related to foreign operations Guatemala 25%. ten August 2017. August 2017, 7% December 31, 2018, 2017, 2016 $2.0 $2.6 $3.3 $0.04, $0.05, $0.07 Israel 26.5% 2015, 25% 2016, 24% 2017 23% 2018 1959 two January 2011, 16% 2014 2011. 25% 25% 2004 2008. may may Kenya 37.5%. September 11, 2015, 2015. 150% 17B 5 10 15 4 15 5 January 1, 2016 January 1, 2015 15 4 15 5 During the fourth 2018, 2014 2017. As previously reported by the Company, the KRA conducted an audit related to the Company’s operations in Kenya for fiscal years 2012 2013. June 20, 2017, $2.6 June 2017 150% $1.2 Guadeloupe 34.43% 2017, 33.3% 2018, 31% 2019, 28% 2020, 26.5% 2021 25% 2022. Honduras first ten Other significant foreign countries 28% 2018 2017. Income taxes related to U.S. tax legislation commonly referred to as the Tax Cuts and Jobs Act On December 22, 2017, not 1 35 21 2 3 one December 31, 2017; ( 4 5 6 December 31, 2017.

Note 19 - Business Segments

Note 19 - Business Segments	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Segment Reporting Disclosure [Text Block]	NOTE 19 In 2018, 280, 2018 three Transfer prices between the operating segments were determined 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) Year Ended December 31, 2018: Revenues from external customers: United States (1) $ 305,962 $ 14,999 $ 7,645 $ 328,606 Foreign (2) 203,917 186,744 — 390,661 Net revenues from external customers 509,879 201,743 7,645 719,267 Intersegment revenues — 48,817 — 48,817 Depreciation and amortization expense 126,181 4,311 1,741 132,233 Operating income (loss) 155,546 38,083 (8,519 ) 185,110 Segment assets at period end (3) (*) 2,896,938 156,942 67,470 3,121,350 Expenditures for long-lived assets 219,803 9,993 28,725 258,521 * Including unconsolidated investments 71,983 — — 71,983 Year Ended December 31, 2017: Net revenues from external customers $ 465,593 $ 224,483 $ 2,736 $ 692,812 Intersegment revenues — 109,040 — 109,040 Depreciation and amortization expense 109,928 3,470 1,748 115,146 Operating income 157,613 50,543 (3,138 ) 205,018 Segment assets at period end (3) (*) 2,457,514 115,713 50,637 2,623,864 Expenditures for long-lived assets 252,581 6,653 — 259,234 * Including unconsolidated investments 34,084 — — 34,084 Year Ended December 31, 2016 : Net revenues from external customers $ 436,292 $ 226,299 $ — 662,591 Intersegment revenues — 56,075 — 56,075 Depreciation and amortization expense 102,698 3,279 — 105,977 Operating income 126,828 75,054 — 201,882 Segment assets at period end 2,204,444 257,125 — 2,461,569 Expenditures for long-lived assets 147,211 4,719 — 151,930 ( 1 Electricity segment revenues in the United States are all accounted under ASC 840, $26.9 December 31, 2018 606 2018. 606, 1 ( 2 Electricity segment revenues in foreign countries are all accounted under ASC 840, 606 1 ( 3 Electricity segment assets include goodwill in the amount of $20.0 $7.6 December 31, 2018 2017, $0 $13.5 December 31, 2018 2017, 9 Reconciling information between reportable segments and the Company’s consolidated totals is shown in the following table: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Revenues: Total segment revenues $ 719,267 $ 692,812 $ 662,591 Intersegment revenues 48,817 109,040 56,075 Elimination of intersegment revenues (48,817 ) (109,040 ) (56,075 ) Total consolidated revenues $ 719,267 $ 692,812 $ 662,591 Operating income: Operating income $ 185,110 $ 205,018 $ 201,882 Interest income 974 988 971 Interest expense, net (70,924 ) (54,142 ) (67,389 ) Foreign currency translation and transaction losses (4,761 ) 2,654 (5,534 ) Income attributable to sale of equity interest 19,003 17,878 16,503 Other non-operating income, net 7,779 (1,666 ) (5,345 ) Total consolidated income before income taxes and equity in income of investees $ 137,181 $ 170,730 $ 141,088 The Company sells electricity and products for power plants and others, mainly to the geographical areas according to location of the customers, as detailed below. The following tables present certain data by geographic area: Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Revenues from external customers attributable to: (1) United States $ 328,606 $ 301,132 $ 307,025 Indonesia 4,379 28,968 100,856 Kenya 119,094 110,243 109,270 Turkey 168,699 125,166 46,270 Chile 980 8,895 58,032 Guatemala 27,975 27,991 30,086 New Zealand 10,451 33,395 — Other foreign countries 59,083 57,022 11,052 Consolidated total $ 719,267 $ 692,812 $ 662,591 ( 1 Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Long-lived assets (primarily power plants and related assets) located in: United States $ 1,696,439 $ 1,510,986 $ 1,414,523 Kenya 301,956 340,970 327,157 Other foreign countries 222,872 281,333 199,559 Consolidated total $ 2,221,267 $ 2,133,289 $ 1,941,239 The following table presents revenues from major customers: Year Ended December 31, 2018 2017 2016 Revenues % Revenues % Revenues % (Dollars in thousands) (Dollars in thousands) (Dollars in thousands) Southern California Public Power (1) $ 109,208 15.2 $ 70,100 10.1 $ 67,566 10.2 Sierra Pacific Power Company and Nevada Power Company (1)(2) 116,149 16.1 125,424 18.1 127,226 19.2 Hyundai (3) 4,379 0.6 28,968 4.2 100,856 15.2 KPLC (1) 119,094 16.6 110,243 15.9 109,270 16.5 ( 1 ( 2 ( 3

Note 20 - Transactions With Rel

Note 20 - Transactions With Related Entities	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Related Party Transactions Disclosure [Text Block]	NOTE 20 There were no

Note 21 - Employee Benefit Plan

Note 21 - Employee Benefit Plan	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Pension and Other Postretirement Benefits Disclosure [Text Block]	NOTE 21 401 (k) Plan The Company has a 401 one one 60% 2018, 2017 2016, 4%, 3% 2% $1.6 $1.4 $1.0 December 31, 2018, 2017, 2016, Severance plan The Company, through Ormat Systems, provides limited non-pension benefits to all current employees in Israel who are entitled to benefits in the event of termination or retirement in accordance with the Israeli Government sponsored programs. These plans generally obligate the Company to pay one no $10.6 $13.9 December 31, 2018 2017, not may not December 31, 2018, 2017, 2016 $3.0 $3.2 $2.3 1.1 $1.8 $0.3 The Company expects to pay the following future benefits to its employees upon their reaching normal retirement age: (Dollars in thousands) Year ending December 31 : 2019 $ 3,677 2020 1,183 2021 1,470 2022 2,032 2023 1,246 2024-2028 4,262 Total $ 13,870 The above amounts were determined based on the employees’ current salary rates and the number of years’ service that will have been accumulated at their retirement date. These amounts do not

Note 22 - Commitments and Conti

Note 22 - Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Commitments and Contingencies Disclosure [Text Block]	NOTE 22 Geothermal resources The Company, through its project subsidiaries in the U.S., controls certain rights to geothermal fluids through certain leases with the BLM or through private leases. Royalties on the utilization of the geothermal resources are computed and paid to the lessors as defined in the respective agreements. Royalty expense under the geothermal resource agreements were $21.6 $19.4 $17.1 December 31, 2018, 2017, 2016, Letters of credit In the ordinary course of business with customers, vendors, and lenders, the Company is contingently liable for performance under letters of credit totaling $229.6 December 31, 2018. not not Purchase commitments The Company purchases raw materials for inventories, construction-in-process and services from a variety of vendors. During the normal course of business, in order to manage manufacturing lead times and help assure adequate supply, the Company enters into agreements with contract manufacturers and suppliers that either allow them to procure goods and services based upon specifications defined by the Company, or that establish parameters defining the Company’s requirements. At December 31, 2018, $129.3 $36.1 2019. Grants and royalties The Company, through Ormat Systems, had historically, through December 31, 2003, 3.5% 5.0% No December 31, 2018, 2017, 2016. not not December 31, 2018 2017, $2.0 $1.9 $1.0 $0.9 Lease commitments The Company entered into lease transactions for a fleet of vehicles. The lease transactions are classified as capital leases and the leased vehicles are classified under Property, Plant and Equipment in the total amount of $7.5 $3.6 December 31, 2018 2017, 5 five (Dollars in thousands) Year ending December 31: 2019 $ 3,118 2020 3,318 2021 2,283 2022 1,941 2023 1,307 Total $ 11,967 The following is a schedule by years of future minimum rental payments required under operating leases that have initial or remaining noncancelable lease terms in excess of one December 31, 2018. Year ending December 31: (Dollars in thousands) 2019 $ 7,771 2020 4,197 2021 3,475 2022 2,474 2023 1,603 Later years 9,292 Total minimum rental payments $ 28,812 Contingencies ● On May 21, 2018, 11 August 3, 2017 May 13, 2018". 31 1 38C 1 2017 2 May 16, 2018, May 11, 2018 2017 ● On June 11, 2018, August 8, 2017 May 15, 2018 10 10b 5 20 10 December 31, 2016 2017, 10 nine September 30, 2017 four ● On September 11, 2018, October 22, 2018, three four 14 2018 ● Following the announcement of the Company’s acquisition of USG, a number of putative shareholder class action complaints were initially filed on behalf of USG shareholders between March 8, 2018 March 30, 2018 No. 2018 0177 Mar. 12, 2018). May 24, 2018 ● On February 18, 2018, January 16, 2018 2 January 2018 3 ● On August 5, 2016, December 12, 2016, August 2014. June 14, 2017, March 25, 2017 two third 2018 January 2019, ● On March 29, 2016, 27th $4.6 3.75% 10 11th 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 23 - Quarterly Financial I

Note 23 - Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Quarterly Financial Information [Text Block]	NOTE 23 Three Months Ended Mar. 31, 2017 June 30, 2017 Sept. 30, 2017 Dec. 31, 2017 Mar. 31, 2018 June 30, 2018 Sept. 30, 2018 Dec. 31, 2018 (Dollars in thousands, except per share amounts) Revenues: Electricity $ 115,776 $ 110,896 $ 110,876 $ 128,045 $ 132,489 $ 122,179 $ 116,891 $ 138,320 Product 74,122 67,587 44,912 37,862 48,672 54,915 48,439 49,717 Other -- 881 1,397 458 2,862 1,205 1,150 2,428 Total revenues 189,898 179,364 157,185 166,365 184,023 178,299 166,480 190,465 Cost of revenues: Electricity 66,036 63,196 64,444 73,164 73,482 81,236 79,845 63,692 Product 49,452 43,432 32,218 26,992 33,726 37,573 35,669 33,729 Other -- 2,243 1,330 1,853 3,443 2,028 2,174 2,235 Total cost of revenues 115,488 108,871 97,992 102,009 110,651 120,837 117,688 99,656 Gross profit 74,410 70,493 59,193 64,356 73,372 57,462 48,792 90,809 Operating expenses: Research and development expenses 602 1,050 716 789 1,108 1,251 706 1,118 Selling and marketing expenses 4,363 4,090 3,630 3,517 3,699 3,712 8,578 3,813 General and administrative expenses 9,949 12,201 10,877 9,854 13,849 15,866 13,606 4,429 Impairment charge -- -- -- -- -- -- -- 13,464 Write-off of unsuccessful exploration activities -- -- -- 1,796 123 -- -- 3 Operating income 59,496 53,152 43,970 48,400 54,593 36,633 25,902 67,982 Other income (expense): Interest income 244 362 255 127 113 189 214 458 Interest expense, net (14,923 ) (14,540 ) (11,692 ) (12,987 ) (14,344 ) (15,846 ) (18,700 ) (22,034 ) Derivatives and foreign currency transaction gains (losses) 1,338 1,703 (1,001 ) 614 (1,599 ) (529 ) (383 ) (2,250 ) Income attributable to sale of tax benefits 6,157 4,356 3,506 3,859 7,361 3,556 4,066 4,020 Other non-operating income (expense), net (92 ) 6 (1,592 ) 12 (20 ) 7,373 309 117 Income from continuing operations, before income tax and equity in earnings (losses) of investees 52,220 45,039 33,446 40,025 46,104 31,376 11,408 48,293 Income tax benefit (provision) (11,004 ) (32,765 ) (6,224 ) 28,329 26,942 (29,105 ) (1,184 ) (31,386 ) Equity in earnings (losses) of investees, net (1,599 ) (428 ) 337 (267 ) 1,210 388 (117 ) 6,182 Income from continuing operations 39,617 11,846 27,559 68,087 74,256 2,659 10,107 23,089 Net loss (income) attributable to noncontrolling interest (4,423 ) (3,206 ) (3,599 ) (3,467 ) (4,748 ) (3,002 ) 474 (4,869 ) Net income (loss) attributable to the Company's stockholders $ 35,194 $ 8,640 $ 23,960 $ 64,620 $ 69,508 $ (343 ) $ 10,581 $ 18,220 Earnings (loss) per share attributable to the Company's stockholders Basic: Net income $ 0.71 $ 0.17 $ 0.48 $ 1.28 $ 1.37 $ (0.01 ) $ 0.21 $ 0.36 Diluted: Net income $ 0.70 $ 0.17 $ 0.47 $ 1.27 $ 1.36 $ (0.01 ) $ 0.21 $ 0.36 Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders: Basic 49,680 49,771 50,367 50,607 50,614 50,623 50,645 50,691 Diluted 50,491 50,624 50,867 51,053 51,051 50,958 50,963 50,936

Note 24 - Subsequent Events

Note 24 - Subsequent Events	12 Months Ended
	Dec. 31, 2018
Notes to Financial Statements
Subsequent Events [Text Block]	NOTE 24 Cash dividend On February 26, 2019, $5.6 $0.11 March 14, 2019, March 28, 2019.

Significant Accounting Policies

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Description Of Business [Policy Text Block]	Business The Company is primarily engaged in the geothermal and recovered energy business, including the supply of equipment that is manufactured by the Company and the design and construction of power plants for projects owned by the Company or for third Most of the Company’s domestic power plant facilities are Qualifying Facilities under the PURPA. The PPAs for certain of such facilities are dependent upon their maintaining Qualifying Facility status. Management believes that all of the facilities located in the U.S. were in compliance with Qualifying Facility status requirements as of December 31, 2018.
Dividend Declared [Policy Text Block]	Cash dividends During the years ended December 31, 2018, 2017, 2016, $26.8 $0.53 $20.5 $0.41 $25.7 $0.52
Rounding [Policy Text Block]	Rounding Dollar amounts, except per share data, in the notes to these financial statements are rounded to the closest $1,000,
Basis of Accounting, Policy [Policy Text Block]	Basis of presentation The consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of the Company and of all majority-owned subsidiaries in which the Company exercises control over operating and financial policies, and variable interest entities in which the Company has an interest and is the primary beneficiary. Intercompany accounts and transactions have been eliminated in consolidation. Investments in less-than-majority-owned entities or other entities in which the Company exercises significant influence over operating and financial policies are accounted for using the equity method of accounting or consolidated if they are a variable interest entity in which the Company has an interest and is the primary beneficiary. Under the equity method, original investments are recorded at cost and adjusted by the Company’s share of undistributed earnings or losses of such companies. The Company’s earnings or losses in investments accounted for under the equity method have been reflected as “equity in earnings (losses) of investees, net” on the Company’s consolidated statements of operations and comprehensive income (loss).
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and cash equivalents The Company considers all highly liquid instruments, with an original maturity of three
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]	Restricted cash, cash equivalents, and marketable securities Under the terms of certain long-term debt agreements, the Company is required to maintain certain debt service reserves, cash collateral and operating fund accounts that have been classified as restricted cash and cash equivalents. Funds that will be used to satisfy obligations due during the next twelve
Reconciliation of Cash and Cash Equivalents and Restricted Cash [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: December 31, 2018 2017 2016 (Dollars in thousands) Cash and cash equivalents $ 98,802 $ 47,818 $ 230,214 Restricted cash and cash equivalents 78,693 48,825 34,262 Total Cash and cash equivalents and restricted cash and cash equivalents $ 177,495 $ 96,643 $ 264,476
Concentration Risk, Credit Risk, Policy [Policy Text Block]	Concentration of credit risk Financial instruments which potentially subject the Company to 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 U.S. and in foreign countries. At December 31, 2018 2017, $31.3 $21.2 ten seven $250,000 December 31, 2018 2017, $93.9 $32.8 not At December 31, 2018 2017, $102.0 $78.1 December 31, 2018, 2017, 19 56% 57%, 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 Additionally, one 1.9% 11 January 2019 may
Inventory, Policy [Policy Text Block]	Inventories Inventories consist primarily of raw material parts and sub-assemblies for power units and are stated at the lower of cost or net realizable value, using the weighted-average cost method. Inventories are reduced by a provision for slow-moving and obsolete inventories. This provision was not December 31, 2018 2017.
Deposit Contracts, Policy [Policy Text Block]	Deposits and other Deposits and other consist primarily of performance bonds for construction projects, long-term insurance contract and receivables, and derivative instruments.
Deferred Charges, Policy [Policy Text Block]	Deferred charges Deferred charges represent prepaid income taxes on intercompany sales. Such amounts were amortized using the straight-line method and included in income tax provision over the life of the related property, plant and equipment. The Company adopted Accounting Standards Update 2016 16, first 2018 $49.8 December 31, 2018"
Property, Plant and Equipment, Policy [Policy Text Block]	Property, plant and equipment, net Property, plant and equipment are stated at cost. All costs associated with the acquisition, development and construction of power plants operated by the Company are capitalized. Major improvements are capitalized and repairs and maintenance (including major maintenance) costs are expensed. Power plants operated by the Company, which include geothermal wells and exploration and resource development costs, are depreciated using the straight-line method over their estimated useful lives, which range from 15 30 Buildings (in years) 25 Leasehold improvements (in years) 15 - 20 Machinery and equipment — manufacturing and drilling (in years) 10 Machinery and equipment — computers (in years) 3 - 5 Office equipment — furniture and fixtures (in years) 5 - 15 Office equipment — other (in years) 5 - 10 Automobiles (in years) 5 - 7 The cost and accumulated depreciation of items sold or retired are removed from the accounts. Any resulting gain or loss is recognized currently and recorded in the accompanying statements of operations. The Company capitalizes interest costs as part of constructing power plant facilities. Such capitalized interest is recorded as part of the asset to which it relates and is amortized over the asset’s estimated useful life. Capitalized interest costs amounted to $3.7 $7.2 $3.3 December 31, 2018, 2017, 2016,
Exploratory Drilling Costs Capitalization and Impairment, Policy [Policy Text Block]	Exploration and development costs The Company capitalizes costs incurred in connection with the exploration and development of geothermal resources once it acquires land rights to the potential geothermal resource. Prior to acquiring land rights, the Company makes an initial assessment that an economically feasible geothermal reservoir is probable on that land. The Company determines the economic feasibility of potential geothermal resources internally, with all available data and external assessments vetted through the exploration department and occasionally using outside service providers. Costs associated with the initial assessment are expensed and included in cost of electricity revenues in the consolidated statements of operations and comprehensive income (loss). Such costs were immaterial during the years ended December 31, 2018, 2017 2016. two three may In most cases, the Company obtains the right to conduct the geothermal development and operations on land owned by the BLM, various states or with private parties. In consideration for certain of these leases, the Company may Following the acquisition of land rights to the potential geothermal resource, the Company conducts further studies and surveys, including water and soil analyses among others, and augments its database with the results of these studies. The Company then initiates a suite of geophysical surveys to assess the resource and determine drilling locations. If the results of these activities support the initial assessment of the feasibility of the geothermal resource, the Company then proceeds to exploratory drilling and other related activities which may may not When deciding whether to continue holding lease rights and/or to pursue exploration activity, we diligently prioritize our prospective investments, taking into account resource and probability assessments in order to make informed decisions about whether a particular project will support commercial operation. As a result, write-off of unsuccessful activities for the year ended December 31, 2018, 2017 2016 $0.1 $1.8 $3.0 2017, 2016, no Grants received from the U.S. DOE are offset against the related exploration and development costs. There were no December 31, 2018 2017. December 31, 2016 $0.3 All exploration and development costs that are being capitalized, including the up-front bonus payments made to secure land leases, will be depreciated over their estimated useful lives when the related geothermal power plant is substantially complete and ready for use. A geothermal power plant is substantially complete and ready for use when electricity generation commences.
Asset Retirement Obligation [Policy Text Block]	Asset retirement obligation The Company records the fair value of a legal liability for an asset retirement obligation in the period in which it is incurred. The Company’s legal liabilities include plugging wells and post-closure costs of power producing sites. When a new liability for asset retirement obligations is recorded, the Company capitalizes the costs of the liability by increasing the carrying amount of the related long-lived asset. The liability is accreted to its present value each period, and the capitalized cost is depreciated over the useful life of the related asset. The Company periodically reassess the assumptions used to estimate the expected cash flows required to settle the asset retirement obligation, including changes in estimated probabilities, amounts, and timing of the settlement of the asset retirement obligation, as well as changes in the legal requirements of an obligation and revises the previously recorded asset retirement obligation accordingly. At retirement, the obligation is settled for its recorded amount at a gain or loss.
Deferred Financing And Lease Transaction Costs [Policy Text Block]	Deferred financing and lease transaction costs Deferred financing costs are amortized over the term of the related obligation using the effective interest method. Amortization of deferred financing costs is presented as interest expense in the consolidated statements of operations and comprehensive income (loss). Accumulated amortization related to deferred financing costs amounted to $21.8 $31.0 December 31, 2018 2017, December 31, 2018, 2017, 2016 $4.6 $5.7 $6.9 December 31, 2018, 2017 2016, $0.0 $0.6 $0.1 Deferred transaction costs relating to the Puna operating lease (see Note 12 $4.2 23 $2.5 $2.3 December 31, 2018 2017, December 31, 2018, 2017, 2016 $0.2
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill Goodwill represents the excess of the fair value of consideration transferred in the business combination transactions of Guadeloupe, Viridity and USG over the fair value of tangible and intangible assets acquired, net of the fair value of liabilities assumed and the fair value of any noncontrolling interest in the acquisitions. Goodwill is not December 31 not first not no one not first January 2017, 2017 04, 350 2018, two two December 31, 2018" 2017 04, one not 9
Intangible Assets, Finite-Lived, Policy [Policy Text Block]	Intangible assets Intangible assets consist of allocated acquisition costs of PPAs, which are amortized using the straight-line method over the 13 25 9 19 may not no no not
Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block]	Impairment of long-lived assets and long-lived assets to be disposed of The Company evaluates long-lived assets, such as property, plant and equipment and construction-in-process for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not not not not The Company tests its operating plants that are operated together as a complex for impairment at the complex level because the cash flows of such plants result from significant shared operating activities. For example, the operating power plants in a complex are managed under a combined operation management generally with one one not not not Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset to the estimated future net undiscounted cash flows expected to be generated by the asset. The significant assumptions that the Company uses in estimating its undiscounted future cash flows include: (i) projected generating capacity of the complex or power plant and rates to be received under the respective PPA(s) and expected market rates thereafter and (ii) projected operating expenses of the relevant complex or power plant. Estimates of future cash flows used to test recoverability of a long-lived asset under development also include cash flows associated with all future expenditures necessary to develop the asset. If the assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds their fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Management believes that no may may
Derivatives, Policy [Policy Text Block]	Derivative instruments Derivative instruments (including certain derivative instruments embedded in other contracts) are measured at their fair value and recorded as either assets or liabilities unless exempted from derivative treatment as a normal purchase and sale. All changes in the fair value of derivatives are recognized in earnings unless specific hedge criteria are met, which requires a company to formally document, designate and assess the effectiveness of transactions that receive hedge accounting. The Company maintains a risk management strategy that may not
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign currency translation The U.S. dollar is the functional currency for all of the Company’s consolidated operations and those of its equity affiliates except for the Guadeloupe power plant. For those entities, all gains and losses from currency translations are included within the line item “Derivatives and foreign currency transaction gains (losses)” within the consolidated statements of operations and comprehensive income (loss). The Euro is the functional currency of the Guadeloupe power plant and thus gains and losses from currency translation adjustments related to Guadeloupe are included as currency translation adjustments in accumulated other comprehensive income in the consolidated statements of equity and in comprehensive income. The accumulated currency translation adjustments amounted to $0.0 $1.4 December 31, 2018 2017,
Comprehensive Income, Policy [Policy Text Block]	Comprehensive income (loss) reporting Comprehensive income (loss) includes net income or loss plus other comprehensive income (loss), which for the Company consists of changes in unrealized gains or losses in respect of the Company’s share in derivatives instruments of unconsolidated investment, foreign currency translation adjustments and amortization of unrealized gains in respect of derivative instruments designated as a cash flow hedge. The changes in foreign currency translation adjustments, amortization of unrealized gains and loss in respect of derivative instruments designated as a cash flow hedge during the years ended December 31, 2018, 2017 2016 5
Revenue Recognition, Policy [Policy Text Block]	Revenues and cost of revenues Revenues are primarily related to: (i) sale of electricity from geothermal and recovered energy-based power plants owned and operated by the Company; (ii) geothermal and recovered energy-based power plant equipment engineering, sale, construction and installation, and operating services and (iii) energy storage, demand-response and energy management services. Electricity segment revenues July 1, 2003, four 840 8 606, 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 customers. Substantially all of the modifications are treated as cumulative catch-ups to revenues since the additional goods are not one Other segment revenues 606 may For additional information please see “Revenues from Contracts with Customers” under “New accounting pronouncement” section below. Our accounting policy for revenues included under the comparative periods were accounted under the previous accounting standard as follows: Revenues related to the sale of electricity from geothermal and recovered energy-based power plants and capacity payments are recorded based upon output delivered and capacity provided at rates specified under relevant contract terms. For PPAs agreed to, modified, or acquired in business combinations on or after July 1, 2003, two 840 8 Revenues from engineering, operating services, and parts and product sales are recorded upon providing the service or delivery of the products and parts and when collectability is reasonably assured. Revenues from the supply and/or construction of geothermal and recovered energy-based power plant equipment and other equipment to third may In specific instances where there is a lack of dependable estimates or inherent risks cause forecast to be doubtful, then the completed-contract method is followed. Revenue is recognized when the contract is substantially complete and when collectability is reasonably assured. Costs that are closely associated with the project are deferred as contract costs and recognized similarly to the associated revenues.
Termination fee [Policy Text Block]	Termination fee Fees to terminate PPAs are recognized in the period incurred as selling and marketing expenses. During 2018, 2 $5 2018. 2017 2016, no
Standard Product Warranty, Policy [Policy Text Block]	Warranty on products sold The Company generally provides a one two December 31, 2018, 2017, 2016.
Research and Development Expense, Policy [Policy Text Block]	Research and development Research and development costs incurred by the Company for the development of existing and new geothermal, recovered energy and remote power technologies are expensed as incurred. Grants received from the DOE are offset against the related research and development expenses. There were no December 31, 2018, 2017, 2016.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	Stock-based compensation The Company accounts for stock-based compensation using the fair value method whereby compensation cost is measured at the grant date, based on the calculated fair value of the award, and is recognized as an expense over the requisite employee service period (generally the vesting period of the grant). Starting in 2016, 2016,
Tax Monetization Transactions Policy [Policy Text Block]	Tax monetization Transactions The Company has two 13 2017 13. 470. 810. 835 7.
Income Tax, Policy [Policy Text Block]	Income taxes Income taxes are accounted for using the asset and liability approach, which requires the recognition of taxes payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in the Company’s financial statements or tax returns. The measurement of current and deferred tax assets and liabilities are based on provisions of the enacted tax law. On December 22, 2017, not 1 35 21 2 3 4 5 6 7 8 December 31, 2017. 18 not not
Earnings Per Share, Policy [Policy Text Block]	Earnings per share Basic earnings per share attributable to the Company’s stockholders (“earnings per share”) 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: Year Ended December 31, 2018 2017 2016 (In thousands) Weighted average number of shares used in computation of basic earnings per share 50,643 50,110 49,469 Add: Additional shares from the assumed exercise of employee stock options 326 659 671 Weighted average number of shares used in computation of diluted earnings per share 50,969 50,769 50,140 The number of stock-based awards that could potentially dilute future earnings per share and were not 176.4 42.9 102.8 December 31, 2018, 2017, 2016.
Use of Estimates, Policy [Policy Text Block]	Use of estimates in preparation of financial statements The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of such financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. The most significant estimates with regard to the Company’s consolidated financial statements relate to the useful lives of property, plant and equipment, impairment of goodwill and long-lived assets, including intangible assets, revenue recognition of product sales using the percentage of completion method, asset retirement obligations, and the provision for income taxes.
Puna Power Plant, Policy [Policy Text Block]	Puna Power Plant On May 3, 2018, 38 three December 31, 2018 $3.3 May 2018 December 31, 2018 $12.1 May 2018.
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Pronouncements New accounting pronouncements effective in the year ended December 31, 2018 Income Taxes In March 2018, 2018 05, 740 No. 118, 118” December 2017. 18 8 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 as of January 1, 2018 24.0 For a detailed description of our Electricity, Products and Other revenues, please see “Revenues and cost of revenues” caption above. Contract Assets and Liabilities related to our Product segment: Contract assets reflect revenue recognized and performance obligations satisfied in advance of customer billing. Contract liabilities relate to payments received in advance of the satisfaction of performance under the contract. We receive payments from customers based on the terms established in our contracts. Total contract assets and contract liabilities as of December 31, 2018 December 31, 2017 December 31, December 31, 2018 2017 (Dollars in thousands) Contract assets (*) $ 42,130 $ 40,945 Contract liabilities (*) (18,402 ) (20,241 ) Contract assets, net $ 23,728 $ 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 year ended December 31, 2018: Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ - $ 33,349 Cash received in advance for which revenues have not yet recognized, net expenditures made - (38,162 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (128,659 ) - Contract assets recognized, net of recognized receivables 136,496 - Net change in contract assets and contract liabilities 7,837 (4,813 ) 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. The majority of payments are received no On December 31, 2018, $188.1 not 100% 24 The following schedule reconciles revenues accounted for under ASC 840, 606, December 31, 2018: Year Ended December 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 481,619 Electricity, Product and Other revenues accounted under ASC 606 237,648 Total consolidated revenues $ 719,267 Disaggregated revenues from contracts with customers for the year ended December 31, 2018 19 Investment in an unconsolidated company 606 one- $24.0 January 1, 2018. not not The following schedule quantifies the impact of adopting ASC 606 December 31, 2018: Year ended December 31, 2018 under previous standard Effect of the New Revenue Standard As reported for the year ended December 31, 2018 (Dollars in thousands) Equity in earnings (losses) of investees, net $ 5,615 $ 2,048 $ 7,663 Income from continuing operations 108,063 2,048 110,111 Net income attributable to the Company’s stockholders 95,918 2,048 97,966 Retained earnings as of the end of the period 420,174 2,048 422,222 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 December 31, 2018 Intra-Entity Transfers of Assets Other than Inventory In October 2016, 2016 16, not December 15, 2017 December 31, 2018 $49.8 Statement of Cash Flows: Classification of Certain Cash Receipts and Cash payments (Topic 230 In August 2016, 2016 15, 230 eight December 15, 2017 December 31, 2018 $8.0 fourth 2017 Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, 2016 01, December 15, 2017 not Intangibles –Goodwill and Other In January 2017, 2017 04, 350 not 2 2 first first December 15, 2019. January 1, 2017. 2018 New accounting pronouncements effective in future periods Derivatives and Hedging In August 2017, 2017 12, December 15, 2018, Leases In February 2016, 2016 02, 842 two 606. February 2016, 2018 11, July 2018 December 15, 2018, The Company performed an evaluation of the impact from adopting the standard on its financial statements which included, among others, utilization of internal resources to lead the implementation efforts and supplement them with external resources and accounting professionals, review of the Company’s existing lease portfolio and assess the impact to its business processes and internal control over financial reporting. The Company will adopt this update on January 1, 2019, no not one not The Company has substantially completed its assessment of the potential impact that the implementation of this update will have on its consolidated financial statements and continues to finalize its efforts relative to the adoption of this update as of January 1, 2019. not $27.0 $30.0 not Reclassification of Certain Tax Effects from Accumulated Other Comprehensive income In February 2018, 2018 02, 220 December 15, 2018, not NOTE 1 Retrospective adjustments as a result of adoption of accounting policies and change in segments As described above in Note 1, 2016 15, 2016 18, December 31, 2017 2016 19, 2018, 280, December 31, 2017.

Note 1 - Business and Signifi_2

Note 1 - Business and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Cash and Cash Equivalents [Table Text Block]	December 31, 2018 2017 2016 (Dollars in thousands) Cash and cash equivalents $ 98,802 $ 47,818 $ 230,214 Restricted cash and cash equivalents 78,693 48,825 34,262 Total Cash and cash equivalents and restricted cash and cash equivalents $ 177,495 $ 96,643 $ 264,476
Schedule Of Estimated Useful Lives [Table Text Block]	Buildings (in years) 25 Leasehold improvements (in years) 15 - 20 Machinery and equipment — manufacturing and drilling (in years) 10 Machinery and equipment — computers (in years) 3 - 5 Office equipment — furniture and fixtures (in years) 5 - 15 Office equipment — other (in years) 5 - 10 Automobiles (in years) 5 - 7
Schedule of Weighted Average Number of Shares [Table Text Block]	Year Ended December 31, 2018 2017 2016 (In thousands) Weighted average number of shares used in computation of basic earnings per share 50,643 50,110 49,469 Add: Additional shares from the assumed exercise of employee stock options 326 659 671 Weighted average number of shares used in computation of diluted earnings per share 50,969 50,769 50,140
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 as of January 1, 2018 24.0 Year Ended December 31, 2018 (Dollars in thousands) Electricity Revenues accounted under ASC 840, Leases $ 481,619 Electricity, Product and Other revenues accounted under ASC 606 237,648 Total consolidated revenues $ 719,267 Year ended December 31, 2018 under previous standard Effect of the New Revenue Standard As reported for the year ended December 31, 2018 (Dollars in thousands) Equity in earnings (losses) of investees, net $ 5,615 $ 2,048 $ 7,663 Income from continuing operations 108,063 2,048 110,111 Net income attributable to the Company’s stockholders 95,918 2,048 97,966 Retained earnings as of the end of the period 420,174 2,048 422,222
Contract with Customer, Asset and Liability [Table Text Block]	December 31, December 31, 2018 2017 (Dollars in thousands) Contract assets (*) $ 42,130 $ 40,945 Contract liabilities (*) (18,402 ) (20,241 ) Contract assets, net $ 23,728 $ 20,704 Contract assets Contract liabilities (Dollars in thousands) Recognition of contract liabilities as revenue as a result of performance obligations satisfied $ - $ 33,349 Cash received in advance for which revenues have not yet recognized, net expenditures made - (38,162 ) Reduction of contract assets as a result of rights to consideration becoming unconditional (128,659 ) - Contract assets recognized, net of recognized receivables 136,496 - Net change in contract assets and contract liabilities 7,837 (4,813 )

Note 2 - Business Acquisition_2

Note 2 - Business Acquisitions and Others (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	Cash and cash equivalents and restricted cash $ 37.9 Property, plant and equipment and construction-in-process 77.3 Intangible assets (1) 127.0 Goodwill (2) 12.7 Deferred taxes 1.7 Total assets acquired $ 256.6 Other working capital $ (8.2 ) Long-term term debt (98.3 ) Asset retirement obligation (9.0 ) Noncontrolling interest (34.9 ) Total liabilities assumed $ (150.4 ) Total assets acquired, and liabilities assumed, net $ 106.2
Business Acquisition, Pro Forma Information [Table Text Block]	Pro forma for the year ended December 31, 2018 Pro forma for the year ended December 31, 2017 (Dollars in thousands) Electricity revenues $ 521,175 $ 497,650 Total revenues 730,563 724,869 Income from continuing operations before income taxes and equity in losses of investees 134,142 169,546

Note 3 - Inventories (Tables)

Note 3 - Inventories (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Inventory, Current [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Raw materials and purchased parts for assembly $ 26,914 $ 12,007 Self-manufactured assembly parts and finished products 18,110 7,544 Total $ 45,024 $ 19,551

Note 4 - Cost and Estimated E_2

Note 4 - Cost and Estimated Earnings on Uncompleted Contracts (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Cost And Estimated Earnings On Uncompleted Contracts [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Costs and estimated earnings incurred on uncompleted contracts $ 278,797 $ 550,823 Less billings to date (255,069 ) (530,119 ) Total $ 23,728 $ 20,704 December 31, 2018 2017 (Dollars in thousands) Costs and estimated earnings in excess of billings on uncompleted contracts $ 42,130 $ 40,945 Billings in excess of costs and estimated earnings on uncompleted contracts (18,402 ) (20,241 ) Total $ 23,728 $ 20,704

Note 5 - Investment in an Unc_2

Note 5 - Investment in an Unconsolidated Company (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Equity Method Investments [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Sarulla $ 71,983 $ 34,084
Other Comprehensive Income (Loss) from Equity Method Investments[Table Text Block]	Year Ended December 3 1 , 2018 2017 (Dollars in thousands) Change, net of deferred tax, in unrealized gains (losses) in respect of the Company’s share in derivative instruments of unconsolidated investment $ 2,235 $ 804

Note 6 - Variable Interest En_2

Note 6 - Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Variable Interest Entities [Table Text Block]	December 31, 2018 Project Debt PPAs (Dollars in thousands) Assets: Restricted cash and cash equivalents $ 76,019 $ 2,304 Other current assets 213,007 9,698 Property, plant and equipment, net 1,552,408 306,820 Construction-in-process 90,812 13,273 Other long-term assets 177,723 9,104 Total assets $ 2,109,969 $ 341,199 Liabilities: Accounts payable and accrued expenses $ 24,245 $ 2,651 Long-term debt 805,850 — Other long-term liabilities 125,769 12,483 Total liabilities $ 955,864 $ 15,134 December 31, 2017 Project Debt PPAs (Dollars in thousands) Assets: Restricted cash, cash equivalents and marketable securities $ 48,676 $ — Other current assets 124,322 18,010 Property, plant and equipment, net 1,252,623 379,277 Construction-in-process 129,832 12,885 Other long-term assets 63,667 276 Total assets $ 1,619,120 $ 410,448 Liabilities: Accounts payable and accrued expenses $ 24,887 $ 6,863 Long-term debt 658,726 — Other long-term liabilities 93,682 6,757 Total liabilities $ 777,295 $ 13,620

Note 7 - Fair Value of Financ_2

Note 7 - Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Fair Value, by Balance Sheet Grouping [Table Text Block]	December 31, 2018 Fair Value Carrying Value at December 31, 2018 Total Level 1 Level 2 Level 3 (Dollars in thousands) Assets: Current assets: Cash equivalents (including restricted cash accounts) $ 18,787 $ 18,787 $ 18,787 $ — $ — Derivatives: Contingent receivable (1) 104 104 — — 104 Liabilities: Current liabilities: Derivatives: Contingent payables (1) (3,424 ) (3,424 ) — — (3,424 ) Currency forward contracts (2) (1,040 ) (1,040 ) — (1,040 ) — $ 14,427 $ 14,427 $ 18,787 $ (1,040 ) $ (3,320 ) 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]	Derivatives not designated as hedging instruments Location of recognized gain (loss) Amount of recognized gain (loss) 2018 2017 2016 (Dollars in thousands) Put options on natural gas price Derivative and foreign currency transaction gains (losses) $ — $ (350 ) $ — Call options on natural gas price Derivative and foreign currency transaction gains (losses) — — (1,340 ) Call and put options on oil price Derivative and foreign currency transaction gains (losses) — — (1,313 ) Contingent considerations Derivative and foreign currency transaction gains (losses) 170 (129 ) (1,527 ) Contingent considerations General and administrative expenses 10,322 2,048 — Currency forward contracts Derivative and foreign currency transaction gains (losses) (3,081 ) 3,699 238 $ 7,411 $ 5,268 $ (3,942 )
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	Fair Value Carrying Amount 2018 2017 2018 2017 (Dollars in millions) (Dollars in millions) Olkaria III Loan - OPIC 211.8 234.6 210.6 228.6 Olkaria IV Loan - DEG 2 47.2 50.7 47.5 50.0 Platanares Loan - OPIC 119.1 — 112.7 — Amatitlan Loan 29.9 32.8 29.8 33.3 Senior Secured Notes: OrCal Geothermal Inc. ("OrCal") 19.0 34.2 18.7 32.1 OFC 2 LLC ("OFC 2") 214.5 234.6 217.8 232.5 Don A. Campbell 1 ("DAC 1") 78.8 85.5 83.3 88.3 USG Prudential - NV 29.4 — 27.8 — USG Prudential - ID 18.6 — 18.9 — USG DOE 48.3 — 51.4 — Senior Unsecured Bonds 199.4 200.3 204.3 204.3 Senior Unsecured Loan 102.2 — 100.0 — Other long-term debt 5.4 7.0 6.2 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 — — 211.8 211.8 Olkaria IV - DEG 2 — — 47.2 47.2 Platanares Loan - OPIC — — 119.1 119.1 Amatitlan Loan — 29.9 — 29.9 Senior Secured Notes: OrCal Senior Secured Notes — — 19.0 19.0 OFC 2 Senior Secured Notes — — 214.5 214.5 DAC 1 Senior Secured Notes — — 78.8 78.8 USG Prudential - NV — — 29.4 29.4 USG Prudential - ID — — 18.6 18.6 USG DOE — — 48.3 48.3 Senior Unsecured Bonds — — 199.4 199.4 Senior Unsecured Loan — — 102.2 102.2 Other long-term debt — — 5.4 5.4 Revolving lines of credit — 159.0 — 159.0 Deposits 12.0 — — 12.0 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 8 - Property, Plant and _2

Note 8 - Property, Plant and Equipment and Construction-in-process (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Property, Plant and Equipment [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Land owned by the Company where the geothermal resource is located $ 38,060 $ 32,178 Leasehold improvements 5,718 3,984 Machinery and equipment 208,646 182,121 Land, buildings and office equipment 35,708 31,128 Automobiles 22,074 12,596 Geothermal and recovered energy generation power plants, including geothermal wells and exploration and resource development costs: United States of America, net of cash grants 2,065,377 1,744,728 Foreign countries 710,775 700,498 Asset retirement cost 11,448 10,563 3,097,806 2,717,797 Less accumulated depreciation (1,138,228 ) (983,106 ) Property, plant and equipment, net $ 1,959,578 $ 1,734,691
Construction In Progress [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Projects under exploration and development: Up-front bonus lease costs $ 17,018 $ 17,018 Exploration and development costs 53,237 46,154 Interest capitalized 703 703 70,958 63,875 Projects under construction: Up-front bonus lease costs 27,473 27,473 Drilling and construction costs 160,398 198,943 Interest capitalized 2,861 3,251 190,732 229,667 Total $ 261,690 $ 293,542
Rollforward Of Construction In Process [Table Text Block]	Projects under Exploration and Development Up-front Bonus Lease Costs Exploration and Development Costs Interest Capitalized Total (Dollars in thousands) Balance at December 31, 2015 $ 26,491 $ 35,726 $ 703 $ 62,920 Cost incurred during the year 1,514 25,165 — 26,679 Write off of unsuccessful exploration costs (380 ) (2,637 ) — (3,017 ) Transfer of projects under exploration and development to projects under construction (10,240 ) (21,895 ) — (32,135 ) Balance at December 31, 2016 17,385 36,359 703 54,447 Cost incurred during the year — 11,224 — 11,224 Write off of unsuccessful exploration costs (367 ) (1,429 ) — (1,796 ) Balance at December 31, 2017 17,018 46,154 703 63,875 Cost incurred during the year — 7,209 — 7,209 Write off of unsuccessful exploration costs — (126 ) — (126 ) Balance at December 31, 2018 $ 17,018 $ 53,237 $ 703 $ 70,958 Projects under Construction Up-front Bonus Lease Costs Drilling and Construction Costs Interest Capitalized Total (Dollars in thousands) Balance at December 31, 2015 $ 27,473 $ 150,467 $ 7,975 $ 185,915 Cost incurred during the year — 116,247 6,510 122,757 Transfer of projects under exploration and development to projects under construction 10,240 21,895 — 32,135 Transfer of completed projects to property, plant and equipment — (86,398 ) (2,147 ) (88,545 ) Balance at December 31, 2016 37,713 202,211 12,338 252,262 Cost incurred during the year — 231,926 7,300 239,226 Transfer of completed projects to property, plant and equipment (10,240 ) (235,194 ) (16,387 ) (261,821 ) Balance at December 31, 2017 27,473 198,943 3,251 229,667 Cost incurred during the year — 219,610 — 219,610 Cost write off — (1,380 ) — (1,380 ) Fair value of projects under construction acquired in a business combination — 4,668 — 4,668 Transfer of completed projects to property, plant and equipment — (261,443 ) (390 ) (261,833 ) Balance at December 31, 2018 $ 27,473 $ 160,398 $ 2,861 $ 190,732

Note 9 - Intangible Assets an_2

Note 9 - Intangible Assets and Goodwill (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	(Dollars in thousands) Year ending December 31: 2019 $ 13,422 2020 13,105 2021 13,105 2022 12,850 2023 12,734 Thereafter 134,658 Total $ 199,874
Schedule of Goodwill [Table Text Block]	2018 2017 (Dollars in thousands) Goodwill as of January 1, $ 21,037 $ 6,650 Goodwill acquired 12,710 13,464 Goodwill impairment charge (13,464 ) - Translation differences (333 ) 923 Goodwill as of December 31, $ 19,950 $ 21,037

Note 10 - Accounts Payable an_2

Note 10 - Accounts Payable and Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Accounts Payable and Accrued Liabilities [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Trade payable $ 56,299 $ 64,289 Salaries and other payroll costs 20,188 19,888 Customer advances 918 1,177 Accrued interest 5,914 4,462 Income tax payable 8,436 43,682 Property tax payable 2,999 1,860 Scheduling and transmission 595 531 Royalty accrual 4,610 2,909 Deferred revenues 2,300 858 Warranty accrual 4,552 3,619 Other 9,551 10,521 Total $ 116,362 $ 153,796

Note 11 - Long-term Debt and _2

Note 11 - Long-term Debt and Credit Agreements (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Long-term Debt Instruments [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Limited and non-recourse agreements: Loans: Non-recourse: Other loans $ 6,241 $ 7,252 Limited recourse: Loan agreement with OPIC (the Olkaria III power plant) 210,641 228,635 Loan agreement with OPIC (the Platanares power plant) 112,652 - Loan agreement with Banco Industrial S.A. and Westrust Bank (International) Limited 29,750 33,251 Senior Secured Notes: Non-recourse: OrCal Senior Secured Notes 18,652 32,142 DAC 1 Senior Secured Notes 83,319 88,339 Limited recourse: OFC 2 Senior Secured Notes 217,810 232,526 Other loans 96,482 - 775,547 622,145 Less current portion (63,180 ) (54,720 ) Non current portion $ 712,367 $ 567,425 Full recourse agreements: Senior Unsecured Bonds $ 204,332 $ 204,332 Senior Unsecured Loan (Migdal) 100,000 - Loan agreements with DEG (the Olkaria III and IV power plants) 47,500 50,000 Loan from a commercial bank - 587 Revolving credit lines with banks 159,000 51,500 510,832 306,419 Less current portion (164,000 ) (54,587 ) Non current portion $ 346,832 $ 251,832
Schedule of Maturities of Long-term Debt [Table Text Block]	(Dollars in thousands) Year ending December 31: 2019 $ 68,180 2020 136,018 2021 64,039 2022 205,908 2023 84,101 Thereafter 570,751 Total $ 1,128,997

Note 12 - Puna Power Plant Le_2

Note 12 - Puna Power Plant Lease Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Year ending December 31: (Dollars in thousands) 2019 $ 7,771 2020 4,197 2021 3,475 2022 2,474 2023 1,603 Later years 9,292 Total minimum rental payments $ 28,812
Projected [Member]
Notes Tables
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	(Dollars in thousands) Year ending December 31: 2019 $ 6,018 2020 2,450 2021 1,723 2022 824 2023 - Thereafter 1,917 Total $ 12,932

Note 14 - Asset Retirement Ob_2

Note 14 - Asset Retirement Obligation (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Asset Retirement Obligations [Table Text Block]	Year Ended December 31, 2018 2017 (Dollars in thousands) Balance at beginning of year $ 27,110 $ 23,348 Revision in estimated cash flows (258 ) 1,888 Liabilities incurred and acquired 10,149 — Accretion expense 2,474 1,874 Balance at end of year $ 39,475 $ 27,110

Note 15 - Stock-based Compens_2

Note 15 - Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands, except per share data) Cost of revenues $ 3,488 $ 3,369 $ 2,400 Selling and marketing expenses 792 452 247 General and administrative expenses 5,938 4,939 2,510 Total stock-based compensation expense 10,218 8,760 5,157 Tax effect on stock-based compensation expense 668 604 617 Net effect of stock-based compensation expense $ 9,550 $ 8,156 $ 4,540
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	Year Ended December 31, 2018 2017 2016 For stock options issued by the Company: Risk-free interest rates 2.8 % 1.9 % 1.3 % Expected lives (in weighted average years) 3.5 3.1 4.5 Dividend yield 0.90 % 0.62 % 1.10 % Expected volatility (weighted average) 25.5 % 27.2 % 30.7 % Forfeiture rate (weighted average) 3.1 % 0.0 % 8.4 %
Schedule of Share-based Payment Award, Equity Awards Other than Options, Valuation Assumptions [Table Text Block]	Risk-free interest rate 1.29 % Expected life (in years) 6 Dividend yield 1.14 % Expected volatility 30.7 % Forfeiture rate: Senior management 0.0 % Other employees 10.5 % Sub-Optimal Exercise Factor: Senior management 2.5 Other employees 2.0 Risk-free interest rate 1.65 % Expected life (in years) 7 Dividend yield 1.1 % Expected volatility 30.6 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 Risk-free interest rate 1.74 % Expected life (in years) 5 Dividend yield 0.66 % Expected volatility 26.3 % Forfeiture rate 10.3 % Sub-Optimal Exercise Factor 2 Risk-free interest rate 2.08 % Expected life (in years) 7 Dividend yield 0.69 % Expected volatility 29.4 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 Risk-free interest rate 2.1 % Expected life (in years) 6 Dividend yield 0.6 % Expected volatility 26.9 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 Risk-free interest rate 2.84 % Expected life (in years) 1.9 – 3.5 Dividend yield 0.79 % Expected volatility 25.24 % Forfeiture rate 0.0 % Sub-Optimal Exercise Factor 2.5 Risk-free interest rate 2.79 % Expected life (in years) 3.5 – 3.7 Dividend yield 0.92 % Expected volatility 25.64 % Forfeiture rate for employees 2.78 % Forfeiture rate for members of the senior management 0.0 % Sub-Optimal Exercise Factor for employees 2.0 Sub-Optimal Exercise Factor for members of the senior management 2.8 Risk-free interest rate 3.11 % Expected life (in years) 2.0 – 3.6 Dividend yield 1.03 % Expected volatility 25.87 % Forfeiture rate for directors 0.0 % Forfeiture rate for employees 2.78 % Sub-Optimal Exercise Factor for directors 2.8 Sub-Optimal Exercise Factor for employees 2.0
Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity [Table Text Block]	Year Ended December 31, 2018 2017 2016 Shares (In thousands) Weighted Average Exercise Price Shares (In thousands) Weighted Average Exercise Price Shares (In thousands) Weighted Average Exercise Price Outstanding at beginning of year 1,548 $ 41.35 2,565 $ 33.36 2,438 $ 25.38 Granted, at fair value: Stock Options — — 30 57.97 1,155 43.01 SARs* 1,172 53.87 132 62.55 — — RSUs** 74 — 23 — — — Exercised (203 ) 29.75 (1,181 ) 25.92 (967 ) 25.33 Forfeited (64 ) 45.73 (21 ) 46.15 (57 ) 24.12 Expired — — — — (4 ) 26.84 Outstanding at end of year 2,527 46.77 1,548 41.35 2,565 33.36 Options and SARs exercisable at end of year 846 42.06 431 32.61 557 25.22 Weighted-average fair value of options and SARs granted during the year $ 16.45 $ 22.82 $ 11.61
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]	Options Outstanding Options Exercisable Exercise Price Number of Stock-based Awards Outstanding Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value Number of Stock-based Awards Exercisable Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value $ - 75 1.8 3,933 - - - 20.13 29 0.3 924 29 0.3 924 23.34 99 0.4 2,897 99 0.4 2,897 35.15 15 4.1 257 15 4.1 257 38.24 15 3.8 211 15 3.8 211 42.87 942 3.5 8,879 521 3.5 4,918 47.46 38 4.9 182 38 4.9 182 53.16 35 5.9 - - - - 53.44 828 5.5 - - - - 55.16 296 4.9 - 66 4.9 - 57.97 30 5.6 - 30 5.6 - 58.79 16 3.5 - - - - 63.35 109 4.9 - 33 4.9 - 2,527 4.3 $ 17,283 846 3.3 $ 9,389 Options Outstanding Options Exercisable Exercise Price Number of Stock-based Awards Outstanding Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value Number of Stock-based Awards Exercisable Weighted Average Remaining Contractual Life in Years Aggregate Intrinsic Value $ - 23 3.9 1,455 - - - 20.13 35 1.3 1,533 35 1.3 1,533 23.34 176 1.4 7,150 176 1.4 7,150 25.65 10 0.3 398 10 0.3 398 35.15 15 5.1 432 15 5.1 432 38.24 15 4.8 386 15 4.8 386 42.87 1,074 4.5 22,651 143 4.5 3,005 47.46 38 5.9 619 38 5.9 619 57.97 30 6.6 180 - - - 58.79 23 4.5 120 - - - 63.35 109 5.9 66 - - - 1,548 4.2 $ 34,990 432 3.0 $ 13,523

Note 17 - Interest Expense, N_2

Note 17 - Interest Expense, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Other Nonoperating Expense, by Component [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Interest related to sale of tax benefits $ 11,284 $ 6,985 $ 9,349 Interest expense 63,368 54,381 61,327 Less — amount capitalized (3,728 ) (7,224 ) (3,287 ) $ 70,924 $ 54,142 $ 67,389

Note 18 - Income Taxes (Tables)

Note 18 - Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) U.S $ 14,097 $ 13,680 $ (7,109 ) Non-U.S. (foreign) 123,084 157,050 148,197 Total income from continuing operations, before income taxes and equity in losses $ 137,181 $ 170,730 $ 141,088
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Current: Federal $ — $ 43,935 $ — State 381 43 (276 ) Foreign 14,992 11,186 13,554 Total current income tax expense $ 15,373 $ 55,164 $ 13,278 Deferred: Federal (6,886 ) (55,718 ) 57 State (2,595 ) (3,284 ) — Foreign 28,841 25,502 23,724 Total deferred tax benefit 19,360 (33,500 ) 23,781 Total Income tax provision $ 34,733 $ 21,664 $ 37,059
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	Year Ended December 31, 2018 2017 2016 U.S. federal statutory tax rate 21.0 % 35.0 % 35.0 % Impact of federal tax reform 2.6 (12.4 ) - Transition tax inclusion (5.7 ) 42.1 - Foreign tax credits (4.2 ) (50.5 ) - Tax basis adjustment - - (4.9 ) Withholding tax 5.9 34.1 - Valuation allowance - U.S. (17.2 ) (22.6 ) 16.5 State income tax, net of federal benefit 1.0 1.1 (0.6 ) Uncertain Tax Positions 2.1 - - Effect of foreign income tax, net 5.6 (10.7 ) (10.3 ) Production tax credits (3.1 ) (1.2 ) (8.3 ) Subpart F income 0.5 1.7 0.3 Tax on global intangible low-tax income 18.6 - - Intra-entity transfers of assets other than inventory (2.1 ) - - Other, net 0.3 (3.9 ) (1.4 ) Effective tax rate 25.3 % 12.7 % 26.3 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	December 31, 2018 2017 (Dollars in thousands) Deferred tax assets (liabilities): Net foreign deferred taxes, primarily depreciation $ (57,202 ) $ (61,961 ) Depreciation (30,500 ) (65,315 ) Intangible drilling costs 7,370 13,003 Net operating loss carryforward - U.S. 65,020 55,084 Tax monetization transaction (17,104 ) (13,134 ) State and Investment tax credits 813 813 Production tax credits 90,913 85,193 Foreign tax credits 58,072 86,206 Withholding tax (8,052 ) (14,400 ) Stock options amortization 1,440 1,166 Basis difference in partnership interest (36,516 ) (16,817 ) Accrued liabilities and other 624 3,109 74,878 72,947 Less - valuation allowance (22,441 ) (77,571 ) Total $ 52,437 $ (4,624 )
Summary of Valuation Allowance [Table Text Block]	2018 2017 2016 (Dollars in thousands) Balance at beginning of the year $ 77,571 $ 116,234 $ 92,898 Additions to valuation allowance 4,747 46,560 23,336 Release of valuation allowance (59,877 ) (85,223 ) - Balance at end of the year $ 22,441 $ 77,571 $ 116,234
Schedule of Deferred Taxes Classified in Balance Sheet [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Non-current deferred tax assets $ 113,760 $ 57,337 $ — Non-current deferred tax liabilities (61,323 ) (61,961 ) (36,411 ) Non-current deferred tax assets, net 52,437 (4,624 ) (36,411 ) Uncertain tax benefit offset (1) (95 ) (95 ) — $ 52,342 $ (4,719 ) $ (36,411 )
Summary of Income Tax Contingencies [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Balance at beginning of year $ 6,357 $ 4,609 $ 7,781 Additions based on tax positions taken in prior years 293 5 675 Additions based on tax positions taken in the current year 2,446 2,580 1,532 Reduction based on tax positions taken in prior years (276 ) (837 ) (5,379 ) Balance at end of year $ 8,820 $ 6,357 $ 4,609
Summary of Income Tax Examinations [Table Text Block]	Israel 2015 - 2018 Kenya 2012 - 2018 Guatemala 2014 - 2018 Honduras 2014 - 2018 Guadeloupe 2016 - 2018 New Zealand 2012 - 2018

Note 19 - Business Segments (Ta

Note 19 - Business Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Electricity Product Other Consolidated (Dollars in thousands) Year Ended December 31, 2018: Revenues from external customers: United States (1) $ 305,962 $ 14,999 $ 7,645 $ 328,606 Foreign (2) 203,917 186,744 — 390,661 Net revenues from external customers 509,879 201,743 7,645 719,267 Intersegment revenues — 48,817 — 48,817 Depreciation and amortization expense 126,181 4,311 1,741 132,233 Operating income (loss) 155,546 38,083 (8,519 ) 185,110 Segment assets at period end (3) (*) 2,896,938 156,942 67,470 3,121,350 Expenditures for long-lived assets 219,803 9,993 28,725 258,521 * Including unconsolidated investments 71,983 — — 71,983 Year Ended December 31, 2017: Net revenues from external customers $ 465,593 $ 224,483 $ 2,736 $ 692,812 Intersegment revenues — 109,040 — 109,040 Depreciation and amortization expense 109,928 3,470 1,748 115,146 Operating income 157,613 50,543 (3,138 ) 205,018 Segment assets at period end (3) (*) 2,457,514 115,713 50,637 2,623,864 Expenditures for long-lived assets 252,581 6,653 — 259,234 * Including unconsolidated investments 34,084 — — 34,084 Year Ended December 31, 2016 : Net revenues from external customers $ 436,292 $ 226,299 $ — 662,591 Intersegment revenues — 56,075 — 56,075 Depreciation and amortization expense 102,698 3,279 — 105,977 Operating income 126,828 75,054 — 201,882 Segment assets at period end 2,204,444 257,125 — 2,461,569 Expenditures for long-lived assets 147,211 4,719 — 151,930
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Revenues: Total segment revenues $ 719,267 $ 692,812 $ 662,591 Intersegment revenues 48,817 109,040 56,075 Elimination of intersegment revenues (48,817 ) (109,040 ) (56,075 ) Total consolidated revenues $ 719,267 $ 692,812 $ 662,591 Operating income: Operating income $ 185,110 $ 205,018 $ 201,882 Interest income 974 988 971 Interest expense, net (70,924 ) (54,142 ) (67,389 ) Foreign currency translation and transaction losses (4,761 ) 2,654 (5,534 ) Income attributable to sale of equity interest 19,003 17,878 16,503 Other non-operating income, net 7,779 (1,666 ) (5,345 ) Total consolidated income before income taxes and equity in income of investees $ 137,181 $ 170,730 $ 141,088
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Revenues from external customers attributable to: (1) United States $ 328,606 $ 301,132 $ 307,025 Indonesia 4,379 28,968 100,856 Kenya 119,094 110,243 109,270 Turkey 168,699 125,166 46,270 Chile 980 8,895 58,032 Guatemala 27,975 27,991 30,086 New Zealand 10,451 33,395 — Other foreign countries 59,083 57,022 11,052 Consolidated total $ 719,267 $ 692,812 $ 662,591
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]	Year Ended December 31, 2018 2017 2016 (Dollars in thousands) Long-lived assets (primarily power plants and related assets) located in: United States $ 1,696,439 $ 1,510,986 $ 1,414,523 Kenya 301,956 340,970 327,157 Other foreign countries 222,872 281,333 199,559 Consolidated total $ 2,221,267 $ 2,133,289 $ 1,941,239
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	Year Ended December 31, 2018 2017 2016 Revenues % Revenues % Revenues % (Dollars in thousands) (Dollars in thousands) (Dollars in thousands) Southern California Public Power (1) $ 109,208 15.2 $ 70,100 10.1 $ 67,566 10.2 Sierra Pacific Power Company and Nevada Power Company (1)(2) 116,149 16.1 125,424 18.1 127,226 19.2 Hyundai (3) 4,379 0.6 28,968 4.2 100,856 15.2 KPLC (1) 119,094 16.6 110,243 15.9 109,270 16.5

Note 21 - Employee Benefit Pl_2

Note 21 - Employee Benefit Plan (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Expected Benefit Payments [Table Text Block]	(Dollars in thousands) Year ending December 31 : 2019 $ 3,677 2020 1,183 2021 1,470 2022 2,032 2023 1,246 2024-2028 4,262 Total $ 13,870

Note 22 - Commitments and Con_2

Note 22 - Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Schedule of Future Minimum Lease Payments for Capital Leases [Table Text Block]	(Dollars in thousands) Year ending December 31: 2019 $ 3,118 2020 3,318 2021 2,283 2022 1,941 2023 1,307 Total $ 11,967
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Year ending December 31: (Dollars in thousands) 2019 $ 7,771 2020 4,197 2021 3,475 2022 2,474 2023 1,603 Later years 9,292 Total minimum rental payments $ 28,812

Note 23 - Quarterly Financial_2

Note 23 - Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Tables
Quarterly Financial Information [Table Text Block]	Three Months Ended Mar. 31, 2017 June 30, 2017 Sept. 30, 2017 Dec. 31, 2017 Mar. 31, 2018 June 30, 2018 Sept. 30, 2018 Dec. 31, 2018 (Dollars in thousands, except per share amounts) Revenues: Electricity $ 115,776 $ 110,896 $ 110,876 $ 128,045 $ 132,489 $ 122,179 $ 116,891 $ 138,320 Product 74,122 67,587 44,912 37,862 48,672 54,915 48,439 49,717 Other -- 881 1,397 458 2,862 1,205 1,150 2,428 Total revenues 189,898 179,364 157,185 166,365 184,023 178,299 166,480 190,465 Cost of revenues: Electricity 66,036 63,196 64,444 73,164 73,482 81,236 79,845 63,692 Product 49,452 43,432 32,218 26,992 33,726 37,573 35,669 33,729 Other -- 2,243 1,330 1,853 3,443 2,028 2,174 2,235 Total cost of revenues 115,488 108,871 97,992 102,009 110,651 120,837 117,688 99,656 Gross profit 74,410 70,493 59,193 64,356 73,372 57,462 48,792 90,809 Operating expenses: Research and development expenses 602 1,050 716 789 1,108 1,251 706 1,118 Selling and marketing expenses 4,363 4,090 3,630 3,517 3,699 3,712 8,578 3,813 General and administrative expenses 9,949 12,201 10,877 9,854 13,849 15,866 13,606 4,429 Impairment charge -- -- -- -- -- -- -- 13,464 Write-off of unsuccessful exploration activities -- -- -- 1,796 123 -- -- 3 Operating income 59,496 53,152 43,970 48,400 54,593 36,633 25,902 67,982 Other income (expense): Interest income 244 362 255 127 113 189 214 458 Interest expense, net (14,923 ) (14,540 ) (11,692 ) (12,987 ) (14,344 ) (15,846 ) (18,700 ) (22,034 ) Derivatives and foreign currency transaction gains (losses) 1,338 1,703 (1,001 ) 614 (1,599 ) (529 ) (383 ) (2,250 ) Income attributable to sale of tax benefits 6,157 4,356 3,506 3,859 7,361 3,556 4,066 4,020 Other non-operating income (expense), net (92 ) 6 (1,592 ) 12 (20 ) 7,373 309 117 Income from continuing operations, before income tax and equity in earnings (losses) of investees 52,220 45,039 33,446 40,025 46,104 31,376 11,408 48,293 Income tax benefit (provision) (11,004 ) (32,765 ) (6,224 ) 28,329 26,942 (29,105 ) (1,184 ) (31,386 ) Equity in earnings (losses) of investees, net (1,599 ) (428 ) 337 (267 ) 1,210 388 (117 ) 6,182 Income from continuing operations 39,617 11,846 27,559 68,087 74,256 2,659 10,107 23,089 Net loss (income) attributable to noncontrolling interest (4,423 ) (3,206 ) (3,599 ) (3,467 ) (4,748 ) (3,002 ) 474 (4,869 ) Net income (loss) attributable to the Company's stockholders $ 35,194 $ 8,640 $ 23,960 $ 64,620 $ 69,508 $ (343 ) $ 10,581 $ 18,220 Earnings (loss) per share attributable to the Company's stockholders Basic: Net income $ 0.71 $ 0.17 $ 0.48 $ 1.28 $ 1.37 $ (0.01 ) $ 0.21 $ 0.36 Diluted: Net income $ 0.70 $ 0.17 $ 0.47 $ 1.27 $ 1.36 $ (0.01 ) $ 0.21 $ 0.36 Weighted average number of shares used in computation of earnings per share attributable to the Company's stockholders: Basic 49,680 49,771 50,367 50,607 50,614 50,623 50,645 50,691 Diluted 50,491 50,624 50,867 51,053 51,051 50,958 50,963 50,936

Note 1 - Business and Signifi_3

Note 1 - Business and Significant Accounting Policies 1 (Details Textual) - USD ($)	May 03, 2018	Jan. 01, 2018	Mar. 15, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends, Common Stock, Cash												$ 26,800,000		$ 25,700,000
Common Stock, Dividends, Per Share, Declared												$ 0.53	$ 0.41	$ 0.52
Cash, FDIC Insured Amount				$ 250,000								$ 250,000
Accounts Receivable, Net, Current, Total				137,581,000				$ 110,410,000				137,581,000	$ 110,410,000
Provision for Doubtful Accounts												0
Deferred Costs, Total								49,834,000					49,834,000
Interest Costs Capitalized												3,728,000	7,224,000	$ 3,287,000
Exploration Abandonment and Impairment Expense				3,000			$ 123,000	1,796,000				126,000	1,796,000	3,017,000
Grants Received to Offset Exploration and Development Costs Incurred												0	0	300,000
Accumulated Amortization, Debt Issuance Costs				21,800,000				31,000,000				21,800,000	31,000,000
Amortization of Debt Issuance Costs												4,600,000	5,700,000	6,900,000
Write off of Deferred Debt Issuance Cost												0	600,000	$ 100,000
Deferred Costs, Leasing, Gross								4,200,000					$ 4,200,000
Lease Payment Term													23 years
Impairment of Long-Lived Assets to be Disposed of												0
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance				0				1,400,000				$ 0	$ 1,400,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent												21.00%	35.00%	35.00%
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount												176,400	42,900	102,800
Insured Event, Gain (Loss)												$ 4,463,000
Accounting Standards Update 2016-02 [Member]
Finance Lease, Right-of-Use Asset				27,000,000								27,000,000
Finance Lease, Liability, Total				30,000,000								30,000,000
Product Segment [Member]
Revenue, Remaining Performance Obligation, Amount				188,100,000								188,100,000
Galena 2 Power Purchase Agreement [Member]
Termination Fees				5,000,000				0				$ 5,000,000	0	0
Viridity Energy, Inc. [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			19 years									19 years
Puna Geothermal Ventures [Member]
Deferred Costs, Leasing, Gross				4,200,000								$ 4,200,000
Lease Payment Term												23 years
Deferred Costs, Leasing, Accumulated Amortization				2,500,000				2,300,000				$ 2,500,000	$ 2,300,000
Amortization of Deferred Leasing Fees														$ 200,000
Puna Geothermal Power Plant [Member]
Insured Event, Gain (Loss)	$ 3,300,000											12,100,000
Accounting Standards Update 2016-16 [Member]
Deferred Costs, Total				49,800,000								49,800,000
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total		$ 24,000,000
Accounting Standards Update 2016-15 [Member] | Reclassifcation of Cash Paid From Investing Activities to Financing Activities [Member]
Prior Period Reclassification Adjustment												$ 8,000,000
Pacific Gas & Electric [Member]
Percentage of Total Revenue												1.90%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Primary Customers [Member]
Concentration Risk, Percentage												56.00%	57.00%
UNITED STATES
Cash, Cash Equivalents, and Short-term Investments, Total				31,300,000				21,200,000				$ 31,300,000	$ 21,200,000
Foreign Countries [Member]
Cash, Cash Equivalents, and Short-term Investments, Total				93,900,000				32,800,000				93,900,000	32,800,000
Accounts Receivable, Net, Current, Total				$ 102,000,000				$ 78,100,000				$ 102,000,000	78,100,000
Maximum [Member]
Dividends, Common Stock, Cash													$ 20,500,000
Finite-Lived Intangible Asset, Useful Life												25 years
Maximum [Member] | Power Plants [Member]
Property, Plant and Equipment, Useful Life												30 years
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life												13 years
Minimum [Member] | Power Plants [Member]
Property, Plant and Equipment, Useful Life												15 years

Note 1 - Business and Signifi_4

Note 1 - Business and Significant Accounting Policies 2 (Details Textual) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Percentage	100.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	2 years

Note 1 - Business and Signifi_5

Note 1 - Business and Significant Accounting Policies - Cash and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents	$ 98,802	$ 47,818	$ 230,214
Restricted Cash and Cash Equivalents, Total	78,693	48,825	34,262
Total Cash and cash equivalents and restricted cash and cash equivalents	$ 177,495	$ 96,643	$ 264,476	$ 235,422

Note 1 - Business and Signifi_6

Note 1 - Business and Significant Accounting Policies - Property, Plant, and Equipment Estimated Useful Life (Details)	12 Months Ended
	Dec. 31, 2018
Building [Member]
Property, plant, and equipment estimated useful lives (Year)	25 years
Leasehold Improvements [Member] | Minimum [Member]
Property, plant, and equipment estimated useful lives (Year)	15 years
Leasehold Improvements [Member] | Maximum [Member]
Property, plant, and equipment estimated useful lives (Year)	20 years
Machinery And Equipment - Manufacturing And Drilling [Member]
Property, plant, and equipment estimated useful lives (Year)	10 years
Machinery and Equipment - Computers [Member] | Minimum [Member]
Property, plant, and equipment estimated useful lives (Year)	3 years
Machinery and Equipment - Computers [Member] | Maximum [Member]
Property, plant, and equipment estimated useful lives (Year)	5 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, plant, and equipment estimated useful lives (Year)	5 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, plant, and equipment estimated useful lives (Year)	15 years
Office Equipment - Other [Member] | Minimum [Member]
Property, plant, and equipment estimated useful lives (Year)	5 years
Office Equipment - Other [Member] | Maximum [Member]
Property, plant, and equipment estimated useful lives (Year)	10 years
Automobiles [Member] | Minimum [Member]
Property, plant, and equipment estimated useful lives (Year)	5 years
Automobiles [Member] | Maximum [Member]
Property, plant, and equipment estimated useful lives (Year)	7 years

Note 1 - Business and Signifi_7

Note 1 - Business and Significant Accounting Policies - Shares Used to Calculate Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted average number of shares used in computation of basic earnings per share (in shares)	50,691	50,645	50,623	50,614	50,607	50,367	49,771	49,680	50,643	50,110	49,469
Additional shares from the assumed exercise of employee stock options (in shares)									326	659	671
Weighted average number of shares used in computation of diluted earnings per share (in shares)	50,936	50,963	50,958	51,051	51,053	50,867	50,624	50,491	50,969	50,769	50,140

Note 1 - Business and Signifi_8

Note 1 - Business and Significant Accounting Policies - Impact of Adoption (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue										$ 719,267	$ 692,812	$ 662,591
Investment in an unconsolidated company as of January 1, 2018		$ 71,983				$ 34,084				71,983	34,084
Equity in earnings (losses) of investees, net		6,182	$ (117)	$ 388	$ 1,210	(267)	$ 337	$ (428)	$ (1,599)	7,663	(1,957)	(7,735)
Income from continuing operations										110,111	147,109	96,294
Net income attributable to the Company’s stockholders		18,220	10,581	(343)	69,508	64,620	23,960	8,640	35,194	97,966	132,414	88,708
Retained earnings as of the end of the period		422,222				327,255				422,222	327,255
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity in earnings (losses) of investees, net										5,615
Income from continuing operations										108,063
Retained earnings as of the end of the period		420,174								420,174
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Net income attributable to the Company’s stockholders										95,918
Electricity [Member]
Revenue		138,320	116,891	122,179	132,489	128,045	110,876	110,896	115,776	509,879	465,593	436,292
Product [Member]
Revenue		49,717	$ 48,439	$ 54,915	$ 48,672	$ 37,862	$ 44,912	$ 67,587	$ 74,122	201,743	224,483	226,299
Other Revenue [Member]
Revenue										7,645	$ 2,736
Accounting Standards Update 2014-09 [Member]
Investment in an unconsolidated company as of January 1, 2018	$ 24,000
Accounting Standards Update 2014-09 [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Equity in earnings (losses) of investees, net										2,048
Income from continuing operations										2,048
Retained earnings as of the end of the period		$ 2,048								2,048
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Net income attributable to the Company’s stockholders										2,048
Accounting Standards Update 2014-09 [Member] | Electricity [Member]
Revenue
Accounting Standards Update 2014-09 [Member] | Product [Member]
Revenue
Accounting Standards Update 2014-09 [Member] | Other Revenue [Member]
Revenue
Accounting Standards Update 2014-09 [Member] | Electricity and Product Revenue [Member]
Revenue										237,648
Accounting Standards Update 2016-02 [Member] | Electricity [Member]
Electricity Revenues accounted under ASC 840, Leases										$ 481,619

Note 1 - Business and Signifi_9

Note 1 - Business and Significant Accounting Policies - Contract Assets (Liabilities) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Contract assets (*)	[1]	$ 42,130	$ 40,945
Contract liabilities (*)	[1]	(18,402)	(20,241)
Contract assets, net		23,728	$ 20,704
Recognition of contract liabilities as revenue as a result of performance obligations satisfied		33,349
Cash received in advance for which revenues have not yet recognized, net expenditures made		(38,162)
Reduction of contract assets as a result of rights to consideration becoming unconditional		(128,659)
Contract assets recognized, net of recognized receivables		136,496
Net change in contract assets and contract liabilities		7,837
Net change in contract assets and contract liabilities		$ (4,813)
[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 2 - Business Acquisition_3

Note 2 - Business Acquisitions and Others (Details Textual) $ in Thousands		Apr. 24, 2018USD ($)MWh	Mar. 15, 2017USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Goodwill, Ending Balance				$ 19,950	$ 21,037	$ 6,650
U.S. Geothermal [Member]
Payments to Acquire Businesses, Gross		$ 110,000
Current Power Generation | MWh		38
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				21,400
Business Acquisition, Pro Forma Operating Income (Loss) since Acquisition Date, Actual				$ 2,500
Business Combination, Consideration Transferred, Total		$ 110,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill, Total	[1]	127,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Working Capital		(8,200)
Goodwill, Ending Balance	[2]	12,700
U.S. Geothermal [Member] | Neal Hot Springs [Member]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		$ 34,900
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Percent		40.00%
U.S. Geothermal [Member] | Neal Hot Springs [Member] | Measurement Input, Expected Term [Member]
Noncontrolling Interest, Measurement Input		20
U.S. Geothermal [Member] | Neal Hot Springs [Member] | Measurement Input, Discount Rate [Member]
Noncontrolling Interest, Measurement Input		0.09
U.S. Geothermal [Member] | Long-term Electricity Power Purchase Agreements [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		19 years
U.S. Geothermal [Member] | Ormat Nevada Inc. [Member]
Payments to Acquire Businesses, Gross		$ 106,000
U.S. Geothermal [Member] | Heit vs Ormat Technologies, Inc. [Member]
Payments to Acquire Businesses, Gross		$ 4,000
Viridity Energy, Inc. [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			19 years	19 years
Business Combination, Consideration Transferred, Total			$ 35,300
Business Combination, Contingent Consideration, Liability, Total			12,400	$ 10,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill, Total			34,700
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Working Capital			400
Goodwill, Ending Balance			13,500
Viridity Energy, Inc. [Member] | General and Administrative Expense [Member]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			$ (600)
[1]	Intangible assets are primarily related to long-term electricity power purchase agreements and depreciated over an average of 19 years.
[2]	Goodwill is primarily related to the expected synergies in operations as a result of the purchase transaction. The goodwill is allocated to the Electricity segment and not deductible for tax purposes.

Note 2 - Business Acquisition_4

Note 2 - Business Acquisitions and Others - Fair Value of Amounts of Identified Assets and Liabilities Assumed in a Business Combination (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Apr. 24, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill (2)		$ 19,950		$ 21,037	$ 6,650
U.S. Geothermal [Member]
Cash and cash equivalents and restricted cash			$ 37,900
Property, plant and equipment and construction-in-process			77,300
Intangible assets (1)	[1]		127,000
Goodwill (2)	[2]		12,700
Deferred taxes			1,700
Total assets acquired			256,600
Other working capital			(8,200)
Long-term term debt			(98,300)
Asset retirement obligation			(9,000)
Noncontrolling interest			(34,900)
Total liabilities assumed			(150,400)
Total assets acquired, and liabilities assumed, net			$ 106,200
[1]	Intangible assets are primarily related to long-term electricity power purchase agreements and depreciated over an average of 19 years.
[2]	Goodwill is primarily related to the expected synergies in operations as a result of the purchase transaction. The goodwill is allocated to the Electricity segment and not deductible for tax purposes.

Note 2 - Business Acquisition_5

Note 2 - Business Acquisitions and Others - Summary of Pro Forma Information Related to a Business Combination (Details) - U.S. Geothermal [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition, Pro Forma Revenue	$ 730,563	$ 724,869
Income from continuing operations before income taxes and equity in losses of investees	134,142	169,546
Electricity Segment [Member]
Business Acquisition, Pro Forma Revenue	$ 521,175	$ 497,650

Note 3 - Inventories - Inventor

Note 3 - Inventories - Inventories, Current (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Raw materials and purchased parts for assembly	$ 26,914	$ 12,007
Self-manufactured assembly parts and finished products	18,110	7,544
Total	$ 45,024	$ 19,551

Note 4 - Cost and Estimated E_3

Note 4 - Cost and Estimated Earnings on Uncompleted Contracts - Cost and Estimated Earnings on Uncompleted Contracts (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Costs and estimated earnings incurred on uncompleted contracts	$ 278,797	$ 550,823
Less billings to date	(255,069)	(530,119)
Total	23,728	20,704
Costs and estimated earnings in excess of billings on uncompleted contracts	42,130	40,945
Billings in excess of costs and estimated earnings on uncompleted contracts	$ (18,402)	$ (20,241)

Note 5 - Investment in an Unc_3

Note 5 - Investment in an Unconsolidated Company (Details Textual)	Jan. 01, 2018USD ($)	Dec. 31, 2018USD ($)MWh	Dec. 31, 2017USD ($)
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000,000
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		$ 3,800,000	$ 46,300,000
Accumulated Cash Contributions to Acquire Projects		$ 62,000,000
Contract Effective Date		April 4, 2013
Sarulla [Member] | Accounting Standards Update 2014-09 [Member]
Equity Method Investments	24,000,000
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000,000
Sarulla [Member] | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax, Ending Balance		$ 2,900,000

Note 5 - Investment in an Unc_4

Note 5 - Investment in an Unconsolidated Company - Unconsolidated Investments Mainly in Power Plants (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Sarulla [Member]
Sarulla	$ (71,983)	$ (34,084)

Note 5 - Investment in an Unc_5

Note 5 - Investment in an Unconsolidated Company - Unrealized Gain (Loss) on Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Interest Rate Swap [Member] | Sarulla [Member]
Change, net of deferred tax, in unrealized gains (losses) in respect of the Company’s share in derivative instruments of unconsolidated investment	$ 2,235	$ 804

Note 6 - Variable Interest En_3

Note 6 - Variable Interest Entities - Assets and Liabilities for the Company's 2015 Variable Interest Entity (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restricted cash and cash equivalents		$ 78,693	$ 48,825
Property, plant and equipment, net		1,959,578	1,734,691
Construction-in-process		261,690	293,542
Total assets	[1]	3,121,350	2,623,864	$ 2,461,569
Accounts payable and accrued expenses		116,362	153,796
Long-term debt		1,128,997
Other long-term liabilities		16,087	18,853
Total liabilities		1,667,651	1,321,748
Assets:
Restricted cash and cash equivalents		78,693	48,825
Property, plant and equipment, net		1,959,578	1,734,691
Construction-in-process		261,690	293,542
Total assets	[1]	3,121,350	2,623,864	$ 2,461,569
Liabilities:
Accounts payable and accrued expenses		116,362	153,796
Long-term debt		1,128,997
Other long-term liabilities		16,087	18,853
Total liabilities		1,667,651	1,321,748
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net		1,859,228	1,631,900
Construction-in-process		104,085	142,717
Assets:
Property, plant and equipment, net		1,859,228	1,631,900
Construction-in-process		104,085	142,717
Variable Interest Entity, Primary Beneficiary [Member] | Project Debt [Member]
Restricted cash and cash equivalents		76,019	48,676
Other current assets		213,007	124,322
Property, plant and equipment, net		1,552,408	1,252,623
Construction-in-process		90,812	129,832
Other long-term assets		177,723	63,667
Total assets		2,109,969	1,619,120
Accounts payable and accrued expenses		24,245	24,887
Long-term debt		805,850	658,726
Other long-term liabilities		125,769	93,682
Total liabilities		955,864	777,295
Assets:
Restricted cash and cash equivalents		76,019	48,676
Other current assets		213,007	124,322
Property, plant and equipment, net		1,552,408	1,252,623
Construction-in-process		90,812	129,832
Other long-term assets		177,723	63,667
Total assets		2,109,969	1,619,120
Liabilities:
Accounts payable and accrued expenses		24,245	24,887
Long-term debt		805,850	658,726
Other long-term liabilities		125,769	93,682
Total liabilities		955,864	777,295
Variable Interest Entity, Primary Beneficiary [Member] | Power Purchase Agreements [Member]
Restricted cash and cash equivalents		2,304
Other current assets		9,698	18,010
Property, plant and equipment, net		306,820	379,277
Construction-in-process		13,273	12,885
Other long-term assets		9,104	276
Total assets		341,199	410,448
Accounts payable and accrued expenses		2,651	6,863
Long-term debt
Other long-term liabilities		12,483	6,757
Total liabilities		15,134	13,620
Assets:
Restricted cash and cash equivalents		2,304
Other current assets		9,698	18,010
Property, plant and equipment, net		306,820	379,277
Construction-in-process		13,273	12,885
Other long-term assets		9,104	276
Total assets		341,199	410,448
Liabilities:
Accounts payable and accrued expenses		2,651	6,863
Long-term debt
Other long-term liabilities		12,483	6,757
Total liabilities		$ 15,134	$ 13,620
[1]	Electricity segment assets include goodwill in the amount of $20.0 million and $7.6 million as of December 31, 2018 and 2017, respectively. Other segment assets include goodwill in the amount of $0 million and $13.5 million as of December 31, 2018 and 2017, respectively. For further information on goodwill, see Note 9 – Intangible assets and goodwill to the consolidated financial statements.

Note 7 - Fair Value of Financ_3

Note 7 - Fair Value of Financial Instruments (Details Textual) $ in Millions	Jan. 12, 2017USD ($)MMBTU$ / BTU	Feb. 24, 2016USD ($)Boe$ / item	Feb. 02, 2016USD ($)Boe$ / item	Mar. 31, 2016Boe$ / item	Feb. 28, 2018$ / item	Feb. 28, 2016$ / item
Derivative, Number of Options Rolled				2
Henry Hub Natural Gas Future ("NG") Contracts [Member] | Put Option [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure	4.1		4,100,000
Derivative, Price Risk Option Strike Price	3		2
Payments for Derivative Instrument, Investing Activities | $	$ 0.7
Henry Hub Natural Gas Future ("NG") Contracts [Member] | Call Option [Member]
Proceeds from Derivative Instrument, Investing Activities | $			$ 1.9
Brent Oil Future Contracts [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure | Boe		185,000
Brent Oil Future Contracts [Member] | Minimum [Member]
Derivative, Price Risk Option Strike Price		32.8
Brent Oil Future Contracts [Member] | Maximum [Member]
Derivative, Price Risk Option Strike Price		35.5
Brent Oil Future Contracts [Member] | Call Option [Member]
Proceeds from Derivative Instrument, Investing Activities | $		$ 1.1
Rolled Two Existing Options [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure | Boe				31,800
Rolled Two Existing Options [Member] | Minimum [Member]
Derivative, Price Risk Option Strike Price				41		32.8
Rolled Two Existing Options [Member] | Maximum [Member]
Derivative, Price Risk Option Strike Price				42.5		33.5
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure | Boe				16,500
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member] | Minimum [Member]
Derivative, Price Risk Option Strike Price						28.5
Short Risk Reversal Transactions, Rolling Existing Call Option 1 [Member] | Maximum [Member]
Derivative, Price Risk Option Strike Price						37.5
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member]
Derivative, Nonmonetary Notional Amount, Energy Measure | Boe				17,000
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member] | Minimum [Member]
Derivative, Price Risk Option Strike Price					28
Short Risk Reversal Transactions, Rolling Existing Call Option 2 [Member] | Maximum [Member]
Derivative, Price Risk Option Strike Price					38.5

Note 7 - Fair Value of Financ_4

Note 7 - Fair Value of Financial Instruments - Financial Assets and Liabilities at Fair Value (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Reported Value Measurement [Member]
Cash equivalents (including restricted cash accounts)		$ 18,787
		14,427	$ 1,588
Cash equivalents (including restricted cash accounts)			18,359
Reported Value Measurement [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	104	108
Reported Value Measurement [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]		992
Derivative Liability, Current	[2]	(1,040)
Reported Value Measurement [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	(3,424)	(13,904)
Reported Value Measurement [Member] | Warrant [Member]
Derivative Liability, Current	[1]		(3,967)
Estimate of Fair Value Measurement [Member]
Cash equivalents (including restricted cash accounts)		18,787
		14,427	1,588
Cash equivalents (including restricted cash accounts)			18,359
Estimate of Fair Value Measurement [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	104	108
Estimate of Fair Value Measurement [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]		992
Derivative Liability, Current	[2]	(1,040)
Estimate of Fair Value Measurement [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	(3,424)	(13,904)
Estimate of Fair Value Measurement [Member] | Warrant [Member]
Derivative Liability, Current	[1]		(3,967)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash equivalents (including restricted cash accounts)		18,787
		18,787	18,359
Cash equivalents (including restricted cash accounts)			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]
Derivative Liability, 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)
		(1,040)	992
Cash equivalents (including restricted cash accounts)
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]		992
Derivative Liability, Current	[2]	(1,040)
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)
		(3,320)	(17,763)
Cash equivalents (including restricted cash accounts)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Receivable [Member]
Derivative Asset, Current	[1]	104	108
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Currency Forward Contracts [Member]
Derivative Asset, Current	[2]
Derivative Liability, Current	[2]
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Contingent Payable [Member]
Derivative Liability, Current	[1]	$ (3,424)	(13,904)
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Warrant [Member]
Derivative Liability, Current	[1]		$ (3,967)
[1]	These amounts relate to contingent receivables and payables and warrants pertaining to the Viridity acquisition 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 December 31, 2018 and 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 December 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 7 - Fair Value of Financ_5

Note 7 - 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	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amount of gain (loss) recognized	$ 7,411	$ 5,268	$ (3,942)
Foreign Currency Gain (Loss) [Member] | Put Options on Natural Gas Price [Member]
Amount of gain (loss) recognized		(350)
Foreign Currency Gain (Loss) [Member] | Call Option on Natural Gas Price [Member]
Amount of gain (loss) recognized			(1,340)
Foreign Currency Gain (Loss) [Member] | Call and Put Options on Oil Price [Member]
Amount of gain (loss) recognized			(1,313)
Foreign Currency Gain (Loss) [Member] | Contingent Considerations [Member]
Amount of gain (loss) recognized	170	(129)	(1,527)
Foreign Currency Gain (Loss) [Member] | Currency Forward Contracts [Member]
Amount of gain (loss) recognized	(3,081)	3,699	238
General and Administrative Expense [Member] | Currency Forward Contracts [Member]
Amount of gain (loss) recognized	$ 10,322	$ 2,048

Note 7 - Fair Value of Financ_6

Note 7 - Fair Value of Financial Instruments - Fair Value of Long-term Debt Approximates Its Carrying Amount, Exceptions (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Estimate of Fair Value Measurement [Member]
Other long-term debt	$ 5.4	$ 7
Reported Value Measurement [Member]
Other long-term debt	6.2	7.9
Olkaria III OPIC [Member]
Loans	211.8	234.6
Olkaria III OPIC [Member] | Estimate of Fair Value Measurement [Member]
Loans	211.8	234.6
Olkaria III OPIC [Member] | Reported Value Measurement [Member]
Loans	210.6	228.6
Olkaria IV Loan - DEG 2 [Member]
Loans	47.2
Olkaria IV Loan - DEG 2 [Member] | Estimate of Fair Value Measurement [Member]
Loans	47.2	50.7
Olkaria IV Loan - DEG 2 [Member] | Reported Value Measurement [Member]
Loans	47.5	50
Platanares Loan - OPIC [Member]
Loans	119.1
Platanares Loan - OPIC [Member] | Estimate of Fair Value Measurement [Member]
Loans	119.1
Platanares Loan - OPIC [Member] | Reported Value Measurement [Member]
Loans	112.7
Amatitlan Loan [Member]
Loans	29.9	32.8
Amatitlan Loan [Member] | Estimate of Fair Value Measurement [Member]
Loans	29.9	32.8
Amatitlan Loan [Member] | Reported Value Measurement [Member]
Loans	29.8	33.3
OrCal Geothermal Inc [Member]
Notes	19	34.2
OrCal Geothermal Inc [Member] | Estimate of Fair Value Measurement [Member]
Notes	19	34.2
OrCal Geothermal Inc [Member] | Reported Value Measurement [Member]
Notes	18.7	32.1
OFC Two Senior Secured Notes [Member] | Estimate of Fair Value Measurement [Member]
Notes	214.5	234.6
OFC Two Senior Secured Notes [Member] | Reported Value Measurement [Member]
Notes	217.8	232.5
Don A. Campbell 1 ("DAC1") [Member]
Notes	78.8	85.5
Don A. Campbell 1 ("DAC1") [Member] | Estimate of Fair Value Measurement [Member]
Notes	78.8	85.5
Don A. Campbell 1 ("DAC1") [Member] | Reported Value Measurement [Member]
Notes	83.3	88.3
USG Prudential - NV [Member]
Notes	29.4
USG Prudential - NV [Member] | Estimate of Fair Value Measurement [Member]
Notes	29.4
USG Prudential - NV [Member] | Reported Value Measurement [Member]
Notes	27.8
USG Prudential - ID [Member]
Notes	18.6
USG Prudential - ID [Member] | Estimate of Fair Value Measurement [Member]
Notes	18.6
USG Prudential - ID [Member] | Reported Value Measurement [Member]
Notes	18.9
USG DOE [Member]
Notes	48.3
USG DOE [Member] | Estimate of Fair Value Measurement [Member]
Notes	48.3
USG DOE [Member] | Reported Value Measurement [Member]
Notes	51.4
Senior Unsecured Bonds [Member]
Senior Unsecured Bonds	199.4	200.3
Senior Unsecured Bonds [Member] | Estimate of Fair Value Measurement [Member]
Senior Unsecured Bonds	199.4	200.3
Senior Unsecured Bonds [Member] | Reported Value Measurement [Member]
Senior Unsecured Bonds	204.3	204.3
Senior Unsecured Loan [Member]
Senior Unsecured Bonds	102.2
Senior Unsecured Loan [Member] | Estimate of Fair Value Measurement [Member]
Senior Unsecured Bonds	102.2
Senior Unsecured Loan [Member] | Reported Value Measurement [Member]
Senior Unsecured Bonds	$ 100

Note 7 - Fair Value of Financ_7

Note 7 - Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Revolving lines of credit	$ 159	$ 51.5
Deposits	12	15.6
Olkaria III OPIC [Member]
Loans	211.8	234.6
Olkaria IV Loan - DEG 2 [Member]
Loans	47.2
Platanares Loan - OPIC [Member]
Loans	119.1
Amatitlan Loan [Member]
Loans	29.9	32.8
OrCal Geothermal Inc [Member]
Notes	19	34.2
OFC Senior Secured Notes [Member]
Notes	214.5	234.6
Don A. Campbell 1 ("DAC1") [Member]
Notes	78.8	85.5
Senior Unsecured Bonds [Member]
Senior Unsecured Bonds	199.4	200.3
USG Prudential - NV [Member]
Notes	29.4
Other Long-term Debt [Member]
Senior Unsecured Bonds	5.4	7
USG Prudential - ID [Member]
Notes	18.6
USG DOE [Member]
Notes	48.3
Senior Unsecured Loan [Member]
Senior Unsecured Bonds	102.2
Fair Value, Inputs, Level 1 [Member]
Revolving lines of credit
Deposits	12	15.6
Fair Value, Inputs, Level 1 [Member] | Olkaria III OPIC [Member]
Loans
Fair Value, Inputs, Level 1 [Member] | Olkaria IV Loan - DEG 2 [Member]
Loans
Fair Value, Inputs, Level 1 [Member] | Platanares Loan - OPIC [Member]
Loans
Fair Value, Inputs, Level 1 [Member] | Amatitlan Loan [Member]
Loans
Fair Value, Inputs, Level 1 [Member] | OrCal Geothermal Inc [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | OFC Senior Secured Notes [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | Don A. Campbell 1 ("DAC1") [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | Senior Unsecured Bonds [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 1 [Member] | USG Prudential - NV [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | Other Long-term Debt [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 1 [Member] | USG Prudential - ID [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | USG DOE [Member]
Notes
Fair Value, Inputs, Level 1 [Member] | Senior Unsecured Loan [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 2 [Member]
Revolving lines of credit	159	51.5
Deposits
Fair Value, Inputs, Level 2 [Member] | Olkaria III OPIC [Member]
Loans
Fair Value, Inputs, Level 2 [Member] | Olkaria IV Loan - DEG 2 [Member]
Loans
Fair Value, Inputs, Level 2 [Member] | Platanares Loan - OPIC [Member]
Loans
Fair Value, Inputs, Level 2 [Member] | Amatitlan Loan [Member]
Loans	29.9	32.8
Fair Value, Inputs, Level 2 [Member] | OrCal Geothermal Inc [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | OFC Senior Secured Notes [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | Don A. Campbell 1 ("DAC1") [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | Senior Unsecured Bonds [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 2 [Member] | USG Prudential - NV [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | Other Long-term Debt [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 2 [Member] | USG Prudential - ID [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | USG DOE [Member]
Notes
Fair Value, Inputs, Level 2 [Member] | Senior Unsecured Loan [Member]
Senior Unsecured Bonds
Fair Value, Inputs, Level 3 [Member]
Revolving lines of credit
Deposits
Fair Value, Inputs, Level 3 [Member] | Olkaria III OPIC [Member]
Loans	211.8	234.6
Fair Value, Inputs, Level 3 [Member] | Olkaria IV Loan - DEG 2 [Member]
Loans	47.2	50.7
Fair Value, Inputs, Level 3 [Member] | Platanares Loan - OPIC [Member]
Loans	119.1
Fair Value, Inputs, Level 3 [Member] | Amatitlan Loan [Member]
Loans
Fair Value, Inputs, Level 3 [Member] | OrCal Geothermal Inc [Member]
Notes	19	34.2
Fair Value, Inputs, Level 3 [Member] | OFC Senior Secured Notes [Member]
Notes	214.5	234.6
Fair Value, Inputs, Level 3 [Member] | Don A. Campbell 1 ("DAC1") [Member]
Notes	78.8	85.5
Fair Value, Inputs, Level 3 [Member] | Senior Unsecured Bonds [Member]
Senior Unsecured Bonds	199.4	200.3
Fair Value, Inputs, Level 3 [Member] | USG Prudential - NV [Member]
Notes	29.4
Fair Value, Inputs, Level 3 [Member] | Other Long-term Debt [Member]
Senior Unsecured Bonds	5.4	$ 7
Fair Value, Inputs, Level 3 [Member] | USG Prudential - ID [Member]
Notes	18.6
Fair Value, Inputs, Level 3 [Member] | USG DOE [Member]
Notes	48.3
Fair Value, Inputs, Level 3 [Member] | Senior Unsecured Loan [Member]
Senior Unsecured Bonds	$ 102.2

Note 8 - Property, Plant and _3

Note 8 - Property, Plant and Equipment and Construction-in-process (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 22, 2014
Depreciation, Total	$ 114.4	$ 98.8	$ 94.8
Depreciation Net Of Amortization Of Cash Grant	6.4	5.5	$ 5.5
Property, Plant and Equipment Including Construction In Progress, Net	1,696.4	1,447.4
Property, Plant and Equipment, Cash Grant, Net	179.7	133.2
Geotermica Platanares [Member]
Property, Plant and Equipment Including Construction In Progress, Net	$ 105.7	140.3
Power Plant Usage Agreement Term	15 years
Geothermie Bouillante SA (“GB”) [Member]
Property, Plant and Equipment Including Construction In Progress, Net	$ 23.9	24.9
Orzunil I de Electricidad, Limitada [Member]
Property, Plant and Equipment Including Construction In Progress, Net	14.6	9.9
Ortitlan Limitada [Member]
Property, Plant and Equipment Including Construction In Progress, Net	$ 43.5	40.7
Kenya Power and Lighting Co Limited [Member]
Power Purchase Agreements Term	20 years
Zunil Power Plant In Guatemala [Member] | Instituto Nacional de Electrificacion (INDE) [Member] | Orzunil I de Electricidad, Limitada [Member]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners				3.00%
ENEE [Member] | Geotermica Platanares [Member]
Power Plant Usage Agreement Term	30 years
EDF [Member] | Geothermie Bouillante SA (“GB”) [Member]
Power Purchase Agreements Term	15 years
Foreign Countries [Member]
Property, Plant and Equipment Including Construction In Progress, Net	$ 524.8	580.8
KENYA | Power Plants [Member]
Property, Plant and Equipment Including Construction In Progress, Net	$ 302	$ 326.1

Note 8 - Property, Plant and _4

Note 8 - Property, Plant and Equipment and Construction-in-process - Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, plant and equipment	$ 3,097,806	$ 2,717,797
Asset retirement cost	11,448	10,563
Less accumulated depreciation	(1,138,228)	(983,106)
Property, plant and equipment, net	1,959,578	1,734,691
Land [Member]
Property, plant and equipment	38,060	32,178
Leasehold Improvements [Member]
Property, plant and equipment	5,718	3,984
Machinery and Equipment [Member]
Property, plant and equipment	208,646	182,121
Office Equipment [Member]
Property, plant and equipment	35,708	31,128
Automobiles [Member]
Property, plant and equipment	22,074	12,596
Geothermal And Recovered Energy Generation Power Plants [Member] | UNITED STATES
Property, plant and equipment	2,065,377	1,744,728
Geothermal And Recovered Energy Generation Power Plants [Member] | Foreign Countries [Member]
Property, plant and equipment	$ 710,775	$ 700,498

Note 8 - Property, Plant and _5

Note 8 - Property, Plant and Equipment and Construction-in-process - Construction-in-process (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Construction-in-process	$ 261,690	$ 293,542
Projects Under Exploration and Development [Member]
Construction-in-process	70,958	63,875	$ 54,447	$ 62,920
Projects Under Exploration and Development [Member] | Up-front Bonus Lease Costs [Member]
Construction-in-process	17,018	17,018	17,385	26,491
Projects Under Exploration and Development [Member] | Exploration and Development Costs [Member]
Construction-in-process	53,237	46,154	36,359	35,726
Projects Under Exploration and Development [Member] | Interest Capitalized [Member]
Construction-in-process	703	703	$ 703	$ 703
Projects Under Construction [Member]
Construction-in-process	190,732	229,667
Projects Under Construction [Member] | Up-front Bonus Lease Costs [Member]
Construction-in-process	27,473	27,473
Projects Under Construction [Member] | Interest Capitalized [Member]
Construction-in-process	2,861	3,251
Projects Under Construction [Member] | Drilling And Construction Costs [Member]
Construction-in-process	$ 160,398	$ 198,943

Note 8 - Property, Plant and _6

Note 8 - Property, Plant and Equipment and Construction-in-process - Activity in Construction and Development (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance				$ 293,542					$ 293,542
Write off of unsuccessful exploration costs	$ (3)			(123)	$ (1,796)				(126)	$ (1,796)	$ (3,017)
Balance	261,690				293,542				261,690	293,542
Projects Under Exploration and Development [Member]
Balance				63,875				54,447	63,875	54,447	62,920
Cost incurred during the year									7,209	11,224	26,679
Write off of unsuccessful exploration costs									(126)	(1,796)	(3,017)
Transfer of projects under exploration and development to projects under construction											(32,135)
Balance	70,958				63,875				70,958	63,875	54,447
Projects Under Exploration and Development [Member] | Up-front Bonus Lease Costs [Member]
Balance				17,018				17,385	17,018	17,385	26,491
Cost incurred during the year											1,514
Write off of unsuccessful exploration costs										(367)	(380)
Transfer of projects under exploration and development to projects under construction											(10,240)
Balance	17,018				17,018				17,018	17,018	17,385
Projects Under Exploration and Development [Member] | Exploration and Development Costs [Member]
Balance				46,154				36,359	46,154	36,359	35,726
Cost incurred during the year									7,209	11,224	25,165
Write off of unsuccessful exploration costs									(126)	(1,429)	(2,637)
Transfer of projects under exploration and development to projects under construction											(21,895)
Balance	53,237				46,154				53,237	46,154	36,359
Projects Under Exploration and Development [Member] | Interest Capitalized [Member]
Balance				703				703	703	703	703
Cost incurred during the year
Write off of unsuccessful exploration costs
Transfer of projects under exploration and development to projects under construction
Balance	703				703				703	703	703
Construction in Progress [Member]
Balance				229,667				252,262	229,667	252,262	185,915
Cost incurred during the year									219,610	239,226	122,757
Transfer of projects under exploration and development to projects under construction											32,135
Balance	190,732				229,667				190,732	229,667	252,262
Transfer of completed projects to property, plant and equipment									(261,833)	(261,821)	(88,545)
Cost write off									(1,380)
Fair value of projects under construction acquired in a business combination									4,668
Construction in Progress [Member] | Up-front Bonus Lease Costs [Member]
Balance				27,473				37,713	27,473	37,713	27,473
Cost incurred during the year
Transfer of projects under exploration and development to projects under construction											10,240
Balance	27,473				27,473				27,473	27,473	37,713
Transfer of completed projects to property, plant and equipment										(10,240)
Cost write off
Fair value of projects under construction acquired in a business combination
Construction in Progress [Member] | Drilling And Construction Costs [Member]
Balance				198,943				202,211	198,943	202,211	150,467
Cost incurred during the year									219,610	231,926	116,247
Transfer of projects under exploration and development to projects under construction											21,895
Balance	160,398				198,943				160,398	198,943	202,211
Transfer of completed projects to property, plant and equipment									(261,443)	(235,194)	(86,398)
Cost write off									(1,380)
Fair value of projects under construction acquired in a business combination									4,668
Construction in Progress [Member] | Interest Capitalized [Member]
Balance				$ 3,251				$ 12,338	3,251	12,338	7,975
Cost incurred during the year										7,300	6,510
Transfer of projects under exploration and development to projects under construction
Balance	$ 2,861				$ 3,251				2,861	3,251	12,338
Transfer of completed projects to property, plant and equipment									(390)	$ (16,387)	$ (2,147)
Cost write off
Fair value of projects under construction acquired in a business combination

Note 9 - Intangible Assets an_3

Note 9 - Intangible Assets and Goodwill (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets, Net, Ending Balance	$ 199,874,000
Amortization of Intangible Assets, Total	11,200,000	$ 6,900,000	$ 4,400,000
Increase (Decrease) in Intangible Assets, Current	127,000,000	35,600,000	33,000,000
Finite Lived Intangible Assets, Write off	0	0	0
Goodwill, Ending Balance	19,950,000	21,037,000	$ 6,650,000
Goodwill, Impairment Loss	13,464,000
Storage and Energy Management Service [Member]
Goodwill, Impairment Loss	13,500,000
Other Segments [Member]
Goodwill, Ending Balance	0	13,500,000
Goodwill, Impairment Loss	0	0
Power Purchase Agreements and Intangible Assets Related to Storage Activities [Member]
Finite-Lived Intangible Assets, Net, Ending Balance	199,900,000	85,400,000
Finite-Lived Intangible Assets, Accumulated Amortization	61,500,000	50,000,000
Intangible Assets Related to Storage Activities [Member]
Finite-Lived Intangible Assets, Net, Ending Balance	32,200,000	33,800,000
Finite-Lived Intangible Assets, Accumulated Amortization	$ 3,400,000	$ 1,700,000

Note 9 - Intangible Assets an_4

Note 9 - Intangible Assets and Goodwill - Estimated Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 13,422
2,020	13,105
2,021	13,105
2,022	12,850
2,023	12,734
Thereafter	134,658
Total	$ 199,874

Note 9 - Intangible Assets an_5

Note 9 - Intangible Assets and Goodwill - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill	$ 21,037	$ 6,650
Goodwill acquired	12,710	13,464
Goodwill impairment charge	(13,464)
Translation differences	(333)	923
Goodwill	$ 19,950	$ 21,037

Note 10 - Accounts Payable an_3

Note 10 - Accounts Payable and Accrued Expenses - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Trade payable	$ 56,299	$ 64,289
Salaries and other payroll costs	20,188	19,888
Customer advances	918	1,177
Accrued interest	5,914	4,462
Income tax payable	8,436	43,682
Property tax payable	2,999	1,860
Scheduling and transmission	595	531
Royalty accrual	4,610	2,909
Deferred revenues	18,402	20,241
Warranty accrual	4,552	3,619
Other	9,551	10,521
Total	116,362	153,796
Deferred Revenue [Member]
Deferred revenues	$ 2,300	$ 858

Note 11 - Long-term Debt and _3

Note 11 - Long-term Debt and Credit Agreements (Details Textual)	Mar. 22, 2018USD ($)	Dec. 21, 2016USD ($)	Nov. 29, 2016USD ($)	Jul. 31, 2015USD ($)MWh	Nov. 30, 2013USD ($)	Sep. 26, 2013	Feb. 28, 2013USD ($)	Nov. 30, 2012USD ($)	Feb. 29, 2012USD ($)	Oct. 31, 2018USD ($)MWh	Sep. 30, 2017USD ($)	Sep. 29, 2016USD ($)	May 31, 2016USD ($)	Aug. 18, 2014USD ($)	Jun. 30, 2014USD ($)	May 31, 2013USD ($)	Nov. 30, 2012USD ($)	Oct. 31, 2011USD ($)	Aug. 31, 2011USD ($)	Mar. 30, 2009USD ($)	Dec. 31, 2005USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2014USD ($)	Jun. 30, 2018	May 31, 2017USD ($)	Oct. 20, 2016USD ($)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 13, 2015USD ($)	Aug. 29, 2014USD ($)	Aug. 23, 2012USD ($)	Sep. 30, 2011USD ($)	Feb. 29, 2004USD ($)
Letters of Credit Outstanding, Amount																							$ 229,600,000
Repayments of Secured Debt																								$ 14,270,000	$ 6,815,000
Repayments of Long-term Debt, Total																							62,774,000	66,223,000	62,052,000
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Total																							81,000	135,000	141,000
Proceeds from Issuance of Unsecured Debt																									203,483,000
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							3.21
Stockholders' Equity Attributable to Parent, Ending Balance																							$ 1,319,837,000	1,211,378,000
Percentage Of Company Assets																							46.30%
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Ending Balance																							$ 1,445,096,000	1,295,700,000	1,168,272,000						$ 1,087,307,000
Payments of Dividends, Total																							$ 26,800,000
Interest Rate Cap [Member]
Payments for Derivative Instrument, Financing Activities														$ 1,500,000
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Total																										$ 900,000
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Total																										$ 600,000
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net																									$ 100,000							$ 100,000
Covenant Requirement Minimum [Member]
Amount Available For Dividend Distribution Percent Of Cumulative Net Income																							35
Stockholders' Equity Attributable to Parent, Ending Balance																							$ 600,000,000
Percentage Of Company Assets																							25.00%
Maximum [Member] | Covenant Requirement Minimum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							6
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member]
Debt Instrument, Term				12 years
Debt Instrument, Face Amount				$ 42,000,000
Power Utilization | MWh				20
Debt Instrument, Payment Frequency				12 years
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | Covenant Requirement Minimum [Member]
Debt Services, Coverage Ratio				1.15
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | Covenant Required to not Limit Dividends [Member]
Debt Services, Coverage Ratio				1.25
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | Minimum [Member]
Debt Instrument, Prepayment Premium Percentage				0.50%
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | Maximum [Member]
Debt Instrument, Prepayment Premium Percentage				1.00%
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Guaranteed [Member]
Debt Instrument, Basis Spread on Variable Rate				4.35%
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Not Guaranteed [Member]
Debt Instrument, Basis Spread on Variable Rate				4.75%
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument, Basis Spread on Variable Rate				1.25%
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited [Member]
Debt Instrument, Face Amount																																		$ 310,000,000
Long-term Debt, Gross																							$ 29,800,000
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited [Member] | Historical [Member]
Debt Services, Coverage Ratio																							1.58
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited [Member] | Projected [Member]
Debt Services, Coverage Ratio																							1.59
Loan Agreement With OPIC [Member]
Debt Services, Coverage Ratio																							1.7
Long-term Debt, Gross																							$ 210,600,000
Restricted Cash and Cash Equivalents, Current, Total																							2,600,000	3,700,000
Letters of Credit Outstanding, Amount																							$ 16,100,000
Loan Agreement With OPIC [Member] | In The First Two Years After the Plant Commercial Operation Date [Member]
Debt Instrument, Prepayment Premium Percentage																							2.00%
Debt Instrument, Interest Rate, Stated Percentage																							6.12%
Loan Agreement With OPIC [Member] | Third Year After the Plant 2 Commercial Operation Date [Member]
Debt Instrument, Prepayment Premium Percentage																							1.00%
Loan Agreement With OPIC [Member] | Historical [Member]
Debt Services, Coverage Ratio																							2.87
Loan Agreement With OPIC [Member] | Projected [Member]
Debt Services, Coverage Ratio																							3.03
Loan Agreement With OPIC [Member] | Tranche One [Member]
Debt Instrument, Face Amount								$ 85,000,000									$ 85,000,000
Long-term Debt, Gross																							$ 56,600,000
Prepayment Deposit On Debt																	20,500,000
Loan Agreement With OPIC [Member] | Tranche Two [Member]
Long-term Debt, Gross								135,000,000									135,000,000						$ 121,800,000
Proceeds from Issuance of Debt							$ 45,000,000
Debt Instrument, Interest Rate, Stated Percentage																							6.31%
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net																							$ 6,310,000
Loan Agreement With OPIC [Member] | Tranche Three [Member]
Debt Instrument, Face Amount								45,000,000									45,000,000
Long-term Debt, Gross																							$ 32,200,000
Proceeds from Issuance of Debt					$ 45,000,000
Loan Agreement With OPIC [Member] | Threshold For Loan Default [Member]
Debt Services, Coverage Ratio																							1.1
Loan Agreement With OPIC [Member] | Minimum [Member] | Historical [Member]
Debt Services, Coverage Ratio																							1.4
Olkaria III DEG [Member]
Debt Instrument, Face Amount																				$ 105,000,000
Debt Instrument, Basis Spread on Variable Rate																				4.00%
Debt Instrument, Interest Rate, Stated Percentage																				6.90%
Payment for Debt Extinguishment or Debt Prepayment Cost											$ 100,000
Repayments of Long-term Debt, Total											11,800,000
Olkaria III DEG [Member] | Tranche One [Member]
Debt Instrument, Face Amount								180,000,000									$ 180,000,000
Prepayment Penalty Charges								$ 1,500,000
Platanares Finance Agreement [Member] | OPIC [Member]
Long-term Debt, Gross																							$ 112,700,000
Prepayment Deposit On Debt																							$ 5,000,000
Proceeds from Issuance of Debt										$ 114,700,000
Debt Instrument, Interest Rate, Stated Percentage										7.02%
Debt Agreement, Maximum Borrowing Capacity										$ 124,700,000
Debt Instrument, Prepayment Premium Percentage, First or Second Year																							2.00%
Debt Instrument, Prepayment Premium Percentage, Third Year																							1.00%
Platanares Finance Agreement [Member] | Historical [Member] | OPIC [Member]
Debt Services, Coverage Ratio																							1.1
Platanares Finance Agreement [Member] | Projected [Member] | OPIC [Member]
Debt Services, Coverage Ratio																							1.5
Platanares Finance Agreement [Member] | Debt Service Reserve [Member] | OPIC [Member]
Restricted Cash and Cash Equivalents, Current, Total																							$ 13,400,000
Letters of Credit Outstanding, Amount																							0
Platanares Finance Agreement [Member] | Well Drilling Reserve [Member] | OPIC [Member]
Restricted Cash and Cash Equivalents, Current, Total																							2,000,000
Letters of Credit Outstanding, Amount																							$ 0
Platanares Finance Agreement [Member] | Threshold For Loan Default [Member] | OPIC [Member]
Debt Services, Coverage Ratio																							1.2
Platanares Finance Agreement [Member] | Maximum [Member] | Scenario, Forecast [Member] | OPIC [Member]
Proceeds from Issuance of Debt																						$ 10,000,000
Platanares [Member]
Current Power Generation | MWh										35
Ormat Funding Corp [Member]
Debt Instrument, Face Amount																																				$ 190,000,000
Repayments of Secured Debt											14,300,000
Payment for Debt Extinguishment or Debt Prepayment Cost											$ 1,300,000
Ormat Funding Corp [Member] | Mammoth Complex [Member]
Percentage of Financing Acquisition Cost																																				50.00%
OrCal Senior Secured Notes [Member]
Debt Instrument, Face Amount																					$ 165,000,000
Proceeds from Issuance of Debt																					$ 161,100,000
Debt Instrument, Interest Rate, Stated Percentage																					6.21%
Restricted Cash and Cash Equivalents, Current, Total																							$ 0	1,900,000
Letters of Credit Outstanding, Amount																							$ 18,700,000	32,100,000
Debt Instrument, Issuance Costs																					$ 3,900,000
Debt Instrument, Redemption Price, Percentage																							100.00%
OrCal Senior Secured Notes [Member] | Historical [Member]
Debt Services, Coverage Ratio																							1.18
OrCal Senior Secured Notes [Member] | Projected [Member]
Debt Services, Coverage Ratio																							1.41
OrCal Senior Secured Notes [Member] | Debt Service Reserve Backing [Member]
Letters of Credit Outstanding, Amount																							$ 4,600,000	4,600,000
OrCal Senior Secured Notes [Member] | Minimum [Member]
Debt Services, Coverage Ratio																					1.25
OFC Two Senior Secured Notes [Member]
Debt Instrument, Face Amount																																			$ 350,000,000
Government Guarantee Percent																							80.00%
Debtor-in-Possession Financing, Letters of Credit Outstanding																							$ 20,000,000
OFC Two Senior Secured Notes [Member] | Senior Notes [Member]
Secured Debt, Total																							$ 217,800,000	$ 232,500,000
OFC Two Senior Secured Notes [Member] | Wholly Owned Subsidiaries With Project Debt [Member]
Debt Instrument, Face Amount																																	$ 140,000,000
Debt Instrument, Interest Rate, Stated Percentage																																	4.61%
OFC Two Senior Secured Notes [Member] | Historical [Member]
Debt Services, Coverage Ratio																							2.55				2.21
OFC Two Senior Secured Notes [Member] | Projected [Member]
Debt Services, Coverage Ratio																							2.09				2.18
OFC Two Senior Secured Notes [Member] | Phase One Series A Senior Notes [Member]
Debt Instrument, Face Amount																		$ 151,700,000
Proceeds from Issuance of Debt																		$ 141,100,000
Debt Instrument, Interest Rate, Stated Percentage																		4.687%
Repayments of Long-term Debt, Total															$ 4,300,000
Other Reserves																							$ 0										$ 28,000,000
OFC Two Senior Secured Notes [Member] | Maximum [Member] | Historical [Member]
Debt Services, Coverage Ratio																							1.2
OFC Two Senior Secured Notes [Member] | Maximum [Member] | Projected [Member]
Debt Services, Coverage Ratio																							1.5
Don A. Cambell Senior Secured Notes [Member]
Debt Instrument, Face Amount			$ 92,500,000
Proceeds from Issuance of Debt			$ 87,100,000
Debt Instrument, Interest Rate, Stated Percentage			4.03%
Secured Debt, Total																							$ 83,300,000
Debt Instrument, Minimum Prepay Amount			$ 2,000,000
Don A. Cambell Senior Secured Notes [Member] | Historical [Member]
Debt Services, Coverage Ratio																							1.35
Don A. Cambell Senior Secured Notes [Member] | Projected [Member]
Debt Services, Coverage Ratio																							1.69
Don A. Cambell Senior Secured Notes [Member] | Minimum [Member]
Debt Services, Coverage Ratio			1.2
Prudential Capital Group Agreement [Member]
Debt Instrument, Term													7 years
Debt Instrument, Face Amount													$ 20,000,000
Long-term Debt, Gross																							$ 18,900,000
Debt Instrument, Interest Rate, Stated Percentage													5.80%
Line of Credit Facility, Maximum Borrowing Capacity													$ 50,000,000
Debt Instrument, Remaining Balance													$ 16,000,000
DOE Loan Guarantee [Member]
Debt Instrument, Term																			21 years 182 days
Long-term Debt, Gross																							51,400,000
Debt Instrument, Interest Rate, Stated Percentage																			2.60%
Line of Credit Facility, Maximum Borrowing Capacity																			$ 96,800,000
Prudential Capital Purchase Agreement [member]
Debt Instrument, Term						24 years
Long-term Debt, Gross																							27,800,000
Debt Instrument, Interest Rate, Stated Percentage						6.75%
Senior Unsecured Bonds [Member]
Debt Instrument, Face Amount																														$ 67,000,000
Proceeds from Issuance of Unsecured Debt												$ 250,000,000
Senior Unsecured Bonds [Member] | Series 3 Bonds [Member]
Debt Instrument, Face Amount																														$ 137,000,000
Senior Unsecured Bonds, Series 2 [Member]
Debt Instrument, Interest Rate, Stated Percentage																														3.70%
Senior Unsecured Bonds, Series 3 [Member]
Debt Instrument, Interest Rate, Stated Percentage																														4.45%
Migdal Loan [Member]
Debt Instrument, Face Amount	$ 100,000,000
Debt Instrument, Interest Rate, Stated Percentage	4.80%
Debt Instrument, Periodic Payment, Total	$ 4,200,000
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	$ 37,000,000
Debt Instrument Increase in Stated Interest Rate if Rating is Downgraded to ILA Negative	0.50%
Debt Instrument Increase in Stated Interest Rate Each Additional Downgrade	0.25%
Debt Instrument Decrease in Stated Interest Rate for Each Rating Upgrade	0.25%
Debt to EBITDA Ratio Threshold for Rate Increase	4.5
Debt Instrument Increase in Stated Interest Rate if Debt to EBITDA Ratio Exceeds Threshold	0.50%
Debt to EBITDA Ratio Requirement	6
Stockholders Equity, Debt Covenant, Minimum Threshold	$ 650,000,000
Stockholders Equity to Total Assets, Ratio	25.00%
Stockholders Equity, Debt Covenant, Minimum Threshold to Pay Dividends	$ 800,000,000
Dividends to Net Income, Ratio	50.00%
Migdal Loan [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage	4.80%
Migdal Loan [Member] | Maximum [Member]
Debt Instrument, Increase in Stated Interest Rate	1.00%
DEG 2 Facility Agreement [Member]
Debt Instrument, Interest Rate, Stated Percentage		6.28%
Debt Instrument, Minimum Prepay Amount		$ 5,000,000
Line of Credit Facility, Maximum Borrowing Capacity																													$ 50,000,000
Proceeds from Lines of Credit, Total		$ 50,000,000
Long-term Line of Credit, Total																							47,500,000
Credit Agreements With Eight Commercial Banks [Member]
Letters of Credit Outstanding, Amount																							229,600,000
Line of Credit Facility, Maximum Borrowing Capacity																							468,000,000
Long-term Line of Credit, Total																							159,000,000
Credit Agreements With Eight Commercial Banks [Member] | Extensions of Credit in The Form of Loans and/or Letters of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							233,000,000
Credit Agreements With Eight Commercial Banks [Member] | Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							235,000,000
Credit Agreements With Eight Commercial Banks [Member] | Non - Committed [Member]
Long-term Line of Credit, Total																							14,100,000
Credit Agreements With Eight Commercial Banks [Member] | Union Bank, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							60,000,000
Credit Agreements With Eight Commercial Banks [Member] | HSBC Bank USA, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							$ 35,000,000
Union Bank, N.A. [Member]
Debt Services, Coverage Ratio																							2.94
Letters of Credit Outstanding, Amount																							$ 51,500,000
Line of Credit Facility, Maximum Borrowing Capacity									$ 60,000,000
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							2.91
Amount Available For Dividend Distribution Percent Of Cumulative Net Income									2														1.1
Union Bank, N.A. [Member] | Minimum [Member]
Debt Services, Coverage Ratio									1.35
Union Bank, N.A. [Member] | Maximum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio									4.5
HSBC Bank USA, N.A. [Member]
Debt Services, Coverage Ratio																							2.94
Letters of Credit Outstanding, Amount																							$ 30,000,000
Line of Credit Facility, Maximum Borrowing Capacity																$ 35,000,000
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							2.91
Amount Available For Dividend Distribution Percent Of Cumulative Net Income																							1.1
Line of Credit Facility, Borrowing Capacity Increase																10,000,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases																$ 10,000,000
HSBC Bank USA, N.A. [Member] | Minimum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																1.35
HSBC Bank USA, N.A. [Member] | Maximum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																4.5
Amount Available For Dividend Distribution Percent Of Cumulative Net Income																2
Surety Agreement [Member] | Chubb [Member]
Surety Bonds Available																												$ 200,000,000
Surety Bonds Outstanding																							$ 141,100,000

Note 11 - Long-term Debt and _4

Note 11 - Long-term Debt and Credit Agreements - Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Limited Resource	$ 775,547	$ 622,145
	775,547	622,145
Less current portion	(63,180)	(54,720)
Non current portion	712,367	567,425
Recourse Debt	510,832	306,419
Less current portion	(164,000)	(54,587)
Non current portion	346,832	251,832
Other Loans, Limited and Non-recourse [Member]
Non-Recourse Debt	6,241	7,252
Loan Agreement With OPIC the Olkaria III Power Plant [Member]
Non-Recourse Debt	210,641	228,635
Platanares Loan - OPIC [Member]
Non-Recourse Debt	112,652
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited [Member]
Non-Recourse Debt	29,750	33,251
OrCal Geothermal Inc [Member]
Non-Recourse Debt	18,652	32,142
Don A. Campbell 1 ("DAC1") [Member]
Non-Recourse Debt	83,319	88,339
Ormat Funding Corp [Member]
Limited Resource	217,810	232,526
	217,810	232,526
Other Loans, Limited Resource [Member]
Limited Resource	96,482
	96,482
Senior Unsecured Bonds [Member]
Recourse Debt	204,332	204,332
Migdal Loan [Member]
Recourse Debt	100,000
Olkaria III DEG [Member]
Recourse Debt	47,500	50,000
Loan From Commercial Bank [Member]
Recourse Debt		587
Revolving Credit Lines With Banks [Member]
Recourse Debt	$ 159,000	$ 51,500

Note 11 - Long-term Debt and _5

Note 11 - Long-term Debt and Credit Agreements - Future Minimum Payments Under Long-term Obligations (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 68,180
2,020	136,018
2,021	64,039
2,022	205,908
2,023	84,101
Thereafter	570,751
Total	$ 1,128,997

Note 12 - Puna Power Plant Le_3

Note 12 - Puna Power Plant Lease Transactions (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2005	Dec. 31, 2018	Dec. 31, 2016
Lease Term		31 years
Deferred Revenue, Leases, Gross		$ 83,000,000
Capital Leases, Balance Sheet, Assets by Major Class, Net, Total	$ 25,300,000		$ 19,700,000
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	$ 35,600,000		33,100,000
Lease Payment Term	23 years
Deferred Costs, Leasing, Gross	$ 4,200,000
Restricted Cash and Cash Equivalents, Total	48,825,000		78,693,000	$ 34,262,000
Cash, Ending Balance	0		0
Lease Agreement, Reserve Funds [Member]
Restricted Cash and Cash Equivalents, Total	$ 7,900,000		$ 1,300,000

Note 12 - Puna Power Plant Le_4

Note 12 - Puna Power Plant Lease Transactions - Future Minimum Lease Payments Under the Project Lease (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 7,771
2,020	4,197
2,021	3,475
2,022	2,474
2,023	1,603
Later years	9,292
Total minimum rental payments	28,812
Projected [Member]
2,019	6,018
2,020	2,450
2,021	1,723
2,022	824
2,023
Later years	1,917
Total minimum rental payments	$ 12,932

Note 13 - Tax Monetization Tr_2

Note 13 - Tax Monetization Transactions (Details Textual) $ in Thousands	Dec. 31, 2022	May 17, 2018USD ($)	Mar. 17, 2018MWh	Oct. 31, 2017USD ($)	Jul. 10, 2017USD ($)	Dec. 16, 2016USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2022USD ($)
Proceeds from Noncontrolling Interests							$ 4,134	$ 2,017	$ 1,972
OPC LLC [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests								(1,932)
Ormat Nevada ORTP LLC [Member]
Payments to Acquire Additional Interest in Subsidiaries								2,400
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests								(4,051)
Noncontrolling Interest [Member] | OPC LLC [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							6,500	6,537
Noncontrolling Interest [Member] | Ormat Nevada ORTP LLC [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							(7,000)	(6,964)
Additional Paid-in Capital [Member] | OPC LLC [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							(8,500)	(8,469)
Additional Paid-in Capital [Member] | Ormat Nevada ORTP LLC [Member]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests							$ 2,900	$ 2,913
Tungsten Mountain [Member]
Power Generated Under Contract | MWh			26
Parternship Agreement, Initial Purchase Price		$ 33,400
Partnership Agreement, Expected Additional Installments		$ 13,000
Partnership Agreement, Percentage of Distributable Cash Flow Generated		97.50%
Partnership Agreement, Percentage of Taxable Income		95.00%
Opal Geo LLC [Member]
Percentage Of Distributable Cash to Controlling Interest						97.50%
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Controlling Interests						1.00%
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Controlling Interests, PTCs Not Available						95.00%
Opal Geo LLC [Member] | Scenario, Forecast [Member]
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Controlling Interests	95.00%
Opal Geo LLC [Member] | Capital Unit, Class A [Member]
Percentage Of Ownership Interests						100.00%
Opal Geo LLC [Member] | JPM Capital Corporation [Member]
Proceeds from Noncontrolling Interests						$ 62,100
Percentage Of Distributable Cash to Nontrolling Interests						2.50%
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Noncontrolling Interests						99.00%
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Noncontrolling Interests, PTCs Not Available						5.00%
Opal Geo LLC [Member] | JPM Capital Corporation [Member] | Liability for Sale of Tax Benefit [Member]
Proceeds from Noncontrolling Interests						$ 58,500
Opal Geo LLC [Member] | JPM Capital Corporation [Member] | Noncontrolling Interest [Member]
Proceeds from Noncontrolling Interests						$ 3,700
Opal Geo LLC [Member] | JPM Capital Corporation [Member] | Scenario, Forecast [Member]
Proceeds from Noncontrolling Interests										$ 21,000
Percentage Of Distributable Cash to Nontrolling Interests	100.00%
Percentage of Income (Loss), Gain, Deduction and Credit Allocated to Noncontrolling Interests	5.00%
Opal Geo LLC [Member] | JPM Capital Corporation [Member] | Capital Unit, Class B [Member]
Percentage of Equity Interest Sold						100.00%
Ormat Nevada, OPC LLC [Member] | OPC Transaction [Member]
Payments to Acquire Additional Interest in Subsidiaries				$ 1,900
Ormat Nevada ORTP LLC [Member] | ORTP Transaction [Member]
Payments to Acquire Interest in Joint Venture					$ 2,400
DAC 2 [Member]
Percentage Of Ownership Interests						63.25%
Other Geothermal Power Plants [Member]
Percentage Of Ownership Interests						100.00%
OPC LLC [Member] | JPM Capital Corporation [Member] | Capital Unit, Class B [Member]
Fair Value of Equity Interest Sold						$ 3,000

Note 14 - Asset Retirement Ob_3

Note 14 - Asset Retirement Obligations - Reconciliation of the Beginning and Ending Aggregate Carrying Amount of Asset Retirement Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance at beginning of year	$ 27,110	$ 23,348
Revision in estimated cash flows	(258)	1,888
Liabilities incurred and acquired	10,149
Accretion expense	2,474	1,874	$ 1,778
Balance at end of year	$ 39,475	$ 27,110	$ 23,348

Note 15 - Stock-based Compens_3

Note 15 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions

Nov. 07, 2018

Jun. 25, 2018

May 08, 2018

May 07, 2018

Nov. 08, 2017

Aug. 04, 2017

Jun. 07, 2017

Nov. 08, 2016

Jun. 13, 2016

May 31, 2012

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total

$ 17

Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition

1 year 109 days

Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Annual Forfeiture Rate

5.30%

1.10%

10.30%

Increase (Decrease) In Stock Based Compensation Expense Due To Forfeitures, Percent

381.80%

(89.30%)

7.00%

Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Dividends Growth Rate

20.00%

Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Weighted Average Expected Dividend Rate

0.90%

Share Price

$ 52.30

$ 63.96

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number

846,215

431,387

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value

$ 5.2

$ 38.9

Weighted Average [Member]

Share Price

$ 55.58

$ 58.82

Stock Appreciation Rights (SARs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

14.80

Stock Appreciation Rights (SARs) [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

14

Restricted Stock Units (RSUs) [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 52.60

SARs and RSUs [Member] | Vesting After the Second Year from the Grant Date [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

SARs and RSUs [Member] | Vesting After the Third and Forth Year from the Grant Date [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

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] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

30,000

Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price

$ 57.97

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized

4,000,000

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

1 year

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

2 years

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche One [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

100.00%

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche Two [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

3 years

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche Three [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

4 years

2012 Stock Incentive Plan [Member] | Stock Options And Stock Appreciation Rights [Member] | Share-based Compensation Award, Tranche Four [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

2012 Stock Incentive Plan [Member] | Employee Stock Option [Member] | 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

7 years

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 18.42

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

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

4 years

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

5 years

6 years

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

23,200

1,080,000

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Exercise Price

$ 58.79

$ 42.87

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 13.67

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | 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

7 years

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

60,000

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Exercise Price

$ 47.46

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 14.51

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

11.98

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Other Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 11.42

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Directors and Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

108,771

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Share-based Compensation Award, Tranche One [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

50.00%

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

2 years

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Share-based Compensation Award, Tranche Two [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

25.00%

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period

3 years

2012 Stock Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Share-based Compensation Award, Tranche Three [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

4 years

2012 Stock Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Directors and Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

22,742

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Exercise Price

$ 63.35

2012 Stock Incentive Plan [Member] | SARs and RSUs [Member] | Directors [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

100.00%

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

6 years

The 2018 Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized

5,000,000

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant

3,605,740

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Minimum [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

6 years

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

10 years

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche One [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

100.00%

100.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche One [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche One [Member] | Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

22.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche One [Member] | Employees and Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche Two [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche Two [Member] | Employees and Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Share-based Compensation Award, Tranche Three [Member] | Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

28.00%

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

6 years

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

295,671

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 14.56

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 14.64

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

841,117

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 13.82

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Director and Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

5 years 182 days

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Exercise Price

$ 55.16

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 14.57

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Employees and Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period

6 years

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 53.44

The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Directors and Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

35,395

Share-based Compensation Arrangements by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Exercise Price

$ 53.16

The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

40,489

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 54.92

The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 52.09

The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

19,848

The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Chief Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 54.23

The 2018 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Directors and Employees [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

13,688

The 2018 Incentive Plan [Member] | SARs and RSUs [Member] | Vesting After the First Year from the Grant Date [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

100.00%

2012 Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

30,000

1,155,000

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 57.97

$ 43.01

2012 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

[1]

1,172,000

132,000

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

[1]

$ 53.87

$ 62.55

2012 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 17.60

2012 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

17.70

2012 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period

[2]

74,000

23,000

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

[2]

2012 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

62.90

2012 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value

$ 62.30

2012 Incentive Plan [Member] | SARs and RSUs [Member] | Vesting Each Year [Member] | Senior Management [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

25.00%

The 2012 and 2004 Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant

0

[1]

Upon exercise, SARs entitle the recipient to receive shares of common stock equal to the increase in value of the award between the grant date and the exercise date.

[2]

An RSU represents the right to receive one share of common stock once certain vesting conditions are met. The value of an RSU is identical to the value of the underlying stock.

Note 15 - Stock-based Compens_4

Note 15 - Stock-based Compensation - Compensation Related to Stock-based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total stock-based compensation expense	$ 10,218	$ 8,760	$ 5,157
Tax effect on stock-based compensation expense	668	604	617
Net effect of stock-based compensation expense	9,550	8,156	4,540
Cost of Sales [Member]
Total stock-based compensation expense	3,488	3,369	2,400
Selling and Marketing Expense [Member]
Total stock-based compensation expense	792	452	247
General and Administrative Expense [Member]
Total stock-based compensation expense	$ 5,938	$ 4,939	$ 2,510

Note 15 - Stock-based Compens_5

Note 15 - Stock-based Compensation - Fair Value of Stock-based Award on the Date of Grant (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Risk-free interest rates	2.80%	1.90%	1.30%
Expected lives (in weighted average years) (Year)	3 years 182 days	3 years 36 days	4 years 182 days
Dividend yield	0.90%	0.62%	1.10%
Expected volatility (weighted average)	25.50%	27.20%	30.70%
Forfeiture rate	3.10%	0.00%	8.40%

Note 15 - Stock-based Compens_6

Note 15 - Stock-based Compensation - Fair Value of Stock-based Award Using Exercise Multiple-based Lattice SAR Pricing Model Assumptions (Details)	Nov. 07, 2018	Jun. 25, 2018	May 08, 2018	Nov. 08, 2017	Aug. 04, 2017	Jun. 07, 2017	Nov. 08, 2016	Jun. 13, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Risk-free interest rate									2.80%	1.90%	1.30%
Contractual life (Year)									3 years 182 days	3 years 36 days	4 years 182 days
Dividend yield									0.90%	0.62%	1.10%
Expected volatility									25.50%	27.20%	30.70%
Forfeiture rate									3.10%	0.00%	8.40%
Senior Management and Other Employees [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Risk-free interest rate								1.29%
Contractual life (Year)								6 years
Dividend yield								1.14%
Expected volatility								30.70%
Employees and Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Risk-free interest rate							1.65%
Contractual life (Year)							7 years
Dividend yield							1.10%
Expected volatility							30.60%
Forfeiture rate							0.00%
Sub-Optimal Exercise Factor							2.5
Employees and Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Risk-free interest rate		2.79%
Dividend yield		0.92%
Expected volatility		25.64%
Employees and Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Minimum [Member]
Contractual life (Year)		3 years 182 days
Employees and Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Maximum [Member]
Contractual life (Year)		3 years 255 days
Director [Member] | Stock Appreciation Rights (SARs) [Member]
Risk-free interest rate						1.74%
Contractual life (Year)						5 years
Dividend yield						0.66%
Expected volatility						26.30%
Forfeiture rate						10.30%
Sub-Optimal Exercise Factor						2
Director [Member] | Employee Stock Option [Member]
Risk-free interest rate					2.08%
Contractual life (Year)					7 years
Dividend yield					0.69%
Expected volatility					29.40%
Sub-Optimal Exercise Factor					2.5
Forfeiture rate					0.00%
Director [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Forfeiture rate	0.00%
Sub-Optimal Exercise Factor	2.8
Directors and Senior Management [Member] | SARs and RSUs [Member]
Risk-free interest rate				2.10%
Contractual life (Year)				6 years
Dividend yield				0.60%
Expected volatility				26.90%
Sub-Optimal Exercise Factor				2.5
Forfeiture rate				0.00%
Director and Chief Executive Officer [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Risk-free interest rate			2.84%
Dividend yield			0.79%
Expected volatility			25.24%
Forfeiture rate			0.00%
Sub-Optimal Exercise Factor			2.5
Director and Chief Executive Officer [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Minimum [Member]
Contractual life (Year)			1 year 328 days
Director and Chief Executive Officer [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Maximum [Member]
Contractual life (Year)			3 years 182 days
Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Forfeiture rate								0.00%
Sub-Optimal Exercise Factor								2.5
Senior Management [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Forfeiture rate		0.00%
Sub-Optimal Exercise Factor		2.8
Other Employees [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Forfeiture rate								10.50%
Sub-Optimal Exercise Factor								2
Employees [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member]
Risk-free interest rate	3.11%
Dividend yield	1.03%
Expected volatility	25.87%
Forfeiture rate	2.78%	2.78%
Sub-Optimal Exercise Factor	2	2
Employees [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Minimum [Member]
Contractual life (Year)	2 years
Employees [Member] | The 2018 Incentive Plan [Member] | Stock Appreciation Rights and Restricted Stock Units [Member] | Maximum [Member]
Contractual life (Year)	3 years 219 days

Note 15 - Stock-based Compens_7

Note 15 - Stock-based Compensation - Summary of the Status of the 2012 Incentive Plan (Details) - $ / shares shares in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding at beginning of year (in shares)		1,548
Outstanding at end of year (in shares)		2,527	1,548
2012 Incentive Plan [Member]
Outstanding at beginning of year (in shares)		1,548	2,565	2,438
Outstanding at beginning of year (in dollars per share)		$ 41.35	$ 33.36	$ 25.38
Stock Options (in shares)			30	1,155
Stock Options (in dollars per share)			$ 57.97	$ 43.01
Exercised (in shares)		(203)	(1,181)	(967)
Exercised (in dollars per share)		$ 29.75	$ 25.92	$ 25.33
Forfeited (in shares)		(64)	(21)	(57)
Forfeited (in dollars per share)		$ 45.73	$ 46.15	$ 24.12
Expired (in shares)				(4)
Expired (in dollars per share)				$ 26.84
Outstanding at end of year (in shares)		2,527	1,548	2,565
Outstanding at end of year (in dollars per share)		$ 46.77	$ 41.35	$ 33.36
Options and SARs exercisable at end of year (in shares)		846	431	557
Options and SARs exercisable at end of year (in dollars per share)		$ 42.06	$ 32.61	$ 25.22
Weighted-average fair value of options and SARs granted during the year (in dollars per share)		$ 16.45	$ 22.82	$ 11.61
2012 Incentive Plan [Member] | Stock Appreciation Rights (SARs) [Member]
Other than Options (in shares)	[1]	1,172	132
Other than Options (in dollars per share)	[1]	$ 53.87	$ 62.55
2012 Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member]
Other than Options (in shares)	[2]	74	23
Other than Options (in dollars per share)	[2]
[1]	Upon exercise, SARs entitle the recipient to receive shares of common stock equal to the increase in value of the award between the grant date and the exercise date.
[2]	An RSU represents the right to receive one share of common stock once certain vesting conditions are met. The value of an RSU is identical to the value of the underlying stock.

Note 15 - Stock-based Compens_8

Note 15 - Stock-based Compensation - Summary of Information About Stock-based Awards Outstanding (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of shares outstanding (in shares)	2,527	1,548
Weighted average remaining contractual life in years, options outstanding (Year)	4 years 109 days	4 years 73 days
Aggregate intrinsic value, options outstanding	$ 17,283	$ 34,990
Number of shares exercisable (in shares)	846	432
Weighted average remaining contractual life in years, options exercisable (Year)	3 years 109 days	3 years
Aggregate intrinsic value, options exercisable	$ 9,389	$ 13,523
Exercise Price 1 [Member]
Exercise price (in dollars per share)
Number of shares outstanding (in shares)	75	23
Weighted average remaining contractual life in years, options outstanding (Year)	1 year 292 days	3 years 328 days
Aggregate intrinsic value, options outstanding	$ 3,933	$ 1,455
Number of shares exercisable (in shares)
Weighted average remaining contractual life in years, options exercisable (Year)
Aggregate intrinsic value, options exercisable
Exercise Price 2 [Member]
Exercise price (in dollars per share)	$ 20.13	$ 20.13
Number of shares outstanding (in shares)	29	35
Weighted average remaining contractual life in years, options outstanding (Year)	109 days	1 year 109 days
Aggregate intrinsic value, options outstanding	$ 924	$ 1,533
Number of shares exercisable (in shares)	29	35
Weighted average remaining contractual life in years, options exercisable (Year)	109 days	1 year 109 days
Aggregate intrinsic value, options exercisable	$ 924	$ 1,533
Exercise Price 3 [Member]
Exercise price (in dollars per share)	$ 23.34	$ 23.34
Number of shares outstanding (in shares)	99	176
Weighted average remaining contractual life in years, options outstanding (Year)	146 days	1 year 146 days
Aggregate intrinsic value, options outstanding	$ 2,897	$ 7,150
Number of shares exercisable (in shares)	99	176
Weighted average remaining contractual life in years, options exercisable (Year)	146 days	1 year 146 days
Aggregate intrinsic value, options exercisable	$ 2,897	$ 7,150
Exercise Price 5 [Member]
Exercise price (in dollars per share)	$ 35.15	$ 35.15
Number of shares outstanding (in shares)	15	15
Weighted average remaining contractual life in years, options outstanding (Year)	4 years 36 days	5 years 36 days
Aggregate intrinsic value, options outstanding	$ 257	$ 432
Number of shares exercisable (in shares)	15	15
Weighted average remaining contractual life in years, options exercisable (Year)	4 years 36 days	5 years 36 days
Aggregate intrinsic value, options exercisable	$ 257	$ 432
Exercise Price 4 [Member]
Exercise price (in dollars per share)		$ 25.65
Number of shares outstanding (in shares)		10
Weighted average remaining contractual life in years, options outstanding (Year)		109 days
Aggregate intrinsic value, options outstanding		$ 398
Number of shares exercisable (in shares)		10
Weighted average remaining contractual life in years, options exercisable (Year)		109 days
Aggregate intrinsic value, options exercisable		$ 398
Exercise Price 6 [Member]
Exercise price (in dollars per share)	$ 38.24	$ 38.24
Number of shares outstanding (in shares)	15	15
Weighted average remaining contractual life in years, options outstanding (Year)	3 years 292 days	4 years 292 days
Aggregate intrinsic value, options outstanding	$ 211	$ 386
Number of shares exercisable (in shares)	15	15
Weighted average remaining contractual life in years, options exercisable (Year)	3 years 292 days	4 years 292 days
Aggregate intrinsic value, options exercisable	$ 211	$ 386
Exercise Price 7 [Member]
Exercise price (in dollars per share)	$ 42.87	$ 42.87
Number of shares outstanding (in shares)	942	1,074
Weighted average remaining contractual life in years, options outstanding (Year)	3 years 182 days	4 years 182 days
Aggregate intrinsic value, options outstanding	$ 8,879	$ 22,651
Number of shares exercisable (in shares)	521	143
Weighted average remaining contractual life in years, options exercisable (Year)	3 years 182 days	4 years 182 days
Aggregate intrinsic value, options exercisable	$ 4,918	$ 3,005
Exercise Price 8 [Member]
Exercise price (in dollars per share)	$ 47.46	$ 47.46
Number of shares outstanding (in shares)	38	38
Weighted average remaining contractual life in years, options outstanding (Year)	4 years 328 days	5 years 328 days
Aggregate intrinsic value, options outstanding	$ 182	$ 619
Number of shares exercisable (in shares)	38	38
Weighted average remaining contractual life in years, options exercisable (Year)	4 years 328 days	5 years 328 days
Aggregate intrinsic value, options exercisable	$ 182	$ 619
Exercise Price 9 [Member]
Exercise price (in dollars per share)	$ 53.16	$ 57.97
Number of shares outstanding (in shares)	35	30
Weighted average remaining contractual life in years, options outstanding (Year)	5 years 328 days	6 years 219 days
Aggregate intrinsic value, options outstanding		$ 180
Number of shares exercisable (in shares)
Weighted average remaining contractual life in years, options exercisable (Year)
Aggregate intrinsic value, options exercisable
Exercise Price 10 [Member]
Exercise price (in dollars per share)	$ 53.44	$ 58.79
Number of shares outstanding (in shares)	828	23
Weighted average remaining contractual life in years, options outstanding (Year)	5 years 182 days	4 years 182 days
Aggregate intrinsic value, options outstanding		$ 120
Number of shares exercisable (in shares)
Weighted average remaining contractual life in years, options exercisable (Year)
Aggregate intrinsic value, options exercisable
Exercise Price 11 [Member]
Exercise price (in dollars per share)	$ 55.16	$ 63.35
Number of shares outstanding (in shares)	296	109
Weighted average remaining contractual life in years, options outstanding (Year)	4 years 328 days	5 years 328 days
Aggregate intrinsic value, options outstanding		$ 66
Number of shares exercisable (in shares)	66
Weighted average remaining contractual life in years, options exercisable (Year)	4 years 328 days
Aggregate intrinsic value, options exercisable
Exercise Price 12 [Member]
Exercise price (in dollars per share)	$ 57.97
Number of shares outstanding (in shares)	30
Weighted average remaining contractual life in years, options outstanding (Year)	5 years 219 days
Aggregate intrinsic value, options outstanding
Number of shares exercisable (in shares)	30
Weighted average remaining contractual life in years, options exercisable (Year)	5 years 219 days
Aggregate intrinsic value, options exercisable
Exercise Price 13 [Member]
Exercise price (in dollars per share)	$ 58.79
Number of shares outstanding (in shares)	16
Weighted average remaining contractual life in years, options outstanding (Year)	3 years 182 days
Aggregate intrinsic value, options outstanding
Number of shares exercisable (in shares)
Weighted average remaining contractual life in years, options exercisable (Year)
Aggregate intrinsic value, options exercisable
Exercise Price 14 [Member]
Exercise price (in dollars per share)	$ 63.35
Number of shares outstanding (in shares)	109
Weighted average remaining contractual life in years, options outstanding (Year)	4 years 328 days
Aggregate intrinsic value, options outstanding
Number of shares exercisable (in shares)	33
Weighted average remaining contractual life in years, options exercisable (Year)	4 years 328 days
Aggregate intrinsic value, options exercisable

Note 17 - Interest Expense, N_3

Note 17 - Interest Expense, Net - Components of Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest related to sale of tax benefits									$ 11,284	$ 6,985	$ 9,349
Interest expense									63,368	54,381	61,327
Less — amount capitalized									(3,728)	(7,224)	(3,287)
	$ 22,034	$ 18,700	$ 15,846	$ 14,344	$ 12,987	$ 11,692	$ 14,540	$ 14,923	$ 70,924	$ 54,142	$ 67,389

Note 18 - Income Taxes (Details

Note 18 - Income Taxes (Details Textual) - USD ($) $ in Thousands		Apr. 24, 2018	Jun. 20, 2017	Sep. 11, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Assets, Investments					$ 813	$ 813					$ 813	$ 813
Deferred Tax Assets, Tax Credit Carryforwards, General Business					90,913	85,193					90,913	85,193
Deferred Tax Assets, Tax Credit Carryforwards, Foreign					58,072	86,206					58,072	86,206
Deferred Tax Assets, Valuation Allowance, Total					22,441	77,571					22,441	$ 77,571	$ 116,234	$ 92,898
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount											$ (55,100)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent											21.00%	35.00%	35.00%
Provisional Tax Effect, 2017 Tax Cuts and Jobs Act, Impact on Income Tax Expense (Benefit)											$ 71,900
Final Tax Effect, 2017 Tax Cuts and Jobs Act, Impact on Income Tax Expense (Benefit)											64,200
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability											(3,500)	$ 22,600
Uncertain Tax Benefit, Reudction to Deferred Tax Asset	[1]				95	95					95	95
Foreign Earnings Repatriated						300,000						396,000
Distribution of Earnings in Foreign Subsidiaries					96,000
Undistributed Earnings of Foreign Subsidiaries					211,300						211,300
Unrecognized Tax Benefits that Would Impact Effective Tax Rate					11,800	8,900					11,800	8,900
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations											$ 300	800	$ 5,400
Placed in Service After December 31, 2022 and Before January 1, 2024 [Member]
Depreciation Bonus Permitted Write Off Equipment Cost Percentage											80.00%
Placed in Service After December 31, 2023 and Before January 1, 2025 [Member]
Depreciation Bonus Permitted Write Off Equipment Cost Percentage											60.00%
Placed in Service After December 31, 2024 and Before January 1, 2026 [Member]
Depreciation Bonus Permitted Write Off Equipment Cost Percentage											40.00%
Placed in Service After December 31, 2025 and Before January 1, 2027 [Member]
Depreciation Bonus Permitted Write Off Equipment Cost Percentage											20.00%
Accounting Standards Update 2013-11 [Member]
Uncertain Tax Benefit, Reudction to Deferred Tax Asset						100						100
U.S. Geothermal [Member]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business Combination, Consideration Transferred, Total		$ 110,000
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets (Liabilities), Net		1,700
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets		1,700
Deferred Taxes, Business Combination, Valuation Allowance, Available to Reduce Deferred Tax Asset		2,100
Investment Tax Credit Carryforward [Member]
Deferred Tax Assets, Investments					800						$ 800
General Business Tax Credit Carryforward [Member]
Deferred Tax Assets, Tax Credit Carryforwards, General Business					90,900						$ 90,900
Tax Credit Carryforward Expiration Period											20 years
Minimum [Member] | General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Year											2,026
Maximum [Member] | General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Year											2,038
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total					230,500						$ 230,500
Operating Loss Carryforwards Expiring Amount					224,500						224,500
Operating Loss Carryforwards Available For Indefinite Period					6,000						$ 6,000
Domestic Tax Authority [Member] | Placed in Service Before January 2018 [Member]
Investment Tax Credit, Percentage of Eligible Cost											30.00%
Domestic Tax Authority [Member] | U.S. Geothermal [Member]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets		115,200
Domestic Tax Authority [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year											2,027
Domestic Tax Authority [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year											2,037
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total					269,100	$ 264,700					$ 269,100	$ 264,700
Operating Loss Carryforwards Available For Indefinite Period					3,300						$ 3,300
State and Local Jurisdiction [Member] | U.S. Geothermal [Member]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets		$ 49,900
State and Local Jurisdiction [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year											2,025
State and Local Jurisdiction [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year											2,038
Foreign Tax Authority [Member]
Tax Credit Carryforward Expiration Period											10 years
Deferred Tax Assets, Tax Credit Carryforwards, Foreign					58,100						$ 58,100
Foreign Tax Authority [Member] | Israel Tax Authority [Member]
Foreign Earnings Repatriated											53,000
Foreign Income Tax Expense (Benefit), Continuing Operations, Total											14,400
Deferred Tax Liabilities, Gross, Total					8,100						8,100
Tax Credit Carryforward, Amount					$ 2,200						$ 2,200
National Corporate Tax Rate											23.00%	24.00%	25.00%	26.50%
Foreign Tax Authority [Member] | Israel Tax Authority [Member] | Ormat Systems Ltd [Member]
Effective Income Tax Rate, Year Four and Thereafter															16.00%
Tax Rate on Exempt Income, in Event of Distribution											25.00%
Deferred Tax Liability, Rate, Respect of Tax Exempt Income											25.00%
Foreign Tax Authority [Member] | Tax Authority of Guatemala in Guatemala [Member]
National Corporate Tax Rate											25.00%
Tax Exemption Period											10 years
Effective Income Tax Rate											7.00%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount											$ 2,000	$ 2,600	$ 3,300
Income Tax Benefit From Examination Per Share											0.04	0.05	0.07
Foreign Tax Authority [Member] | Kenya Revenue Authority [Member]
National Corporate Tax Rate											37.50%
Investment Deduction Percentage			150.00%	150.00%
Income Tax Examination, Penalties Paid			$ 2,600
Income Tax Examination, Interest Accrued and Waiver Requested			$ 1,200
Foreign Tax Authority [Member] | Ministry of the Economy, Finance and Industry, France [Member]
National Corporate Tax Rate												34.43%
Corporate Income Tax Rate, Taxable Income Exceeding Euro 0.5 Million											33.30%
Foreign Tax Authority [Member] | Ministry of the Economy, Finance and Industry, France [Member] | Scenario, Forecast [Member]
National Corporate Tax Rate							25.00%	26.50%	28.00%
Corporate Income Tax Rate, Taxable Income Exceeding Euro 0.5 Million										31.00%
Foreign Tax Authority [Member] | Sistema de Administración de Rentas [Member]
Income Taxes Exempt Period											10 years
Foreign Tax Authority [Member] | Inland Revenue Department, New Zealand [Member]
National Corporate Tax Rate														28.00%	28.00%	28.00%
Foreign Tax Authority [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year											2,027
Foreign Tax Authority [Member] | Minimum [Member] | Kenya Revenue Authority [Member]
Tax Losses Carryforward Period											5 years
Foreign Tax Authority [Member] | Maximum [Member] | Kenya Revenue Authority [Member]
Tax Losses Carryforward Period											10 years
[1]	The non-current deferred tax asset has been reduced by the uncertain tax benefit of $0.1 million in accordance with ASU 2013-11, Income Taxes.

Note 18 - Income Taxes - Income

Note 18 - Income Taxes - Income From Continuing Operations Before Income Taxes and Equity in Income (Losses) of Investees (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S									$ 14,097	$ 13,680	$ (7,109)
Non-U.S. (foreign)									123,084	157,050	148,197
Total income from continuing operations, before income taxes and equity in losses	$ 48,293	$ 11,408	$ 31,376	$ 46,104	$ 40,025	$ 33,446	$ 45,039	$ 52,220	$ 137,181	$ 170,730	$ 141,088

Note 18 - Income Taxes - Compon

Note 18 - Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal										$ 43,935
State									381	43	(276)
Foreign									14,992	11,186	13,554
Total current income tax expense									15,373	55,164	13,278
Deferred:
Federal									(6,886)	(55,718)	57
State									(2,595)	(3,284)
Foreign									28,841	25,502	23,724
Total deferred tax benefit									19,360	(33,500)	23,781
Total Income tax provision	$ 31,386	$ 1,184	$ 29,105	$ (26,942)	$ (28,329)	$ 6,224	$ 32,765	$ 11,004	$ 34,733	$ 21,664	$ 37,059

Note 18 - Income Taxes - Differ

Note 18 - Income Taxes - Difference Between US Federal Statutory Tax Rate and Company's Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. federal statutory tax rate	21.00%	35.00%	35.00%
Impact of federal tax reform	2.60%	(12.40%)
Transition tax inclusion	(5.70%)	42.10%
Foreign tax credits	(4.20%)	(50.50%)
Tax basis adjustment			(4.90%)
Withholding tax	5.90%	34.10%
State income tax, net of federal benefit	1.00%	1.10%	(0.60%)
Uncertain Tax Positions	2.10%
Effect of foreign income tax, net	5.60%	(10.70%)	(10.30%)
Production tax credits	(3.10%)	(1.20%)	(8.30%)
Subpart F income	0.50%	1.70%	0.30%
Tax on global intangible low-tax income	18.60%
Intra-entity transfers of assets other than inventory	(2.10%)
Other, net	0.30%	(3.90%)	(1.40%)
Effective tax rate	25.30%	12.70%	26.30%
Domestic Tax Authority [Member]
Valuation allowance	(17.20%)	(22.60%)	16.50%

Note 18 - Income Taxes - Net De

Note 18 - Income Taxes - Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets (liabilities):
Net foreign deferred taxes, primarily depreciation	$ (57,202)	$ (61,961)
Depreciation, deferred tax liability	(30,500)	(65,315)
Intangible drilling costs	7,370	13,003
Net operating loss carryforward - U.S.	65,020	55,084
Tax monetization transaction	(17,104)	(13,134)
State and Investment tax credits	813	813
Production tax credits	90,913	85,193
Foreign tax credits	58,072	86,206
Withholding tax	(8,052)	(14,400)
Stock options amortization	1,440	1,166
Basis difference in partnership interest	(36,516)	(16,817)
Accrued liabilities and other	624	3,109
	74,878	72,947
Less - valuation allowance	(22,441)	(77,571)	$ (116,234)	$ (92,898)
Total	$ 52,437
Total		$ (4,624)

Note 18 - Income Taxes - Reconc

Note 18 - Income Taxes - Reconciliation of Beginning and Ending Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance at beginning of the year	$ 77,571	$ 116,234	$ 92,898
Additions to valuation allowance	4,747	46,560	23,336
Release of valuation allowance	(59,877)	(85,223)
Balance at end of the year	$ 22,441	$ 77,571	$ 116,234

Note 18 - Income Taxes - Balanc

Note 18 - Income Taxes - Balance Sheet Presentation of Deferred Taxes (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Non-current deferred tax assets		$ 113,760	$ 57,337
Non-current deferred tax liabilities		(61,323)	(61,961)	(36,411)
Non-current deferred tax assets, net		52,437
Non-current deferred tax liabilities, net			(4,624)	(36,411)
Uncertain tax benefit offset (1)	[1]	(95)	(95)
		$ 52,342	$ (4,719)	$ (36,411)
[1]	The non-current deferred tax asset has been reduced by the uncertain tax benefit of $0.1 million in accordance with ASU 2013-11, Income Taxes.

Note 18 - Income Taxes - Reco_2

Note 18 - Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance at beginning of year	$ 6,357	$ 4,609	$ 7,781
Additions based on tax positions taken in prior years	293	5	675
Additions based on tax positions taken in the current year	2,446	2,580	1,532
Reduction based on tax positions taken in prior years	(276)	(837)	(5,379)
Balance at end of year	$ 8,820	$ 6,357	$ 4,609

Note 18 - Income Taxes - Foreig

Note 18 - Income Taxes - Foreign Subsidiaries Income Tax Years Open to Examination (Details)	12 Months Ended
	Dec. 31, 2018
Earliest Tax Year [Member] | ISRAEL
Countries	2,015
Earliest Tax Year [Member] | KENYA
Countries	2,012
Earliest Tax Year [Member] | GUATEMALA
Countries	2,014
Earliest Tax Year [Member] | HONDURAS
Countries	2,014
Earliest Tax Year [Member] | GUADELOUPE
Countries	2,016
Earliest Tax Year [Member] | NEW ZEALAND
Countries	2,012
Latest Tax Year [Member] | ISRAEL
Countries	2,018
Latest Tax Year [Member] | KENYA
Countries	2,018
Latest Tax Year [Member] | GUATEMALA
Countries	2,018
Latest Tax Year [Member] | HONDURAS
Countries	2,018
Latest Tax Year [Member] | GUADELOUPE
Countries	2,018
Latest Tax Year [Member] | NEW ZEALAND
Countries	2,018

Note 19 - Business Segments (De

Note 19 - Business Segments (Details Textual)	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Number of Reportable Segments	3
Revenue from Contract with Customer, Including Assessed Tax	$ 719,267,000	$ 692,812,000	$ 662,591,000
Goodwill, Ending Balance	19,950,000	21,037,000	$ 6,650,000
Electricity Segment [Member]
Goodwill, Ending Balance	20,000,000	7,600,000
Electricity Segment [Member] | Accounting Standards Update 2014-09 [Member]
Revenue from Contract with Customer, Including Assessed Tax	26,900,000
Other Segments [Member]
Goodwill, Ending Balance	$ 0	$ 13,500,000

Note 19 - Business Segments - S

Note 19 - Business Segments - Summarized Financial Information Concerning Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenues		$ 190,465	$ 166,480	$ 178,299	$ 184,023	$ 166,365	$ 157,185	$ 179,364	$ 189,898	$ 719,267	[1]	$ 692,812	[1]	$ 662,591	[1]
Depreciation and amortization expense										132,233		115,146		105,977
Operating income (loss)		67,982	$ 25,902	$ 36,633	$ 54,593	48,400	$ 43,970	$ 53,152	$ 59,496	185,110		205,018		201,882
Segment assets at period end	[2]	3,121,350				2,623,864				3,121,350		2,623,864		2,461,569
Expenditures for long-lived assets										258,521		259,234		151,930
Unconsolidated Investments [Member]
Segment assets at period end		71,983				34,084				71,983		34,084
Intersegment Eliminations [Member]
Revenues										48,817		109,040		56,075
Electricity Segment [Member]
Revenues										509,879		465,593		436,292
Depreciation and amortization expense										126,181		109,928		102,698
Operating income (loss)										155,546		157,613		126,828
Segment assets at period end	[2]	2,896,938				2,457,514				2,896,938		2,457,514		2,204,444
Expenditures for long-lived assets										219,803		252,581		147,211
Electricity Segment [Member] | Unconsolidated Investments [Member]
Segment assets at period end		71,983				34,084				71,983		34,084
Electricity Segment [Member] | Intersegment Eliminations [Member]
Revenues
Product Segment [Member]
Revenues										201,743		224,483		226,299
Depreciation and amortization expense										4,311		3,470		3,279
Operating income (loss)										38,083		50,543		75,054
Segment assets at period end	[2]	156,942				115,713				156,942		115,713		257,125
Expenditures for long-lived assets										9,993		6,653		4,719
Product Segment [Member] | Unconsolidated Investments [Member]
Segment assets at period end
Product Segment [Member] | Intersegment Eliminations [Member]
Revenues										48,817		109,040		56,075
Other Segments [Member]
Revenues										7,645		2,736
Depreciation and amortization expense										1,741		1,748
Operating income (loss)										(8,519)		(3,138)
Segment assets at period end	[2]	67,470				50,637				67,470		50,637
Expenditures for long-lived assets										28,725
Other Segments [Member] | Unconsolidated Investments [Member]
Segment assets at period end
Other Segments [Member] | Intersegment Eliminations [Member]
Revenues
UNITED STATES
Revenues	[1]									328,606	[3]	$ 301,132		$ 307,025
UNITED STATES | Electricity Segment [Member]
Revenues	[3]									305,962
UNITED STATES | Product Segment [Member]
Revenues	[3]									14,999
UNITED STATES | Other Segments [Member]
Revenues	[3]									7,645
Foreign Countries [Member]
Revenues	[4]									390,661
Foreign Countries [Member] | Electricity Segment [Member]
Revenues	[4]									203,917
Foreign Countries [Member] | Product Segment [Member]
Revenues	[4]									186,744
Foreign Countries [Member] | Other Segments [Member]
Revenues	[4]
[1]	Revenues as reported in the geographic area in which they originate.
[2]	Electricity segment assets include goodwill in the amount of $20.0 million and $7.6 million as of December 31, 2018 and 2017, respectively. Other segment assets include goodwill in the amount of $0 million and $13.5 million as of December 31, 2018 and 2017, respectively. For further information on goodwill, see Note 9 – Intangible assets and goodwill to the consolidated financial statements.
[3]	Electricity segment revenues in the United States are all accounted under ASC 840, Leases, except for $26.9 million for the year ended December 31, 2018 that are accounted under ASC 606 starting in 2018. Product and Other segment revenues in the United States are accounted under ASC 606, as further described under Note 1 to the consolidated financial statements.
[4]	Electricity segment revenues in foreign countries are all accounted under ASC 840, Leases, and Product revenues in foreign countries are accounted under ASC 606 as further described under Note 1 to the consolidated financial statements.

Note 19 - Business Segments - R

Note 19 - Business Segments - Reconciling Information Between Reportable Segments and Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue									$ 719,267	$ 692,812	$ 662,591
Revenue									(719,267)	(692,812)	(662,591)
Operating income (loss)	$ 67,982	$ 25,902	$ 36,633	$ 54,593	$ 48,400	$ 43,970	$ 53,152	$ 59,496	185,110	205,018	201,882
Interest income	458	214	189	113	127	255	362	244	974	988	971
Interest expense, net	(22,034)	(18,700)	(15,846)	(14,344)	(12,987)	(11,692)	(14,540)	(14,923)	(70,924)	(54,142)	(67,389)
Derivatives and foreign currency transaction gains (losses)	(2,250)	(383)	(529)	(1,599)	614	(1,001)	1,703	1,338	(4,761)	2,654	(5,534)
Income attributable to sale of tax benefits	4,020	4,066	3,556	7,361	3,859	3,506	4,356	6,157	19,003	17,878	16,503
Other non-operating income (expense), net	117	309	7,373	(20)	12	(1,592)	6	(92)	7,779	(1,666)	(5,345)
Income from continuing operations, before income tax and equity in earnings (losses) of investees	$ 48,293	$ 11,408	$ 31,376	$ 46,104	$ 40,025	$ 33,446	$ 45,039	$ 52,220	137,181	170,730	141,088
Intersegment Eliminations [Member]
Revenue									48,817	109,040	56,075
Revenue									(48,817)	(109,040)	(56,075)
Consolidation, Eliminations [Member]
Revenue									48,817	109,040	56,075
Revenue									$ (48,817)	$ (109,040)	$ (56,075)

Note 19 - Business Segments -_2

Note 19 - Business Segments - Revenues as Reported in the Geographic Area (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenues		$ 190,465	$ 166,480	$ 178,299	$ 184,023	$ 166,365	$ 157,185	$ 179,364	$ 189,898	$ 719,267	[1]	$ 692,812	[1]	$ 662,591	[1]
UNITED STATES
Revenues	[1]									328,606	[2]	301,132		307,025
INDONESIA
Revenues	[1]									4,379		28,968		100,856
KENYA
Revenues	[1]									119,094		110,243		109,270
TURKEY
Revenues	[1]									168,699		125,166		46,270
CHILE
Revenues	[1]									980		8,895		58,032
GUATEMALA
Revenues	[1]									27,975		27,991		30,086
NEW ZEALAND
Revenues	[1]									10,451		33,395
Other Foreign Countries [Member]
Revenues	[1]									$ 59,083		$ 57,022		$ 11,052
[1]	Revenues as reported in the geographic area in which they originate.
[2]	Electricity segment revenues in the United States are all accounted under ASC 840, Leases, except for $26.9 million for the year ended December 31, 2018 that are accounted under ASC 606 starting in 2018. Product and Other segment revenues in the United States are accounted under ASC 606, as further described under Note 1 to the consolidated financial statements.

Note 19 - Business Segments - L

Note 19 - Business Segments - Long Lived Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Long Lived Assets, Geographic Area	$ 2,221,267	$ 2,133,289	$ 1,941,239
UNITED STATES
Long Lived Assets, Geographic Area	1,696,439	1,510,986	1,414,523
KENYA
Long Lived Assets, Geographic Area	301,956	340,970	327,157
Other Foreign Countries [Member]
Long Lived Assets, Geographic Area	$ 222,872	$ 281,333	$ 199,559

Note 19 - Business Segments -_3

Note 19 - Business Segments - Revenue From Major Customers (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenues		$ 190,465	$ 166,480	$ 178,299	$ 184,023	$ 166,365	$ 157,185	$ 179,364	$ 189,898	$ 719,267	[1]	$ 692,812	[1]	$ 662,591	[1]
Southern California Public Power Authority [Member]
Revenues	[2]									$ 109,208		$ 70,100		$ 67,566
Percentage of revenues	[2]									15.20%		10.10%		10.20%
Sierra Pacific Power Company And Nevada Power Company [Member]
Revenues	[2],[3]									$ 116,149		$ 125,424		$ 127,226
Percentage of revenues	[2],[3]									16.10%		18.10%		19.20%
Hyundai [Member]
Revenues	[4]									$ 4,379		$ 28,968		$ 100,856
Percentage of revenues	[4]									0.60%		4.20%		15.20%
Kenya Power and Lighting Co LTD [Member]
Revenues	[2]									$ 119,094		$ 110,243		$ 109,270
Percentage of revenues	[2]									16.60%		15.90%		16.50%
[1]	Revenues as reported in the geographic area in which they originate.
[2]	Revenues reported in Electricity segment.
[3]	Subsidiaries of NV Energy, Inc.
[4]	Revenues related to the Sarulla project that are reported in Product segment.

Note 21 - Employee Benefit Pl_3

Note 21 - Employee Benefit Plan (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	60.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	4.00%	3.00%	2.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 1,600	$ 1,400	$ 1,000
Deposits And Other Assets Noncurrent	18,209	21,599
Severance Costs	3,000	3,200	2,300
Gain (Loss) Of Severance Fund	1,100	1,800	$ 300
Israeli Severance Funds [Member]
Deposits And Other Assets Noncurrent	$ 10,600	$ 13,900

Note 21 - Employee Benefit Pl_4

Note 21 - Employee Benefit Plan - Expected Future Benefit Payments (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 3,677
2,020	1,183
2,021	1,470
2,022	2,032
2,023	1,246
2024-2028	4,262
Total	$ 13,870

Note 22 - Commitments and Con_3

Note 22 - Commitments and Contingencies (Details Textual) - USD ($) $ in Millions	Mar. 29, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Letters of Credit Outstanding, Amount		$ 229.6
Recorded Unconditional Purchase Obligation, Total		129.3
Royalty Cap Amount		2	$ 1.9
Royalty Cap Amount LIBOR Rate		1	0.9
Capital Leased Assets, Gross, Total		$ 7.5	3.6
Former Local Sales Representative vs. Ormat [Member] | Pending Litigation [Member]
Loss Contingency, Damages Sought, Value	$ 4.6
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
Minimum [Member]
Percentage For Royalty To Be Paid		3.50%
Maximum [Member]
Percentage For Royalty To Be Paid		5.00%
Construction In Process [Member]
Recorded Unconditional Purchase Obligation, Total		$ 36.1
Geothermal Resource Agreement [Member]
Royalty Expense		$ 21.6	$ 19.4	$ 17.1

Note 22 - Commitments and Con_4

Note 22 - Commitments and Contingencies - Minimum Lease Rentals (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 3,118
2,020	3,318
2,021	2,283
2,022	1,941
2,023	1,307
Total	$ 11,967

Note 22 - Commitments and Con_5

Note 22 - Commitments and Contingencies - Future Minimum Payments, Operating Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
2,019	$ 7,771
2,020	4,197
2,021	3,475
2,022	2,474
2,023	1,603
Later years	9,292
Total minimum rental payments	$ 28,812

Note 23 - Quarterly Financial_3

Note 23 - Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenue									$ 719,267		$ 692,812		$ 662,591
Revenues	$ 190,465	$ 166,480	$ 178,299	$ 184,023	$ 166,365	$ 157,185	$ 179,364	$ 189,898	719,267	[1]	692,812	[1]	662,591	[1]
Cost of revenues	99,656	117,688	120,837	110,651	102,009	97,992	108,871	115,488	448,832		424,360		391,796
Gross profit	90,809	48,792	57,462	73,372	64,356	59,193	70,493	74,410	270,435		268,452		270,795
Research and development expenses	1,118	706	1,251	1,108	789	716	1,050	602	4,183		3,157		2,762
Selling and marketing expenses	3,813	8,578	3,712	3,699	3,517	3,630	4,090	4,363	19,802		15,600		16,424
General and administrative expenses	4,429	13,606	15,866	13,849	9,854	10,877	12,201	9,949	47,750		42,881		46,710
Impairment charge	13,464								13,464
Write-off of unsuccessful exploration activities	3			123	1,796				126		1,796		3,017
Operating income (loss)	67,982	25,902	36,633	54,593	48,400	43,970	53,152	59,496	185,110		205,018		201,882
Interest income	458	214	189	113	127	255	362	244	974		988		971
Interest expense, net	(22,034)	(18,700)	(15,846)	(14,344)	(12,987)	(11,692)	(14,540)	(14,923)	(70,924)		(54,142)		(67,389)
Derivatives and foreign currency transaction gains (losses)	(2,250)	(383)	(529)	(1,599)	614	(1,001)	1,703	1,338	(4,761)		2,654		(5,534)
Income attributable to sale of tax benefits	4,020	4,066	3,556	7,361	3,859	3,506	4,356	6,157	19,003		17,878		16,503
Other non-operating income (expense), net	117	309	7,373	(20)	12	(1,592)	6	(92)	7,779		(1,666)		(5,345)
Income from continuing operations, before income tax and equity in earnings (losses) of investees	48,293	11,408	31,376	46,104	40,025	33,446	45,039	52,220	137,181		170,730		141,088
Income tax (provision) benefit	(31,386)	(1,184)	(29,105)	26,942	28,329	(6,224)	(32,765)	(11,004)	(34,733)		(21,664)		(37,059)
Equity in earnings (losses) of investees, net	6,182	(117)	388	1,210	(267)	337	(428)	(1,599)	7,663		(1,957)		(7,735)
Income from continuing operations	23,089	10,107	2,659	74,256	68,087	27,559	11,846	39,617
Net loss (income) attributable to noncontrolling interest	(4,869)	474	(3,002)	(4,748)	(3,467)	(3,599)	(3,206)	(4,423)	12,145		14,695		7,586
Net income attributable to the Company’s stockholders	$ 18,220	$ 10,581	$ (343)	$ 69,508	$ 64,620	$ 23,960	$ 8,640	$ 35,194	$ 97,966		$ 132,414		$ 88,708
Net income (in dollars per share)	$ 0.36	$ 0.21	$ (0.01)	$ 1.37	$ 1.28	$ 0.48	$ 0.17	$ 0.71	$ 1.93		$ 2.64		$ 1.79
Net income (in dollars per share)	$ 0.36	$ 0.21	$ (0.01)	$ 1.36	$ 1.27	$ 0.47	$ 0.17	$ 0.70	$ 1.92		$ 2.61		$ 1.77
Basic (in shares)	50,691	50,645	50,623	50,614	50,607	50,367	49,771	49,680	50,643		50,110		49,469
Diluted (in shares)	50,936	50,963	50,958	51,051	51,053	50,867	50,624	50,491	50,969		50,769		50,140
Electricity [Member]
Revenue	$ 138,320	$ 116,891	$ 122,179	$ 132,489	$ 128,045	$ 110,876	$ 110,896	$ 115,776	$ 509,879		$ 465,593		$ 436,292
Cost of revenues	63,692	79,845	81,236	73,482	73,164	64,444	63,196	66,036	298,255		266,840		261,573
Product [Member]
Revenue	49,717	48,439	54,915	48,672	37,862	44,912	67,587	74,122	201,743		224,483		226,299
Cost of revenues	33,729	35,669	37,573	33,726	26,992	32,218	43,432	49,452	$ 140,697		$ 152,094		$ 130,223
Product and Service, Other [Member]
Revenue	2,428	1,150	1,205	2,862	458	1,397	881
Cost of revenues	$ 2,235	$ 2,174	$ 2,028	$ 3,443	$ 1,853	$ 1,330	$ 2,243
[1]	Revenues as reported in the geographic area in which they originate.

Note 24 - Subsequent Events (De

Note 24 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	Feb. 26, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends, Common Stock, Total		$ 26,834	$ 20,511	$ 25,682
Common Stock, Dividends, Per Share, Declared		$ 0.53	$ 0.41	$ 0.52
Subsequent Event [Member]
Dividends, Common Stock, Total	$ 5,600
Common Stock, Dividends, Per Share, Declared	$ 0.11
Dividends Payable, Date Declared	Feb. 26, 2019
Dividends Payable, Date of Record	Mar. 14, 2019
Dividends Payable, Date to be Paid	Mar. 28, 2019