Note 18 - Income Taxes (Details Textual) $ in Thousands				1 Months Ended	12 Months Ended										13 Months Ended
		Jun. 20, 2017 USD ($)	Sep. 11, 2015	Dec. 31, 2017 USD ($) $ / item	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) $ / item shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013	Dec. 31, 2018 USD ($)
Deferred Tax Assets, Investments				$ 813						$ 813	$ 1,341
Deferred Tax Assets, Tax Credit Carryforwards, General Business				85,193						85,193	82,435
Deferred Tax Assets, Tax Credit Carryforwards, Foreign				86,206						86,206
Deferred Tax Assets, Valuation Allowance, Total				77,571						77,571	116,234	$ 92,898	$ 183,598
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount										(38,600)
Uncertain Tax Benefit, Reudction to Deferred Tax Asset	[1]			95						95
Foreign Earnings Repatriated				300,000
Income Tax Expense (Benefit), Impact of Reinvestment of Undistributed Foreign Earnings, Withholding Tax										58,300
Undistributed Earnings of Foreign Subsidiaries				401,000						401,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate				$ 8,900						8,900	6,400
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations										$ 800	$ 5,400	$ 1,300
Depreciation Bonus Permitted Write Off Equipment Cost Percentage										50.00%
Depreciation Bonus Period to Write Off The Reminder of Equipment Cost										60 days
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent										35.00%	35.00%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability										$ 22,600
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount										$ 71,900
Investment Tax Credit Per Unit | $ / item				2.4						2.4
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%
Scenario, Forecast [Member]
Foreign Earnings Repatriated															$ 396,000
Distribution of Earnings in Foreign Subsidiaries									$ 96,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent									21.00%
Accounting Standards Update 2013-11 [Member]
Uncertain Tax Benefit, Reudction to Deferred Tax Asset				$ 100						$ 100
Investment Tax Credit Carryforward [Member]
Deferred Tax Assets, Investments				800						$ 800
General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Period										20 years
Minimum [Member] | General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Year										2026
Maximum [Member] | General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Year										2037
Deferred Tax Assets, Tax Credit Carryforwards, General Business				85,200						$ 85,200
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total				190,000						$ 190,000
Domestic Tax Authority [Member] | Placed in Service Before January 2018 [Member]
Investment Tax Credit, Percentage of Eligible Cost										30.00%
Domestic Tax Authority [Member] | Placed in Service After January 2018 [Member]
Investment Tax Credit, Percentage of Eligible Cost										10.00%
Domestic Tax Authority [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year										2029
Domestic Tax Authority [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year										2037
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total				238,100						$ 238,100
State and Local Jurisdiction [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year										2018
State and Local Jurisdiction [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year										2037
Foreign Tax Authority [Member]
Tax Credit Carryforward Expiration Period										10 years
Deferred Tax Assets, Tax Credit Carryforwards, Foreign				$ 86,200						$ 86,200
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										$ 2,600	$ 3,300	$ 3,600
Income Tax Benefit From Examination Per Share | shares										0.05	0.07	0.08
Foreign Tax Authority [Member] | Israel Tax Authority [Member]
National Corporate Tax Rate										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] | Kenya Revenue Authority [Member]
National Corporate Tax Rate										37.50%
Investment Deduction Percentage		150.00%	150.00%
Other Tax Expense (Benefit)												$ 49,400
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%
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] | Scenario, Forecast [Member] | Israel Tax Authority [Member]
National Corporate Tax Rate									23.00%
Foreign Tax Authority [Member] | Scenario, Forecast [Member] | Ministry of the Economy, Finance and Industry, France [Member]
National Corporate Tax Rate					25.00%	26.50%	28.00%
Corporate Income Tax Rate, Taxable Income of Euro 0.5 Million								28.00%	28.00%
Corporate Income Tax Rate, Taxable Income Exceeding Euro 0.5 Million								31.00%	33.30%
Foreign Tax Authority [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year										2027
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