Note 16 - Income Taxes (Details Textual) - USD ($) $ in Thousands					1 Months Ended	12 Months Ended
		Jun. 27, 2023	Jun. 26, 2023	Apr. 24, 2018	Sep. 30, 2019	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Deferred Tax Assets, Tax Credit Carryforwards, Foreign						$ 33,412	$ 32,333
Deferred Tax Assets, Valuation Allowance						2,870	2,473	$ 11,298
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount						400
Uncertain Tax Benefit, Reudction to Deferred Tax Asset	[1]					$ 95	$ 95
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent						21.00%	21.00%	21.00%
Israel Tax Authority [Member]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate						$ 8,700	$ 6,600
Kenya [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		30.00%	37.50%			30.00%
Effective Income Tax Rate Reconciliation, Change in Foreign Enacted Tax Rate, Amount						$ (7,400)
Accounting Standards Update 2013-11 [Member]
Uncertain Tax Benefit, Reudction to Deferred Tax Asset												$ 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
Deferred Taxes, Business Combination, Valuation Allowance, Available to Reduce Deferred Tax Asset				1,800
General Business Tax Credit Carryforward [Member]
Tax Credit Carryforward Expiration Period (Year)						20 years
General Business Tax Credit Carryforward [Member] | Minimum [Member]
Tax Credit Carryforward Expiration Year						2026
Domestic Tax Authority [Member]
Operating Loss Carryforwards						$ 35,400
Operating Loss Carryforwards Expiring Amount						$ 109,600
Open Tax Year						2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
Domestic Tax Authority [Member] | U.S. Geothermal [Member]
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets				113,900
Foreign Tax Authority [Member]
Tax Credit Carryforward Expiration Period (Year)						10 years
Tax Credit Carryforward Expiration Year						2027
Deferred Tax Assets, Tax Credit Carryforwards, Foreign						$ 33,400
Foreign Tax Authority [Member] | Israel Tax Authority [Member]
Foreign Income Tax Expense (Benefit), Continuing Operations						$ 15,500
National Corporate Tax Rate										16.00%	23.00%	16.00%
Foreign Tax Authority [Member] | Israel Tax Authority [Member] | Ormat Systems Ltd [Member]
Effective Income Tax Rate, Year Four and Thereafter													16.00%
Foreign Tax Authority [Member] | Ministry of the Economy, Finance and Industry, France [Member]
National Corporate Tax Rate						25.00%	25.00%		28.00%
Foreign Tax Authority [Member] | Guadeloupe Tax Authority [Member]
National Corporate Tax Rate								26.50%
Foreign Tax Authority [Member] | Tax Authority of Guatemala in Guatemala [Member]
National Corporate Tax Rate						25.00%
Effective Income Tax Rate						7.00%
Foreign Tax Authority [Member] | Sistema de Administración de Rentas [Member]
Income Taxes Exempt Period (Year)					10 years
Foreign Tax Authority [Member] | Kenya Revenue Authority [Member]
National Corporate Tax Rate							37.50%
State and Local Jurisdiction [Member]
Operating Loss Carryforwards						$ 268,000
Operating Loss Carryforwards Expiring Amount						268,300
Operating Loss Carryforwards Available For Indefinite Period						4,700
Deferred Tax Assets, Investments						$ 800
Open Tax Year						2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022
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						2025
State and Local Jurisdiction [Member] | Maximum [Member]
Tax Credit Carryforward Expiration Year						2034

[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.