Note 11 - Long-term Debt, Credit Agreements and Finance Liability (Details Textual) $ / shares in Units, $ in Thousands, ₪ in Billions																				1 Months Ended		6 Months Ended	12 Months Ended
		Nov. 01, 2023 USD ($)	Sep. 29, 2023 USD ($)	Apr. 04, 2023 USD ($)	Feb. 27, 2023 USD ($)	Nov. 28, 2022 USD ($)	Jun. 27, 2022 USD ($)	Jun. 22, 2022 USD ($) $ / shares shares	Apr. 12, 2022 USD ($)	Sep. 02, 2021 USD ($)	Jul. 15, 2021 USD ($)	Jul. 12, 2021 USD ($)	May 30, 2019	Apr. 09, 2019 USD ($)	Mar. 25, 2019 USD ($)	Mar. 22, 2018 USD ($)	Dec. 21, 2016 USD ($)	Jul. 31, 2015 USD ($) MWh	Feb. 29, 2012	Oct. 31, 2018 MWh	May 31, 2013	Sep. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) $ / shares		Dec. 31, 2022 USD ($) $ / shares	Dec. 31, 2021 USD ($)	Sep. 30, 2023	Mar. 14, 2023 $ / shares	Jan. 28, 2022	Dec. 31, 2020 USD ($)	Jul. 01, 2020 USD ($)	Jul. 01, 2020 ILS (₪)	Apr. 30, 2020 USD ($)	May 04, 2019 USD ($)	Apr. 29, 2019	Apr. 04, 2019 USD ($)	Jan. 04, 2019 USD ($)	Apr. 30, 2018 USD ($)	May 31, 2017 USD ($)	Nov. 29, 2016 USD ($)	Oct. 20, 2016 USD ($)	Aug. 29, 2014 USD ($)	Aug. 23, 2012 USD ($)	Oct. 31, 2011 USD ($)	Sep. 30, 2011 USD ($)	Aug. 31, 2011 USD ($)
Proceeds from Lines of Credit, Total																							$ 55,000		$ 0	$ 0
Long-Term Debt, Total																							1,989,557
Proceeds from Notes Payable																							$ 0		$ 419,698	0
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares								$ 0.001															$ 0.001		$ 0.001			$ 0.001
Amortization of Debt Issuance Costs																							$ 5,900		$ 4,200	3,200
Purchase of Capped Call Instruments																							(0)		24,538	(0)
Payments for Repurchase of Common Stock																						$ 18,000	(0)		17,964	(0)
Treasury Stock, Shares, Acquired (in shares) | shares																						258,667
Shares Acquired, Average Cost Per Share (in dollars per share) | $ / shares																						$ 69.45
Letters of Credit Outstanding, Amount																							$ 302,800
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							3.74
Stockholders' Equity Attributable to Parent, Ending Balance																							$ 2,315,427		1,867,571
Percentage Of Company Assets																							46.90%
Equity, Including Portion Attributable to Noncontrolling Interest																							$ 2,440,987		2,020,975	1,998,461				$ 1,941,437
Payments of Dividends																							28,400		$ 27,100	$ 27,000
Covenant Requirement Minimum [Member]
Stockholders' Equity Attributable to Parent, Ending Balance																							$ 750,000
Percentage Of Company Assets																							25.00%
Call Option [Member]
Option Indexed to Issuer's Equity, Shares (in shares) | shares								4,800,000
Option Indexed to Issuer's Equity, Strike Price (in dollars per share) | $ / shares								$ 90.27
Option Indexed to Issuer's Equity, Cap Price								107.63%
Option Indexed to Issuer's Equity, Premium Percentage								55.00%
Purchase of Capped Call Instruments								$ 24,500
Convertible Senior Notes [Member]
Debt Instrument, Face Amount							$ 431,250	$ 375,000
Debt Instrument, Interest Rate, Stated Percentage							2.50%	2.50%
Proceeds from Notes Payable							$ 56,250
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger								130.00%
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares								$ 90.27															$ 90.27		$ 90.27
Debt Instrument, Convertible, Maximum Percentage of Stock Price Trigger Per $1000								98.00%
Debt Instrument, Convertible, Conversion Shares Per $1000								11.0776
Debt Instrument, Redemption Price, Percentage								100.00%
Debt Issuance Costs, Gross																							$ 11,600
Amortization of Debt Issuance Costs																							$ 2,300
Debt Instrument, Interest Rate, Effective Percentage																							3.10%
Maximum [Member] | Covenant Requirement Minimum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							6
Mizrahi Loan Agreement 2023 [Member]
Debt Instrument, Face Amount		$ 50,000																					$ 50,000
Debt Instrument, Number of Semi-annual Payments		16
Debt Instrument, Periodic Payment		$ 3,100
Debt Instrument, Term (Year)		8 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio		6
Debt Instrument, Covenant, Minimum Equity Capital, Amount		$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent		25.00%
Debt Instrument, Interest Rate, Stated Percentage	[1]																						7.15%
Long-Term Debt, Gross																							$ 50,000
Hapoalim Loan Agreement 2023 [Member]
Debt Instrument, Face Amount					$ 100,000																		$ 100,000
Debt Instrument, Number of Semi-annual Payments					20
Debt Instrument, Periodic Payment					$ 5,000
Debt Instrument, Term (Year)					10 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio					6
Debt Instrument, Covenant, Minimum Equity Capital, Amount					$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent					25.00%
Debt Instrument, Interest Rate, Stated Percentage																							6.45%
Long-Term Debt, Gross																							$ 95,000
Mizrahi Loan Agreement [Member]
Debt Instrument, Face Amount									$ 75,000														$ 75,000
Debt Instrument, Number of Semi-annual Payments									16
Debt Instrument, Periodic Payment									$ 4,700
Debt Instrument, Term (Year)									8 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio									6
Debt Instrument, Covenant, Minimum Equity Capital, Amount									$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent									25.00%
Debt Instrument, Interest Rate, Stated Percentage	[1]																						4.10%
Long-Term Debt, Gross																							$ 60,900
Hapoalim Loan Agreement [Member] | Bank Hapoalim B.M. [Member]
Debt Instrument, Face Amount												$ 125,000
Debt Instrument, Number of Semi-annual Payments												14
Debt Instrument, Periodic Payment												$ 8,900
Debt Instrument, Term (Year)												7 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio												6
Debt Instrument, Covenant, Minimum Equity Capital, Amount												$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent												25.00%
HSBC Loan Agreement [Member] | HSBC Bank PLC [Member]
Debt Instrument, Face Amount											$ 50,000
Debt Instrument, Number of Semi-annual Payments											14
Debt Instrument, Periodic Payment											$ 3,600
Debt Instrument, Term (Year)											7 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio											6
Debt Instrument, Covenant, Minimum Equity Capital, Amount											$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent											25.00%
Discount Loan Agreement [Member]
Debt Instrument, Face Amount																							$ 100,000
Debt Instrument, Interest Rate, Stated Percentage	[1]																						2.90%
Long-Term Debt, Gross																							$ 75,000
Discount Loan Agreement [Member] | Israel Discount Bank Ltd. [Member]
Debt Instrument, Face Amount										$ 100,000
Debt Instrument, Number of Semi-annual Payments										16
Debt Instrument, Periodic Payment										$ 6,250
Debt Instrument, Term (Year)										8 years
Debt Instrument, Covenant, Maximum Debt to EBITDA Ratio										6
Debt Instrument, Covenant, Minimum Equity Capital, Amount										$ 750,000
Debt Instrument, Covenant, Equity Capital to Total Assets, Percent										25.00%
Senior Unsecured Bonds, Series 4 [Member]
Debt Instrument, Face Amount																							$ 289,800								$ 289,800	₪ 1
Debt Instrument, Number of Annual Payments																															10	10
Debt Instrument, Interest Rate, Stated Percentage	[1]																						3.35%
Long-Term Debt, Gross																							$ 220,600
Senior Unsecured Bonds, Series 4 [Member] | Cross Currency Interest Rate Contract [Member]
Derivative, Fixed Interest Rate																															4.34%	4.34%
Senior Unsecured Loan (Migdal) [Member]
Debt Instrument, Face Amount																$ 100,000							$ 100,000
Debt Instrument, Periodic Payment																4,200
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid																$ 37,000
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 Instrument, Interest Rate, Stated Percentage	[2]																						4.80%
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																$ 750,000
Stockholders Equity to Total Assets, Ratio																25.00%
Long-Term Debt, Gross																							$ 79,000
Senior Unsecured Loan (Migdal) [Member] | Maximum [Member]
Debt Instrument, Increase in Stated Interest Rate																1.00%
Senior Unsecured Loan (Migdal) [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage																4.80%
Additional Migdal Loan [Member]
Debt Instrument, Face Amount															$ 50,000								$ 50,000
Debt Instrument, Number of Semi-annual Payments															15
Debt Instrument, Periodic Payment															$ 2,100
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid															$ 18,500
Debt Instrument, Interest Rate, Stated Percentage	[2]																						4.60%
Long-Term Debt, Gross																							$ 39,500
Second Addendum Migdal Loan [Member]
Debt Instrument, Face Amount																							$ 50,000										$ 50,000
Debt Instrument, Number of Semi-annual Payments																																	15
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid																																	$ 18,500
Debt Instrument, Interest Rate, Stated Percentage	[2]																						5.44%
Debt Instrument, Principal to Be Repaid in Installments																																	$ 31,500
Long-Term Debt, Gross																							$ 39,500
DEG 2 Facility Agreement [Member]
Debt Instrument, Interest Rate, Stated Percentage																	6.28%
Line of Credit Facility, Maximum Borrowing Capacity																																									$ 50,000
Proceeds from Lines of Credit, Total																	$ 50,000
DEG 3 Loan Agreement [Member]
Debt Instrument, Number of Semi-annual Payments																																					19
Debt Instrument, Interest Rate, Stated Percentage																																					6.04%
DEG 3 Loan Agreement [Member] | OrPower 4, Inc [Member]
Debt Instrument, Face Amount																																					$ 41,500
Loan Agreement With OPIC the Olkaria III Power Plant [Member]
Debt Instrument, Face Amount																							310,000																				$ 310,000
Long-Term Debt, Gross																							120,600
Platanares Finance Agreement [Member]
Debt Instrument, Face Amount																							$ 114,700
Debt Instrument, Interest Rate, Stated Percentage	[3]																						7.02%
Long-Term Debt, Gross																							$ 71,700
Platanares Finance Agreement [Member] | OPIC [Member]
Debt Instrument, Face Amount																																						$ 114,700
Current Power Generation (Megawatt-Hour) | MWh																				35
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member]
Debt Instrument, Face Amount																		$ 42,000
Debt Instrument, Term (Year)																		12 years
Power Utilization (Megawatt-Hour) | MWh																		20
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | Not Guaranteed [Member]
Repayments of Debt			$ 14,000
Loan Agreement with Banco Industrial S.A. and Westrust Bank (International) Limited1 [Member] | London Interbank Offered Rate [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 [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] | Minimum [Member] | London Interbank Offered Rate [Member]
Debt Instrument, Basis Spread on Variable Rate																		1.25%
Plumstriker Loan Agreement [Member] | Plumstriker and its Two Subsidiaries [Member]
Debt Instrument, Face Amount																																		$ 23,500
Repayments of Debt				$ 11,100
Plumstriker Loan Agreement [Member] | Plumstriker and its Two Subsidiaries [Member] | London Interbank Offered Rate [Member]
Debt Instrument, Basis Spread on Variable Rate													3.50%
Don A. Cambell Senior Secured Notes [Member]
Debt Instrument, Face Amount																																								$ 92,500
OFC Two Senior Secured Notes [Member]
Debt Instrument, Face Amount																																												$ 151,700	$ 350,000
Government Guarantee Percent																																													80.00%
OFC Two Senior Secured Notes [Member] | Wholly Owned Subsidiaries With Project Debt [Member]
Debt Instrument, Face Amount																																										$ 140,000
Idaho Refinancing Note [Member]
Debt Instrument, Face Amount						$ 61,600
Debt Instrument, Number of Semi-annual Payments																													31
Debt Instrument, Interest Rate, Stated Percentage						6.26%
Idaho Refinancing Note [Member] | Raft River Energy I LLC [Member]
Debt Instrument, Secured, Percentage of Ownership Interests						100.00%
Idaho Refinancing Note [Member] | Oregon USG Holdings, LLC [Member]
Debt Instrument, Secured, Percentage of Ownership Interests						60.00%
Idaho Refinancing Note [Member] | Revolving Note Tranche [Member]
Line of Credit Facility, Maximum Borrowing Capacity						$ 4,300
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage						0.50%
Idaho Refinancing Note [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] | Revolving Note Tranche [Member]
Debt Instrument, Basis Spread on Variable Rate						1.40%
USG Prudential - ID [Member]
Long-Term Debt, Total						$ 16,000
DOE Loan Guarantee [Member]
Line of Credit Facility, Maximum Borrowing Capacity																																														$ 96,800
Loan Agreement with Bpifrance [Member] | Guadeloupe 1 [Member]
Debt Instrument, Face Amount																																				$ 8,900
Debt Instrument, Interest Rate, Stated Percentage																																			1.93%
Long-Term Debt, Gross																							4,200
Loan Agreement with Société Général [Member] | Guadeloupe 1 [Member]
Debt Instrument, Face Amount														$ 8,900
Debt Instrument, Interest Rate, Stated Percentage														1.52%
Long-Term Debt, Gross																							$ 3,500
Debt Instrument Number of Quarterly Payments														28
Senior Unsecured Bonds, Series 3 [Member]
Repayments of Long-Term Debt							221,900
Extinguishment of Debt, Amount							218,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities							2,800
Debt Instrument, Unamortized Premium							$ 1,100
Finance Liability [Member]
Debt Instrument, Interest Rate, Stated Percentage																							6.12%	[1]			2.55%
Long-Term Debt, Gross																							$ 225,800
Credit Agreements With Eight Commercial Banks [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							608,000
Long-Term Line of Credit																							20,000
Letters of Credit Outstanding, Amount																							302,800
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																							453,000
Credit Agreements With Eight Commercial Banks [Member] | Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							155,000
Credit Agreements With Eight Commercial Banks [Member] | Union Bank, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							60,000
Credit Agreements With Eight Commercial Banks [Member] | HSBC Bank USA, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							35,000
Union Bank, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							60,000
Long-Term Line of Credit																							$ 59,300
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							1.24
Debt Services, Coverage Ratio																							5.75
Amount Available For Dividend Distribution Percent Of Cumulative Net Income																			2				0.7
Union Bank, N.A. [Member] | Maximum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																			4.5
Union Bank, N.A. [Member] | Minimum [Member]
Debt Services, Coverage Ratio																			1.35
HSBC Bank USA, N.A. [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							$ 35,000
Long-Term Line of Credit																							$ 34,300
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																							1.24
Debt Services, Coverage Ratio																							5.75
Amount Available For Dividend Distribution Percent Of Cumulative Net Income																							0.7
Uncommitted Line of Credit Facility, Maximum Borrowing Capacity																							$ 20,000
Uncommitted Long-term Line of Credit																							36,300
HSBC Bank USA, N.A. [Member] | Letter of Credit [Member]
Line of Credit Facility, Maximum Borrowing Capacity																							65,000
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
HSBC Bank USA, N.A. [Member] | Minimum [Member]
Debt To Earnings Before Interest Tax Depreciation And Amortization Ratio																					1.35
Surety Agreement [Member] | Chubb [Member]
Surety Bonds Available																																							$ 635,000
Surety Bonds Outstanding																							$ 237,700

[1] payable semi-annually

[2] payable semi-annually in arrears.

[3] payable quarterly