Note 4 - Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions | Mar. 31, 2023 | Dec. 31, 2022 |
Finance liability - Dixie Valley | $ 213.3 | $ 219.8 |
Deposits | 13.9 | 13.9 |
Mizrahi Loan Agreement [Member] | | |
Loans | 71.4 | 71.4 |
Convertible Senior Notes [Member] | | |
Notes | 485.4 | 505.3 |
HSBC Loan Agreement [Member] | | |
Loans | 36.6 | 40.3 |
Hapoalim Loan Agreement [Member] | | |
Loans | 92.4 | 91.1 |
Hapoalim Loan Agreement 2023 [Member] | | |
Loans | 100 | |
Discount Loan Agreement [Member] | | |
Loans | 74.5 | 81.1 |
Olkaria III Loan DFC [Member] | | |
Loans | 129.7 | 134.2 |
Olkaria III Plant 4 Loan - DEG 2 [Member] | | |
Loans | 26.9 | 26.5 |
Olkaria III plant 1 Loan - DEG 3 [Member] | | |
Loans | 23.7 | 23.3 |
Platanares Loan - OPIC [Member] | | |
Loans | 78 | 80.2 |
Amatitlan Loan [Member] | | |
Loans | 13.8 | 14.7 |
OFC Senior Secured Notes [Member] | | |
Notes | 145 | 149.8 |
Don A. Campbell 1 ("DAC1") [Member] | | |
Notes | 55.8 | 57.4 |
USG Prudential - NV [Member] | | |
Notes | 23.5 | 23.7 |
USG Prudential - ID [Member] | | |
Notes | 54.6 | 56.8 |
USG DOE [Member] | | |
Notes | 31.1 | 32.8 |
Senior Unsecured Bonds [Member] | | |
Senior Unsecured debt | 232.1 | 235.1 |
Senior Unsecured Loan [Member] | | |
Senior Unsecured debt | 156.1 | 166.4 |
Plumstriker Loan Agreement [Member] | | |
Loans | 10.9 | 11.2 |
Other Long-term Debt [Member] | | |
Senior Unsecured debt | 8.8 | 9.2 |
Fair Value, Inputs, Level 1 [Member] | | |
Finance liability - Dixie Valley | 0 | 0 |
Deposits | 13.9 | 13.9 |
Fair Value, Inputs, Level 1 [Member] | Mizrahi Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Convertible Senior Notes [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | HSBC Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Hapoalim Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Hapoalim Loan Agreement 2023 [Member] | | |
Loans | 0 | |
Fair Value, Inputs, Level 1 [Member] | Discount Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Olkaria III Loan DFC [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Olkaria III Plant 4 Loan - DEG 2 [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Olkaria III plant 1 Loan - DEG 3 [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Platanares Loan - OPIC [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Amatitlan Loan [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | OFC Senior Secured Notes [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Don A. Campbell 1 ("DAC1") [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | USG Prudential - NV [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | USG Prudential - ID [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | USG DOE [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Senior Unsecured Bonds [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Senior Unsecured Loan [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Plumstriker Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 1 [Member] | Other Long-term Debt [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | | |
Finance liability - Dixie Valley | 0 | 0 |
Deposits | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Mizrahi Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Convertible Senior Notes [Member] | | |
Notes | 485.4 | 505.3 |
Fair Value, Inputs, Level 2 [Member] | HSBC Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Hapoalim Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Hapoalim Loan Agreement 2023 [Member] | | |
Loans | 0 | |
Fair Value, Inputs, Level 2 [Member] | Discount Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Olkaria III Loan DFC [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Olkaria III Plant 4 Loan - DEG 2 [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Olkaria III plant 1 Loan - DEG 3 [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Platanares Loan - OPIC [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Amatitlan Loan [Member] | | |
Loans | 13.8 | 14.7 |
Fair Value, Inputs, Level 2 [Member] | OFC Senior Secured Notes [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Don A. Campbell 1 ("DAC1") [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | USG Prudential - NV [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | USG Prudential - ID [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | USG DOE [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Senior Unsecured Bonds [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Senior Unsecured Loan [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | Plumstriker Loan Agreement [Member] | | |
Loans | 10.9 | 11.2 |
Fair Value, Inputs, Level 2 [Member] | Other Long-term Debt [Member] | | |
Senior Unsecured debt | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | | |
Finance liability - Dixie Valley | 213.3 | 219.8 |
Deposits | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Mizrahi Loan Agreement [Member] | | |
Loans | 71.4 | 71.4 |
Fair Value, Inputs, Level 3 [Member] | Convertible Senior Notes [Member] | | |
Notes | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | HSBC Loan Agreement [Member] | | |
Loans | 36.6 | 40.3 |
Fair Value, Inputs, Level 3 [Member] | Hapoalim Loan Agreement [Member] | | |
Loans | 92.4 | 91.1 |
Fair Value, Inputs, Level 3 [Member] | Hapoalim Loan Agreement 2023 [Member] | | |
Loans | 100 | |
Fair Value, Inputs, Level 3 [Member] | Discount Loan Agreement [Member] | | |
Loans | 74.5 | 81.1 |
Fair Value, Inputs, Level 3 [Member] | Olkaria III Loan DFC [Member] | | |
Loans | 129.7 | 134.2 |
Fair Value, Inputs, Level 3 [Member] | Olkaria III Plant 4 Loan - DEG 2 [Member] | | |
Loans | 26.9 | 26.5 |
Fair Value, Inputs, Level 3 [Member] | Olkaria III plant 1 Loan - DEG 3 [Member] | | |
Loans | 23.7 | 23.3 |
Fair Value, Inputs, Level 3 [Member] | Platanares Loan - OPIC [Member] | | |
Loans | 78 | 80.2 |
Fair Value, Inputs, Level 3 [Member] | Amatitlan Loan [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | OFC Senior Secured Notes [Member] | | |
Notes | 145 | 149.8 |
Fair Value, Inputs, Level 3 [Member] | Don A. Campbell 1 ("DAC1") [Member] | | |
Notes | 55.8 | 57.4 |
Fair Value, Inputs, Level 3 [Member] | USG Prudential - NV [Member] | | |
Notes | 23.5 | 23.7 |
Fair Value, Inputs, Level 3 [Member] | USG Prudential - ID [Member] | | |
Notes | 54.6 | 56.8 |
Fair Value, Inputs, Level 3 [Member] | USG DOE [Member] | | |
Notes | 31.1 | 32.8 |
Fair Value, Inputs, Level 3 [Member] | Senior Unsecured Bonds [Member] | | |
Senior Unsecured debt | 232.1 | 235.1 |
Fair Value, Inputs, Level 3 [Member] | Senior Unsecured Loan [Member] | | |
Senior Unsecured debt | 156.1 | 166.4 |
Fair Value, Inputs, Level 3 [Member] | Plumstriker Loan Agreement [Member] | | |
Loans | 0 | 0 |
Fair Value, Inputs, Level 3 [Member] | Other Long-term Debt [Member] | | |
Senior Unsecured debt | $ 8.8 | $ 9.2 |