FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Long-term Debt Approximates Its Carrying Amount, Exceptions (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing Liability - Dixie Valley	$ 223.4	$ 207.2
Other long-term debt	3.8	6.8
Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Financing Liability - Dixie Valley	220.6	225.8
Other long-term debt	3.9	7.7
Hapoalim 2024 Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	69.7	0.0
Hapoalim 2024 Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	68.0	0.0
HSBC Bank 2024 Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	117.2	0.0
HSBC Bank 2024 Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	112.5	0.0
Mammoth Senior Secured Notes | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	130.8	0.0
Mammoth Senior Secured Notes | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	129.2	0.0
Discount 2024 Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	30.6	0.0
Discount 2024 Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	29.8	0.0
Discount 2024 II Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	48.5	0.0
Discount 2024 II Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	48.4	0.0
Bottleneck Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	72.9	0.0
Bottleneck Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	72.6	0.0
Mizrahi Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	51.7	61.4
Mizrahi Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	51.6	60.9
Mizrahi Loan 2023 | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	45.1	52.0
Mizrahi Loan 2023 | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	43.8	50.0
Convertible Senior Notes | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	471.2	444.6
Convertible Senior Notes | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	476.4	431.3
HSBC Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	27.6	33.8
HSBC Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	28.6	35.7
Hapoalim Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	59.3	75.0
Hapoalim Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	62.5	80.4
Hapoalim Loan 2023 | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	89.6	99.7
Hapoalim Loan 2023 | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	85.0	95.0
Discount Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	59.0	69.9
Discount Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	62.5	75.0
Olkaria III Loan - DFC | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	99.4	116.4
Olkaria III Loan - DFC | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	102.5	120.7
Olkaria III plant 4 Loan - DEG 2 | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	17.0	21.6
Olkaria III plant 4 Loan - DEG 2 | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	17.5	22.5
Olkaria III plant 1 Loan - DEG 3 | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	14.9	19.0
Olkaria III plant 1 Loan - DEG 3 | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	15.3	19.7
DEG 4 Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	30.9	0.0
DEG 4 Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	30.0	0.0
Platanares Loan - DFC | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	62.8	71.3
Platanares Loan - DFC | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans payable, fair value disclosure	63.5	71.7
OFC 2 LLC Senior Secured Notes ("OFC 2") | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	119.4	134.2
OFC 2 LLC Senior Secured Notes ("OFC 2") | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	126.9	142.5
Don A. Campbell 1 Senior Secured Notes ("DAC 1") | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	47.6	52.3
Don A. Campbell 1 Senior Secured Notes ("DAC 1") | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	52.2	57.4
USG Prudential - NV | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	21.2	22.3
USG Prudential - NV | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	23.0	23.9
USG Prudential - ID Refinancing | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	51.3	54.1
USG Prudential - ID Refinancing | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	55.9	58.9
USG DOE | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	27.3	30.0
USG DOE | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Notes payable, fair value disclosure	27.5	30.2
Senior Unsecured Bonds | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt, fair value	172.0	202.8
Senior Unsecured Bonds | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt, fair value	192.2	220.6
Senior Unsecured Loan | Fair Value
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt, fair value	135.8	150.4
Senior Unsecured Loan | Carrying Amount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Long-term debt, fair value	$ 141.2	$ 158.0