Note 8 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2022

Notes Tables

Fair Value, by Balance Sheet Grouping [Table Text Block]

				December 31, 2022
				Fair Value
	Carrying Value at December 31, 2022			Total			Level 1		Level 2			Level 3
	(Dollars in thousands)
Assets:
Current assets:
Cash equivalents (including restricted cash accounts)	$	34,832		$	34,832		$	34,832	$	—		$	—
Marketable securities (including cash equivalents)		136			136			136		—			—
Derivatives:
Long-term assets:
Cross currency swap (3)		3,029			3,029			—		3,029			—
Liabilities:
Current liabilities:
Derivatives:
Currency forward contracts (2)		(800	)		(800	)		—		(800	)		—
Cross currency swap (3)		(2,777	)		(2,777	)		—		(2,777	)		—
	$	34,420		$	34,420		$	34,968	$	(548	)	$	—

				December 31, 2021
				Fair Value
	Carrying Value at December 31, 2021			Total			Level 1		Level 2		Level 3
	(Dollars in thousands)
Assets
Current assets:
Cash equivalents (including restricted cash accounts)	$	31,675		$	31,675		$	31,675	$	—	$	—
Marketable securities		47,029			47,029			47,029		—		—
Derivatives:
Cross currency swap (3)		1,461			1,461			—		1,461		—
Currency forward contracts (2)		813			813			—		813		—
Long-term assets:
Cross currency swap (3)		37,883			37,883			—		37,883		—
Liabilities:
Long-term liabilities:
Contingent payables (1)		(2,425	)		(2,425	)		—		—		(2,425	)
	$	116,436		$	116,436		$	78,704	$	40,157	$	(2,425	)

Derivative Instruments, Gain (Loss) [Table Text Block]

Derivatives not designated as hedging instruments	Location of recognized gain (loss)	Amount of recognized gain (loss)
		2022			2021			2020
		(Dollars in thousands)
Swap transaction on RRS prices (1)	Derivative and foreign currency transaction gains (losses)	$	—		$	(14,540	)	$	—
Currency forward contracts (1)	Derivative and foreign currency transaction gains (losses)		(5,466	)		1,368			5,175
		$	(5,466	)	$	(13,172	)	$	5,175
Derivatives designated as cash flow hedging instruments
Cross currency swap (2)	Derivative and foreign currency transaction gains (losses)	$	(36,803	)	$	10,501		$	21,187

Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]

	Year Ended December 31,
	2022			2021			2020
	(Dollars in thousands)
Cross currency swap cash flow hedge:
Balance in Other comprehensive income (loss) beginning of period	$	5,745		$	3,366		$	—
Gain or (loss) recognized in Other comprehensive income (loss) (1)		(38,628	)		12,880			24,553
Amount reclassified from Other comprehensive income (loss) into earnings		36,803			(10,501	)		(21,187	)
Balance in Other comprehensive income (loss) end of period	$	3,920		$	5,745		$	3,366

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]

	Fair Value				Carrying Amount
	2022		2021		2022		2021
	(Dollars in millions)				(Dollars in millions)
Mizrahi Loan	$	71.4	$	—	$	70.3	$	—
Convertible Senior Notes		505.3		—		431.3		—
HSBC Loan		40.3		50.4		42.9		50.0
Hapoalim Loan		91.1		117.8		98.2		116.1
Discount Loan		81.1		100.2		87.5		100.0
Financing Liability - Dixie Valley		219.8		248.4		242.0		252.9
Olkaria III Loan - DFC		134.2		166.5		138.7		156.7
Olkaria III plant 4 Loan - DEG 2		26.5		34.1		27.5		32.5
Olkaria III plant 1 Loan - DEG 3		23.3		30.1		24.0		28.4
Platanares Loan - DFC		80.2		98.2		79.9		88.1
Amatitlan Loan		14.7		19.8		15.8		19.3
OFC 2 LLC Senior Secured Notes ("OFC 2")		149.8		183.3		158.0		173.3
Don A. Campbell 1 Senior Secured Notes ("DAC 1")		57.4		69.8		62.7		67.9
USG Prudential - NV		23.7		28.9		25.0		26.3
USG Prudential - ID Refinancing (prior year: USG Prudential - ID)		56.8		17.3		61.6		17.3
USG DOE		32.8		39.9		32.8		35.5
Senior Unsecured Bonds		235.1		578.9		255.8		539.6
Senior Unsecured Loan		166.4		204.3		174.8		191.6
Plumstriker		11.2		14.8		11.4		14.7
Other long-term debt		9.2		13.3		10.4		13.6

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Mizrahi Loan	$	—	$	—	$	71.4	$	71.4
Convertible Senior Notes		—		505.3		—		505.3
HSBC Loan		—		—		40.3		40.3
Hapoalim Loan		—		—		91.1		91.1
Discount Loan		—		—		81.1		81.1
Financing Liability - Dixie Valley		—		—		219.8		219.8
Olkaria III - DFC		—		—		134.2		134.2
Olkaria III plant 4 - DEG 2		—		—		26.5		26.5
Olkaria III plant 1 - DEG 3		—		—		23.3		23.3
Platanares Loan - DFC		—		—		80.2		80.2
Amatitlan Loan		—		14.7		—		14.7
OFC 2 Senior Secured Notes		—		—		149.8		149.8
DAC 1 Senior Secured Notes		—		—		57.4		57.4
USG Prudential - NV		—		—		23.7		23.7
USG Prudential - ID		—		—		56.8		56.8
USG DOE		—		—		32.8		32.8
Senior Unsecured Bonds		—		—		235.1		235.1
Senior Unsecured Loan		—		—		166.4		166.4
Plumstriker		—		11.2		—		11.2
Other long-term debt		—		—		9.2		9.2
Deposits		13.9		—		—		13.9

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
HSBC Loan	$	—	$	—	$	50.4	$	50.4
Hapoalim Loan		—		—		117.8		117.8
Discount Loan		—		—		100.2		100.2
Financing Liability - Dixie Valley		—		—		248.4		248.4
Olkaria III Loan - DFC		—		—		166.5		166.5
Olkaria III plant 4 - DEG 2		—		—		34.1		34.1
Olkaria III plant 1 - DEG 3		—		—		30.1		30.1
Platanares Loan - DFC		—		—		98.2		98.2
Amatitlan Loan		—		19.8		—		19.8
Senior Secured Notes:
OFC 2 Senior Secured Notes		—		—		183.3		183.3
DAC 1 Senior Secured Notes		—		—		69.8		69.8
USG Prudential - NV		—		—		28.9		28.9
USG Prudential - ID		—		—		17.3		17.3
USG DOE		—		—		39.9		39.9
Senior Unsecured Bonds		—		—		578.9		578.9
Senior Unsecured Loan		—		—		204.3		204.3
Plumstriker		—		14.8		—		14.8
Other long-term debt		—		—		13.3		13.3
Deposits		17.1		—		—		17.1