Note 4 - Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2020

Notes Tables

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

				March 31, 2020
				Fair Value
	Carrying Value at March 31, 2020			Total			Level 1		Level 2		Level 3
	(Dollars in thousands)
Assets:
Current assets:
Cash equivalents (including restricted cash accounts)	$	36,978		$	36,978		$	36,978	$	—	$	—
Derivatives:
Contingent receivable (1)		99			99			—		—		99
Currency forward contracts (2)		928			928			—		928		—
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(3,272	)		(3,272	)		—		—		(3,272	)
	$	34,733		$	34,733		$	36,978	$	928	$	(3,173	)

				December 31, 2019
				Fair Value
	Carrying Value at December 31, 2019			Total			Level 1		Level 2		Level 3
	(Dollars in thousands)
Assets
Current assets:
Cash equivalents (including restricted cash accounts)	$	28,316		$	28,316		$	28,316	$	—	$	—
Derivatives:
Contingent receivables (1)		102			102			—		—		102
Currency forward contracts (2)		362			362			—		362		—
Liabilities:
Current liabilities:
Derivatives:
Contingent payable (1)		(3,359	)		(3,359	)		—		—		(3,359	)
	$	25,421		$	25,421		$	28,316	$	362	$	(3,257	)

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

		Amount of recognized gain (loss)
Derivatives not designated as hedging instruments	Location of recognized gain (loss)	Three Months Ended March 31,
		2020		2019
Currency forward contracts	Derivative and foreign currency transaction gains (losses)		1,090		1,083
		$	1,090	$	1,083

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

	Fair Value				Carrying Amount
	March 31, 2020		December 31, 2019		March 31, 2020		December 31, 2019
	(Dollars in millions)				(Dollars in millions)
Olkaria III Loan - OPIC	$	206.5	$	202.1	$	188.1	$	192.6
Olkaria III plant 4 Loan - DEG 2		46.2		43.8		42.5		42.5
Olkaria III plant 1 Loan - DEG 3		40.8		38.8		37.1		37.1
Platanares Loan - OPIC		118.9		115.3		102.4		104.5
Amatitlan Loan		25.5		26.4		25.4		26.3
Senior Secured Notes:
OFC 2 LLC ("OFC 2")		218.1		210.9		198.4		203.0
Don A. Campbell 1 ("DAC 1")		81.7		78.5		76.6		78.2
USG Prudential - NV		32.8		30.6		28.3		28.4
USG Prudential - ID		18.3		18.6		18.9		19.6
USG DOE		46.2		45.0		39.4		40.8
Senior Unsecured Bonds		207.7		205.7		204.3		204.3
Senior Unsecured Loan		169.0		161.3		150.0		150.0
Plumstriker		21.4		21.7		21.3		21.6
Other long-term debt		16.2		16.3		16.6		17.4

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

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III - OPIC		—		—		206.5		206.5
Olkaria III plant 4 Loan - DEG 2		—		—		46.2		46.2
Olkaria III plant 1 Loan - DEG 3		—		—		40.8		40.8
Platanares Loan - OPIC		—		—		118.9		118.9
Amatitlan Loan		—		25.5		—		25.5
Senior Secured Notes:
OFC 2 Senior Secured Notes		—		—		218.1		218.1
DAC 1 Senior Secured Notes		—		—		81.7		81.7
USG Prudential - NV		—		—		32.8		32.8
USG Prudential - ID		—		—		18.3		18.3
USG DOE		—		—		46.2		46.2
Senior Unsecured Bonds		—		—		207.7		207.7
Senior Unsecured Loan		—		—		169.0		169.0
Plumstriker		—		21.4		—		21.4
Other long-term debt		—		—		16.2		16.2
Commercial paper		—		8.3		—		8.3
Revolving lines of credit		—		270.5		—		270.5
Deposits		11.8		—		—		11.8

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III Loan - OPIC		—		—		202.1		202.1
Olkaria IV - DEG 2		—		—		43.8		43.8
Olkaria IV - DEG 3		—		—		38.8		38.8
Platanares Loan - OPIC		—		—		115.3		115.3
Amatitlan Loan		—		26.4		—		26.4
Senior Secured Notes:
OFC 2 Senior Secured Notes		—		—		210.9		210.9
DAC 1 Senior Secured Notes		—		—		78.5		78.5
USG Prudential - NV		—		—		30.6		30.6
USG Prudential - ID		—		—		18.6		18.6
USG DOE		—		—		45.0		45.0
Senior Unsecured Bonds		—		—		205.7		205.7
Senior Unsecured Loan		—		—		161.3		161.3
Plumstriker		—		21.7		—		21.7
Other long-term debt		—		—		16.3		16.3
Commercial paper		—		50.0		—		50.0
Revolving lines of credit		—		40.6		—		40.6
Deposits		12.2		—		—		12.2