Note 8 - Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

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

				December 31, 2016
				Fair Value
	Carrying Value at December 31, 2016			Total			Level 1		Level 2			Level 3
	(Dollars in thousands)
Assets:
Current assets:
Cash equivalents (including restricted cash accounts)	$	14,922		$	14,922		$	14,922	$	—		$	—
Derivatives:
Contingent receivable (1)		1,443			1,443			—		—			1,443
Liabilities:
Current liabilities:
Derivatives:
Contingent payables (1)		(11,581	)		(11,581	)		—		—			(11,581	)
Warrants (1)		(3,429	)		(3,429	)							(3,429	)
Currency forward contracts (2)		(481	)		(481	)		—		(481	)		—
	$	874		$	874		$	14,922	$	(481	)	$	(13,567	)

				December 31, 2015
				Fair Value
	Carrying Value at December 31, 2015			Total			Level 1		Level 2			Level 3
	(Dollars in thousands)
Assets
Current assets:
Cash equivalents (including restricted cash accounts)	$	31,428		$	31,428		$	31,428	$	—		$	—
Derivatives:
Currency forward contracts (2)		7			7			—		7			—
Liabilities:
Current liabilities:
Derivatives:
Currency forward contracts (2)		(169	)		(169	)		—		(169	)		—
	$	31,266		$	31,266		$	31,428	$	(162	)	$	—

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

		Amount of recognized gain (loss)
Derivatives not designated as hedging instruments	Location of recognized gain (loss)	2016			2015			2014
		(Dollars in thousands)
Call options on natural gas price	Derivatives and foreign currency transaction gain (losses)	$	(1,340	)	$	—		$	—
Call and put options on oil price	Derivatives and foreign currency transaction gain (losses)		(1,313	)		—			—
Swap transaction on oil price	Electricity revenues		—			—			2,728
Swap transactions on natural gas price	Electricity revenues		—			1,158			2,996
Contingent considerations	Derivatives and foreign currency transaction gain (losses)		(1,527	)		—			—
Currency forward contracts	Derivatives and foreign currency transaction gain (losses)		238			(1,206	)		(4,949	)
		$	(3,942	)	$	(48	)	$	775

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

	Fair Value				Carrying Amount
	2016		2015		2016		2015
	(Dollars in millions)				(Dollars in millions)
Olkaria III Loan - DEG	$	16.3	$	24.2	$	15.8	$	23.7
Olkaria III Loan - OPIC		253.4		262.6		246.6		264.6
Olkaria IV Loan - DEG 2		50.9		—		50.0		—
Amatitlan Loan		37.3		41.7		36.8		40.3
Senior Secured Notes:
Ormat Funding Corp. ("OFC")	17.0			30.0		17.0		30.0
OrCal Geothermal Inc. ("OrCal")		37.4		43.8		35.2		43.3
OFC 2 LLC ("OFC 2")		249.0		231.1		247.2		262.0
Don A. Campbell 1 ("DAC1")		88.9		—		92.4		—
Senior Unsecured Bonds		200.1		264.5		204.3		250.0
Other long-term debt		10.4		6.7		11.2		6.7

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

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III - DEG	$	—	$	—	$	16.3	$	16.3
Olkaria III - OPIC		—		—		253.4		253.4
Olkaria IV - DEG 2		—		—		50.9		50.9
Amatitlan loan		—		37.3		—		37.3
Senior Secured Notes:
OFC		—		17.0		—		17.0
OrCal		—		—		37.4		37.4
OFC 2		—		—		249.0		249.0
Don A. Campbell 1 ("DAC1")		—		—		88.9		88.9
Senior unsecured bonds		—		—		200.1		200.1
Other long-term debt		—		3.3		7.1		10.4
Deposits		14.4		—		—		14.4

	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Olkaria III Loan - DEG	$	—	$	—	$	24.2	$	24.2
Olkaria III Loan - OPIC		—		—		262.6		262.6
Amatitlan Loan		—		41.7		—		41.7
Senior Secured Notes:
OFC		—		30.0		—		30.0
OrCal		—		—		43.8		43.8
OFC 2		—		—		231.1		231.1
Senior unsecured bonds		—		—		264.5		264.5
Other long-term debt		—		6.7		—		6.7
Deposits		15.9		—		—		15.9