Note 6 - Fair Value of Financial Instruments (Details) (USD $)	0 Months Ended	3 Months Ended	12 Months Ended								0 Months Ended
	Oct. 16, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Design Capacity [Member] North Brawley Geothermal Power Plant [Member]	Dec. 31, 2013 Target Level [Member] North Brawley Geothermal Power Plant [Member]	Dec. 31, 2013 North Brawley Geothermal Power Plant [Member]	Dec. 31, 2013 North Brawley Geothermal Power Plant [Member] Minimum [Member]	Dec. 31, 2013 North Brawley Geothermal Power Plant [Member] Maximum [Member]	Dec. 31, 2013 OREG 4 [Member]	Oct. 16, 2013 NGI Swap Contract [Member] MMBTU	Sep. 03, 2013 NGI Swap Contract [Member] MMBTU	Oct. 16, 2013 New York Harbor ULSD Swap Contract [Member] Boe
Note 6 - Fair Value of Financial Instruments (Details) [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure (in Millions of British Thermal Units)											4,200,000	4,400,000	275,000
Underlying, Derivative Energy Measure (in Dollars per Million British Thermal Units)	125.15										4.103	4.035
Derivative, Nonmonetary Notional Amount, Energy Measure (in Barrels of Oil Equivalent)											4,200,000	4,400,000	275,000
Underlying, Derivative Energy Measure (in Dollars per Barrel (of Oil))	125.15										4.103	4.035
Gain (Loss) on Price Risk Derivative Instruments Not Designated as Hedging Instruments (in Dollars)			$ 5,000,000	$ 2,300,000
Capacity of Plant					50	27		20	33
Assets, Fair Value Disclosure (in Dollars)							32,000,000			3,600,000
Asset Impairment Charges (in Dollars)		$ 7,264,000		$ 236,377,000			$ 229,100,000			$ 7,300,000
Fair Value Inputs, Discount Rate			8.00%							8.00%