Note 6 - Fair Value of Financial Instruments (Details) - Significant Unobservable Inputs (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012 MWh
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Generation output (MWh) (in Megawatt-hours)	224,836
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Generation output (MWh) (in Megawatt-hours)		11,916
Average realized price ($/MWh) (in Dollars per Item)	84.50	49.00
Operating costs	$ 12,687	$ 86
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Generation output (MWh) (in Megawatt-hours)		15,456
Average realized price ($/MWh) (in Dollars per Item)	111.25	71.50
Operating costs	20,430	595
Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Generation output (MWh) (in Megawatt-hours)	224,836	15,097
Average realized price ($/MWh) (in Dollars per Item)	92.31	60.36
Operating costs	$ 16,163	$ 400