Note 15 - Fair Value Measurements and Disclosures (Details) - Assets and Liabilities Measured on a Nonrecurring Basis (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Note 15 - Fair Value Measurements and Disclosures (Details) - Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Long-lived assets held for use - Power plant and related equipment	$ 17,000		$ 41,000	$ 58,000		$ 0	$ 0
Long-Lived Assets Held For Use [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Note 15 - Fair Value Measurements and Disclosures (Details) - Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Long-lived assets held for use - Power plant and related equipment	32,801	[1]		32,801	[1]
Long-Lived Assets Held For Use [Member]
Note 15 - Fair Value Measurements and Disclosures (Details) - Assets and Liabilities Measured on a Nonrecurring Basis [Line Items]
Long-lived assets held for use - Power plant and related equipment				$ 58,000

[1] Represents fair value at the time of impairment.