Note 13 - Discontinued Operations (Details) - Summary of Financial Information Related to Discontinued Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues - electricity	$ 94,817
Cost of revenues - electricity	88,977
Gross margin	53,459
Selling and marketing expenses	3,379
General and administrative expenses	7,596
Operating income	42,571	7,684
Momotombo Power Plant [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues - electricity		2,804
Cost of revenues - electricity		1,849
Gross margin		955
Selling and marketing expenses		67
General and administrative expenses		66
Operating income		827
Income from discontinued operations before income taxes		827
Income tax provision		(222)
Total income from discontinued operations		$ 605