Note 16 - Discontinued Operations (Details) - Summary of Financial Information Related to Discontinued Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended						12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues - electricity	$ 84,742	$ 88,994	$ 87,713	$ 77,612	$ 81,882	$ 82,247	$ 329,747		$ 312,296
Cost of revenues - electricity	88,001	90,993	102,298	102,054	88,383	92,558	373,421		311,681
Gross margin	42,904	39,756	50,381	30,243	38,325	39,794	159,818		113,775
Selling and marketing expenses	6,752	2,575	3,777	3,346	4,570	4,922	24,613		16,053
General and administrative expenses	8,924	6,546	7,134	6,132	6,757	7,314	29,188		27,366
Operating income	21,615	29,797	37,862	12,065	24,383	25,742	96,958	(159,896)	61,555
Income from discontinued operations, net of taxes			4,480	2,123	1,613		5,311		2,452
Momotombo Power Plant [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues - electricity							4,866	12,635	11,553
Cost of revenues - electricity							2,869	7,219	8,428
Gross margin							1,997	5,416	3,125
Selling and marketing expenses							192	404	154
General and administrative expenses							140	201	519
Operating income							1,665	4,811	2,452
Income from discontinued operations before income taxes							5,311	4,811	2,452
Income tax provision							(614)	(1,264)	(295)
Income from discontinued operations, net of taxes							$ 4,697	$ 3,547	$ 2,157