Investment in Sunrise Energy (Condensed Statement of Operations - Sunrise) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenue		$ 95,253	$ 38,460	$ 193,254	$ 74,227
Expenses		(85,945)	(34,950)	(172,943)	(66,015)
Net income (loss)	[1]	$ 6,853	$ 3,068	14,444	6,594
Sunrise Energy [Member]
Revenue				1,167	1,583
Expenses				(1,161)	(1,409)
Net income (loss)				$ 6	$ 174

[1] There is no material difference between net income and comprehensive income.