Investment in Sunrise Energy (Condensed Statement of Operations - Sunrise) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue		$ 68,564	$ 95,253	$ 144,449	$ 193,254
Expenses		(62,329)	(85,945)	(130,314)	(172,943)
Net income	[1]	$ 5,853	$ 6,853	12,015	14,444
Sunrise Energy [Member]
Revenue				796	1,167
Expenses				(1,113)	(1,161)
Net income				$ (317)	$ 6

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