Equity - Net Income and Income Tax on Non-controlling Interest (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015		Sep. 30, 2016		Sep. 30, 2015
Equity [Abstract]
Net income allocated to non-controlling interest	$ 6,569		$ 5,011		$ 35,356		$ 19,058
Income tax expense (benefit) allocated to non-controlling interest	(49)		450		517		99
Net income attributable to non-controlling interest	$ 6,618	[1]	$ 4,561	[2]	$ 34,839	[1]	$ 18,959	[2]

[1] Financial information has been recast to include results attributable to the acquisition of Major Energy Companies by an affiliate on April 15, 2016. See Notes 2 and 3 "Basis of Presentation" and "Acquisitions," respectively, for further discussion.

[2] Financial information has been recast to include results attributable to the acquisition of Oasis Power Holdings LLC from an affiliate on May 12, 2015. See Notes 2 "Basis of Presentation" for further discussion.