Equity - Net Income and Income Tax on Non-controlling Interest (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Net income allocated to non-controlling interest		$ 3,164	$ 16,777	$ 11,569	$ 28,785
Income tax expense (benefit) allocated to non-controlling interest		(428)	124	(885)	564
Net income attributable to non-controlling interest	[1],[2]	$ 3,592	$ 16,653	$ 12,454	$ 28,221

[1] Financial information has been recast to include results attributable to the acquisition of Perigee Energy, LLC by an affiliate on February 3, 2017. See Notes 2 and 3 "Basis of Presentation and Summary of Significant Accounting Policies" and "Acquisitions" for further discussion.

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