Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income tax
(Loss) income before provision for income tax	$ 51,435	$ 97,078	$ (45,013)	$ 135,648
Federal income tax at statutory rate			(10,107)	9,091
Permanent items			23	32
State income taxes, net of federal benefit			(1,413)	1,689
Tax rate changes			(1,517)	4,250
Provision on income from Class A units			(334)	5,574
Total provision for income tax expense (benefit)	$ 2,229	$ 11,030	(13,348)	20,636
Eliminations
Income tax
(Loss) income before provision for income tax			$ (71)	$ (481)
Federal statutory rate (as a percent)			0.00%	0.00%
Corporation | Reportable legal entities
Income tax
(Loss) income before provision for income tax			$ (28,878)	$ 25,973
Federal statutory rate (as a percent)			35.00%	35.00%
Federal income tax at statutory rate			$ (10,107)	$ 9,091
Permanent items			23	32
State income taxes, net of federal benefit			(864)	652
Tax rate changes				4,250
Provision on income from Class A units			(334)	5,574
Total provision for income tax expense (benefit)			(11,282)	19,599
Partnership | Reportable legal entities
Income tax
(Loss) income before provision for income tax			$ (16,064)	$ 110,156
Federal statutory rate (as a percent)			0.00%	0.00%
State income taxes, net of federal benefit			$ (549)	$ 1,037
Tax rate changes			(1,517)
Total provision for income tax expense (benefit)			$ (2,066)	$ 1,037