Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Income tax
(Loss) income before provision for income tax	$ 1,400	$ 28,462
Federal income tax at statutory rate	(4,491)	6,461
Permanent items	9	21
State income taxes, net of federal benefit	(219)	619
Federal and state tax rate change		4,250
Provision on income from Class A units	580	1,195
Total provision for income tax	(4,121)us-gaap_IncomeTaxExpenseBenefit	12,546us-gaap_IncomeTaxExpenseBenefit
Eliminations
Income tax
(Loss) income before provision for income tax	(682)	(5,103)
Federal statutory rate (as a percent)	0.00%	0.00%
Corporation \| Reportable legal entities
Income tax
(Loss) income before provision for income tax	(12,830)	18,459
Federal statutory rate (as a percent)	35.00%	35.00%
Federal income tax at statutory rate	(4,491)	6,461
Permanent items	9	21
State income taxes, net of federal benefit	(384)	463
Federal and state tax rate change		4,250
Provision on income from Class A units	580	1,195
Total provision for income tax	(4,286)	12,390
Partnership \| Reportable legal entities
Income tax
(Loss) income before provision for income tax	14,912	15,106
Federal statutory rate (as a percent)	0.00%	0.00%
State income taxes, net of federal benefit	165	156
Total provision for income tax	$ 165	$ 156

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