Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective income tax rate reconciliation, percent
Federal statutory rate (as a percent)						35.00%	35.00%	35.00%
Effective income tax rate reconciliation
Income tax (benefit) expense computed at statutory rate						$ 13,155	$ 4,320	$ (522)
State income tax (benefit) expense, net of federal benefit						1,201	1,452	823
Change in valuation allowance on deferred tax assets						(124,525)	(5,336)	(370)
Change in state rate						688
Other						(40)		$ 69
Total income tax expense	$ (438)	$ (38)	$ 110,065	$ (68)	$ (436)	$ (109,521)	$ 436