Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current
Federal	$ 983	$ 44,887	$ 56,544
State	(1,397)	(4,387)	10,841
Total	(414)	40,500	67,385
Deferred
Federal	(72,869)	(32,375)	111,147
State	(99)	(80,192)	27,233
Total	(72,968)	(112,567)	138,380
Income tax (benefit) expense	$ (73,382)	$ (72,067)	$ 205,765