Income Taxes - Provision for Income Tax (Benefit) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal	$ (22,416)	$ (1,377)	$ 69,245
State	(64)	(138)	135
Total	(22,480)	(1,515)	69,380
Deferred:
Federal	29,796	2,261	35,314
State	(169)	62	10,813
Total	29,627	2,323	46,127
Income tax expense	$ 7,147	$ 808	$ 115,507