Income Taxes (Details) - Components of Income Tax Benefit - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax expense (benefit):
Federal	$ 46,748	$ 18,524	$ 16,343
State	790	2,326	(1,388)
Total	47,538	20,850	14,955
Deferred income tax (benefit) expense:
Federal	(7,786)	12,048	7,901
State	6,419	4,849	8,314
Total	(1,367)	16,897	16,215
Total income tax expense	$ 46,171	$ 37,747	$ 31,170