Income Taxes Provision for Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal	$ 91,762	$ 57,605	$ 60,826
State	12,274	6,933	7,164
Foreign	66	41	11
Total current provision	104,102	64,579	68,001
Federal	(6,833)	9,391	(9,855)
State	2,532	2,644	(2,216)
Foreign	(5)	(47)	0
Total deferred (benefit) provision	(4,306)	11,988	(12,071)
Total provision	$ 99,796	$ 76,567	$ 55,930