Income Taxes - Provision (benefit) for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal	$ 60,835	$ 67,349	$ 33,194
State	6,449	7,960	3,614
Foreign	2,281	2,404	2,722
Current Income Tax Expense	69,565	77,713	39,530
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal	(10,664)	(13,591)	(22,126)
State	(3,771)	(396)	(2,261)
Deferred Income Tax Expense (Benefit)	(14,435)	(13,987)	(24,387)
Provision for income taxes	$ 55,130	$ 63,726	$ 15,143