Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Federal:
Current	$ 59,792	$ 61,688	$ 54,915
Deferred	48,962	8,394	16,150
Federal, Total	108,754	70,082	71,065
State:
Current	13,584	12,965	11,156
Deferred	9,184	1,013	3,017
State, Total	22,768	13,978	14,173
Foreign:
Current	5,445	3,372	3,318
Deferred	(1,424)	(554)	(1,103)
Foreign, Total	4,021	2,818	2,215
Total income tax expense (benefit)	$ 135,543	$ 86,878	$ 87,453