Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Federal:
Current	$ 61,688	$ 54,915	$ 51,342
Deferred	8,394	16,150	(27,103)
Federal, Total	70,082	71,065	24,239
State:
Current	12,965	11,156	9,896
Deferred	1,013	3,017	(5,081)
State, Total	13,978	14,173	4,815
Current	3,372	3,318	4,035
Deferred	(554)	(1,103)	(1,214)
Foreign, Total	2,818	2,215	2,821
Income Tax Expense (Benefit), Total	$ 86,878	$ 87,453	$ 31,875