Income Taxes Provision for Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Contingency [Line Items]
Current provision (benefit), Federal	$ 75,505	$ 63,195	$ 57,773
Current provision (benefit), State	10,601	9,108	7,668
Current provision (benefit), Foreign	293	348	313
Current provision (benefit)	86,399	72,651	65,754
Deferred provision (benefit) Federal	(3,209)	3,894	723
Deferred provision (benefit), State	(97)	983	(996)
Deferred Provision (benefit)	(3,306)	4,877	(273)
Non-current provision (benefit), Federal	(787)	(474)	1,067
Non-current provision (benefit), State	(116)	274	288
Non-current provision (benefit), Foreign	6	27	(92)
Non-Current Provision (Benefit)	(897)	(173)	1,263
Total provision for income taxes	$ 82,196	$ 77,355	$ 66,744