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
Current tax expense [Abstract]
Federal	$ 40,642	$ 48,494	$ 41,833
State	2,629	3,609	3,436
Foreign	1,712	1,892	1,571
Deferred tax expense [Abstract]
Federal	2,151	(3,264)	5,452
State	544	310	85
Foreign	(17)	(271)	7
Income taxes	$ 47,661	$ 50,770	$ 52,384