Stock-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009
Stock-Based Compensation [Abstract]
Options, Outstanding, Beginning Balance	1,568,384	1,973,301	2,227,032
Options, Exercised	(343,685)	(394,420)	(185,801)
Options, Forfeited		(10,497)	(67,930)
Options, Outstanding, Ending Balance		1,568,384	1,973,301
Options, Outstanding and exercisable, Ending Balance	1,224,699
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 21.38	$ 20.92	$ 19.85
Weighted-Average Exercise Price, Exercised	$ 20.34	$ 19.01	$ 8.69
Weighted-Average Exercise Price, Forfeited		$ 24.62	$ 19.11
Weighted-Average Exercise Price, Outstanding, Ending Balance		$ 21.38	$ 20.92
Weighted-Average Exercise Price, Outstanding and exercisable, Ending Balance	$ 21.64
Weighted-Average Remaining Contractual Term (years), Outstanding and exercisable, Ending Balance	1.5
Aggregate Intrinsic Value, Outstanding and exercisable, Ending Balance	$ 4,485