Stock-Based Compensation (Schedule Of Option Activity And Changes) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Stock-Based Compensation [Abstract]
Options, Outstanding at December 31, 2010	1,314,524
Options, Granted	99,380
Options, Exercised	(274,872)
Options, Cancelled	(5,885)
Options, Outstanding at December 31, 2011	1,133,147
Options, Exercisable at December 31, 2011	503,830
Weighted Average Exercise Price, Outstanding at December 31, 2010	$ 20.81
Weighted Average Exercise Price, Granted	$ 45.83
Weighted Average Exercise Price, Exercised	$ 19.44
Weighted Average Exercise Price, Cancelled	$ 34.41
Weighted Average Exercise Price, Outstanding at December 31, 2011	$ 23.26
Weighted Average Exercise Price, Exercisable at December 31, 2011	$ 18.74
Weighted Average Remaining Term (in years), Outstanding at December 31, 2011	6.5
Weighted Average Remaining Term (in years), Exercisable at December 31, 2011	5.8
Aggregate Intrinsic Value, Outstanding at December 31, 2011	$ 19,788
Aggregate Intrinsic Value, Exercisable at December 31, 2011	$ 10,835