Stock-Based Compensation (Schedule Of Option Activity And Changes) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 Y
Stock-Based Compensation [Abstract]
Options, Outstanding at December 31, 2011	1,133,147
Options, Granted	115,340
Options, Exercised	(19,430)
Options, Cancelled
Options, Outstanding at March 31, 2012	1,229,057
Options, Exercisable at March 31, 2012	850,834
Weighted Average Exercise Price, Outstanding at December 31, 2011	$ 23.26
Weighted Average Exercise Price, Granted	$ 60.09
Weighted Average Exercise Price, Exercised	$ 24.75
Weighted Average Exercise Price, Cancelled
Weighted Average Exercise Price, Outstanding at March 31, 2012	$ 26.70
Weighted Average Exercise Price, Exercisable at March 31, 2012	$ 20.64
Weighted Average Remaining Term (Years), Outstanding at March 31, 2012	6.6
Weighted Average Remaining Term (Years), Exercisable at March 31, 2012	6.0
Aggregate Intrinsic Value, Outstanding at March 31, 2012	$ 46,820
Aggregate Intrinsic Value, Exercisable at March 31, 2012	$ 37,570