Stock-Based Compensation (Schedule Of Option Activity And Changes) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Share-based Compensation [Abstract]
Options, Outstanding, beginning balance	1,133,147
Options, Granted	115,340
Options, Exercised	(522,425)
Options, Cancelled	(13,742)
Options, Outstanding, ending balance	712,320
Options, Exercisable, ending balance	358,537
Weighted Average Exercise Price, Outstanding, beginning balance	$ 23.26
Weighted Average Exercise Price, Granted	$ 60.09
Weighted Average Exercise Price, Exercised	$ 19.95
Weighted Average Exercise Price, Cancelled	$ 36.59
Weighted Average Exercise Price, Outstanding, ending balance	$ 31.40
Weighted Average Exercise Price, Exercisable, ending balance	$ 21.93
Weighted Average Remaining Term (Years), Outstanding	6 years 4 months 24 days
Weighted Average Remaining Term (Years), Exercisable	5 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding	$ 34,120
Aggregate Intrinsic Value, Exercisable	$ 20,568