Calculation Of Net Income Per Share (Schedule Of Weighted-Average Potential Shares Excluded From Computation Of EPS) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average exercise price	$ 40.81	$ 27.14	$ 40.81	$ 38.43
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average potential shares excluded from computation of EPS	58	2,443	59	270
Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average potential shares excluded from computation of EPS	4	2,856	3	17
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-average potential shares excluded from computation of EPS	0	653	60	255