Share-based Payment Arrangements (Summary Of Information Regarding Stock Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 Y
Share-based Payment Arrangements [Abstract]
Options outstanding at December 31, 2011, Number of Options	2,326,776
Options outstanding at December 31, 2011, Weighted Average Exercise Price per Share	$ 40.11
Granted, Number of Options	327,500
Granted, Weighted Average Exercise Price per Share	$ 51.99
Exercised, Number of Options	(817,040)
Exercised, Weighted Average Exercise Price per Share	$ 39.68
Forfeited, Number of Options	(4,500)
Forfeited, Weighted Average Exercise Price per Share	$ 41.32
Options outstanding at March 31, 2012, Number of Options	1,832,736
Options outstanding at March 31, 2012, Weighted Average Exercise Price per Share	$ 42.42
Options outstanding at March 31, 2012, Weighted Average Remaining Contractual Term (years)	6.8
Options outstanding at March 31, 2012, Aggregate Intrinsic Value	$ 28,048
Options exercisable at March 31, 2012, Number of Options	686,719
Options exercisable at March 31, 2012, Weighted Average Exercise Price per Share	$ 40.33
Options exercisable at March 31, 2012, Weighted Average Remaining Contractual Term (years)	4.9
Options exercisable at March 31, 2012, Aggregate Intrinsic Value	$ 11,944