Stock Compensation Plans (Schedule Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Stock Compensation Plans [Abstract]
Options Outstanding, Beginning Balance	1,098,859
Options, Granted	272,412
Options, Forfeited	(34,129)
Options, Exercised	(471,697)
Options Outstanding, Ending Balance	865,445
Options exercisable	419,474
Weighted-Average Exercise Price, Outstanding, Beginning Balance	$ 21.37
Weighted-Average Exercise Price, Granted	$ 35.89
Weighted-Average Exercise Price, Forfeited	$ 27.93
Weighted-Average Exercise Price, Exercised	$ 19.41
Weighted-Average Exercise Price, Outstanding, Ending Balance	$ 26.72
Weighted-Average Exercise Price, Options exercisable	$ 23.66
Weighted Average Remaining Contractual Term as of December 31, 2011, Outstanding, years	4.7
Weighted Average Remaining Contractual Term as of December 31, 2011, Exercisable, years	3.7
Aggregate Intrinsic Value as of December 31, 2011, Outstanding	$ 16,684
Aggregate Intrinsic Value as of December31, 2011, Options exercisable	$ 9,372