Employee Benefit Plans (Schedule Of Employee Option Plan) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Employee Benefit Plans [Abstract]
Options, Outstanding at beginning of year	1,272,739
Options, Granted	494,885
Options, Exercised	(179,807)
Options, Forfeited	(60,766)
Options, Expired	(1,198)
Options, Outstanding at end of year	1,525,853
Outstanding, Weighted Average Exercise Price, beginning of year	$ 38.77
Weighted Average Exercise Price, Granted	$ 61.51
Weighted Average Exercise Price, Exercised	$ (38.02)
Weighted Average Exercise Price, Forfeited	$ 51.49
Weighted Average Exercise Price, Expired	$ 43.00
Outstanding, Weighted Average Exercise Price, end of year	$ 45.72
Options, Exercisable at end of year	681,870
Weighted Average Exercise Price, Exercisable at end of year	$ 36.35
Weighted Average Contractual Term, Outstanding at end of year (in years)	6.9
Weighted Average Contractual Term, Exercisable at end of year (in years)	5.0
Average Intrinsic Value, Outstanding at end of year	$ 26,255
Average Intrinsic Value, Exercisable at end of year	$ 18,127