Employee Benefit Plans (Summary Of Stock Option Activity) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Employee Benefit Plans [Abstract]
Options Outstanding, beginning balance	293,817	287,393
Options, Granted	16,876	16,000
Options, Exercised	(18,899)	(6,576)
Options, Forfeited	(1,500)
Options Outstanding, ending balance	290,294	296,817
Weighted-Average Exercise Price, Outstanding, beginning balance	$ 33.95	$ 33.64
Weighted-Average Exercise Price, Granted	$ 35.39	$ 35.09
Weighted-Average Exercise Price, Exercised	$ 28.78	$ 25.54
Weighted-Average Exercise Price, Forfeited	$ 34.73
Weighted-Average Exercise Price, Outstanding, ending balance	$ 34.37	$ 33.90