Employee Benefit Plans (Summary Of Stock Option Activity) (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Employee Benefit Plans [Abstract]
Options Outstanding, beginning balance	293,817	287,393
Options, Granted	16,876	16,000
Options, Exercised	(16,899)	(5,476)
Options, Forfeited	(1,500)
Options Outstanding, ending balance	292,294	297,917
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	$ 28.87	$ 28.00
Weighted-Average Exercise Price, Forfeited	$ 34.73
Weighted-Average Exercise Price, Outstanding, ending balance	$ 34.32	$ 33.83