Stock Option And Stock Award Plans (Summary Of Stock Options Outstanding) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Options
Number of Options, Outstanding, Beginning Balance	1,164,120	1,046,800	1,076,700
Number of Options, Granted	0	181,476	184,700
Number of Options, Forfeited and Expired	(60,207)	(22,581)	(34,000)
Number of Options, Exercised	(222,400)	(41,575)	(180,600)
Number of Options, Outstanding, Ending Balance	881,513	1,164,120	1,046,800
Weighted Average
Weighted Average Option Exercise Price/Share, Outstanding, Beginning Balance	$ 19.59	$ 19.06	$ 17.81
Weighted Average Option Exercise Price/Share, Granted	0.00	22.41	24.97
Weighted Average Option Exercise Price/Share, Forfeited and Expired	22.30	21.42	21.10
Weighted Average Option Exercise Price/Share, Exercised	16.34	17.55	17.32
Weighted Average Option Exercise Price/Share, Outstanding, Ending Balance	20.22	19.59	19.06
Minimum
Option Exercise Price/Share Range
Exercise Price, Outstanding, Beginning Balance	14.06	14.06	14.06
Exercise Price, Granted	0	19.84	24.84
Exercise Price, Forfeited and Expired	17.13	15.8	15.11
Exercise Price, Exercised	14.06	15.8	14.27
Exercise Price, Outstanding, Ending Balance	17.13	14.06	14.06
Maximum
Option Exercise Price/Share Range
Exercise Price, Outstanding, Beginning Balance	30.01	30.01	19.84
Exercise Price, Granted	0	22.49	30.01
Exercise Price, Forfeited and Expired	30.01	24.84	24.84
Exercise Price, Exercised	19.84	19.84	19.84
Exercise Price, Outstanding, Ending Balance	$ 30.01	$ 30.01	$ 30.01