Employee Benefits (Summary Of Activity In Stock Option Plans) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SARs/Options
Outstanding Options, Exercised	(499)	(17,366)	(6,800)
Employee Stock Option and Stock Appreciation Rights (SARs) [Member]
SARs/Options
Outstanding Options, Beginning Balance	330,703	232,091	250,291
Outstanding Options, Granted	0	138,125	0
Outstanding Options, Exercised	(1,400)	(31,613)	(6,800)
Outstanding Options, Forfeited	0	0	(3,200)
Outstanding Options, Expired	(100)	(7,900)	(8,200)
Outstanding Options, Ending Balance	329,203	330,703	232,091
Exercise Price
Outstanding, Weighted-Average Exercise Price, Beginning Balance	$ 20.44	$ 17.36	$ 17.75
Outstanding, Weighted-Average Exercise Price, Granted	0	23.94	0
Outstanding, Weighted-Average Exercise Price, Exercised	12.01	11.83	17.79
Outstanding, Weighted-Average Exercise Price, Forfeited	0	0	25.50
Outstanding, Weighted-Average Exercise Price, Expired	18.26	25.83	25.54
Outstanding, Weighted-Average Exercise Price, Ending Balance	$ 20.47	$ 20.44	$ 17.36
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 1,118
Options Outstanding, Wted. Avg. Remaining Contractual Life (yrs)	6 years 4 months 2 days
Exercisable Options, Ending Balance	177,875	104,889	95,924
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 1,118	$ 1,203	$ 583
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 3 months 7 days	5 years 8 months 26 days	6 years 14 days
Exercisable Options, Weighted-Average Exercise Price, Ending Balance	$ 17.07	$ 15.62	$ 14.82