Employee Benefits (Summary Of Activity In Stock Option Plans) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Options / SARs
Outstanding Options, Exercised	(17,366)	(6,800)	(36,925)
Employee Stock Option and Stock Appreciation Rights (SARs) [Member]
Options / SARs
Outstanding Options, Beginning Balance	232,091	250,291	217,857
Outstanding Options, Granted	138,125	0	87,615
Outstanding Options, Exercised	(31,613)	(6,800)	(51,781)
Outstanding Options, Forfeited	0	(3,200)	0
Outstanding Options, Expired	(7,900)	(8,200)	(3,400)
Outstanding Options, Ending Balance	330,703	232,091	250,291
Exercise Price
Outstanding, Weighted-Average Exercise Price, Beginning Balance	$ 17.36	$ 17.75	$ 13.56
Outstanding, Weighted-Average Exercise Price, Granted	23.94	0.00	26.01
Outstanding, Weighted-Average Exercise Price, Exercised	11.83	17.79	13.62
Outstanding, Weighted-Average Exercise Price, Forfeited	0.00	25.50	0.00
Outstanding, Weighted-Average Exercise Price, Expired	25.83	25.54	24.97
Outstanding, Weighted-Average Exercise Price, Ending Balance	$ 20.44	$ 17.36	$ 17.75
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 2,200
Options Outstanding, Wted. Avg. Remaining Contractual Life (yrs)	7 years 3 months 29 days
Exercisable Options, Ending Balance	104,889	95,924	62,646
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 1,203	$ 583	$ 687
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5 years 8 months 27 days	6 years 15 days	4 years 11 months 1 day
Exercisable Options, Weighted-Average Exercise Price, Ending Balance	$ 15.62	$ 14.82	$ 15.35