Employee Benefits (Summary Of Activity In Stock Option Plans) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Options / SARs
Outstanding Options, Granted		0	0
Outstanding Options, Exercised	(18,340)	(24,740)	(6,560)
Employee Stock Option and Stock Appreciation Rights (SARs) [Member]
Options / SARs
Outstanding Options, Beginning Balance	217,857	244,147	157,170
Outstanding Options, Granted	87,615	0	166,717
Outstanding Options, Exercised	(51,781)	(24,740)	(6,560)
Outstanding Options, Forfeited	0	0	0
Outstanding Options, Expired	(3,400)	(1,550)	(73,180)
Outstanding Options, Ending Balance	250,291	217,857	244,147
Exercise Price
Outstanding, Weighted-Average Exercise Price, Beginning Balance	$ 13.56	$ 14.05	$ 20.43
Outstanding, Weighted-Average Exercise Price, Granted	26.01	0.00	12.01
Outstanding, Weighted-Average Exercise Price, Exercised	13.62	18.08	7.87
Outstanding, Weighted-Average Exercise Price, Forfeited	0.00	0.00	0.00
Outstanding, Weighted-Average Exercise Price, Expired	24.97	18.79	23.67
Outstanding, Weighted-Average Exercise Price, Ending Balance	$ 17.75	$ 13.56	$ 14.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 2,146
Options Outstanding, Wted. Avg. Remaining Contractual Life (yrs)	7 years 4 months 2 days
Exercisable Options, Ending Balance	62,646	84,483	77,430
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 687	$ 974	$ 103
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4 years 11 months 1 day	4 years 8 months 23 days	2 years 7 months 13 days
Exercisable Options, Weighted-Average Exercise Price, Ending Balance	$ 15.35	$ 16.00	$ 18.43