Earnings Per Common Share (Summary Of Computation Of Basic And Diluted Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Income available to common shareholders	$ 35,434	$ 30,846	$ 117,397	$ 82,723
Denominator for basic earnings per share (weighted average common shares outstanding)	16,292,312	16,300,720	16,315,996	16,300,250
Effect of dilutive options and warrants	131,600	93,072	129,572	98,100
Denominator for diluted earnings per share (weighted average common shares outstanding adjusted for the effect of dilutive options and warrants)	16,423,912	16,393,792	16,445,568	16,398,350
Basic earnings per common share	$ 2.17	$ 1.89	$ 7.20	$ 5.07
Diluted earnings per common share	$ 2.16	$ 1.88	$ 7.14	$ 5.04