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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Income available to common shareholders	$ 20,040	$ 18,269	$ 60,123	$ 59,656
Denominator for basic earnings per share (weighted average common shares outstanding)	15,361,087	15,392,421	15,370,380	15,395,320
Effect of dilutive options and warrants	40,721	21,243	41,131	18,305
Denominator for diluted earnings per share (weighted average common shares outstanding adjusted for the effect of dilutive options and warrants)	15,401,808	15,413,664	15,411,511	15,413,625
Basic earnings per common share	$ 1.30	$ 1.19	$ 3.91	$ 3.87
Diluted earnings per common share	$ 1.30	$ 1.19	$ 3.90	$ 3.87