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, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Income available to common shareholders	$ 27,449	$ 20,040	$ 66,133	$ 60,123
Denominator for basic earnings per share (weighted average common shares outstanding)	15,330,791	15,361,087	15,330,802	15,370,380
Effect of dilutive options and warrants	68,916	40,721	71,023	41,131
Denominator for diluted earnings per share (weighted average common shares outstanding adjusted for the effect of dilutive options and warrants)	15,399,707	15,401,808	15,401,825	15,411,511
Basic earnings per common share	$ 1.79	$ 1.30	$ 4.31	$ 3.91
Diluted earnings per common share	$ 1.78	$ 1.30	$ 4.29	$ 3.90