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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Income available to common shareholders	$ 24,762	$ 22,112	$ 84,126	$ 61,411
Denominator for basic earnings per share (weighted average common shares outstanding)	15,686,542	15,287,974	15,420,135	15,299,039
Effect of dilutive options and warrants	146,192	63,616	140,531	95,160
Denominator for diluted earnings per share (weighted average common shares outstanding adjusted for the effect of dilutive options and warrants)	15,832,734	15,351,590	15,560,666	15,394,199
Basic earnings per common share	$ 1.58	$ 1.45	$ 5.46	$ 4.01
Diluted earnings per common share	$ 1.56	$ 1.44	$ 5.41	$ 3.99