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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Income available to common shareholders	$ 28,241	$ 19,032	$ 59,364	$ 39,299
Denominator for basic earnings per share (weighted average common shares outstanding)	15,285,532	15,297,085	15,286,932	15,304,572
Effect of dilutive options and warrants	132,075	101,780	137,653	111,193
Denominator for diluted earnings per share (weighted average common shares outstanding adjusted for the effect of dilutive options and warrants)	15,417,607	15,398,865	15,424,585	15,415,765
Basic earnings per common share	$ 1.85	$ 1.24	$ 3.88	$ 2.57
Diluted earnings per common share	$ 1.83	$ 1.24	$ 3.85	$ 2.55