Earnings Per Common Share (Calculation of Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 9,797	$ 8,983	$ 19,095	$ 16,404
Dividends and undistributed earnings allocated to participating securities	(33)	(39)	(74)	(78)
Net income applicable to common shareholders	$ 9,764	$ 8,944	$ 19,021	$ 16,326
Weighted average common shares outstanding - basic	16,678	16,454	16,653	16,428
Dilutive effect of common stock equivalents	153	127	164	130
Weighted average common shares outstanding - diluted	16,831	16,581	16,817	16,558
Basic earnings per common share	$ 0.59	$ 0.54	$ 1.14	$ 0.99
Diluted earnings per common share	$ 0.58	$ 0.54	$ 1.13	$ 0.99
Antidilutive common stock equivalents	55	241	55	394