Earnings Per Common Share (Calculations of Basic and Diluted Earnings per Common Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Distributed earnings allocated to common shareholders									$ 11,532	$ 10,426	$ 7,095
Undistributed earnings allocated to common shareholders									19,483	404	9,472
Net earnings allocated to common shareholders									$ 31,015	$ 10,830	$ 16,567
Weighted-average number of common shares outstanding - basic	18,009,056	17,993,443	17,980,797	18,071,746	18,142,997	18,127,131	18,116,090	15,802,334	18,013,693	17,555,140	12,183,352
Effect of potentially dilutive common shares									141,770	132,655	122,872
Total weighted-average diluted common shares outstanding	18,172,030	18,110,710	18,113,812	18,194,990	18,278,272	18,271,979	18,253,918	15,930,235	18,155,463	17,687,795	12,306,224
Earnings per common share - basic	$ 0.41	$ 0.43	$ 0.44	$ 0.44	$ 0.14	$ 0.23	$ 0.27	$ (0.04)	$ 1.72	$ 0.62	$ 1.36
Earnings per common share - diluted	$ 0.41	$ 0.43	$ 0.44	$ 0.44	$ 0.14	$ 0.22	$ 0.27	$ (0.04)	$ 1.71	$ 0.61	$ 1.35
Antidilutive Securities Excluded from Computation of Earnings Per Share
Stock options and stock appreciation rights									20,769	46,109	55,184