Per Share Data (Computations of Basic Earnings Per Share and Diluted Earnings Per 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
Basic Earnings per Share:
Net Income	$ 10,065	$ 10,185	$ 9,788	$ 5,146	$ 7,712	$ 7,721	$ 7,325	$ 7,306	$ 35,184	$ 30,064	$ 28,344
Weighted Average Shares Outstanding (in shares)									14,926,091	13,255,002	13,202,822
Basic Earnings per Share (in usd per share)	$ 0.66	$ 0.67	$ 0.64	$ 0.37	$ 0.58	$ 0.58	$ 0.55	$ 0.55	$ 2.36	$ 2.27	$ 2.15
Diluted Earnings per Share:
Net Income	$ 10,065	$ 10,185	$ 9,788	$ 5,146	$ 7,712	$ 7,721	$ 7,325	$ 7,306	$ 35,184	$ 30,064	$ 28,344
Weighted Average Shares Outstanding (in shares)									14,926,091	13,255,002	13,202,822
Stock Options, Net									1,319	3,914	20,356
Diluted Weighted Average Shares Outstanding									14,927,410	13,258,916	13,223,178
Diluted Earnings per Share (in usd per share)	$ 0.66	$ 0.67	$ 0.64	$ 0.37	$ 0.58	$ 0.58	$ 0.55	$ 0.55	$ 2.36	$ 2.27	$ 2.14
Antidilutive securities excluded from computation of earnings per share (shares)									0	0	0