CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2015	$ 109,138	$ 8,805	$ 19,953	$ 81,385	$ (1,005)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,398			13,398
Other comprehensive income	2,291				2,291
Cash dividends declared ($0.45 for 9 months ended September 30, 2017 and $0.45 for 9 months ended September 30, 2016)	(4,757)			(4,757)
Dividend reinvestment plan shares issued from reserve (149,758 shares 9 months ended September 30, 2017 and 17,972 shares 9 months ended September 30, 2016)	379	15	364
Exercise of stock options (143,092 shares 9 months ended September 30, 2017 and 41,351 for 9 months ended September 30, 2016)	503	35	468
Issuance of restricted common stock (4,459 shares 9 months ended September 30, 2017 and 6,205 shares for 9 months ended September 30, 2016)	128	5	123
Stock-based compensation	251		251
Balance at Sep. 30, 2016	121,331	8,860	21,159	90,026	1,286
Balance at Dec. 31, 2016	120,530	8,881	21,779	91,439	(1,569)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,455			13,455
Other comprehensive income	377				377
Cash dividends declared ($0.45 for 9 months ended September 30, 2017 and $0.45 for 9 months ended September 30, 2016)	(6,287)			(6,287)
Dividend reinvestment plan shares issued from reserve (149,758 shares 9 months ended September 30, 2017 and 17,972 shares 9 months ended September 30, 2016)	3,926	125	3,801
Exercise of stock options (143,092 shares 9 months ended September 30, 2017 and 41,351 for 9 months ended September 30, 2016)	2,060	120	1,940
Issuance of restricted common stock (4,459 shares 9 months ended September 30, 2017 and 6,205 shares for 9 months ended September 30, 2016)	129	4	125
Issuance of common stock (9,516,097 shares)	285,673	7,946	277,727
Stock-based compensation	310		310
Balance at Sep. 30, 2017	$ 420,173	$ 17,076	$ 305,682	$ 98,607	$ (1,192)