CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred Stock	Common Stock [Member]	Surplus [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total
Balance at Dec. 31, 2014		$ 12,954	$ 195,829	$ (8,988)	$ 41,251	$ 1,221	$ 242,267
Shares outstanding at Dec. 31, 2014		15,155,717
Net income					19,972		19,972
Accumulated other comprehensive income (loss)						(1,600)	(1,600)
Issuance of restricted stock, net of forfeitures		$ 134	(134)
Issuance of restricted stock, net of forfeitures, shares		160,457
Restricted stock repurchased on vesting to pay taxes		$ (3)	(78)				(81)
Restricted stock repurchased on vesting to pay taxes, shares		(3,776)
Amortization of restricted stock awards/units			1,621				1,621
Cash dividends declared on common stock					(3,100)		(3,100)
Common stock option expense			219				219
Common stock options exercised and related tax benefits		$ 11	75				86
Common stock options exercised and related tax benefits, shares		18,891
Common stock options exercised, shares used for exercise		7,506
Common stock options, related tax benefits, shares		11,385
Sales of shares (dividend reinvestment program)		$ 555	13,093				13,648
Sales of shares (dividend reinvestment program), shares		665,654
Issuance of shares for Employee Stock Purchase Plan		$ 26	618				644
Issuance of shares for Employee Stock Purchase Plan, shares		30,766
Issuance of common stock for acquisition		$ 40	960				1,000
Issuance of common stock for acquisition, shares		47,916
Issuance of warrants			1,000				1,000
Balance at Dec. 31, 2015		$ 13,717	213,203	(8,988)	58,123	(379)	275,676
Shares outstanding at Dec. 31, 2015		16,068,119
Net income					26,477		26,477
Accumulated other comprehensive income (loss)						(1,152)	(1,152)
Issuance of restricted stock, net of forfeitures		$ (10)	10
Issuance of restricted stock, net of forfeitures, shares		(12,133)
Restricted stock repurchased on vesting to pay taxes		$ (24)	(530)				(554)
Restricted stock repurchased on vesting to pay taxes, shares		(29,088)
Amortization of restricted stock awards/units			2,836				2,836
Cash dividends declared on common stock					(3,296)		(3,296)
Common stock option expense			56				56
Common stock options exercised and related tax benefits		$ 59	1,010				1,069
Common stock options exercised and related tax benefits, shares		70,632
Common stock options exercised, shares used for exercise		9,723
Common stock options, related tax benefits, shares		60,909
Sales of shares (dividend reinvestment program)		$ 948	21,513				22,461
Sales of shares (dividend reinvestment program), shares		1,137,998
Issuance of shares for Employee Stock Purchase Plan		$ 27	610				637
Issuance of shares for Employee Stock Purchase Plan, shares		32,190
Balance at Dec. 31, 2016		$ 14,717	238,708	(8,988)	81,304	(1,531)	324,210
Shares outstanding at Dec. 31, 2016		17,257,995
Net income					36,497		36,497
Accumulated other comprehensive income (loss)						534	534
Restricted stock units issued		$ 62	(62)
Restricted stock units issued, shares		74,936
Restricted stock awards forfeitures		$ (1)	1
Restricted stock awards forfeitures, shares		(479)
Restricted stock repurchased on vesting to pay taxes		$ (49)	(1,777)				(1,826)
Restricted stock repurchased on vesting to pay taxes, shares		(58,598)
Amortization of restricted stock awards/units			3,741				3,741
Cash dividends declared on common stock					(3,548)		(3,548)
Common stock option expense			6				6
Common stock options exercised and related tax benefits		$ 42	$ 648				$ 690
Common stock options exercised and related tax benefits, shares		50,473					50,473
Common stock options exercised, shares used for exercise		8,764
Common stock options, related tax benefits, shares		41,709
Sales of shares (dividend reinvestment program)		$ 1,004	$ 35,584				$ 36,588
Sales of shares (dividend reinvestment program), shares		1,204,710
Issuance of shares for Employee Stock Purchase Plan		$ 21	776				797
Issuance of shares for Employee Stock Purchase Plan, shares		25,404
Issuance of shares for Employees Savings and Investment plan		$ 25	864				889
Issuance of shares for Employees Savings and Investment plan, shares		30,123
Issuance of stock offering net of costs			3,600				3,600
Issuance of common stock for acquisition		$ 37	1,463				1,500
Issuance of common stock for acquisition, shares		43,834
Reclassification of certain deferred tax effects					215	(215)
Balance at Dec. 31, 2017		$ 15,858	$ 283,552	$ (8,988)	$ 114,468	$ (1,212)	$ 403,678
Shares outstanding at Dec. 31, 2017		18,619,634