CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Surplus	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2014	$ 117	$ 118,846	$ 64,547	$ (25)	$ (8,367)	$ 175,118
Increase (Decrease) in Stockholders' Equity
Net income			21,111			21,111
Shares issued under the dividend reinvestment plan ("DRP")		779				779
Shares issued in the acquisition of CNB net of offering costs (5,647,268 shares)	56	157,143				157,199
Stock awards granted and distributed	1	(263)		262
Stock awards forfeited		125		(125)
Repurchase of surrendered stock from vesting of restricted stock awards				(228)		(228)
Exercise of stock options		(36)		116		80
Tax effect of stock plans		50				50
Share based compensation expense		1,689				1,689
Cash dividend declared, $0.92 per share for December 31, 2015 and $0.92 per share for December 31, 2016 and $0.92 per share for December 31, 2017			(13,415)			(13,415)
Other comprehensive income (loss), net of deferred income taxes					(1,255)	(1,255)
Balance at Dec. 31, 2015	174	278,333	72,243		(9,622)	341,128
Increase (Decrease) in Stockholders' Equity
Net income			35,491			35,491
Shares issued under the dividend reinvestment plan ("DRP")		921				921
Shares issued in common stock offering, net of offering costs (1,613,000 shares)	16	47,505				47,521
Shares issued for trust preferred securities conversions (10,344 shares at December 2016) and (529,292 shares at December 2017)		292				292
Stock awards granted and distributed	1	(205)		204
Stock awards forfeited		173		(173)
Repurchase of surrendered stock from vesting of restricted stock awards				(344)		(344)
Exercise of stock options		(90)		152		62
Impact of modification of convertible trust preferred securities		356				356
Share based compensation expense		2,142				2,142
Cash dividend declared, $0.92 per share for December 31, 2015 and $0.92 per share for December 31, 2016 and $0.92 per share for December 31, 2017			(16,140)			(16,140)
Other comprehensive income (loss), net of deferred income taxes					(3,442)	(3,442)
Balance at Dec. 31, 2016	191	329,427	91,594	(161)	(13,064)	407,987
Increase (Decrease) in Stockholders' Equity
Net income			20,539			20,539
Shares issued under the dividend reinvestment plan ("DRP")		951				951
Shares issued for trust preferred securities conversions (10,344 shares at December 2016) and (529,292 shares at December 2017)	5	14,944				14,949
Stock awards granted and distributed	1	(434)		433
Stock awards forfeited		218		(218)
Repurchase of surrendered stock from vesting of restricted stock awards				(350)		(350)
Share based compensation expense		2,585				2,585
Impact of Tax Cuts and Jobs Act related to accumulated other comprehensive income reclassification			2,652		(2,652)
Cash dividend declared, $0.92 per share for December 31, 2015 and $0.92 per share for December 31, 2016 and $0.92 per share for December 31, 2017			(18,238)			(18,238)
Other comprehensive income (loss), net of deferred income taxes					777	777
Balance at Dec. 31, 2017	$ 197	$ 347,691	$ 96,547	$ (296)	$ (14,939)	$ 429,200