CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Common Stock [Member]	Common Stock [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Surplus [Member]	Surplus [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Treasury Stock [Member]	Treasury Stock [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Other Comprehensive Income/(Loss) [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income/(Loss) [Member] Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Balance at Dec. 31, 2017	$ 403,678		$ 403,678	$ 15,858	$ 15,858	$ 283,552	$ 283,552	$ (8,988)	$ (8,988)	$ 114,468		$ 114,341	$ (1,212)		$ (1,085)
Balance (ASU 2016-01 [Member]) at Dec. 31, 2017											$ (127)			$ 127
Net income	44,170									44,170
Other comprehensive income (loss)	(1,260)												(1,260)
Restricted stock units issued				76		(76)
Restricted stock forfeitures				(78)		78
Restricted stock units/awards repurchased on vesting to pay taxes	(1,540)			(38)		(1,502)
Amortization of restricted stock awards/units	4,445					4,445
Cash dividends declared on common stock	(3,712)									(3,712)
Common stock options exercised and related tax benefits	275			19		256
Sales of shares (Dividend Reinvestment Program)	16,677			452		16,225
Issuance of shares for Employee Stock Purchase Plan	958			24		934
Issuance of shares for Employee’s Savings and Investment plan	1,039			29		1,010
Issuance of common stock for acquisition	4,283			117		4,166
Balance at Dec. 31, 2018	469,013		$ 469,674	16,459	$ 16,459	309,088	$ 309,088	(8,988)	$ (8,988)	154,799		$ 155,460	(2,345)		$ (2,345)
Balance (ASU 842 [Member]) at Dec. 31, 2018		$ 661									$ 661
Net income	47,434									47,434
Other comprehensive income (loss)	850												850
Restricted stock units issued				120		(120)
Restricted stock units/awards repurchased on vesting to pay taxes	(1,106)			(33)		(1,073)
Amortization of restricted stock awards/units	5,909					5,909
Cash dividends declared on common stock	(3,865)									(3,865)
Common stock options exercised and related tax benefits	251			15		236
Issuance of shares for Employee Stock Purchase Plan	533			16		517
Shares repurchase	(21,002)							(21,002)
Issuance of common stock for acquisition	4,974			154		4,820
Exercise of warrants				2		(2)
Balance at Dec. 31, 2019	503,652			16,733		319,375		(29,990)		199,029			(1,495)
Net income	26,192									26,192
Other comprehensive income (loss)	103												103
Restricted stock units issued				142		(142)
Restricted stock units/awards repurchased on vesting to pay taxes	(741)			(37)		(704)
Amortization of restricted stock awards/units	6,875					6,875
Cash dividends declared on common stock	(3,780)									(3,780)
Common stock options exercised and related tax benefits	230			17		213
Issuance of shares for Employee Stock Purchase Plan	1,078			47		1,031
Shares repurchase	(6,487)							(6,487)
Issuance of common stock for acquisition				50		(50)
Exercise of warrants				6		(6)
Balance at Dec. 31, 2020	$ 527,122			$ 16,958		$ 326,592		$ (36,477)		$ 221,441			$ (1,392)