CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Surplus [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2019	$ 503,652	$ 16,733	$ 319,375	$ (29,990)	$ 199,029	$ (1,495)
Net income	23,162				23,162
Comprehensive income (loss)	(252)					(252)
Restricted stock units issued		131	(131)
Restricted stock units/awards repurchased on vesting to pay taxes	(643)	(33)	(610)
Amortization of restricted stock awards/units	5,062		5,062
Cash dividends declared on common stock	(2,832)				(2,832)
Share repurchase	(6,487)			(6,487)
Common stock options exercised	76	7	69
Exercise of warrants		6	(6)
Issuance of shares for Employee Stock Purchase Plan	990	43	947
Issuance of common stock for acquisition		29	(29)
Balance at Sep. 30, 2020	522,728	16,916	324,677	(36,477)	219,359	(1,747)
Balance at Jun. 30, 2020	507,980	16,900	322,796	(36,477)	206,757	(1,996)
Net income	13,547				13,547
Comprehensive income (loss)	249					249
Amortization of restricted stock awards/units	1,798		1,798
Cash dividends declared on common stock	(945)				(945)
Issuance of shares for Employee Stock Purchase Plan	99	4	95
Issuance of common stock for acquisition		12	(12)
Balance at Sep. 30, 2020	522,728	16,916	324,677	(36,477)	219,359	(1,747)
Balance at Dec. 31, 2020	527,122	16,958	326,592	(36,477)	221,441	(1,392)
Net income	41,767				41,767
Comprehensive income (loss)	(7,643)					(7,643)
Restricted stock units issued		240	(240)
Restricted stock units/awards repurchased on vesting to pay taxes	(2,231)	(60)	(2,171)
Amortization of restricted stock awards/units	5,229		5,229
Cash dividends declared on common stock	(2,843)				(2,843)
Share repurchase	(19,416)			(19,416)
Common stock options exercised	40	3	37
Exercise of warrants		14	(14)
Issuance of shares for Employee Stock Purchase Plan	656	18	638
Issuance of common stock for acquisition	333	12	321
Balance at Sep. 30, 2021	543,014	17,185	330,392	(55,893)	260,365	(9,035)
Balance at Jun. 30, 2021	538,459	17,164	328,035	(48,461)	247,136	(5,415)
Net income	14,171				14,171
Comprehensive income (loss)	(3,620)					(3,620)
Amortization of restricted stock awards/units	1,807		1,807
Cash dividends declared on common stock	(942)				(942)
Share repurchase	(7,432)			(7,432)
Common stock options exercised	6	1	5
Exercise of warrants		2	(2)
Issuance of shares for Employee Stock Purchase Plan	232	6	226
Issuance of common stock for acquisition	333	12	321
Balance at Sep. 30, 2021	$ 543,014	$ 17,185	$ 330,392	$ (55,893)	$ 260,365	$ (9,035)