Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income, Net of Tax [Member]	Total	Cumulative Effect, Period of Adoption, Adjustment [Member] Common Stock [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Capital Surplus [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Accumulated Other Comprehensive Income, Net of Tax [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Dec. 31, 2019	$ 88,966	$ 224,907	$ 296,760	$ 4,253	$ 614,886	$ 88,966	$ 224,907	$ 294,394	$ 4,253	$ 612,520
Balance (ASU 2016-13 [Member]) at Dec. 31, 2019								$ (2,366)		$ (2,366)
Balance (in shares) at Dec. 31, 2019	17,793,165					17,793,165
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			43,678		43,678
Other comprehensive income (loss), net of tax				8,341	8,341
Cash dividends declared			(20,324)		(20,324)
Issuance of common stock	$ 185	504			689
Issuance of common stock (in shares)	36,952
Repurchase of common stock	$ (164)	(935)			(1,099)
Repurchase of common stock (in shares)	(32,664)
Issuance of restricted stock	$ 108	(108)			0
Issuance of restricted stock (in shares)	21,544
Vesting of restricted stock	$ (85)	85			0
Vesting of restricted stock (in shares)	(16,985)
Stock-based compensation		645			645
Balance at Sep. 30, 2020	$ 89,010	225,098	317,748	12,594	644,450
Balance (in shares) at Sep. 30, 2020	17,802,012
Balance at Jun. 30, 2020	$ 88,973	224,688	307,134	11,052	631,847
Balance (in shares) at Jun. 30, 2020	17,794,598
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			17,447		17,447
Other comprehensive income (loss), net of tax				1,542	1,542
Cash dividends declared			(6,833)		(6,833)
Issuance of common stock	$ 37	195			232
Issuance of common stock (in shares)	7,414
Stock-based compensation		215			215
Balance at Sep. 30, 2020	$ 89,010	225,098	317,748	12,594	644,450
Balance (in shares) at Sep. 30, 2020	17,802,012
Balance at Dec. 31, 2020	$ 89,052	225,507	326,738	13,568	$ 654,865
Balance (in shares) at Dec. 31, 2020	17,810,401				17,810,401
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			68,691		$ 68,691
Other comprehensive income (loss), net of tax				(12,405)	(12,405)
Cash dividends declared			(20,808)		(20,808)
Issuance of common stock	$ 178	541			719
Issuance of common stock (in shares)	35,400
Repurchase of common stock	$ 0	0			0
Repurchase of common stock (in shares)	0
Issuance of restricted stock	$ 46	(46)			0
Issuance of restricted stock (in shares)	9,193
Vesting of restricted stock	$ (88)	88			0
Vesting of restricted stock (in shares)	(17,681)
Stock-based compensation		581			581
Balance at Sep. 30, 2021	$ 89,188	226,671	374,621	1,163	$ 691,643
Balance (in shares) at Sep. 30, 2021	17,837,313				17,837,313
Balance at Jun. 30, 2021	$ 89,158	226,268	360,595	8,062	$ 684,083
Balance (in shares) at Jun. 30, 2021	17,831,479
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			21,142		21,142
Other comprehensive income (loss), net of tax				(6,899)	(6,899)
Cash dividends declared			(7,116)		(7,116)
Issuance of common stock	$ 30	209			239
Issuance of common stock (in shares)	5,834
Stock-based compensation		194			194
Balance at Sep. 30, 2021	$ 89,188	$ 226,671	$ 374,621	$ 1,163	$ 691,643
Balance (in shares) at Sep. 30, 2021	17,837,313				17,837,313