Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Total	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member] Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]
Balance at Dec. 31, 2017	$ 88,465	$ 221,472	$ 224,268	$ (3,506)	$ 530,699
Balance (ASU 2014-09 [Member]) at Dec. 31, 2017						$ 358		$ 358
Balance (ASU 2016-01 [Member]) at Dec. 31, 2017						(507)	$ 507	0
Balance (in shares) at Dec. 31, 2017	17,692,912
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			59,228		59,228
Other comprehensive income (loss), net of tax				(3,612)	(3,612)
Cash dividends declared			(24,412)		(24,412)
Issuance of common stock	$ 211	1,019			1,230
Issuance of common stock (in shares)	42,133
Issuance of restricted stock	$ 57	(57)			0
Issuance of restricted stock (in shares)	11,320
Vesting of restricted stock	$ (60)	60			0
Vesting of restricted stock (in shares)	(11,997)
Forfeiture of restricted stock	$ (8)	8			0
Forfeiture of restricted stock (in shares)	(1,515)
Stock-based compensation		659			659
Balance at Dec. 31, 2018	$ 88,665	223,161	258,935	(6,611)	564,150
Balance (ASU 2016-02 [Member]) at Dec. 31, 2018						(480)		(480)
Balance (in shares) at Dec. 31, 2018	17,732,853
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			64,540		64,540
Other comprehensive income (loss), net of tax				10,864	10,864
Cash dividends declared			(26,235)		(26,235)
Issuance of common stock	$ 228	1,036			1,264
Issuance of common stock (in shares)	45,639
Issuance of restricted stock	$ 140	(140)			0
Issuance of restricted stock (in shares)	27,921
Vesting of restricted stock	$ (64)	64			0
Vesting of restricted stock (in shares)	(12,660)
Forfeiture of restricted stock	$ (3)	3			0
Forfeiture of restricted stock (in shares)	(588)
Stock-based compensation		783			783
Balance at Dec. 31, 2019	$ 88,966	224,907	296,760	4,253	$ 614,886
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			59,504		$ 59,504
Other comprehensive income (loss), net of tax				9,315	9,315
Cash dividends declared			(27,160)		(27,160)
Issuance of common stock	$ 226	700			926
Issuance of common stock (in shares)	45,341
Repurchase of common stock	$ (163)	(936)			(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)
Forfeiture of restricted stock	$ 0	0			0
Forfeiture of restricted stock (in shares)	0
Stock-based compensation		859			859
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