Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net of Tax [Member]	Total
Increase (Decrease) in Stockholders' Equity [Roll forward]
Implementation of ASU | ASU 2014-09 [Member]			$ 453		$ 453
Implementation of ASU | ASU 2016-01 [Member]			(507)	$ 507	0
Balance at Dec. 31, 2017	$ 88,465	$ 221,472	224,268	(3,506)	530,699
Balance (in shares) at Dec. 31, 2017	17,692,912
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			15,814		15,814
Other comprehensive income (loss), net of tax				(4,461)	(4,461)
Cash dividends declared			(5,836)		(5,836)
Issuance of common stock	$ 145	451			596
Issuance of common stock (in shares)	29,087
Vesting of restricted stock	$ (63)	63			0
Vesting of restricted stock (in shares)	(12,582)
Issuance of restricted stock	$ 57	(57)			0
Issuance of restricted stock (in shares)	11,435
Forfeiture of restricted stock	$ (1)	1			0
Forfeiture of restricted stock (in shares)	(115)
Stock-based compensation		224			224
Balance at Mar. 31, 2018	$ 88,603	222,154	234,192	(7,460)	537,489
Balance (in shares) at Mar. 31, 2018	17,720,737
Balance at Dec. 31, 2017	$ 88,465	221,472	224,268	(3,506)	530,699
Balance (in shares) at Dec. 31, 2017	17,692,912
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			27,413		27,413
Other comprehensive income (loss), net of tax				(5,893)	(5,893)
Cash dividends declared			(11,672)		(11,672)
Issuance of common stock	$ 165	635			800
Issuance of common stock (in shares)	33,078
Vesting of restricted stock	$ (60)	60			0
Vesting of restricted stock (in shares)	(11,997)
Issuance of restricted stock	$ 57	(57)			0
Issuance of restricted stock (in shares)	11,435
Forfeiture of restricted stock	$ (1)	1			0
Forfeiture of restricted stock (in shares)	(115)
Stock-based compensation		375			375
Balance at Jun. 30, 2018	$ 88,626	222,486	239,955	(8,892)	542,175
Balance (in shares) at Jun. 30, 2018	17,725,313
Balance at Mar. 31, 2018	$ 88,603	222,154	234,192	(7,460)	537,489
Balance (in shares) at Mar. 31, 2018	17,720,737
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			11,599		11,599
Other comprehensive income (loss), net of tax				(1,432)	(1,432)
Cash dividends declared			(5,836)		(5,836)
Issuance of common stock	$ 20	184			204
Issuance of common stock (in shares)	3,991
Vesting of restricted stock	$ 3	(3)			0
Vesting of restricted stock (in shares)	585
Stock-based compensation		151			151
Balance at Jun. 30, 2018	$ 88,626	222,486	239,955	(8,892)	542,175
Balance (in shares) at Jun. 30, 2018	17,725,313
Increase (Decrease) in Stockholders' Equity [Roll forward]
Implementation of ASU | ASU 2016-02 [Member]			(480)	0	(480)
Balance at Dec. 31, 2018	$ 88,665	223,161	258,935	(6,611)	$ 564,150
Balance (in shares) at Dec. 31, 2018	17,732,853				17,732,853
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			14,939		$ 14,939
Other comprehensive income (loss), net of tax				4,837	4,837
Cash dividends declared			(6,378)		(6,378)
Issuance of common stock	$ 95	163			258
Issuance of common stock (in shares)	19,065
Vesting of restricted stock	$ (61)	61			0
Vesting of restricted stock (in shares)	(12,186)
Issuance of restricted stock	$ 140	(140)			0
Issuance of restricted stock (in shares)	27,921
Forfeiture of restricted stock	$ 0	0			0
Forfeiture of restricted stock (in shares)	(59)
Stock-based compensation		181			181
Balance at Mar. 31, 2019	$ 88,839	223,426	267,016	(1,774)	577,507
Balance (in shares) at Mar. 31, 2019	17,767,594
Balance at Dec. 31, 2018	$ 88,665	223,161	258,935	(6,611)	$ 564,150
Balance (in shares) at Dec. 31, 2018	17,732,853				17,732,853
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			33,263		$ 33,263
Other comprehensive income (loss), net of tax				9,664	9,664
Cash dividends declared			(12,758)		(12,758)
Issuance of common stock	$ 123	351			474
Issuance of common stock (in shares)	24,783
Vesting of restricted stock	$ (63)	63			0
Vesting of restricted stock (in shares)	(12,660)
Issuance of restricted stock	$ 140	(140)			0
Issuance of restricted stock (in shares)	27,921
Forfeiture of restricted stock	$ (3)	3			0
Forfeiture of restricted stock (in shares)	(588)
Stock-based compensation		395			395
Balance at Jun. 30, 2019	$ 88,862	223,833	278,960	3,053	$ 594,708
Balance (in shares) at Jun. 30, 2019	17,772,309				17,772,309
Balance at Mar. 31, 2019	$ 88,839	223,426	267,016	(1,774)	$ 577,507
Balance (in shares) at Mar. 31, 2019	17,767,594
Increase (Decrease) in Stockholders' Equity [Roll forward]
Net income			18,324		18,324
Other comprehensive income (loss), net of tax				4,827	4,827
Cash dividends declared			(6,380)		(6,380)
Issuance of common stock	$ 28	188			216
Issuance of common stock (in shares)	5,718
Vesting of restricted stock	$ (2)	2			0
Vesting of restricted stock (in shares)	(474)
Forfeiture of restricted stock	$ (3)	3			0
Forfeiture of restricted stock (in shares)	(529)
Stock-based compensation		214			214
Balance at Jun. 30, 2019	$ 88,862	$ 223,833	$ 278,960	$ 3,053	$ 594,708
Balance (in shares) at Jun. 30, 2019	17,772,309				17,772,309