Consolidated Statements of Changes In Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), net of Tax	Cumulative effect of adoption of accounting principles related to equity compensation expense	Cumulative effect of adoption of accounting principles related to equity compensation expense Additional Paid-in Capital	Cumulative effect of adoption of accounting principles related to equity compensation expense  Retained Earnings
Beginning balance (in shares) at Dec. 31, 2018		6,883,000
Beginning balance, value at Dec. 31, 2018	$ 205,947	$ 6,883	$ 62,132	$ 137,452	$ (520)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,087)			(2,087)
Stock-based compensation expense	196		196
Exercise of stock options and vesting of restricted stock units, net (in shares)		2,000
Exercise of stock options and vesting of restricted stock units, net	0	$ 2	(2)
Repurchase of common stock (in shares)		(6,000)
Repurchase of common stock	(205)	$ (6)	(199)
Other comprehensive (loss) income, net of tax	675				675
Net income	4,312			4,312
Ending balance (in shares) at Mar. 31, 2019		6,879,000
Ending balance, value at Mar. 31, 2019	208,838	$ 6,879	62,127	139,677	155
Beginning balance (in shares) at Dec. 31, 2018		6,883,000
Beginning balance, value at Dec. 31, 2018	205,947	$ 6,883	62,132	137,452	(520)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive (loss) income, net of tax	386
Net income	16,111
Ending balance (in shares) at Sep. 30, 2019		6,540,000
Ending balance, value at Sep. 30, 2019	204,039	$ 6,540	50,416	147,217	(134)
Beginning balance (in shares) at Mar. 31, 2019		6,879,000
Beginning balance, value at Mar. 31, 2019	208,838	$ 6,879	62,127	139,677	155
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,060)			(2,060)
Stock-based compensation expense	155		155
Repurchase of common stock (in shares)		(150,000)
Repurchase of common stock	(5,198)	$ (150)	(5,048)
Other comprehensive (loss) income, net of tax	342				342
Net income	4,261			4,261
Ending balance (in shares) at Jun. 30, 2019		6,729,000
Ending balance, value at Jun. 30, 2019	206,338	$ 6,729	57,234	141,878	497
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,199)			(2,199)
Stock-based compensation expense	193		193
Exercise of stock options and vesting of restricted stock units, net (in shares)		3,000
Exercise of stock options and vesting of restricted stock units, net	(34)	$ 3	(37)
Repurchase of common stock (in shares)		(192,000)
Repurchase of common stock	(7,166)	$ (192)	(6,974)
Other comprehensive (loss) income, net of tax	(631)				(631)
Net income	7,538			7,538
Ending balance (in shares) at Sep. 30, 2019		6,540,000
Ending balance, value at Sep. 30, 2019	204,039	$ 6,540	50,416	147,217	(134)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,182)			(2,182)
Stock-based compensation expense	288		288
Exercise of stock options and vesting of restricted stock units, net (in shares)		19,000
Exercise of stock options and vesting of restricted stock units, net	(173)	$ 19	(192)
Other comprehensive (loss) income, net of tax	565				565
Net income	$ 4,580			4,580
Ending balance (in shares) at Dec. 31, 2019	6,558,809	6,559,000
Ending balance, value at Dec. 31, 2019	$ 207,117	$ 6,559	50,512	149,615	431	$ 0	$ 139	$ (139)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,223)			(2,223)
Stock-based compensation expense	242		242
Repurchase of common stock (in shares)		(193,000)
Repurchase of common stock	(6,310)	$ (193)	(6,117)
Other comprehensive (loss) income, net of tax	(2,136)				(2,136)
Net income	1,033			1,033
Ending balance (in shares) at Mar. 31, 2020		6,366,000
Ending balance, value at Mar. 31, 2020	$ 197,723	$ 6,366	44,776	148,286	(1,705)
Beginning balance (in shares) at Dec. 31, 2019	6,558,809	6,559,000
Beginning balance, value at Dec. 31, 2019	$ 207,117	$ 6,559	50,512	149,615	431	$ 0	$ 139	$ (139)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive (loss) income, net of tax	(666)
Net income	$ 22,788
Ending balance (in shares) at Sep. 30, 2020	6,279,304	6,279,000
Ending balance, value at Sep. 30, 2020	$ 214,616	$ 6,279	42,966	165,606	(235)
Beginning balance (in shares) at Mar. 31, 2020		6,366,000
Beginning balance, value at Mar. 31, 2020	197,723	$ 6,366	44,776	148,286	(1,705)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,188)			(2,188)
Stock-based compensation expense	238		238
Exercise of stock options and vesting of restricted stock units, net (in shares)		2,000
Exercise of stock options and vesting of restricted stock units, net	(6)	$ 2	(8)
Other comprehensive (loss) income, net of tax	1,256				1,256
Net income	9,900			9,900
Ending balance (in shares) at Jun. 30, 2020		6,368,000
Ending balance, value at Jun. 30, 2020	206,923	$ 6,368	45,006	155,998	(449)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend on common stock ($0.30 per share)	(2,247)			(2,247)
Stock-based compensation expense	237		237
Repurchase of common stock (in shares)		(89,000)
Repurchase of common stock	(2,366)	$ (89)	(2,277)
Other comprehensive (loss) income, net of tax	214				214
Net income	$ 11,855			11,855
Ending balance (in shares) at Sep. 30, 2020	6,279,304	6,279,000
Ending balance, value at Sep. 30, 2020	$ 214,616	$ 6,279	$ 42,966	$ 165,606	$ (235)