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
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 declared	(2,087)			(2,087)
Stock-based compensation expense	$ 196		196
Exercise of stock options and vesting of restricted stock units, net (in shares)	1,723	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 income (loss), 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared	(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 income (loss), 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 declared	(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 income (loss), 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 declared	(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 income (loss), 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cash dividend declared	(2,223)			(2,223)
Stock-based compensation expense	$ 242		242
Exercise of stock options and vesting of restricted stock units, net (in shares)	0
Repurchase of common stock (in shares)		(193,000)
Repurchase of common stock	$ (6,310)	$ (193)	(6,117)
Other comprehensive income (loss), net of tax	(2,136)				(2,136)
Net income	$ 1,033			1,033
Ending balance (in shares) at Mar. 31, 2020	6,366,100	6,366,000
Ending balance, value at Mar. 31, 2020	$ 197,723	$ 6,366	$ 44,776	$ 148,286	$ (1,705)