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)
Beginning balance (shares) at Dec. 31, 2019		15,703,276
Beginning balance at Dec. 31, 2019	$ 140,576	$ 86,381	$ 7,524	$ 46,483	$ 188
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,310			9,310
Other comprehensive income (loss)	789				789
Stock issued under stock-based compensation plans (shares)		268,591
Stock issued under stock-based compensation plans	305	$ 305
Stock-based compensation, net	858		858
Repurchase of common stock (shares)		(845,597)
Repurchase of common stock	(7,086)	$ (7,086)
Cash dividends declared	(3,203)			(3,203)
Ending balance (shares) at Sep. 30, 2020		15,126,270
Ending balance at Sep. 30, 2020	141,549	$ 79,600	8,382	52,590	977
Beginning balance (shares) at Jun. 30, 2020		15,068,030
Beginning balance at Jun. 30, 2020	139,136	$ 79,925	8,218	50,056	937
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,595			3,595
Other comprehensive income (loss)	40				40
Stock issued under stock-based compensation plans (shares)		116,356
Stock issued under stock-based compensation plans	0	$ 0
Stock-based compensation, net	164		164
Repurchase of common stock (shares)		(58,116)
Repurchase of common stock	(325)	$ (325)
Cash dividends declared	(1,061)			(1,061)
Ending balance (shares) at Sep. 30, 2020		15,126,270
Ending balance at Sep. 30, 2020	141,549	$ 79,600	8,382	52,590	977
Beginning balance (shares) at Dec. 31, 2020		15,016,700
Beginning balance at Dec. 31, 2020	143,366	$ 78,657	8,521	55,348	840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,706			19,706
Other comprehensive income (loss)	(861)				(861)
Stock issued under stock-based compensation plans (shares)		120,537
Stock issued under stock-based compensation plans	89	$ 89
Stock-based compensation, net	(30)		(30)
Repurchase of common stock (shares)		(3,830)
Repurchase of common stock	(28)	$ (28)
Cash dividends declared	(3,618)			(3,618)
Ending balance (shares) at Sep. 30, 2021		15,133,407
Ending balance at Sep. 30, 2021	158,624	$ 78,718	8,491	71,436	(21)
Beginning balance (shares) at Jun. 30, 2021		15,133,407
Beginning balance at Jun. 30, 2021	151,962	$ 78,718	8,324	64,700	220
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,250			8,250
Other comprehensive income (loss)	(241)				(241)
Stock issued under stock-based compensation plans (shares)		0
Stock issued under stock-based compensation plans	0	$ 0
Stock-based compensation, net	167		167
Repurchase of common stock (shares)		0
Repurchase of common stock	0	$ 0
Cash dividends declared	(1,514)			(1,514)
Ending balance (shares) at Sep. 30, 2021		15,133,407
Ending balance at Sep. 30, 2021	$ 158,624	$ 78,718	$ 8,491	$ 71,436	$ (21)