Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance (in shares) at Dec. 31, 2018	21,110,224				1,501,511
Balance at Dec. 31, 2018	$ 211	$ 98,442	$ 45,831	$ (3,900)	$ (10,349)	$ 130,235
Net income			3,513			3,513
Other comprehensive income (loss)				(192)		(192)
Issuance of common stock for stock options exercised (in shares)	61,419
Issuance of common stock for stock options exercised	$ 1	478				479
Vested restricted stock units (in shares)	2,026
Vested restricted stock units	$ 0					0
Stock-based compensation expense		746				746
Repurchase of common stock at cost (in shares)					926
Repurchase of common stock at cost					$ (21)	(21)
Common stock dividend			(1,672)			(1,672)
Balance (in shares) at Mar. 31, 2019	21,173,669				1,502,437
Balance at Mar. 31, 2019	$ 212	99,666	47,672	(4,092)	$ (10,370)	133,088
Balance (in shares) at Dec. 31, 2018	21,110,224				1,501,511
Balance at Dec. 31, 2018	$ 211	98,442	45,831	(3,900)	$ (10,349)	130,235
Net income						8,137
Other comprehensive income (loss)						82
Balance (in shares) at Jun. 30, 2019	21,250,872				1,503,445
Balance at Jun. 30, 2019	$ 213	100,890	50,624	(3,818)	$ (10,372)	137,537
Balance (in shares) at Mar. 31, 2019	21,173,669				1,502,437
Balance at Mar. 31, 2019	$ 212	99,666	47,672	(4,092)	$ (10,370)	133,088
Net income			4,624			4,624
Other comprehensive income (loss)				274		274
Issuance of common stock for stock options exercised (in shares)	77,032
Issuance of common stock for stock options exercised	$ 1	530				531
Vested restricted stock units (in shares)	171
Vested restricted stock units	$ 0	0				0
Stock-based compensation expense		694				694
Repurchase of common stock at cost (in shares)					1,008
Repurchase of common stock at cost					$ (2)	(2)
Common stock dividend			(1,672)			(1,672)
Balance (in shares) at Jun. 30, 2019	21,250,872				1,503,445
Balance at Jun. 30, 2019	$ 213	100,890	50,624	(3,818)	$ (10,372)	137,537
Balance (in shares) at Dec. 31, 2019	21,678,927				1,522,035
Balance at Dec. 31, 2019	$ 217	105,934	57,029	(4,007)	$ (11,032)	148,141
Net income			3,174			3,174
Other comprehensive income (loss)				(1,518)		(1,518)
Issuance of common stock for stock options exercised (in shares)	19,141
Issuance of common stock for stock options exercised	$ 0	233				233
Vested restricted stock units (in shares)	4,074
Vested restricted stock units	$ 0					0
Stock-based compensation expense		779				779
Repurchase of common stock at cost (in shares)					1,601
Repurchase of common stock at cost					$ (57)	(57)
Common stock dividend			(1,917)			(1,917)
Balance (in shares) at Mar. 31, 2020	21,702,142				1,523,636
Balance at Mar. 31, 2020	$ 217	106,946	58,286	(5,525)	$ (11,089)	148,835
Balance (in shares) at Dec. 31, 2019	21,678,927				1,522,035
Balance at Dec. 31, 2019	$ 217	105,934	57,029	(4,007)	$ (11,032)	148,141
Net income						6,674
Other comprehensive income (loss)						(152)
Balance (in shares) at Jun. 30, 2020	21,705,334				1,523,636
Balance at Jun. 30, 2020	$ 217	107,791	59,869	(4,159)	$ (11,089)	152,629
Balance (in shares) at Mar. 31, 2020	21,702,142				1,523,636
Balance at Mar. 31, 2020	$ 217	106,946	58,286	(5,525)	$ (11,089)	148,835
Net income			3,500			3,500
Other comprehensive income (loss)				1,366		1,366
Issuance of common stock for stock options exercised (in shares)	3,000
Issuance of common stock for stock options exercised	$ 0	42				42
Vested restricted stock units (in shares)	192
Vested restricted stock units	$ 0	0				0
Stock-based compensation expense		803				803
Common stock dividend			(1,917)			(1,917)
Balance (in shares) at Jun. 30, 2020	21,705,334				1,523,636
Balance at Jun. 30, 2020	$ 217	$ 107,791	$ 59,869	$ (4,159)	$ (11,089)	$ 152,629