Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
Beginning Balance at Dec. 31, 2014	$ 68,207	$ 188	$ 75,389	$ 3,248	$ (2,365)	$ (8,253)
Beginning Balance, Shares at Dec. 31, 2014		18,778,436				1,407,211
Net income	7,758			7,758
Other comprehensive income	(1,684)				(1,684)
Issuance of common stock for stock options exercised	4,836	$ 9	4,827
Issuance of common stock for stock options exercised, Shares		906,936
Vested restricted stock units	0	$ 0	0	0	0	$ 0
Vested restricted stock units, shares		62,949
Excess tax benefits from stock-based compensation awards	454		454
Stock based compensation expense	1,424		1,424
Repurchase of common stock at cost	(266)					$ (266)
Repurchase of common stock at cost, shares						23,928
Common stock cash dividend paid	(2,845)			(2,845)
Ending Balance at Dec. 31, 2015	77,884	$ 197	82,094	8,161	(4,049)	$ (8,519)
Ending Balance, Shares at Dec. 31, 2015		19,748,321				1,431,139
Net income	10,590			10,590
Other comprehensive income	(534)				(534)
Cumulative effect adjustment to retained earnings	72		165	(93)
Issuance of common stock for stock options exercised	1,442	$ 3	1,439
Issuance of common stock for stock options exercised, Shares		233,798
Vested restricted stock units	0	$ 0	0	0	0	$ 0
Vested restricted stock units, shares		58,229
Stock based compensation expense	1,680		1,680
Repurchase of common stock at cost	(311)					$ (311)
Repurchase of common stock at cost, shares						21,671
Common stock cash dividend paid	(3,323)			(3,323)
Ending Balance at Dec. 31, 2016	87,500	$ 200	85,378	15,335	(4,583)	$ (8,830)
Ending Balance, Shares at Dec. 31, 2016		20,040,348				1,452,810
Net income	17,177			17,177
Other comprehensive income	2,294				2,294
Issuance of common stock for stock options exercised	$ 5,500	$ 7	5,493
Issuance of common stock for stock options exercised, Shares	635,503	635,503
Vested restricted stock units	$ 0	$ 0	0	0	0	$ 0
Vested restricted stock units, shares		69,190
Stock based compensation expense	2,256		2,256
Repurchase of common stock at cost	(778)					$ (778)
Repurchase of common stock at cost, shares						27,291
Common stock cash dividend paid	(4,179)			(4,179)
Ending Balance at Dec. 31, 2017	$ 109,770	$ 207	$ 93,127	$ 28,333	$ (2,289)	$ (9,608)
Ending Balance, Shares at Dec. 31, 2017		20,745,041				1,480,101