Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2015	9,692,864
Balance at Dec. 31, 2015	$ 26,916	$ 6,168,635	$ (6,602,930)	$ 53,067,234	$ (1,687,679)	$ 50,972,176
Share-based compensation (in shares)	20,780
Share-based compensation	$ 50	199,820				199,870
Net income				6,402,259		$ 6,402,259
Purchase of Treasury stock (in shares)	(520,482)					(520,482)
Purchase of Treasury stock			(3,675,654)			$ (3,675,654)
Translation adjustment					(205,450)	$ (205,450)
Shares issued - stock options exercised (in shares)
Purchase of treasury stock (in shares)	520,482					520,482
Balance (in shares) at Dec. 31, 2016	9,193,162
Balance at Dec. 31, 2016	$ 26,966	6,368,455	(10,278,584)	59,469,493	(1,893,129)	$ 53,693,201
Share-based compensation (in shares)	33,300
Share-based compensation	$ 80	239,519				239,599
Net income				4,451,751		$ 4,451,751
Purchase of Treasury stock (in shares)
Translation adjustment					931,026	$ 931,026
Shares issued - stock options exercised (in shares)	44,400					44,400
Shares issued - stock options exercised	$ 107	223,297				$ 223,404
Purchase of treasury stock (in shares)
Balance (in shares) at Dec. 31, 2017	9,270,862
Balance at Dec. 31, 2017	$ 27,153	6,831,271	(10,278,584)	63,921,244	(962,103)	$ 59,538,981
Share-based compensation (in shares)	33,086
Share-based compensation	$ 79	327,550				327,629
Net income				1,963,828		$ 1,963,828
Purchase of Treasury stock (in shares)	243,387					(243,387)
Purchase of Treasury stock			(1,653,266)			$ (1,653,266)
Translation adjustment					(548,557)	(548,557)
Cumulative effect of accounting change at Dec. 31, 2017				(168,311)		$ (168,311)
Purchase of treasury stock (in shares)	(243,387)					243,387
Balance (in shares) at Dec. 31, 2018	9,060,561
Balance at Dec. 31, 2018	$ 27,232	$ 7,158,821	$ (11,931,850)	$ 65,716,761	$ (1,510,660)	$ 59,460,304