CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Total	Common Class A Stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury stock [Member]	Accumulated other comprehensive loss [Member]
Balance at Dec. 31, 2015	$ 43,642,000	$ 4,170,000	$ 12,884,000	$ 31,495,000	$ (4,566,000)	$ (341,000)
Balance (in shares) at Dec. 31, 2015		4,170,000			(554,000)
Net (loss) income	6,901,000	$ 0	0	6,901,000	$ 0	0
Exercise of stock options	23,000	$ 6,000	17,000	0	$ 0	0
Exercise of stock options (in shares)		6,000			0
Restricted common stock compensation	50,000	$ 5,000	45,000	0	$ 0	0
Restricted common stock compensation (in shares)		5,000			0
Stock-based compensation	(22,000)	$ 0	(22,000)	0	$ 0	0
Purchase of Class A common stock	(255,000)	$ 0	0	0	$ (255,000)	0
Purchase of Class A common stock (in shares)		0			(30,000)
Tax benefit on stock-based compensation	(18,000)	$ 0	(18,000)	0	$ 0	0
Dividends	(2,335,000)	0	0	(2,335,000)	0	0
Foreign currency translation adjustment	(396,000)	0	0	0	0	(396,000)
Balance at Dec. 31, 2016	47,590,000	$ 4,181,000	12,906,000	36,061,000	$ (4,821,000)	(737,000)
Balance (in shares) at Dec. 31, 2016		4,181,000			(584,000)
Net (loss) income	(884,000)	$ 0	0	(884,000)	$ 0	0
Exercise of stock options	62,000	$ 17,000	45,000	0	$ 0	0
Exercise of stock options (in shares)		17,000			0
Restricted common stock compensation	38,000	$ 5,000	33,000	0	$ 0	0
Restricted common stock compensation (in shares)		5,000			0
Stock-based compensation	80,000	$ 0	80,000	0	$ 0	0
Purchase of Class A common stock	(358,000)	$ 0	0	0	$ (358,000)	0
Purchase of Class A common stock (in shares)		0			(47,000)
Dividends	(722,000)	$ 0	0	(722,000)	$ 0	0
Foreign currency translation adjustment	207,000	0	0	0	0	207,000
Balance at Dec. 31, 2017	$ 46,013,000	$ 4,203,000	$ 13,064,000	$ 34,455,000	$ (5,179,000)	$ (530,000)
Balance (in shares) at Dec. 31, 2017		4,203,000			(631,000)