CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - 3 months ended Mar. 31, 2018 - USD ($)	Total	Common Class A [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury stock [Member]	Accumulated other comprehensive loss [Member]
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)
Net income	65,000	$ 0	0	65,000	$ 0	0
Exercise of stock options	105,000	$ 26,000	79,000	0	$ 0	0
Exercise of stock options (in shares)		26,000			0
Restricted common stock compensation	7,000	$ 0	7,000	0	$ 0	0
Restricted common stock compensation (in shares)		0			0
Purchase of Class A common stock	(82,000)	$ 0	0	0	$ (82,000)	0
Purchase of Class A common stock (in shares)		0			(10,000)
Stock-based compensation	60,000	$ 0	60,000	0	$ 0	0
Dividends	(180,000)	0	0	(180,000)	0	0
Foreign currency translation adjustment	96,000	0	0	0	0	96,000
Balance at Mar. 31, 2018	$ 46,084,000	$ 4,229,000	$ 13,210,000	$ 34,340,000	$ (5,261,000)	$ (434,000)
Balance (in shares) at Mar. 31, 2018		4,229,000			(641,000)