CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - 6 months ended Jun. 30, 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	370,000	$ 0	0	370,000	$ 0	0
Exercise of stock options	737,000	$ 184,000	553,000	0	0	0
Exercise of stock options (in shares)		184,000
Restricted common stock compensation	18,000	$ 7,000	11,000	0	0	0
Restricted common stock compensation (in shares)		7,000
Purchase of Class A common stock	(430,000)	$ 0	0	0	$ (430,000)	0
Purchase of Class A common stock (in shares)					(52,000)
Stock-based compensation	120,000	0	120,000	0	$ 0	0
Dividends	(359,000)	0	0	(359,000)	0	0
Foreign currency translation adjustment	(59,000)	0	0	0	0	(59,000)
Balance at Jun. 30, 2018	$ 46,410,000	$ 4,394,000	$ 13,748,000	$ 34,466,000	$ (5,609,000)	$ (589,000)
Balance (in shares) at Jun. 30, 2018		4,394,000			(683,000)