CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - 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 loss	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
Restricted common stock compensation	7,000	$ 0	7,000	0	0	0
Purchase of Class A common stock	(82,000)	0	0	0	$ (82,000)	0
Purchase of Class A common stock (in shares)					(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)
Balance at Dec. 31, 2018	45,535,000	$ 4,410,000	13,904,000	34,588,000	$ (6,695,000)	(672,000)
Balance (in shares) at Dec. 31, 2018		4,410,000			(816,000)
Net loss	(26,000)	$ 0	0	(26,000)	$ 0	0
Restricted common stock compensation	13,000	0	13,000	0	$ 0	0
Restricted common stock compensation (in shares)					0
Purchase of Class A common stock	(3,202,000)	0	0	0	$ (3,202,000)	0
Purchase of Class A common stock (in shares)					(418,000)
Stock-based compensation	29,000	0	29,000	0	$ 0	0
Dividends	(158,000)	0	0	(158,000)	0	0
Foreign currency translation adjustment	44,000	0	0	0	0	44,000
Balance at Mar. 31, 2019	$ 42,235,000	$ 4,410,000	$ 13,946,000	$ 34,404,000	$ (9,897,000)	$ (628,000)
Balance (in shares) at Mar. 31, 2019		4,410,000			(1,234,000)