CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Common Class A [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury stock [Member]	Accumulated other comprehensive loss [Member]	Total
Balance at Dec. 31, 2018	$ 4,410,000	$ 13,904,000	$ 34,588,000	$ (6,695,000)	$ (672,000)	$ 45,535,000
Balance (in shares) at Dec. 31, 2018	4,410,000			(816,000)
Net (loss) income	$ 0	0	4,911,000	$ 0	0	4,911,000
Restricted common stock compensation	$ 6,000	46,000	0	0	0	52,000
Restricted common stock compensation (in shares)	6,000
Purchase of Class A common stock	$ 0	0	0	$ (3,518,000)	0	(3,518,000)
Purchase of Class A common stock (in shares)	0			(457,000)
Stock-based compensation	$ 0	106,000	0	$ 0	0	106,000
Dividends	0	0	(632,000)	0	0	(632,000)
Foreign currency translation adjustment	0	0	0	0	52,000	52,000
Balance at Dec. 31, 2019	$ 4,416,000	14,056,000	38,867,000	$ (10,213,000)	(620,000)	46,506,000
Balance (in shares) at Dec. 31, 2019	4,416,000			(1,273,000)
Net (loss) income	$ 0	0	(4,954,000)	$ 0	0	(4,954,000)
Exercise of stock options	$ 6,000	12,000	0	0	0	18,000
Exercise of stock options (in shares)	6,000
Restricted common stock compensation	$ 6,000	35,000	0	0	0	41,000
Restricted common stock compensation (in shares)	6,000
Stock-based compensation	$ 0	41,000	0	0	0	41,000
Dividends	0	0	(157,000)	0	0	(157,000)
Foreign currency translation adjustment	0	0	0	0	43,000	43,000
Balance at Dec. 31, 2020	$ 4,428,000	$ 14,144,000	$ 33,756,000	$ (10,213,000)	$ (577,000)	$ 41,538,000
Balance (in shares) at Dec. 31, 2020	4,428,000			(1,273,000)