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	5,662,000	$ 0	0	5,662,000
Exercise of stock options (in shares)				(450,000)
Restricted common stock compensation	$ 6,000	20,000	0	$ 0	0	26,000
Restricted common stock compensation (in shares)	6,000			0
Purchase of Class A common stock	$ 0	0	0	$ (3,467,000)	0	(3,467,000)
Purchase of Class A common stock (in shares)	0
Stock-based compensation	$ 0	62,000	0	0	0	62,000
Dividends	0	0	(317,000)	0	0	(317,000)
Foreign currency translation adjustment	0	0	0	0	(7,000)	(7,000)
Balance at Jun. 30, 2019	$ 4,416,000	13,986,000	39,933,000	$ (10,162,000)	(679,000)	47,494,000
Balance (in shares) at Jun. 30, 2019	4,416,000			(1,266,000)
Balance at Mar. 31, 2019	$ 4,410,000	13,946,000	34,404,000	$ (9,897,000)	(628,000)	42,235,000
Balance (in shares) at Mar. 31, 2019	4,410,000			(1,234,000)
Net (loss) income	$ 0	0	5,688,000	$ 0	0	5,688,000
Restricted common stock compensation	$ 6,000	7,000	0	$ 0	0	13,000
Restricted common stock compensation (in shares)	6,000			0
Purchase of Class A common stock	$ 0	0	0	$ (265,000)	0	(265,000)
Purchase of Class A common stock (in shares)	0			(32,000)
Stock-based compensation	$ 0	33,000	0	$ 0	0	33,000
Dividends	0	0	(159,000)	0	0	(159,000)
Foreign currency translation adjustment	0	0	0	0	(51,000)	(51,000)
Balance at Jun. 30, 2019	$ 4,416,000	13,986,000	39,933,000	$ (10,162,000)	(679,000)	47,494,000
Balance (in shares) at Jun. 30, 2019	4,416,000			(1,266,000)
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	(3,139,000)	$ 0	0	(3,139,000)
Exercise of stock options	$ 1,000	2,000	0	0	0	3,000
Exercise of stock options (in shares)	1,000
Restricted common stock compensation	$ 6,000	19,000	0	0	0	25,000
Restricted common stock compensation (in shares)	6,000
Stock-based compensation	$ 0	29,000	0	0	0	29,000
Dividends	0	0	(157,000)	0	0	(157,000)
Foreign currency translation adjustment	0	0	0	0	(137,000)	(137,000)
Balance at Jun. 30, 2020	$ 4,423,000	14,106,000	35,571,000	$ (10,213,000)	(757,000)	43,130,000
Balance (in shares) at Jun. 30, 2020	4,423,000			(1,273,000)
Balance at Mar. 31, 2020	$ 4,417,000	14,087,000	37,952,000	$ (10,213,000)	(745,000)	45,498,000
Balance (in shares) at Mar. 31, 2020	4,417,000			(1,273,000)
Net (loss) income	$ 0	0	(2,381,000)	$ 0	0	(2,381,000)
Restricted common stock compensation	$ 6,000	6,000	0	$ 0	0	12,000
Restricted common stock compensation (in shares)	6,000			0
Stock-based compensation	$ 0	13,000	0	$ 0	0	13,000
Foreign currency translation adjustment	0	0	0	0	(12,000)	(12,000)
Balance at Jun. 30, 2020	$ 4,423,000	$ 14,106,000	$ 35,571,000	$ (10,213,000)	$ (757,000)	$ 43,130,000
Balance (in shares) at Jun. 30, 2020	4,423,000			(1,273,000)