Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Common Class A [Member]	Common Class B [Member]	Total
Balances at Dec. 31, 2017			$ 26	$ 4	$ 51,025	$ 77,574	$ (1,635)	$ (36,953)			$ 90,041
Purchase of shares of treasury stock								(7,950)			(7,950)
Issuance of common shares for the exercise of stock options					6,098						6,098
Non-cash stock compensation expense					1,514						1,514
Settlement of class B restricted common shares and stock options in connection with Recapitalization for cash of $3,271 and 90,369 class A common shares					(2,548)			(723)			(3,271)
Settlement of class B common shares in connection with Recapitalization (3,527,246 class B common shares exchanged for $69,099 cash and 3,527,246 class A common shares)			4		118,335			(187,438)			(69,099)
Retirement of 4,328,552 class B common shares in connection with Recapitalization				$ (4)	(17,112)	(186,944)		204,060
Dividends declared						(29,751)					(29,751)
Other comprehensive income, foreign currency translation adjustment							(1,281)				(1,281)
Net income						30,047			$ 25,423	$ 4,624	30,047
Balances at Dec. 31, 2018	$ 2,735	$ 2,735	30		157,312	(106,339)	(2,916)	(29,004)			19,083
Purchase of shares of treasury stock								(4,722)			(4,722)
Issuance of common shares for the exercise of stock options					3,618						3,618
Non-cash stock compensation expense					1,224						1,224
Dividends declared						(19,424)					(19,424)
Other comprehensive income, foreign currency translation adjustment							707				707
Net income						32,406					32,406
Balances at Dec. 31, 2019			30		162,154	(93,357)	(2,209)	(33,726)			32,892
Purchase of shares of treasury stock								(10,001)			(10,001)
Issuance of common shares for the exercise of stock options			1		8,951						8,952
Non-cash stock compensation expense					680						680
Dividends declared						(5,278)					(5,278)
Other comprehensive income, foreign currency translation adjustment							(190)				(190)
Net income						37,260					37,260
Balances at Dec. 31, 2020			$ 31		$ 171,785	$ (61,375)	$ (2,399)	$ (43,727)			$ 64,315