Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock Common Class A	Common Stock Common Class B	Additional Paid In Capital	Treasury Stock Common Class A	Retained Earnings	Accumulated Comprehensive Loss	Non-controlling Interest	Total
Balance at the beginning of the period at Dec. 31, 2019	$ 3	$ 2	$ 274,518	$ (60,521)	$ 16,075	$ (792)	$ 1,384	$ 230,669
Balance at the beginning of the period (in shares) at Dec. 31, 2019	25,202	19,720
Condensed Consolidated Statements of Changes in Stockholders' Equity
Net income (loss)					(10,813)		(118)	(10,931)
Vesting of restricted stock				(510)				(510)
Vesting of restricted stock (in shares)	237
Stock-based compensation			3,951					3,951
Other comprehensive income, net of tax						(1,433)		(1,433)
Balance at the end of the period at Sep. 30, 2020	$ 3	$ 2	278,469	(61,031)	5,262	(2,225)	1,266	221,746
Balance at the end of the period (in shares) at Sep. 30, 2020	25,439	19,720
Balance at the beginning of the period at Jun. 30, 2020	$ 3	$ 2	277,154	(61,031)	(35)	(2,598)	1,346	214,841
Balance at the beginning of the period (in shares) at Jun. 30, 2020	25,439	19,720
Condensed Consolidated Statements of Changes in Stockholders' Equity
Net income (loss)	$ 0	$ 0	0	0	5,297	0	(80)	5,217
Vesting of restricted stock	$ 0	$ 0	0	0	0	0	0	0
Vesting of restricted stock (in shares)	0	0
Stock-based compensation	$ 0	$ 0	1,315	0	0	0	0	1,315
Other comprehensive income, net of tax	0	0	0	0	0	373	0	373
Balance at the end of the period at Sep. 30, 2020	$ 3	$ 2	278,469	(61,031)	5,262	(2,225)	1,266	221,746
Balance at the end of the period (in shares) at Sep. 30, 2020	25,439	19,720
Balance at the end of the period at Jun. 30, 2021	$ 3	$ 2	285,373	(64,719)	41,912	(1,513)	449	261,507
Balance at the end of the period (in shares) at Jun. 30, 2021	25,988	19,720
Balance at the beginning of the period at Dec. 31, 2020	$ 3	$ 2	279,800	(61,453)	14,840	(2,187)	481	231,486
Balance at the beginning of the period (in shares) at Dec. 31, 2020	25,458	19,720
Condensed Consolidated Statements of Changes in Stockholders' Equity
Net income (loss)					12,271		(32)	12,239
Vesting of restricted stock				(844)				(844)
Vesting of restricted stock (in shares)	284
Issuance of Class A Common Stock	$ 0	$ 0	2,778	(1,077)	0	0	0	1,701
Issuance of Class A Common Stock (in shares)	238	0
Repurchases of Class A common stock				(1,346)				(1,346)
Stock-based compensation			4,485					4,485
Exercise of stock options			0	(43)				(43)
Exercise of stock options (in shares)	13
Other comprehensive income, net of tax						1,018		1,018
Acquisition of non-controlling interest					449		(449)
Balance at the end of the period at Sep. 30, 2021	$ 3	$ 2	287,063	(64,763)	27,560	(1,169)	0	248,696
Balance at the end of the period (in shares) at Sep. 30, 2021	25,993	19,720
Balance at the beginning of the period at Jun. 30, 2021	$ 3	$ 2	285,373	(64,719)	41,912	(1,513)	449	261,507
Balance at the beginning of the period (in shares) at Jun. 30, 2021	25,988	19,720
Condensed Consolidated Statements of Changes in Stockholders' Equity
Net income (loss)					(14,801)			(14,801)
Vesting of restricted stock				(19)				(19)
Vesting of restricted stock (in shares)	5
Repurchases of Class A common stock				(25)				(25)
Stock-based compensation			1,690					1,690
Other comprehensive income, net of tax						344		344
Acquisition of non-controlling interest					449		(449)
Balance at the end of the period at Sep. 30, 2021	$ 3	$ 2	$ 287,063	$ (64,763)	$ 27,560	$ (1,169)	$ 0	$ 248,696
Balance at the end of the period (in shares) at Sep. 30, 2021	25,993	19,720