Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Class A Common Stock	Common Class A	Common Class B Common Stock	Common Class B	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive income (loss), net of tax	Non-controlling interest	Total
Beginning balance, Value at Dec. 31, 2019	$ 2				$ 466,945	$ 30,732	$ 414	$ (411,267)	$ 86,826
Beginning balance, Shares at Dec. 31, 2019	17,838,233		1
Net income (loss)						2,714		2,724	5,438
Distributions to non-controlling unitholders								(2,777)	(2,777)
Equity-based compensation expense and dividend equivalents, Value					5,962	(289)			5,673
Equity-based compensation expense and dividend equivalents, Shares	368,375
Dividends to Class A common stockholders						(3,986)			(3,986)
Change in accumulated other comprehensive income (loss)							(36)	(194)	(230)
Payroll taxes related to net settled restricted stock units, Value					(2,268)				(2,268)
Payroll taxes related to net settled restricted stock units, Shares	(82,645)
Ending balance, Value at Mar. 31, 2020	$ 2				470,639	29,171	378	(411,514)	88,676
Ending balance, Shares at Mar. 31, 2020	18,123,963		1
Beginning balance, Value at Dec. 31, 2019	$ 2				466,945	30,732	414	(411,267)	86,826
Beginning balance, Shares at Dec. 31, 2019	17,838,233		1
Net income (loss)									18,319
Change in accumulated other comprehensive income (loss)									(43)
Ending balance, Value at Sep. 30, 2020	$ 2				485,664	28,368	476	(413,502)	101,008
Ending balance, Shares at Sep. 30, 2020	18,372,134		1
Beginning balance, Value at Mar. 31, 2020	$ 2				470,639	29,171	378	(411,514)	88,676
Beginning balance, Shares at Mar. 31, 2020	18,123,963		1
Net income (loss)						3,552		2,491	6,043
Distributions to non-controlling unitholders								(2,789)	(2,789)
Equity-based compensation expense and dividend equivalents, Value					2,812				2,812
Dividends to Class A common stockholders						(3,987)			(3,987)
Change in accumulated other comprehensive income (loss)							62	55	117
Other						2			2
Ending balance, Value at Jun. 30, 2020	$ 2				473,451	28,738	440	(411,757)	90,874
Ending balance, Shares at Jun. 30, 2020	18,123,963		1
Net income (loss)						3,617		3,221	6,838
Distributions to non-controlling unitholders								(5,000)	(5,000)
Equity-based compensation expense and dividend equivalents, Value					3,413				3,413
Dividends to Class A common stockholders						(3,988)			(3,988)
Change in accumulated other comprehensive income (loss)							36	34	70
Acquisitions, Value					8,800				8,800
Acquisitions, Shares	248,171
Other						1			1
Ending balance, Value at Sep. 30, 2020	$ 2				485,664	28,368	476	(413,502)	101,008
Ending balance, Shares at Sep. 30, 2020	18,372,134		1
Beginning balance, Value at Dec. 31, 2020	$ 2				491,422	25,628	612	(416,007)	101,657
Beginning balance, Shares at Dec. 31, 2020	18,390,691	18,390,691	1	1
Net income (loss)						1,163		600	1,763
Distributions to non-controlling unitholders								(2,889)	(2,889)
Equity-based compensation expense and dividend equivalents, Value					12,679	(472)			12,207
Equity-based compensation expense and dividend equivalents, Shares	459,330
Dividends to Class A common stockholders						(4,326)			(4,326)
Change in accumulated other comprehensive income (loss)							41	38	79
Payroll taxes related to net settled restricted stock units, Value					(5,291)				(5,291)
Payroll taxes related to net settled restricted stock units, Shares	(130,773)
Ending balance, Value at Mar. 31, 2021	$ 2				498,810	21,993	653	(418,258)	103,200
Ending balance, Shares at Mar. 31, 2021	18,719,248		1
Beginning balance, Value at Dec. 31, 2020	$ 2				491,422	25,628	612	(416,007)	101,657
Beginning balance, Shares at Dec. 31, 2020	18,390,691	18,390,691	1	1
Net income (loss)									(30,240)
Change in accumulated other comprehensive income (loss)									30
Ending balance, Value at Sep. 30, 2021	$ 2				510,424	(6,585)	639	(438,299)	66,181
Ending balance, Shares at Sep. 30, 2021	18,806,194	18,806,194	1	1
Beginning balance, Value at Mar. 31, 2021	$ 2				498,810	21,993	653	(418,258)	103,200
Beginning balance, Shares at Mar. 31, 2021	18,719,248		1
Net income (loss)						5,261		5,099	10,360
Distributions to non-controlling unitholders								(4,110)	(4,110)
Equity-based compensation expense and dividend equivalents, Value					4,615				4,615
Equity-based compensation expense and dividend equivalents, Shares	640
Dividends to Class A common stockholders						(4,345)			(4,345)
Change in accumulated other comprehensive income (loss)							110	97	207
Payroll taxes related to net settled restricted stock units, Value					(7)				(7)
Payroll taxes related to net settled restricted stock units, Shares	(223)
Other					12				12
Ending balance, Value at Jun. 30, 2021	$ 2				503,430	22,909	763	(417,172)	109,932
Ending balance, Shares at Jun. 30, 2021	18,719,665		1
Net income (loss)						(25,149)		(17,214)	(42,363)
Distributions to non-controlling unitholders								(3,781)	(3,781)
Equity-based compensation expense and dividend equivalents, Value					7,004				7,004
Equity-based compensation expense and dividend equivalents, Shares	87,428
Dividends to Class A common stockholders						(4,345)			(4,345)
Change in accumulated other comprehensive income (loss)							(124)	(132)	(256)
Payroll taxes related to net settled restricted stock units, Value					(31)				(31)
Payroll taxes related to net settled restricted stock units, Shares	(899)
Other					21				21
Ending balance, Value at Sep. 30, 2021	$ 2				$ 510,424	$ (6,585)	$ 639	$ (438,299)	$ 66,181
Ending balance, Shares at Sep. 30, 2021	18,806,194	18,806,194	1	1