Consolidated Statements of Stockholders' Equity - USD ($)	Common Stock Common Class A	Common Stock Common Class B	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss), net of tax	Non-controlling interest	Common Class A	Common Class B	Total
Beginning balance, Value at Dec. 31, 2018	$ 2,000	$ 0	$ 460,101,000	$ 21,138,000	$ 328,000	$ (402,294,000)			$ 79,275,000
Beginning balance, Shares at Dec. 31, 2018	17,754,416	1
Net income	$ 0	$ 0	0	4,409,000	0	3,848,000			8,257,000
Distributions to non-controlling unitholders	0	0	0	0	0	(2,693,000)			(2,693,000)
Equity-based compensation expense and related dividend equivalents, value	$ 0	$ 0	3,213,000	(42,000)	0	0			3,171,000
Equity-based compensation expense and related dividend equivalents, shares	70,797	0
Dividends to Class A common stockholders	$ 0	$ 0	0	(3,740,000)	0	0	$ (3,740,000)		(3,740,000)
Change in accumulated other comprehensive income	0	0	0	0	36,000	33,000			69,000
Payroll taxes related to net settled restricted stock units, value	$ 0	$ 0	(713,000)	0	0	0			(713,000)
Payroll taxes related to net settled restricted stock units, shares	(17,265)	0
Ending balance, Value at Mar. 31, 2019	$ 2,000	$ 0	462,601,000	21,765,000	364,000	(401,106,000)			83,626,000
Ending balance, Shares at Mar. 31, 2019	17,807,948	1
Beginning balance, Value at Dec. 31, 2019	$ 2,000	$ 0	466,945,000	30,525,000	414,000	(399,510,000)			98,376,000
Beginning balance, Shares at Dec. 31, 2019	17,838,233	1					17,838,233	1
Net income	$ 0	$ 0	0	2,631,000	0	2,659,000			5,290,000
Distributions to non-controlling unitholders	0	0	0	0	0	(2,777,000)			(2,777,000)
Equity-based compensation expense and related dividend equivalents, value	$ 0	$ 0	5,962,000	(289,000)	0	0			5,673,000
Equity-based compensation expense and related dividend equivalents, shares	368,375	0
Dividends to Class A common stockholders	$ 0	$ 0	0	(3,986,000)	0	0	$ (3,986,000)		(3,986,000)
Change in accumulated other comprehensive income	0	0	0	0	(36,000)	(194,000)			(230,000)
Payroll taxes related to net settled restricted stock units, value	$ 0	$ 0	(2,268,000)	0	0	0			(2,268,000)
Payroll taxes related to net settled restricted stock units, shares	(82,645)	0
Ending balance, Value at Mar. 31, 2020	$ 2,000	$ 0	$ 470,639,000	$ 28,881,000	$ 378,000	$ (399,822,000)			$ 100,078,000
Ending balance, Shares at Mar. 31, 2020	18,123,963	1					18,123,963	1