Condensed Consolidated Statements of Shareholder's Equity And Partner's Capital - USD ($) $ in Thousands	Total	Class A common stock [Member]	Class C common stock [Member]	Additional Paid In Capital	Partners' Capital	Non-controlling interests	Retained Earnings
Balance at Dec. 31, 2017	$ 289,157				$ 288,528	$ 629
Distributions	(107,535)				(107,497)	(38)
Net income	53,914				53,866	48
Balance at Mar. 31, 2018	235,536				234,897	639
Balance at Dec. 31, 2017	289,157				288,528	629
Distributions to non-controlling interests	(100)
Net income	86,515
Balance at Sep. 30, 2018	263,579	$ 5	$ 4	$ 137,866		123,175	$ 2,529
Balance, shares at Sep. 30, 2018		45,855,000	40,000,000
Balance at Mar. 31, 2018	235,536				234,897	639
Net income	17,003				16,956	47
Balance at Jun. 30, 2018	252,539				251,853	686
Distributions	(36,253)				(36,253)
Net income prior to Transaction	10,157				10,137	20
Recapitalization in connection with the Transaction	31,694	$ 5	$ 4	137,866	$ (225,737)	119,556
Recapitalization in connection with the Transaction, shares		45,855,000	40,000,000
Net income post Transaction	5,442					2,913	2,529
Net income	15,600
Balance at Sep. 30, 2018	263,579	$ 5	$ 4	137,866		123,175	2,529
Balance, shares at Sep. 30, 2018		45,855,000	40,000,000
Balance at Dec. 31, 2018	269,714	$ 5	$ 4	137,866		127,029	4,810
Balance, shares at Dec. 31, 2018		45,855,000	40,000,000
Vested restricted stock grants, shares		4,000
Stock-based compensation	99			99
Distribution equivalent rights paid	(15)			(15)
Distributions to non-controlling interests	(8,559)					(8,559)
Dividends to shareholders	(9,171)						(9,171)
Net income	11,303					5,921	5,382
Balance at Mar. 31, 2019	263,371	$ 5	$ 4	137,950		124,391	1,021
Balance, shares at Mar. 31, 2019		45,859,000	40,000,000
Balance at Dec. 31, 2018	269,714	$ 5	$ 4	137,866		127,029	4,810
Balance, shares at Dec. 31, 2018		45,855,000	40,000,000
Vested restricted stock grants, shares		95,716
Distributions to non-controlling interests	(22,300)
Net income	26,562
Balance at Sep. 30, 2019	251,601	$ 5	$ 4	132,325		119,267
Balance, shares at Sep. 30, 2019		45,950,716	40,000,000
Balance at Mar. 31, 2019	263,371	$ 5	$ 4	137,950		124,391	1,021
Balance, shares at Mar. 31, 2019		45,859,000	40,000,000
Vested restricted stock grants, shares		3,000
Stock-based compensation	761			761
Distribution equivalent rights paid	(56)			(56)
Distributions to non-controlling interests	(7,397)					(7,397)
Dividends to shareholders	(8,025)			(3,248)			(4,777)
Net income	8,902					5,146	3,756
Balance at Jun. 30, 2019	257,556	$ 5	$ 4	135,407		122,140
Balance, shares at Jun. 30, 2019		45,862,000	40,000,000
Vested restricted stock grants, shares		89,000
Stock-based compensation	970			970
Distribution equivalent rights paid	(43)			(43)
Distributions to non-controlling interests	(6,346)					(6,346)
Dividends to shareholders	(6,893)			(4,009)			(2,884)
Net income	6,357					3,473	$ 2,884
Balance at Sep. 30, 2019	$ 251,601	$ 5	$ 4	$ 132,325		$ 119,267
Balance, shares at Sep. 30, 2019		45,950,716	40,000,000