Consolidated and Combined Statement of Changes in Shareholders' and Members' Equity - USD ($) $ in Thousands	Total	Members' Contributed Capital	Additional Paid-In Capital	AOCI	[1]	Retained Earnings	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock	December Offering	December Offering Additional Paid-In Capital	December Offering Class A Common Stock Common Stock	December Offering Class B Common Stock Common Stock
Beginning balance at Dec. 31, 2016	$ 300,498	$ 280,648				$ 19,850
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contributions	37,600	37,600
Distributions	(152,218)	(152,218)
Other comprehensive income	682			$ 682
NET INCOME	115,612					115,612
Net income attributable to predecessor	115,612
Net income attributable to shareholders	0
Ending balance at Dec. 31, 2017	302,174	166,030		682		135,462
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Contributions	45,078	45,078
Distributions	(3,313)	(3,313)
Other comprehensive income	(682)			$ (682)
NET INCOME	32,815
Net income attributable to predecessor	30,976					30,976
Deferred tax liability arising from corporate reorganization	(3,057)		$ (3,057)
Proceeds from sale of equity securities	933	933
Net income attributable to shareholders	1,839					1,839
Ending balance at Dec. 31, 2018	373,948	208,728	(3,057)			168,277
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to predecessor	5,092					5,092
Net income attributable to shareholders	848					848
Ending balance at Apr. 16, 2019	379,888	208,728	(3,057)			174,217
Beginning balance at Dec. 31, 2018	373,948	208,728	(3,057)			168,277
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	0
NET INCOME	21,639
Net income attributable to predecessor	5,092
Net income attributable to shareholders	6,901
Ending balance at Dec. 31, 2019	317,319		323,578			(6,599)		$ 340
Ending balance (in shares) at Dec. 31, 2019							34,040,934	34,041,000	22,847,045	22,847,000
Beginning balance at Apr. 16, 2019	379,888	208,728	(3,057)			174,217
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of PE Units for Class A Common Stock and Class B Common Stock	0	$ (208,728)	380,205			(171,530)		$ 53
Conversion of PE Units for Class A Common Stock and Class B Common Stock (in shares)								5,322,000		28,778,000
Issuance of common stock in IPO, net of offering cost (in shares)								16,675,000					6,000,000
Issuance of common stock in IPO, net of offering cost	273,448		273,281					$ 167			$ 102,680	$ 102,620	$ 60
Deferred tax asset arising from the IPO	13,664		13,664								9,508	9,508
Reclassification of noncontrolling interests to temporary equity	(518,000)		(518,000)
Share-based compensation expense (in shares)								124,000
Share-based compensation expense	12,633		12,632					$ 1
Dividends paid	(14,663)					(14,663)
Dividend equivalent rights	(676)					(676)
Net income attributable to shareholders	6,053					6,053
Adjustment of temporary equity to redemption amount	(51,572)		(51,572)
Conversion of Class B shares to Class A shares (in shares)													5,931,000	(5,931,000)
Conversion of Class B shares to Class A shares	104,390		104,331										$ 59
Restricted stock forfeited (in shares)													(11,000)
Restricted stock forfeited											$ (34)	$ (34)
Ending balance at Dec. 31, 2019	$ 317,319		$ 323,578			$ (6,599)		$ 340
Ending balance (in shares) at Dec. 31, 2019							34,040,934	34,041,000	22,847,045	22,847,000

[1] AOCI - Accumulated other comprehensive income