Earnings (Loss) Per Class A Share - Computation of Basic and Diluted Earnings (Loss) Per Class A Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Line Items]
Net Income (Loss) Attributable to Class A Shareholders	$ (28,267)	$ 37,083
Net Income (Loss) Attributable to Class A Shareholders, Diluted	$ (48,683)	$ 37,083
Weighted-Average Class A Shares Outstanding, Basic (in shares)	22,304,713	20,475,359
Weighted-Average Class A Shares Outstanding, Diluted (in shares)	38,319,348	21,491,970
Earnings (Loss) Per Class A Share, Basic (in dollars per share)	$ (1.27)	$ 1.81
Earnings (Loss) Per Class A Share, Diluted (in dollars per share)	$ (1.27)	$ 1.73
Group A Units
Earnings Per Share [Line Items]
Net Income (Loss) Attributable to Class A Shareholders, Effect of dilutive securities	$ (20,416)	$ 0
Weighted-Average Class A Shares Outstanding, Effect of dilutive securities (in shares)	16,014,635	0
Number of Antidilutive Units Excluded from Diluted Calculation (in shares)	0	20,039,945
Group E Units
Earnings Per Share [Line Items]
Weighted-Average Class A Shares Outstanding, Effect of dilutive securities (in shares)	0	1,016,611
Number of Antidilutive Units Excluded from Diluted Calculation (in shares)	13,450,821	0
RSUs
Earnings Per Share [Line Items]
Net Income (Loss) Attributable to Class A Shareholders, Effect of dilutive securities	$ 0	$ 0
Weighted-Average Class A Shares Outstanding, Effect of dilutive securities (in shares)	0	0
Number of Antidilutive Units Excluded from Diluted Calculation (in shares)	4,169,785	4,606,223