Stock Transactions and Unit Redemptions - Gross Unit Redemptions and Share Repurchases of Class A Common Stock (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended						3 Months Ended				6 Months Ended
	Jun. 30, 2023	May 31, 2023	Apr. 30, 2023	Jun. 30, 2022	May 31, 2022	Apr. 30, 2022	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Class of Stock [Line Items]
Redemptions (in shares)					1,150,000		422,000	23,000	1,010,000	43,000	445,000	1,053,000
Repurchases (in shares)	3,428,000	3,300,000	3,086,000	7,595,000		0	9,814,000	846,000	8,745,000	0	10,660,000	8,745,000
Total redemptions and repurchases (in shares)											11,105,000	9,798,000
Redemptions, weighted average price paid per unit or share (in dollars per share)					$ 3.70		$ 4.91	$ 3.90	$ 3.81	$ 4.01	$ 4.85	$ 3.82
Repurchases, weighted average price paid per unit or shares (in dollars per share)	$ 4.48	$ 4.36	$ 4.48	$ 3.31		$ 0		$ 4.97		$ 0	4.48	3.36
Total redemptions and repurchases, weighted average price paid per unit or shares (in dollars per share)											$ 4.50	$ 3.41
Approximate Dollar Value of Units and Shares That Could Be Redeemed/ Purchased Under the Program at June 30, 2023	$ 326,449			$ 158,404			$ 326,449		$ 158,404		$ 326,449	$ 158,404
Weighted-average price for redemption of limited partnership units (in dollars per share)									$ 3.84			$ 3.85
Aggregate purchase price of Class A common stock											$ 46,481	$ 26,408
Class A Common Stock
Class of Stock [Line Items]
Repurchases (in shares)							9,813,827		8,745,310		10,659,717	8,745,310
Approximate Dollar Value of Units and Shares That Could Be Redeemed/ Purchased Under the Program at June 30, 2023	$ 326,400						$ 326,400				$ 326,400
Common stock, shares issued (in shares)							13,300,000		4,700,000		20,200,000	7,900,000
Stock issued during period, shares, exchange of units							7,100,000		700,000		13,400,000	4,500,000
Stock repurchased during period (in shares)							9,800,000		8,700,000		10,700,000	8,700,000
Aggregate purchase price of Class A common stock							$ 43,600		$ 29,400		$ 47,800	$ 29,400
Stock repurchased, weighted average price (in dollars per share)							$ 4.44		$ 3.36		$ 4.48	$ 3.36
Limited Partnership
Class of Stock [Line Items]
Redeemed limited partnership units (in shares)							300,000		1,000,000		300,000	1,000,000
Aggregate redemption price of limited partnership units							$ 1,400		$ 3,700		$ 1,400	$ 3,800
Weighted-average price for redemption of founding/working partner units (in dollars per share)							$ 4.71				$ 4.71
FPUs
Class of Stock [Line Items]
Redeemed limited partnership units (in shares)							100,000		40,000		200,000	100,000
Aggregate redemption price of limited partnership units							$ 700		$ 100		$ 800	$ 200
Weighted-average price for redemption of founding/working partner units (in dollars per share)							$ 5.32		$ 2.94		$ 5.11	$ 3.33