Variable Interest Entities - Summary of Assets and Liabilities of Consolidated VIE (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Assets
Loans receivable	$ 24,423,133			$ 22,003,017
Current expected credit loss reserve	(144,431)	$ (133,024)	$ (122,221)	(124,679)	$ (130,388)	$ (128,945)	$ (172,100)	$ (173,549)
Loans receivable, net	24,278,702			21,878,338
Other assets	248,028			273,797
Assets	24,798,629			22,703,289
Liabilities
Securitized debt obligations, net	2,844,032			2,838,062
Other liabilities	209,375			231,358
Liabilities	20,114,722			18,084,578
VIE
Assets
Loans receivable	3,500,000			3,486,750
Current expected credit loss reserve	(9,743)			(4,502)
Loans receivable, net	3,490,257			3,482,248
Other assets	12,389			20,746
Assets	3,502,646			3,502,994
Liabilities
Securitized debt obligations, net	2,844,032			2,838,062
Other liabilities	5,547			1,800
Liabilities	$ 2,849,579			$ 2,839,862