Variable Interest Entities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Assets
Loans receivable	$ 23,715,901			$ 25,017,880
Current expected credit loss reserve	(463,423)	$ (363,875)	$ (336,591)	(326,137)	$ (144,431)	$ (133,024)	$ (122,221)	$ (124,679)
Loans receivable, net	23,252,478			24,691,743
Other assets	369,446			370,902
Total assets	24,043,419			25,353,985
Liabilities
Securitized debt obligations, net	2,509,254			2,664,010
Other liabilities	278,027			426,904
Total liabilities	19,549,898			20,809,785
VIE
Assets
Loans receivable	3,155,701			3,317,316
Current expected credit loss reserve	(178,185)			(93,396)
Loans receivable, net	2,977,516			3,223,920
Other assets	15,228			15,995
Total assets	2,992,744			3,239,915
Liabilities
Securitized debt obligations, net	2,509,254			2,664,010
Other liabilities	7,601			7,234
Total liabilities	$ 2,516,855			$ 2,671,244