Loan Sales - Summary of Cash Flows between Company and Transferees in Transfers Accounted for Sales (Detail) - Variable Interest Entity, Not Primary Beneficiary [Member] - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Cash flows:
Proceeds from sales	$ 5,172,208	$ 3,107,613	$ 9,340,802	$ 13,576,673
Loan servicing fees received	$ 162,605	$ 166,809	$ 485,089	$ 496,522

Cash Flows between a transferor and a transferee attributable to newly transferred assets related to either a securitization, asset-backed financing arrangement, or similar transfer in which the transferor has continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-3

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration