Loans at Fair Value - Summary of Distribution of Company's Loans at Fair Value (Parenthetical) (Detail) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Mortgage Loans At Fair Value [Abstract]
Securities retained at fair value pledged to secure Assets sold under agreements to repurchase	$ 78.3	$ 85.3

Fair value portion of interest continued to be held by a transferor after transferring financial assets to a third party.

No definition available.

Name:	us-gaap_RetainedInterestFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant