Long-Term Debt - Summary of Financial Information Relating to Note Payable Secured by Credit Risk Transfer and Mortgage Servicing Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Short Term Debt [Line Items]
Amortization of premiums and debt issuance costs			$ 9,244	$ 8,212
Notes Payable [Member] \| Freddie Mac MSR Financing
Short Term Debt [Line Items]
Amortization of premiums and debt issuance costs	$ 2,000	$ 2,200	$ 3,700	$ 4,400

Amount of amortization expense attributable to debt discount (premium) and debt issuance costs.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
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