Long-Term Debt - Summary of Term Note Issued to Qualified Institutional Buyers (Detail) $ in Thousands	6 Months Ended
Jun. 30, 2025 USD ($)
Secured Debt \| CRT Arrangement Financing [Member]
Debt Instrument [Line Items]
Unpaid principal balance	$ 638,735
Secured Term Notes \| Fannie Mae MSR Financing
Debt Instrument [Line Items]
Unpaid principal balance	1,075,000
August 28, 2024 [Member] \| Secured Debt \| CRT Arrangement Financing [Member]
Debt Instrument [Line Items]
Notes Issued	158,500
Unpaid principal balance	$ 144,451
Interest rate spread (Annual)	3.10%
Maturity date, Stated	Sep. 27, 2028
April 4, 2024 [Member] \| Secured Debt \| CRT Arrangement Financing [Member]
Debt Instrument [Line Items]
Notes Issued	$ 247,000
Unpaid principal balance	$ 221,477
Interest rate spread (Annual)	3.35%
Maturity date, Stated	Mar. 29, 2027
March 6, 2024 [Member] \| Secured Debt \| CRT Arrangement Financing [Member]
Debt Instrument [Line Items]
Notes Issued	$ 306,000
Unpaid principal balance	$ 272,807
Interest rate spread (Annual)	3.50%
Maturity date, Stated	Mar. 01, 2027
May 25, 2023 [Member] \| Secured Term Notes \| Fannie Mae MSR Financing
Debt Instrument [Line Items]
Unpaid principal balance	$ 370,000
Interest rate spread (Annual)	3.00%
Maturity date, Stated	May 25, 2028
Maturity date, Optional extension	May 25, 2029
June 27, 2024 [Member] \| Secured Term Notes \| Fannie Mae MSR Financing
Debt Instrument [Line Items]
Unpaid principal balance	$ 355,000
Interest rate spread (Annual)	2.75%
Maturity date, Stated	Dec. 27, 2027
Maturity date, Optional extension	Jun. 26, 2028
March 30, 2021 [Member] \| Secured Term Notes \| Fannie Mae MSR Financing
Debt Instrument [Line Items]
Unpaid principal balance	$ 350,000
Interest rate spread (Annual)	3.00%
Maturity date, Stated	Mar. 25, 2026
Maturity date, Optional extension	Mar. 27, 2028

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