v3.26.3
Fair Value - Key Assumptions Used in Determining Fair Value of MSRs at Time of Initial Recognition (Detail)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
UsdPerLoan
Sep. 30, 2025
USD ($)
UsdPerLoan
Sep. 30, 2026
USD ($)
UsdPerLoan
Sep. 30, 2025
USD ($)
UsdPerLoan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value, MSR recognized | $ $ 16,926 $ 45,744 $ 88,188 $ 136,783
Fair value, Unpaid principal balance of underlying loans | $ $ 1,162,008 $ 2,488,333 $ 5,250,518 $ 7,433,949
Fair value, Weighted-average annual servicing fee rate (in basis points) 0.27% 0.32% 0.30% 0.32%
Minimum [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value inputs, Pricing spread during period 4.80% 5.20% 4.70% 5.20%
Fair Value inputs, Prepayment speed during period 8.40% 9.80% 8.10% 9.40%
Fair Value inputs, Weighted average equivalent average life during period 5 years 8 months 12 days 3 years 9 months 18 days 3 years 8 months 12 days 3 years 8 months 12 days
Fair Value inputs, Annual per loan cost of servicing during period 69 68 69 68
Maximum [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value inputs, Pricing spread during period 10.30% 7.30% 10.30% 7.30%
Fair Value inputs, Prepayment speed during period 14.30% 15.30% 14.90% 15.50%
Fair Value inputs, Weighted average equivalent average life during period 8 years 7 months 6 days 8 years 9 years 8 years 2 months 12 days
Fair Value inputs, Annual per loan cost of servicing during period 137 91 137 91
Weighted Average [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair Value inputs, Pricing spread during period 7.70% 5.20% 6.80% 5.30%
Fair Value inputs, Prepayment speed during period 9.20% 9.90% 9.50% 9.80%
Fair Value inputs, Weighted average equivalent average life during period 8 years 3 months 18 days 7 years 10 months 24 days 8 years 2 months 12 days 8 years
Fair Value inputs, Annual per loan cost of servicing during period 88 68 78 69