v3.25.2
Fair Value - Quantitative Summary of Key Assumptions Used in Valuation of MSRs as of Dates Presented, and Effect on Estimated Fair Value from Adverse Changes in Those Inputs (Detail)
$ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2025
USD ($)
UsdPerLoan
Dec. 31, 2024
USD ($)
UsdPerLoan
Mar. 31, 2025
USD ($)
Jun. 30, 2024
USD ($)
Mar. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Balance at end of period $ 3,739,106 $ 3,867,394 $ 3,770,034 $ 3,941,861 $ 3,951,737 $ 3,919,107
Unpaid principal balance of underlying loans, Fair Value $ 221,632,326 $ 226,237,613        
Weighted-average annual servicing fee rate (in basis points), Fair value input 27.00% 27.00%        
Weighted-average note interest rate, Fair value 3.90% 3.80%        
Pricing Spread [Member] | Effect On Value Of Five Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input $ (46,780) $ (47,568)        
Pricing Spread [Member] | Effect On Value Of Ten Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (92,450) (94,018)        
Pricing Spread [Member] | Effect On Value Of Twenty Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (180,597) (183,710)        
Prepayment Speed [Member] | Effect On Value Of Five Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (54,493) (51,798)        
Prepayment Speed [Member] | Effect On Value Of Ten Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (107,260) (102,010)        
Prepayment Speed [Member] | Effect On Value Of Twenty Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (207,940) (197,970)        
Cost of Servicing [Member] | Effect On Value Of Five Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (16,355) (16,645)        
Cost of Servicing [Member] | Effect On Value Of Ten Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input (32,710) (33,291)        
Cost of Servicing [Member] | Effect On Value Of Twenty Percentage Adverse Change            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Effect on value of percentage adverse change, Fair value input $ (65,421) $ (66,582)        
Minimum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Pricing spread 5.40% 5.40%        
Estimated fair value inputs, Prepayment speed 7.10% 6.50%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 69 69        
Minimum [Member] | Mortgage service rights [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Life (in years) 2 years 3 months 18 days 2 years 4 months 24 days        
Maximum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Pricing spread 8.10% 8.10%        
Estimated fair value inputs, Prepayment speed 18.50% 17.70%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 89 89        
Maximum [Member] | Mortgage service rights [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Life (in years) 8 years 8 months 12 days 8 years 10 months 24 days        
Weighted Average [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Pricing spread 5.40% 5.40%        
Estimated fair value inputs, Prepayment speed 7.30% 6.70%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 69 69        
Weighted Average [Member] | Mortgage service rights [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Life (in years) 8 years 3 months 18 days 8 years 7 months 6 days