v3.26.1
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, 2026
USD ($)
UsdPerLoan
Dec. 31, 2025
USD ($)
UsdPerLoan
Mar. 31, 2026
USD ($)
Jun. 30, 2025
USD ($)
 [1]
Mar. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Balance at end of period $ 3,575,603 [1] $ 3,644,702 $ 3,623,979 $ 3,739,106 $ 3,770,034 $ 3,867,394
Unpaid principal balance of underlying loans, Fair Value $ 208,426,764 $ 215,781,639        
Weighted-average annual servicing fee rate (in basis points), Fair value input 28.00% 28.00%        
Weighted-average note interest rate, Fair value 3.90% 3.90%        
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 $ (42,931) $ (61,563)        
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 (85,475) (120,960)        
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 (168,902) (233,683)        
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 (33,357) (30,295)        
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 (67,581) (60,089)        
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 (134,995) (118,218)        
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 (14,469) (15,979)        
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 (28,939) (31,959)        
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 $ (57,877) $ (63,918)        
Minimum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Option-adjusted spread 3.20% 3.60%        
Estimated fair value inputs, Prepayment speed 6.90% 7.00%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 69 68        
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 2 years 1 month 6 days        
Maximum [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Estimated fair value inputs, Option-adjusted spread 6.30% 6.20%        
Estimated fair value inputs, Prepayment speed 26.80% 21.50%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 100 90        
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 10 months 24 days 7 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 7.10% 8.40%        
Estimated fair value inputs, Option-adjusted spread 4.60% 3.60%        
Estimated fair value inputs, Annual per-loan cost of servicing | UsdPerLoan 69 68        
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 6 months 7 years 8 months 12 days        
[1] During June 2026, the Company entered into an agreement to sell a portfolio of conventional MSRs with an aggregate UPB of approximately $13.0 billion. The transaction is expected to close in August 2026.