v3.26.3
Mortgage Servicing Rights - Summary of MSRs Carried at Fair Value (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Summary Of Mortgage Servicing Rights [Line Items]          
Balance at beginning of period $ 3,575,603 $ 3,739,106 $ 3,644,702 $ 3,867,394  
Servicing Asset At Fair Value Additions From Loan Sales 16,926 45,744 88,188 136,783  
Sale of mortgage servicing rights, net of transfers to Agency relating to delinquent loans (204,172) 284 (201,770) 675  
Due to changes in inputs used in valuation model [1] 209,927 (26,975) 274,418 (60,093)  
Other changes in fair value [2] (84,524) (89,404) (291,778) (276,004)  
Change in fair value, Total 125,403 (116,379) (17,360) (336,097)  
Balance at end of period [3] 3,513,760 $ 3,668,755 3,513,760 $ 3,668,755  
Pledged Assets [Member]          
Summary Of Mortgage Servicing Rights [Line Items]          
Fair value of mortgage servicing rights pledged to secure Assets sold under agreements to repurchase and Notes payable secured by credit risk transfer and mortgage servicing assets $ 3,430,494   $ 3,430,494   $ 3,582,211
[1] Primarily reflects changes in prepayment speed, OAS or pricing spread, servicing cost, and UPB of underlying loan inputs.
[2] Represents changes due to realization of expected cash flows.
[3] During the third quarter of 2026, the Company entered into an agreement to sell a portfolio of Agency MSRs with an aggregate UPB of approximately $10.0 billion. The transaction is expected to close in the fourth quarter of 2026.