v3.26.1
Use of Special Purpose Entities and Variable Interest Entities - Schedule of Loan Securitization Transaction (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Variable Interest Entity [Line Items]      
Weighted average rate for Senior Bonds issued 4.44%   4.51%
Asset-backed Securities, Securitized Loans and Receivables      
Variable Interest Entity [Line Items]      
Aggregate unpaid principal balance of residential whole loans sold $ 11,398,498   $ 11,489,998
Outstanding amount of Senior Bonds, at carrying value 465,386   489,718
Outstanding amount of Senior Bonds, at fair value 5,805,738   5,846,744
Outstanding amount of Senior Bonds, total $ 6,271,124   $ 6,336,462
Weighted average rate for Senior Bonds issued 5.03%   5.07%
Weighted average contractual maturity of Senior Bonds 38 years   37 years
Cash received $ 10,088,396   $ 10,061,131
Debt issuance cost $ 800   $ 900
Percentage of debt with fixed rate 99.10%   99.60%
Percentage of debt with variable rate 0.90%   0.40%
Asset-backed Securities, Securitized Loans and Receivables | Senior Notes      
Variable Interest Entity [Line Items]      
Debt instrument, face amount $ 10,166,134   $ 10,142,071
Cash received 710,900 $ 283,400  
Proceeds from Senior bond sold with Step up feature $ 4,600,000   4,700,000
Asset-backed Securities, Securitized Loans and Receivables | Senior Notes | Minimum      
Variable Interest Entity [Line Items]      
Debt instrument, coupon step-up period 30 months    
Asset-backed Securities, Securitized Loans and Receivables | Senior Notes | Maximum      
Variable Interest Entity [Line Items]      
Debt instrument, coupon step-up period 48 months    
Asset-backed Securities, Securitized Loans and Receivables | Senior Notes | Variable Rate, Option 1      
Variable Interest Entity [Line Items]      
Debt instrument, basis spread on variable rate (in percent) 1.00%    
Asset-backed Securities, Securitized Loans and Receivables | Senior Notes | Variable Rate, Option 2      
Variable Interest Entity [Line Items]      
Debt instrument, basis spread on variable rate (in percent) 3.00%    
Asset-backed Securities, Securitized Loans and Receivables | Senior Support Certificates      
Variable Interest Entity [Line Items]      
Debt instrument, face amount $ 1,194,304   $ 1,307,153