Summary of Significant Accounting Policies - Residential Whole Loans (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2026 |
Dec. 31, 2025 |
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| LTV ratio (as a percent) | 80.00% | |
| Residential whole loans | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| LTV ratio (as a percent) | 64.00% | 64.00% |
| Residential whole loans | Business purpose loans | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| LTV ratio (as a percent) | 70.00% | 66.00% |
| Residential whole loans | Business purpose loans | Multifamily Properties | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Threshold balance (below) | $ 10 |