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Loans Receivable, Net - Overall Statistics for Loans Receivable Portfolio (Detail) $ in Thousands | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2025 USD ($) | Sep. 30, 2025 USD ($) loan | Sep. 30, 2025 USD ($) security_loan | Sep. 30, 2025 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2024 USD ($) loan | Dec. 31, 2024 USD ($) security_loan | Dec. 31, 2024 USD ($) | Sep. 30, 2024 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |  |
Number of loans |  | 137 | 137 |  |  | 130 | 130 |  |
Principal balance | $ 18,188,534 | $ 18,188,534 | $ 18,188,534 | $ 18,188,534 | $ 19,203,126 | $ 19,203,126 | $ 19,203,126 | $ 19,203,126 |
Net book value | 17,371,200 | 17,371,200 | 17,371,200 | 17,371,200 | 18,313,582 | 18,313,582 | 18,313,582 | 18,313,582 |
Unfunded loan commitments | $ 13,741 | $ 13,741 | $ 13,741 | $ 13,741 | $ 10,412 | $ 10,412 | $ 10,412 | $ 10,412 | $ 8,300
Weighted-average cash coupon (percentage) | 3.24% | 3.24% | 3.24% | 3.24% | 3.46% | 3.46% | 3.46% | 3.46% |
Weighted-average all-in yield (percentage) |  |  |  | 3.46% |  |  |  | 3.78% |
Weighted-average maximum maturity (years) | 2 years 4 months 24 days |  |  |  | 2 years 1 month 6 days |  |  |  |
Debt instrument, variable interest rate, type [Extensible Enumeration] | SOFR |  |  |  | SOFR |  |  |  |
Percentage of loans by principal balance, floating rate | 98.00% | 98.00% | 98.00% | 98.00% |  |  |  |  |
Percentage of loans by principal balance, fixed rate | 2.00% | 2.00% | 2.00% | 2.00% |  |  |  |  |
Percent of loans subject to prepayment restrictions | 31.00% | 31.00% | 31.00% | 31.00% | 10.00% | 10.00% | 10.00% | 10.00% |
Percent of loans not subject to prepayment restrictions | 69.00% | 69.00% | 69.00% | 69.00% | 90.00% | 90.00% | 90.00% | 90.00% |
Unfunded Loan Commitment |  |  |  |  |  |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |  |  |  |  |  |
Number of loans | loan |  | 57 |  |  |  |  |  |  |
Unfunded loan commitments | $ 1,532,429 | $ 1,532,429 | $ 1,532,429 | $ 1,532,429 | $ 1,263,068 | $ 1,263,068 | $ 1,263,068 | $ 1,263,068 |

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