Commercial Mortgage Loans, Held for Investment - Schedule of Past Due (Details) $ in Thousands	Sep. 30, 2026 USD ($) loan	Dec. 31, 2025 USD ($) loan
Financing Receivable, Past Due [Line Items]
Amortized cost	$ 22,800,000	$ 21,600,000
Commercial Mortgage Receivable, Held-For-Investment
Financing Receivable, Past Due [Line Items]
Amortized cost	$ 4,039,522	$ 4,421,436
Number of loans \| loan	175	169
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment
Financing Receivable, Past Due [Line Items]
Amortized cost	$ 4,039,522	$ 4,421,436
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment \| Nonperforming Financial Instruments
Financing Receivable, Past Due [Line Items]
Number of loans \| loan	7
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment \| Current
Financing Receivable, Past Due [Line Items]
Amortized cost	$ 3,804,278
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment \| Less than 90 days past due
Financing Receivable, Past Due [Line Items]
Amortized cost	81,189
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment \| 90 or more days past due
Financing Receivable, Past Due [Line Items]
Amortized cost	$ 154,055
Commercial Portfolio Segment \| Commercial Mortgage Receivable, Held-For-Investment \| 90 or more days past due \| Multifamily
Financing Receivable, Past Due [Line Items]
Number of loans \| loan	5