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Fair Value Measurement - Narrative (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Percentage of portfolio of unadjusted fair values obtained | 98.40% |
Three private equity funds using NAV | $ 90,700,000 |
Transfers between Levels 1, 2, and 3 of the fair value hierarchy | 0 | $ 0
Fair Value, Nonrecurring |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Assets, fair value disclosure | 0 | 0
Liabilities, fair value disclosure | 0 | 0
Unsecured Notes Two | Revolving Credit Facility |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Drawn down amount under credit facility | $ 200,000,000 | 200,000,000
Minimum |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Fair Value, liquidating investment, remaining period | 1 year |
Maximum |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Fair Value, liquidating investment, remaining period | 8 years |
Venture Capital Investments |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
One private equity fund using NAV | $ 4,500,000 |
Private Equity Funds |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Unfunded commitments | 5,000,000 | 8,000,000
Level 2 | Unsecured notes |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Unsecured notes | 375,000,000 | 375,000,000
Level 2 | Commercial Mortgage Back Securities |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Debt securities, trading, and equity securities, FV-NI | $ 16,000,000.0 | $ 33,000,000.0

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