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Fair Value Measurement (Narrative) (Details) - USD ($) | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Dec. 31, 2024
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 | $ 90,900,000 |  |
Unfunded commitments to VIEs |  |  | $ 5,000,000
Transfers between Levels 1, 2, and 3 of the fair value hierarchy | 0 | $ 0 |
Fair Value, Measurements, Nonrecurring |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Assets, fair value disclosure | 0 |  |
Liabilities, fair value disclosure | 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 | 7 years |  |
Venture Capital Investments |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
One private equity fund using NAV | $ 6,200,000 |  |
Private Equity Funds |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Unfunded commitments to VIEs | 5,000,000 |  |
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 | $ 13,400,000 |  | $ 16,000,000.0

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