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Investments - Schedule of Aggregated Income Statement Summarized Financial Information for Partnerships in our Alternative Investment Portfolio (Details) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2025 | Mar. 31, 2024
Schedule of Equity Method Investments [Line Items] |  |
Net investment income earned | $ 120,691 | $ 107,849
Investments Accounted For Under The Equity Method |  |
Schedule of Equity Method Investments [Line Items] |  |
Net investment income (loss) | 400,700 | (346,000)
Realized gains | 612,000 | 1,830,800
Net change in unrealized appreciation (depreciation) | 1,879,400 | 3,819,000
Net income | 2,892,100 | 5,303,800
Alternative investments |  |
Schedule of Equity Method Investments [Line Items] |  |
Net investment income earned | $ 7,079 | $ 6,881

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