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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 | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Schedule of Equity Method Investments [Line Items] |  |  |  |
Net investment income earned | $ 117,759 | $ 100,863 | $ 334,250 | $ 290,065
Investments Accounted For Under The Equity Method |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Net investment income (loss) | 230,600 | 74,300 | 127,000 | (66,900)
Realized gains | 1,878,300 | 1,108,500 | 5,263,400 | 3,752,800
Net change in unrealized appreciation (depreciation) | 607,700 | 2,216,300 | 7,277,000 | 7,414,100
Net income | 2,716,600 | 3,399,100 | 12,667,400 | 11,100,000
Alternative investments |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Net investment income earned | $ 9,031 | $ 6,473 | $ 26,429 | $ 25,637

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