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Equity Method Eligible Investments - Carrying Value and Ownership Percentages (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022
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Kudu’s Participation Contracts |  |
Investments in and Advances to Affiliates [Line Items] |  |
Carrying Value | $ 890.5 | $ 695.9
Investment in MediaAlpha |  |
Investments in and Advances to Affiliates [Line Items] |  |
Ownership Interest | 34.90% | 27.10%
Carrying Value | $ 254.9 | $ 168.6
PassportCard/DavidShield |  |
Investments in and Advances to Affiliates [Line Items] |  |
Ownership Interest | 53.80% | 53.80%
Carrying Value | $ 150.0 | $ 135.0
Elementum Holdings, L.P. |  |
Investments in and Advances to Affiliates [Line Items] |  |
Ownership Interest | 26.60% | 29.70%
Carrying Value | $ 35.0 | $ 30.0
Other equity method eligible investments, at fair value |  |
Investments in and Advances to Affiliates [Line Items] |  |
Carrying Value | 291.7 | 84.4
Other equity method eligible investments, at fair value |  |
Investments in and Advances to Affiliates [Line Items] |  |
Carrying Value | $ 24.8 | $ 0.0
Minimum | Kudu’s Participation Contracts |  |
Investments in and Advances to Affiliates [Line Items] |  |
Ownership Interest | 4.10% | 4.10%
Maximum | Kudu’s Participation Contracts |  |
Investments in and Advances to Affiliates [Line Items] |  |
Ownership Interest | 30.00% | 30.00%

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