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Equity Method Investments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Equity method investments | $ 582.8 |  | $ 582.8 |  | $ 494.0
Income (loss) from equity method investments | 4.2 | $ (7.1) | (0.4) | $ (36.1) |
Hagerty, Inc. [Member] |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Equity method investments | $ 235.4 |  | $ 235.4 |  | $ 245.1
Equity method investment, ownership percentage | 23.00% |  | 23.00% |  | 23.00%
Equity method investment, quoted market value | $ 637.3 |  | $ 637.3 |  | $ 656.0

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