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Significant Transactions - Ark (Details) - USD ($) $ in Millions |  | 3 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Oct. 01, 2020 | Mar. 31, 2021 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Sep. 30, 2021 | Jan. 01, 2021 | Dec. 31, 2020
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Cash pre-funded/placed in escrow for Ark Transaction |  |  |  |  |  |  |  | $ 646.3
Change in fair value of contingent consideration - Ark |  |  | $ 48.7 | $ 17.3 | $ 5.5 |  |  |
Other Operations |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Cash pre-funded/placed in escrow for Ark Transaction |  |  |  |  |  |  |  | 366.3
Change in fair value of contingent consideration - Ark |  |  | $ 0.0 | 0.0 | 0.0 |  |  |
Ark |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Basic ownership |  |  |  |  |  |  | 72.00% |
Ownership percentage, after equity incentives |  |  |  |  |  |  | 63.00% |
Percent of shares outstanding |  |  | 12.50% |  |  |  |  |
Subordinated Debt | Ark 2021 Subordinated Notes |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Long-term line of credit |  |  |  |  |  | $ 163.3 |  |
Ark | Lloyd |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Cash pre-funded/placed in escrow for Ark Transaction |  |  |  |  |  |  |  | $ 280.0
Ark |  |  |  |  |  |  |  |
Other Significant Noncash Transactions [Line Items] |  |  |  |  |  |  |  |
Merger agreement, equity capital contributed | $ 605.4 |  |  |  |  |  |  |
Equity capital, pre money valuation amount | 300.0 |  |  |  |  |  |  |
Additional equity purchase from shareholders | 40.9 |  |  |  |  |  |  |
Investment, potential additional contribution of equity capital | $ 200.0 |  |  |  |  |  | $ 200.0 |
Percent of shares outstanding |  |  | 12.50% |  |  |  |  |
Assets acquired |  |  |  |  |  |  | 2,500.0 |
Goodwill and intangible assets acquired |  |  |  |  |  |  | 292.5 |
Liabilities acquired |  |  |  |  |  |  | 1,700.0 |
Contingent consideration |  |  | $ 94.0 | 45.3 |  |  | 22.5 |
Noncontrolling interest acquired |  |  |  |  |  |  | $ 220.2 |
Transaction costs |  | $ 25.3 |  |  |  |  |  |
Amortization |  |  | 0.0 | 7.5 | 64.2 |  |  |
Change in fair value of contingent consideration - Ark |  |  | $ 48.7 | $ 17.3 | $ 5.5 |  |  |

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