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Debt - Summary of Debt Outstanding (Details) € in Millions, $ in Millions | Mar. 31, 2024 USD ($) | Mar. 31, 2024 EUR (€) | Dec. 31, 2023 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | --- | --- | --- | ---
Debt Instrument |  |  |  |  |
Total debt | $ 532.1 |  | $ 534.6 |  |
Ark 2021 Subordinated Notes |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | 155.4 |  | 155.5 |  |
HG Global Senior Notes |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | 147.0 |  | 146.9 |  |
Kudu Credit Facility |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | 203.8 |  | 203.8 |  |
Other Operations debt |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | 25.9 |  | 28.4 |  |
Subordinated Debt | Ark |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | $ 155.4 |  | $ 185.5 |  |
Effective Rate | 13.10% | 13.10% | 11.00% |  |
Subordinated Debt | Ark 2007 Notes | Ark Subordinated Debt |  |  |  |  |
Debt Instrument |  |  |  |  |
Total debt | $ 0.0 |  | $ 30.0 |  |
Subordinated Debt | Ark 2021 Subordinated Notes |  |  |  |  |
Debt Instrument |  |  |  |  |
Unamortized issuance cost | (4.0) |  | (4.2) |  |
Total debt | 155.4 |  | 155.5 |  |
Subordinated Debt | Ark 2021 Subordinated Notes Tranche 1 |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | 42.4 | € 39.1 | 42.7 |  |
Subordinated Debt | Ark 2021 Subordinated Notes Tranche 2 |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | 47.0 |  | 47.0 |  |
Subordinated Debt | Ark 2021 Subordinated Notes Tranche 3 |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | 70.0 |  | 70.0 |  |
Senior Notes | HG Global Senior Notes |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | 150.0 |  | 150.0 |  |
Unamortized discount and issuance cost | (3.0) |  | (3.1) |  |
Total debt | $ 147.0 |  | $ 146.9 |  |
Effective Rate | 11.90% | 11.90% | 11.90% |  |
Secured Debt | Kudu Credit Facility |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | $ 210.3 |  | $ 210.3 |  |
Unamortized issuance cost | (6.5) |  | (6.5) |  |
Total debt | $ 210.3 |  | $ 210.3 | $ 198.3 | $ 215.2
Effective Rate | 10.60% | 10.60% | 10.10% |  |
Secured Debt | Other Operations debt |  |  |  |  |
Debt Instrument |  |  |  |  |
Amount borrowed | $ 26.4 |  | $ 28.9 |  |
Unamortized issuance cost | $ (0.5) |  | $ (0.5) |  |
Effective Rate | 10.20% | 10.20% | 10.20% |  |

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