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SCHEDULE III - SUPPLEMENTARY INSURANCE INFORMATION (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
P&C Insurance and Reinsurance (Ark/WM Outrigger) |  |  |
SUPPLEMENTARY INSURANCE INFORMATION |  |  |
Deferred Acquisition Costs | $ 211.1 | $ 165.2 | $ 145.3
Future Policy Benefits, Losses, Claims and Loss Expenses | 2,481.0 | 2,127.5 | 1,605.1
Unearned Premiums | 1,026.1 | 853.3 | 743.6
Other Policy Claims and Benefits Payable | 0.0 | 0.0 | 0.0
Premiums Earned | 1,697.4 | 1,587.8 | 1,409.7
Net Investment Income | 106.5 | 90.7 | 61.4
Benefits, Claims, Losses and Settlement Expenses | 844.2 | 855.8 | 726.8
Amortization of Deferred Acquisition Costs | 374.4 | 294.1 | 273.1
Other Operating Expenses | 143.9 | 136.1 | 113.6
Premiums Written | 1,811.6 | 1,679.1 | 1,520.9
Financial Guarantee (HG Global) |  |  |
SUPPLEMENTARY INSURANCE INFORMATION |  |  |
Deferred Acquisition Costs | 96.9 | 86.6 | 40.1
Future Policy Benefits, Losses, Claims and Loss Expenses | 0.0 | 0.0 | 0.0
Unearned Premiums | 327.9 | 297.3 | 325.8
Other Policy Claims and Benefits Payable | 0.0 | 0.0 | 0.0
Premiums Earned | 30.8 | 31.7 | 31.2
Net Investment Income | 27.1 | 32.2 | 31.7
Benefits, Claims, Losses and Settlement Expenses | 0.0 | 0.0 | 0.0
Amortization of Deferred Acquisition Costs | 8.0 | 8.2 | 8.6
Other Operating Expenses | 0.0 | 0.2 | 0.4
Premiums Written | 61.4 | 56.0 | $ 58.6
Bamboo Captive |  |  |
SUPPLEMENTARY INSURANCE INFORMATION |  |  |
Deferred Acquisition Costs | 0.0 | 10.2 |
Future Policy Benefits, Losses, Claims and Loss Expenses | 0.0 | 17.8 |
Unearned Premiums | 0.0 | 31.5 |
Other Policy Claims and Benefits Payable | 0.0 | 0.0 |
Premiums Earned | 26.7 | 39.4 |
Net Investment Income | 1.8 | 1.4 |
Benefits, Claims, Losses and Settlement Expenses | 18.0 | 20.6 |
Amortization of Deferred Acquisition Costs | 9.7 | 14.1 |
Other Operating Expenses | 0.0 | 0.0 |
Premiums Written | 16.1 | 50.0 |
Bamboo CRV |  |  |
SUPPLEMENTARY INSURANCE INFORMATION |  |  |
Deferred Acquisition Costs | 2.5 | 5.8 |
Future Policy Benefits, Losses, Claims and Loss Expenses | 13.6 | 12.1 |
Unearned Premiums | 9.6 | 29.0 |
Other Policy Claims and Benefits Payable | 0.0 | 0.0 |
Premiums Earned | 22.2 | 32.7 |
Net Investment Income | 1.5 | 0.4 |
Benefits, Claims, Losses and Settlement Expenses | 20.0 | 12.1 |
Amortization of Deferred Acquisition Costs | 8.3 | 12.1 |
Other Operating Expenses | 0.0 | 0.0 |
Premiums Written | $ 1.4 | $ 61.7 |

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