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Income Taxes - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
Income Tax Contingency [Line Items] |  |  |
Net deferred tax benefit |  |  | $ (68.0)
Net income tax payments to US | $ 30.7 | $ 34.3 | 42.7
P&C Insurance and Reinsurance (Ark/WM Outrigger) | Ark |  |  |
Income Tax Contingency [Line Items] |  |  |
Net deferred tax benefit |  |  | (51.0)
Financial Guarantee (HG Global) | HG Global |  |  |
Income Tax Contingency [Line Items] |  |  |
Net deferred tax benefit |  |  | $ (17.0)
Deferred tax liabilities |  | 5.0 |
Deferred tax expense (benefit) |  | $ (5.0) |
Domestic Tax Jurisdiction |  |  |
Income Tax Contingency [Line Items] |  |  |
Separate return limitation year operating loss carryforwards | 8.2 |  |
Separate return limitation year internal revenue | 0.6 |  |
Foreign Tax Jurisdiction |  |  |
Income Tax Contingency [Line Items] |  |  |
Tax credit carryforwards | 3.7 |  |
Bermuda |  |  |
Income Tax Contingency [Line Items] |  |  |
Deferred tax liabilities | 5.1 |  |
Deferred tax expense (benefit) | (5.1) |  |
LUXEMBOURG |  |  |
Income Tax Contingency [Line Items] |  |  |
Deferred tax expense (benefit) | $ (78.1) |  |

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- Definition Amount of other deferred income tax expense (benefit) pertaining to income (loss) from continuing operations. For example, but not limited to, acquisition-date income tax benefits or expenses recognized from changes in the acquirer's valuation allowance for its previously existing deferred tax assets resulting from a business combination and adjustments to beginning-of-year balance of a valuation allowance because of a change in circumstance causing a change in judgment about the realizability of the related deferred tax asset in future periods. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-9 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)(1)(Note 1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 + Details
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- Definition Amount, after refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2A -Publisher FASB -URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 23 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-23 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-22 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482913/230-10-50-2 + Details
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- Definition The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-3 + Details
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