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Income Taxes - Valuation Allowance (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023
Valuation Allowance [Line Items] |  |
Valuation allowance | $ 89.2 | $ 116.1
Financial Guarantee (HG Global) | BAM |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 5.7 | 6.3
Net Operating Losses in Luxembourg Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 43.4 | 20.8
U S Losses and Other Federal Deferred Tax Benefits |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 25.2 | 47.6
Net Operating Losses in Israel Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 20.6 | 46.9
Net Operating Losses in United Kingdom Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance |  | 0.8
Net Deferred Tax Assets For Certain U.S. Operations - Other Operations |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | (8.6) | 7.2
Net Deferred Tax Assets For BAM |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | (3.1) | (8.7)
Investments Held in Luxembourg-Domiciled Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 4.2 | 31.6
Investments Held in Israel-Domiciled Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | $ 0.2 | $ (0.4)

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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
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- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
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