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Income Taxes - Valuation Allowance (Detail) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Valuation Allowance [Line Items] |  |
Valuation allowance | $ 116.1 | $ 94.3
HG Global/BAM - Segment | BAM |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 6.3 | 17.5
Net Operating Losses in Luxembourg Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 47.6 | 16.0
U S Losses and Other Federal Deferred Tax Benefits |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 46.9 | 56.6
Net Operating Losses in Israel Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 20.8 | 20.4
Net Operating Losses in United Kingdom Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Valuation allowance | 0.8 | 1.3
Net Deferred Tax Assets For Certain U.S. Operations - Other Operations |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | (7.2) | 7.8
Net Deferred Tax Assets For BAM |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | (8.7) | (10.9)
Investments and Net Operating Losses At United States Branches Of United Kingdom Holding Companies |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | (0.6) | 4.0
Net Deferred Tax Assets For Certain U.S. Operations - Ark |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 0.1 |
Investments Held in Luxembourg-Domiciled Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 31.6 | (9.2)
Investments Held in Israel-Domiciled Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | 0.4 | (1.5)
Investments Held in U.K.-Domiciled Subsidiaries |  |
Valuation Allowance [Line Items] |  |
Increase (decrease) in valuation allowance | $ (0.4) | $ 1.0

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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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