Segment Information - Additional Information (Detail) $ in Millions	2 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($)	Nov. 15, 2023 USD ($)	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 16, 2023 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of reportable segments | segment			2
Assets associated with trade capital providers				$ 303.7
Other intangible assets, net of accumulated amortization	$ 324.2		$ 324.2	0.0		$ 362.1
Impairment of goodwill and intangibles	$ 0.0	$ 0.0		28.5	$ 43.2
Impairment of indefinite lived intangible assets				17.3
Impairment of goodwill and intangibles				11.2
ArgoGlobal Syndicate 1200
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of goodwill and intangibles				$ 28.5