Investments - Schedule of Fair Value of Foreign Currency Exchange Forward Contracts (Detail) - Foreign Currency Exchange Forward Contracts - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Schedule of Investments [Line Items]
Foreign currency exchange, fair value	$ (7.7)	$ (0.6)
Operational currency exposure
Schedule of Investments [Line Items]
Foreign currency exchange, fair value	(8.5)	(0.3)
Asset manager investment exposure
Schedule of Investments [Line Items]
Foreign currency exchange, fair value	$ 0.8	$ (0.3)

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

Name:	us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant