Acquisitions - Additional Information (Detail) - USD ($) $ in Millions					12 Months Ended
	Oct. 01, 2023	Aug. 23, 2022	Mar. 25, 2022	Mar. 16, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2022	May 31, 2022
Business Acquisition [Line Items]
Total revenues					$ 5,502.8	$ 5,283.0	$ 5,051.0
O' Shares Exchange Traded Funds [Member]
Business Acquisition [Line Items]
Asset Acquisition Acquired, Amount									$ 28.3
Iress Managed Funds Administration Business [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition	Oct. 01, 2023
Consideration paid, net of cash plus the costs of transaction	$ 32.5
Total revenues					$ 3.6
Innovest [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Amortized period								14 years
Innovest [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Amortized period								13 years
Captricity [Member] | Completed Technology [Member]
Business Acquisition [Line Items]
Amortized period								15 years
Blue Prism [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition				Mar. 16, 2022
Consideration paid, net of cash plus the costs of transaction				$ 1,600.0
Total revenues						201.2
Hubwise Holdings Limited [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition			Mar. 25, 2022
Consideration paid, net of cash plus the costs of transaction		$ 32.5	$ 75.0
Total revenues						4.1
Tier1 Customer Relationship Management Business [Member]
Business Acquisition [Line Items]
Business acquisition, effective date of acquisition		Aug. 23, 2022
Total revenues						4.7
Minerals Management, LLC [Member]
Business Acquisition [Line Items]
Asset Acquisition Acquired, Amount										$ 18.0
Complete Financial Ops Inc Cfo
Business Acquisition [Line Items]
Asset Acquisition Acquired, Amount						$ 5.7