Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 505.6	$ 426.6	$ 417.2
Quant & Solutions
Disaggregation of Revenue [Line Items]
Total revenue	505.6	426.6	417.2
Management fees
Disaggregation of Revenue [Line Items]
Total revenue	431.1	373.2	367.4
Management fees | Quant & Solutions | U.S.
Disaggregation of Revenue [Line Items]
Total revenue	327.5	281.9	279.1
Management fees | Quant & Solutions | Non-U.S.
Disaggregation of Revenue [Line Items]
Total revenue	$ 103.6	$ 91.3	$ 88.3