Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 563.7	$ 505.6	$ 426.6
Management fees
Disaggregation of Revenue [Line Items]
Management fee revenue	517.7	431.1	373.2
Management fees | Quant & Solutions | U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	389.3	327.5	281.9
Management fees | Quant & Solutions | Non-U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 128.4	$ 103.6	$ 91.3