Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 167.0	$ 119.9
Management fees
Disaggregation of Revenue [Line Items]
Management fee revenue	159.3	112.9
Management fees | Quant & Solutions | U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	118.8	85.9
Management fees | Quant & Solutions | Non-U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 40.5	$ 27.0