Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 144.2	$ 123.1	$ 391.5	$ 337.8
Management fees
Disaggregation of Revenue [Line Items]
Management fee revenue	136.1	112.1	371.3	319.8
Management fees | Quant & Solutions | U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	101.7	85.6	280.5	242.4
Management fees | Quant & Solutions | Non-U.S.
Disaggregation of Revenue [Line Items]
Management fee revenue	$ 34.4	$ 26.5	$ 90.8	$ 77.4