Investments - Schedule of Investments (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Investment Holdings [Line Items]
Total investments per Condensed Consolidated Balance Sheets	$ 222.5	$ 221.9
Consolidated Funds
Investment Holdings [Line Items]
Investments	181.7	154.0
Total investments per Condensed Consolidated Balance Sheets	181.7	154.0
Consolidated Entity Excluding Consolidated Funds
Investment Holdings [Line Items]
Total investments per Condensed Consolidated Balance Sheets	40.8	67.9
Consolidated Entity Excluding Consolidated Funds | Other investments
Investment Holdings [Line Items]
Investments	3.4	19.4
Consolidated Entity Excluding Consolidated Funds | Investments related to long-term incentive compensation plans
Investment Holdings [Line Items]
Investments	$ 37.4	$ 48.5