Investments - Principal Investments in CLOs and Other Investments (Details) - USD ($) $ in Millions |
Mar. 31, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Fair value of assets | $ 14,844.4 | |
| Level III | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Fair value of assets | 12,247.3 | $ 11,479.4 |
| Level III | Other | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Fair value of assets | 34.1 | |
| CLO Senior and Subordinated Notes and Derivative Instruments | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Trading securities | $ 309.9 | 349.0 |
| BDC preferred shares | Level III | Other | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Investments | $ 37.5 |
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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