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Investment Securities - Investments, Debt and Equity Securities (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Seed Investments |  |
Marketable Securities [Line Items] |  |
Seed investments in equity securities | $ 70,078 | $ 66,349
Seed investments in equity securities accounted for under the equity method | 2,119 | 7,964
Long-Term Cash Awards |  |
Marketable Securities [Line Items] |  |
Seed investments in equity securities | 167,055 | 127,430
Seed investments in equity securities accounted for under the equity method | 18,157 | 7,049
Consolidated Entity, Excluding VIE |  |
Marketable Securities [Line Items] |  |
Total investment securities | $ 257,409 | $ 208,792

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