Segment Reporting - Supplemental Information Related to Significant Segment Expenses (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
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| Personnel Compensation and Benefits Expense [Abstract] | ||||||||
| Salaries, payroll related taxes and employee benefits | $ 39,267 | $ 41,407 | $ 77,942 | $ 63,152 | ||||
| Incentive compensation | 55,692 | 38,116 | 99,382 | 61,783 | ||||
| Sales-based compensation | [1] | 10,071 | 10,612 | 21,798 | 17,832 | |||
| Equity awards granted to employees and directors | [2] | 15,776 | 5,658 | 23,188 | 9,162 | |||
| Acquisition and transaction-related compensation | 4,694 | 13,125 | 9,045 | 13,125 | ||||
| Total personnel compensation and benefits expense | 125,500 | 108,918 | 231,355 | 165,054 | ||||
| Distribution and Other Asset-Based Expenses [Abstract] | ||||||||
| Broker-dealer distribution fees | 22,862 | 20,833 | 45,120 | 25,633 | ||||
| Platform distribution fees | 34,552 | 31,444 | 69,094 | 53,055 | ||||
| Sub-administration | 5,855 | 5,274 | 11,527 | 9,664 | ||||
| Sub-advisory | 2,187 | 1,678 | 4,196 | 3,550 | ||||
| Middle-office | 3,134 | 2,810 | 6,063 | 5,614 | ||||
| Total distribution and other asset-based expenses | $ 68,590 | $ 62,039 | $ 136,000 | $ 97,516 | ||||
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