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Goodwill and Acquired Client Relationships - Additional Information (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Intangible Assets |  |  |  |  |
Goodwill impairment |  |  |  | $ 0 |
Acquired Client Relationships |  |  |  |  |
Intangible Assets |  |  |  |  |
Amortization and impairment expenses of intangible assets |  |  |  | 62,700,000 |
Estimated Future Amortization Expense of Finite-Lived Intangibles |  |  |  |  |
Finite-lived intangible, future amortization expense in 2020 | $ 10,000,000 |  |  | 10,000,000 |
Finite-lived intangible, future amortization expense in 2021 | 30,000,000 |  |  | 30,000,000 |
Finite-lived intangible, future amortization expense in 2022 | 30,000,000 |  |  | 30,000,000 |
Finite-lived intangible, future amortization expense in 2023 | 30,000,000 |  |  | 30,000,000 |
Finite-lived intangible, future amortization expense in 2024 | 20,000,000 |  |  | 20,000,000 |
Finite-lived intangible, future amortization expense in 2025 | 10,000,000 |  |  | 10,000,000 |
Intangible impairments | $ 14,000,000.0 | $ 60,300,000 |  | 70,700,000 |
Average projected growth rate | (14.00%) |  |  |  |
Discount rate for assets based fees | 15.00% |  |  |  |
Market participant tax rate | 25.00% |  |  |  |
Acquired Client Relationships | Closure of Certain Retail Investment Products |  |  |  |  |
Estimated Future Amortization Expense of Finite-Lived Intangibles |  |  |  |  |
Intangible impairments | $ 10,900,000 |  |  |  |
Acquired Client Relationships | Intangible amortization and impairments |  |  |  |  |
Intangible Assets |  |  |  |  |
Amortization and impairment expenses of intangible assets | 7,000,000.0 |  | $ 21,100,000 | $ 48,200,000 | $ 72,000,000.0
Controlling Interest | Acquired Client Relationships |  |  |  |  |
Estimated Future Amortization Expense of Finite-Lived Intangibles |  |  |  |  |
Intangible impairments | 12,500,000 | $ 32,800,000 |  |  |
Controlling Interest | Acquired Client Relationships | Closure of Certain Retail Investment Products |  |  |  |  |
Estimated Future Amortization Expense of Finite-Lived Intangibles |  |  |  |  |
Intangible impairments | $ 7,400,000 |  |  |  |

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