Goodwill and Other Intangible Assets - Gross Cost and Accumulated Amortization of Other Intangible Assets (Detail) - USD ($) $ in Thousands |
Sep. 30, 2021 |
Dec. 31, 2020 |
---|---|---|
Finite-Lived Intangible Assets [Line Items] | ||
Other intangible assets, Gross Cost | $ 70,365 | $ 70,365 |
Other intangible assets, accumulated amortization | 70,200 | 70,155 |
Other intangible assets, Net Carrying Amount | 165 | 210 |
Success/Incentive Fees [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Other intangible assets, Gross Cost | 35,385 | 35,385 |
Other intangible assets, accumulated amortization | 35,385 | 35,385 |
Management Fees, Customer Relationships and Non-Compete Agreements [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Other intangible assets, Gross Cost | 34,980 | 34,980 |
Other intangible assets, accumulated amortization | 34,815 | 34,770 |
Other intangible assets, Net Carrying Amount | $ 165 | $ 210 |