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Significant Accounting Policies - Narrative (Detail) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 USD ($) | Sep. 30, 2020 USD ($) | Sep. 30, 2021 USD ($) Segment | Sep. 30, 2020 USD ($) | Dec. 31, 2020 USD ($)
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Number of business segment | Segment |  |  | 1 |  |
Accounts receivable, related parties | $ 11,200,000 |  | $ 11,200,000 |  | $ 10,500,000
Client performance period |  |  | 5 years |  |
Revenue | 55,054,554 | $ 31,175,755 | $ 139,138,640 | $ 91,350,429 |
Advance commissions amortization period |  |  | 12 months |  |
Variable Rate Fees |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Revenue | $ 1,400,000 | $ 700,000 | $ 3,500,000 | $ 1,900,000 |

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