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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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