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Significant Accounting Policies - Narrative (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Segment	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Business Organization And Significant Accounting Policies [Line Items]
Number of business segment | Segment			1
Accounts receivable, related parties	$ 9,900,000		$ 9,900,000		$ 9,400,000
Client performance period			5 years
Revenue	34,592,372	$ 37,471,647	$ 100,716,763	$ 111,181,363
Advance commissions amortization period			12 months
Variable Rate Fees
Business Organization And Significant Accounting Policies [Line Items]
Revenue	$ 900,000	$ 600,000	$ 900,000	$ 600,000

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