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Investments - Summary of Market Value of Investments (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Investment Holdings [Line Items]
Company sponsored equity method investments	$ 16,339,649	$ 36,043,704
Total Investments	203,488,217	138,476,022
Securities held in Consolidated Funds
Investment Holdings [Line Items]
Fair value investments	153,730,480	65,890,500
Company sponsored investments
Investment Holdings [Line Items]
Fair value investments	$ 33,418,088	$ 36,541,818

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