Investment Portfolio - Summary of Market Value of Investments (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Investment Holdings [Line Items]
Company sponsored equity method investments	$ 44,663,232	$ 16,339,649
Total Investments	150,772,310	203,488,217
Securities held in Consolidated Funds
Investment Holdings [Line Items]
Fair value investments	83,249,245	153,730,480
Securities held in Consolidated Funds \| Parent
Investment Holdings [Line Items]
Fair value investments	50,500,000	84,700,000
Securities held in Consolidated Funds \| Redeemable Noncontrolling Interest
Investment Holdings [Line Items]
Fair value investments	32,800,000	69,000,000.0
Company sponsored investments
Investment Holdings [Line Items]
Fair value investments	$ 22,859,833	$ 33,418,088

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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