Investment Portfolio - Summary of Market Value of Investments (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Investment Holdings [Line Items]
Seed capital equity method investments	$ 36,457,449	$ 11,284,109
Deferred compensation plan assets	14,182,470	7,961,412
Total Investment Portfolio	108,015,635	52,490,820
Securities held in Consolidated Funds
Investment Holdings [Line Items]
Trading Investments	57,355,471	0
Securities held in Consolidated Funds \| Total
Investment Holdings [Line Items]
Trading Investments	42,600,000
Securities held in Consolidated Funds \| Redeemable Noncontrolling Interest
Investment Holdings [Line Items]
Trading Investments	14,700,000
Company Sponsored Investments
Investment Holdings [Line Items]
Trading Investments	$ 20,245	$ 33,245,299

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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-Publisher FASB
-Name Accounting Standards Codification
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+ References

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