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Investments - Textual (Details) - Securities held in Consolidated Funds - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Trading Investments	$ 153,730,480	$ 65,890,500
Parent
Debt and Equity Securities, FV-NI [Line Items]
Trading Investments	84,700,000	42,600,000
Redeemable Noncontrolling Interest
Debt and Equity Securities, FV-NI [Line Items]
Trading Investments	$ 69,000,000	$ 23,300,000

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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