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FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Derivative Instruments (Details) - USD ($)
Sep. 30, 2019
Dec. 31, 2018
Commodity Contracts [Member] | Futures - Commodity Contracts [Member] | Assets [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Derivatives not Accounted for as Hedging Instruments $ (36,647,195) $ (67,021,257)