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FAIR VALUE OF FINANCIAL INSTRUMENTS - Effect of Derivative Instruments on Condensed Statements of Operations (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]        
Realized Gain (Loss) on Derivatives Recognized in Income $ (129,946) $ (42,291) $ (180,182) $ (466,362)
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income     (497,248) 575,122
Commodity Contracts [Member] | Futures [Member] | Realized gain (loss) on closed futures contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Realized Gain (Loss) on Derivatives Recognized in Income     (180,182) (466,362)
Commodity Contracts [Member] | Futures [Member] | Change in unrealized gain (loss) on open positions        
Derivative Instruments, Gain (Loss) [Line Items]        
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income     $ (497,248) $ 575,122