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FAIR VALUE OF FINANCIAL INSTRUMENTS - Effect of Derivative Instruments on Condensed Statements of Operations (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]        
Realized Gain (Loss) on Derivatives Recognized in Income $ (41,649) $ (57,654) $ (50,236) $ (424,071)
Change in Unrealized Gain (Loss) on Derivatives Recognized in Income     (493,923) 583,201
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     (50,236) (424,071)
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     $ (493,923) $ 583,201