FAIR VALUE OF FINANCIAL INSTRUMENTS - Fair Value of Derivative Instrument held by Usci, Cper, Usag and Usmi (Details) - Not designated as Hedging Instrument - Commodity Contracts - Futures - Assets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
United States Commodity Index Fund
FAIR VALUE OF FINANCIAL INSTRUMENTS
Derivatives not Accounted for as Hedging Instruments	$ 2,138,868	$ (14,487,984)
United States Copper Index Fund
FAIR VALUE OF FINANCIAL INSTRUMENTS
Derivatives not Accounted for as Hedging Instruments	$ 346,250	$ (903,475)