FINANCIAL HIGHLIGHTS (Per Unit Performance Data and Other Supplemental Financial Data) (Parenthetical) (Details)		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
United States Copper Index Fund [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Percentage of average daily net assets paid monthly, waiver expense	[1],[2],[3]	0.76%	0.24%
Percentage of Expenses Exceeded		0.15%
United States Copper Index Fund [Member] | Effective January 1, 2016 [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Percentage of average daily net assets paid monthly, waiver expense		0.65%
United States Commodity Index Fund [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Percentage of average daily net assets paid monthly, waiver expense	[1],[4]	0.00%	0.00%
United States Commodity Index Fund [Member] | Effective January 1, 2016 [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Percentage of average daily net assets paid monthly, waiver expense		0.80%

[1] Annualized

[2] Effective January 1, 2016, USCF permanently lowered the management fee to 0.65% (65 basis points) per annum of average daily total net assets for CPER.

[3] USCF paid certain expenses on a discretionary basis typically borne by CPER where expenses exceeded 0.15% (15 basis points) of CPER’s NAV, on an annualized basis. USCF has no obligation to continue such payments into subsequent periods.

[4] Effective January 1, 2016, USCF permanently lowered the management fee to 0.80% (80 basis points) per annum of average daily total net assets for USCI.