CONTRACTS AND AGREEMENTS - Additional Information (Details) - USD ($)		4 Months Ended	12 Months Ended
	May 01, 2018	Apr. 30, 2018	Dec. 31, 2019
Contracts and Agreements
Annual transfer agency services fee			$ 20,000
SummerHaven Agreements | United States Commodity Index Fund
Contracts and Agreements
Fee percentage	0.06%
Percentage of fee paid less than base fee		0.14%
Multiplier to calculate base fee		0.5
Percentage multiplied to get the calculate fee to be paid		0.06%
Annual licensing fee	$ 15,000
SummerHaven Agreements | United States Commodity Index Fund | Licensing Agreements
Contracts and Agreements
Annual licensing fee			15,000
SummerHaven Agreements | United States Copper Index Fund
Contracts and Agreements
Percentage of fee paid less than base fee		0.18%
Multiplier to calculate base fee		0.5
Percentage multiplied to get the calculate fee to be paid		0.60%
Maximum
Contracts and Agreements
Transaction fees per transaction			15
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts			$ 8
Maximum | Marketing Agreement
Contracts and Agreements
Fee percentage			10.00%
Minimum
Contracts and Agreements
Base amount for determining fee percentage			$ 75,000
Transaction fees per transaction			7
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts			$ 7
Minimum | Marketing Agreement
Contracts and Agreements
Fee percentage			0.04%
For the first $500 million
Contracts and Agreements
Fee percentage			0.06%
For the first $500 million | SummerHaven Agreements | United States Commodity Index Fund
Contracts and Agreements
Fee percentage			0.06%
For the first $500 million | Maximum
Contracts and Agreements
Base amount for determining fee percentage			$ 500,000,000
Combined net assets greater than $500 million but less than $1 billion
Contracts and Agreements
Fee percentage			0.0465%
Combined net assets greater than $500 million but less than $1 billion | Maximum
Contracts and Agreements
Base amount for determining fee percentage			$ 1,000,000,000
Combined net assets greater than $500 million but less than $1 billion | Minimum
Contracts and Agreements
Base amount for determining fee percentage			$ 500,000,000
Combined net assets exceed $1 billion
Contracts and Agreements
Fee percentage			0.035%
Combined net assets exceed $1 billion | Minimum
Contracts and Agreements
Base amount for determining fee percentage			$ 1,000,000,000
On each Trust Series' assets up to 3 billion | Marketing Agreement
Contracts and Agreements
Fee percentage			0.06%
On each Trust Series' assets up to 3 billion | Maximum | Marketing Agreement
Contracts and Agreements
Base amount for determining fee percentage			$ 3,000,000,000
On each Trust Series' assets in excess of $3 billion | Maximum | Marketing Agreement
Contracts and Agreements
Base amount for determining fee percentage			$ 3,000,000,000