FEES PAID BY EACH TRUST SERIES AND RELATED PARTY TRANSACTIONS - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fees Paid and Related Party Transactions
Trustee annual fee	$ 3,000
Noninterest Expense Directors Fees	110,755	$ 94,778	$ 72,525
Expense waiver	67,628	77,884	$ 85,686
Directors and Officers Liability Insurance
Fees Paid and Related Party Transactions
Noninterest Expense Directors Fees	$ 556,951	521,689
United States Commodity Index Fund
Fees Paid and Related Party Transactions
Percentage of average daily net assets paid	0.95%
Noninterest Expense Directors Fees	$ 108,435	91,761
Estimated investor tax reporting cost	$ 476,864
United States Commodity Index Fund | Effective January 1, 2016
Fees Paid and Related Party Transactions
Percentage of average daily net assets paid	0.80%
United States Copper Index Fund
Fees Paid and Related Party Transactions
Noninterest Expense Directors Fees	$ 2,320	2,100
Estimated investor tax reporting cost	$ 75,053
Costs and expenses annual limit for reimbursement	0.15%
Expense waiver	$ 67,628
United States Agriculture Index Fund
Fees Paid and Related Party Transactions
Noninterest Expense Directors Fees		$ 917
United States Agriculture Index Fund | Effective January 1, 2016
Fees Paid and Related Party Transactions
Percentage of average daily net assets paid	0.65%