Contracts And Agreements (Additional Information) (Details) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Annual transfer agency services fee $ 20,000    
Brokerage commissions 394,735 314,411 307,461
Management fee paid to SummerHaven by USCF For USCI, the fee is equal to the percentage fees paid to USCF minus 0.14%, with that result multiplied by 0.5, minus 0.06% to arrive at the actual fee paid. For each of CPER, USAG and USMI, the fee is equal to the percentage fees paid to USCF minus 0.18%, with that result multiplied by 0.5, minus 0.6% to arrive at the actual fee paid.    
Management fee description USCI, CPER, USAG and USMI is contractually obligated to pay USCF a fee, which is paid monthly, equal to 0.95%per annum of average daily total net assets.    
Licensing Agreements [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Annual licensing fee 15,000    
Management fee description an annual fee of 0.06% of the average daily total net assets of each Trust Series.    
United States Commodity Index Fund [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 390,945 310,109 307,284
Brokerage commissions as a percentage of average daily net assets 0.95%    
United States Commodity Index Fund [Member] | Rebalancing Investments Transaction [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 376,294 296,759 286,584
Brokerage commissions as a percentage of average daily net assets 96.25% 95.70% 93.26%
United States Commodity Index Fund [Member] | Trades Necessitated By Creation And Redemption Activity [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 14,651 13,350 20,700
Brokerage commissions as a percentage of average daily net assets 3.75% 4.30% 6.74%
United States Commodity Index Fund [Member] | Futures Contracts and options on Futures Contracts [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions as a percentage of average daily net assets 0.08% 0.07% 0.08%
United States Copper Index Fund [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 916 [1] 956 [1] 177 [1]
Brokerage commissions as a percentage of average daily net assets 0.65%    
United States Copper Index Fund [Member] | Rebalancing Investments Transaction [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 916 799 45
Brokerage commissions as a percentage of average daily net assets 100.00% 83.58% 25.42%
United States Copper Index Fund [Member] | Trades Necessitated By Creation And Redemption Activity [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions   157 132
Brokerage commissions as a percentage of average daily net assets   16.42% 74.58%
United States Copper Index Fund [Member] | Futures Contracts and options on Futures Contracts [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions as a percentage of average daily net assets 0.04% 0.04% 0.06%
United States Agriculture Index Fund [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 2,003 [2] 2,632 [2] 0 [2]
Brokerage commissions as a percentage of average daily net assets 0.80%    
United States Agriculture Index Fund [Member] | Rebalancing Investments Transaction [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 2,003 2,090  
Brokerage commissions as a percentage of average daily net assets 100.00% 79.41%  
United States Agriculture Index Fund [Member] | Trades Necessitated By Creation And Redemption Activity [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions   542  
Brokerage commissions as a percentage of average daily net assets   20.59%  
United States Agriculture Index Fund [Member] | Futures Contracts and options on Futures Contracts [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions as a percentage of average daily net assets 0.08% 0.12%  
United States Metals Index Fund [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 871 [3] 714 [3] 0 [3]
Brokerage commissions as a percentage of average daily net assets 0.70%    
United States Metals Index Fund [Member] | Rebalancing Investments Transaction [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 774 512  
Brokerage commissions as a percentage of average daily net assets 88.91% 71.71%  
United States Metals Index Fund [Member] | Trades Necessitated By Creation And Redemption Activity [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions 97 202  
Brokerage commissions as a percentage of average daily net assets 11.09% 28.29%  
United States Metals Index Fund [Member] | Futures Contracts and options on Futures Contracts [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Brokerage commissions as a percentage of average daily net assets 0.03% 0.05%  
Maximum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Transaction fees per transaction 15    
Commissions per round-turn trade, including applicable exchange and NFA fees for Futures Contracts and options on Futures Contracts 15    
Minimum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
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    
For the first $500 million [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Fee percentage 0.06%    
For the first $500 million [Member] | Maximum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage 500,000,000    
Combined net assets greater than $500 million but less than $1 billion [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Fee percentage 0.0465%    
Combined net assets greater than $500 million but less than $1 billion [Member] | Maximum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage 1,000,000,000    
Combined net assets greater than $500 million but less than $1 billion [Member] | Minimum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage 500,000,000    
Combined net assets exceed $1 billion [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Fee percentage 0.035%    
Combined net assets exceed $1 billion [Member] | Minimum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage 1,000,000,000    
Marketing Agreement [Member] | On each Trust Series' assets up to 3 billion [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Fee percentage 0.06%    
Marketing Agreement [Member] | On each Trust Series' assets up to 3 billion [Member] | Maximum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage 3,000,000,000    
Marketing Agreement [Member] | On each Trust Series' assets in excess of $3 billion [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Fee percentage 0.04%    
Marketing Agreement [Member] | On each Trust Series' assets in excess of $3 billion [Member] | Minimum [Member]
     
Long-Duration Contracts, Assumptions by Product and Guarantee [Line Items]      
Base amount for determining fee percentage $ 3,000,000,000    
[1] The commencement of operations of the United States Copper Index Fund was November 15, 2011.
[2] The commencement of operations of the United States Agriculture Index Fund was April 13, 2012.
[3] The commencement of operations of the United States Metals Index Fund was June 19, 2012.