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ORGANIZATION AND BUSINESS (Additional Information) (Details)
Dec. 06, 2007
USD ($)
$ / shares
shares
Sep. 30, 2017
Contracts
$ / shares
$ / Units
Dec. 31, 2016
$ / shares
Sep. 30, 2016
$ / shares
Dec. 31, 2015
$ / shares
Dec. 04, 2007
Contracts
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]            
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets | $ / Units   350        
Net asset value per share | $ / shares $ 50.00 $ 18.31 $ 20.39 $ 18.75 $ 17.00  
Number of shares issued | shares 300,000          
Value of shares issued | $ $ 15,000,000          
Number of registered shares | Contracts   111,000,000       11,000,000
Creation Baskets            
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]            
Number of shares per basket | $ / Units   50,000        
Open Futures Contracts, Long | United States            
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]            
Number of Contracts | Contracts [1]   2,061        
[1] Collateral amounted to $19,614,897 on open futures contracts.