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ORGANIZATION AND BUSINESS - Additional Information (Detail) (USD $) | 1 Months Ended |  |  |  |  |  |  |  |  |  |
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Nov. 30, 2009 | Nov. 18, 2009 | Dec. 31, 2012 | Dec. 31, 2011 | Sep. 30, 2011 | Dec. 31, 2010 | Dec. 31, 2009 | Feb. 29, 2012 Creation Baskets | Dec. 31, 2012 Open Futures Contracts, Long United States | Dec. 31, 2011 Open Futures Contracts, Long United States | Dec. 31, 2012 Partnership Unit [Member] | Feb. 29, 2012 Prior to February 29, 2012 Creation Baskets
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of Contracts |  |  |  |  |  |  |  |  | 1,197 | 642 |  |
Number of units per basket |  |  |  |  |  |  |  | 50,000 |  |  |  | 100,000
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets |  |  | 350 |  | 1,000 |  |  |  |  |  | 1,000 |
Number of initially registered units on Form S-1 with the U.S. Securities and Exchange Commission | 30,000,000 |  |  |  |  |  |  |  |  |  |  |
Net asset value per unit |  | $ 50.00 | $ 17.23 | $ 21.21 |  | $ 35.02 | $ 53.77 |  |  |  |  |
Number of units issued |  | 200,000 |  |  |  |  |  |  |  |  |  |
Value of unit issued |  | $ 10,001,000 |  |  |  |  |  |  |  |  |  |
Commenced investment operations date |  | Nov. 18, 2009 |  |  |  |  |  |  |  |  |  |
Number of registered units |  |  | 30,000,000 |  |  |  |  |  |  |  |  |

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