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FINANCIAL HIGHLIGHTS (Tables) | 6 Months Ended
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Jun. 30, 2017
Financial Highlights [Abstract] |
Per Unit Performance Data and Other Supplemental Financial Data | The following table presents per share performance data and other supplemental financial data for the six months ended June 30, 2017 and 2016 for the shareholders. This information has been derived from information presented in the condensed financial statements.
|  | For the six months ended June 30, 2017 (Unaudited) |  |  | For the six months ended June 30, 2016 (Unaudited) |
Per Share Operating Performance: |  |  |  |  |  |  |  |
Net asset value, beginning of period |  | $ | 20.39 |  |  | $ | 17.00 |
Total income (loss) |  |  | (3.52) |  |  |  | 2.40 |
Total expenses |  |  | (0.08) |  |  |  | (0.06) |
Net increase (decrease) in net asset value |  |  | (3.60) |  |  |  | 2.34 |
Net asset value, end of period |  | $ | 16.79 |  |  | $ | 19.34 |
Total Return |  |  | (17.66) | % |  |  | 13.76 | %
Ratios to Average Net Assets |  |  |  |  |  |  |  |
Total income (loss) |  |  | (18.40) | % |  |  | 20.77 | %
Management fees* |  |  | 0.60 | % |  |  | 0.60 | %
Expenses excluding management fees* |  |  | 0.27 | % |  |  | 0.13 | %
Net income (loss) |  |  | (18.83) | % |  |  | 20.40 | %
* Annualized.

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