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CONTRACTS AND AGREEMENTS (Brokerage Commission) (Detail) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Brokerage commissions | $ 4,675,687 | $ 6,875,314 | $ 5,196,820
Commission [Member] |  |  |
Brokerage commissions | $ 4,675,687 | $ 6,875,314 | $ 5,196,820
Percentage of average daily net assets | 0.18% | 0.20% | 0.20%
Rebalancing Investments Transaction [Member] |  |  |
Brokerage commissions | $ 4,112,340 | $ 6,297,055 | $ 4,288,005
Percentage of average daily net assets | 87.95% | 91.59% | 82.51%
Creation And Redemption Activity [Member] |  |  |
Brokerage commissions | $ 563,347 | $ 578,259 | $ 908,815
Percentage of average daily net assets | 12.05% | 8.41% | 17.49%

X
- Definition The amount of expense during the period for floor brokerage fees paid to other broker-dealers to execute trades on their behalf, stock exchange fees, order flow fees, and clearance fees. + References No definition available. + Details
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- Details
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- Details
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