Derivative Instruments - Effect of Derivative Instruments on Statements of Income and Expenses (Detail) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, realized gain (loss)	$ (108,439,638)	$ 43,624,801	$ 58,338,714
Futures contracts, unrealized gain (loss)	291,494,569	(359,469,489)	14,636,898
Commodity Futures Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, realized gain (loss)	(108,439,638)	43,624,801	58,338,714
Futures contracts, unrealized gain (loss)	291,494,569	(359,469,489)	14,636,898
Net Realized and Net Change in Unrealized Gain (Loss)	$ 183,054,931	$ (315,844,688)	$ 72,975,612

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Amount of realized and unrealized gain (loss) on investment.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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The difference between the book value and the sale price of agreements to purchase or sell mineral resources, energy, and agricultural products at some future point. This element refers to the gain (loss) included in earnings and not to the cash proceeds.

+ References

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of open agreements to purchase or sell mineral resources, energy, and agricultural products at some future point held at each balance sheet date, that was included in earnings for the period.

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