Derivative Instruments - Effect of Derivative Instruments on Statements of Income and Expenses (Detail) - USD ($)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, net realized gain (loss)	$ (3,245,313)	$ (5,102,144)
Futures contracts, net unrealized gain (loss)	(17,088,357)	21,462,988
Commodity Futures Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, net realized gain (loss)	(3,245,313)	(5,102,144)
Futures contracts, net unrealized gain (loss)	(17,088,357)	21,462,988
Future contracts, net realized and unrealized gain (loss)	$ (20,333,670)	$ 16,360,844

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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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-Publisher FASB
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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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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