Derivative Instruments - Effect of Derivative Instruments on Statements of Income and Expenses (Detail) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments Gain Loss [Line Items]
Futures contracts, realized gain (loss)	$ 10,751,584	$ (605,640)	$ 27,223,337	$ 13,026,223
Futures Contracts, Net Unrealized Gain (Loss)	(6,547,240)	23,056,627	(35,692,566)	5,635,477
Commodity Futures Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments Gain Loss [Line Items]
Futures contracts, realized gain (loss)	10,751,584	(605,640)	27,223,337	13,026,223
Futures Contracts, Net Unrealized Gain (Loss)	(6,547,240)	23,056,627	(35,692,566)	5,635,477
Future Contracts, Net Realized and Unrealized Gain (Loss)	$ 4,204,344	$ 22,450,987	$ (8,469,229)	$ 18,661,700

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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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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