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, realized gain (loss)	$ 13,631,863	$ 2,697,238
Futures Contracts, Net Unrealized Gain (Loss)	(17,421,150)	(3,639,773)
Commodity Futures Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments Gain Loss [Line Items]
Futures contracts, realized gain (loss)	13,631,863	2,697,238
Futures Contracts, Net Unrealized Gain (Loss)	(17,421,150)	(3,639,773)
Future Contracts, Net Realized and Unrealized Gain (Loss)	$ (3,789,287)	$ (942,535)