Derivative Instruments - Effect of Derivative Instruments on Statements of Income and Expenses (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, Net realized gain (loss)	$ 571,129	$ (1,220,796)
Futures contracts, Net change in unrealized gain (loss)	54,494	(286,781)
Currency Futures Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Futures contracts, Net realized gain (loss)	571,129	(1,220,796)
Futures contracts, Net change in unrealized gain (loss)	54,494	(286,781)
Futures Contracts, Net Realized and Net Change in Unrealized Gain (Loss)	$ 625,623	$ (1,507,577)