Derivative Instruments - Summary of Average Monthly Notional Value of Future Contracts Outstanding (Detail) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Weighted Average [Member] \| Currency Futures Contracts [Member]
Derivative [Line Items]
Average Notional Value	$ 365,530,668	$ 536,033,993	$ 386,624,196	$ 523,224,443

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.

No definition available.

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