Trading Activities - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) Contracts	Jun. 30, 2016 USD ($) Contracts	Jun. 30, 2017 USD ($) Contracts	Jun. 30, 2016 USD ($) Contracts
Futures Contracts [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Average number of derivative contracts traded	4,688	5,781	4,689	7,038
Forward Contracts [Member] | Metals [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Average number of derivative contracts traded	506	1,168	557	1,209
Forward Contracts [Member] | Currencies [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Average notional value of derivative | $	$ 162,758,395	$ 118,755,428	$ 143,084,513	$ 115,451,266