Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Average charges paid to broker per round-turn trade, maximum	$ 6.00	$ 6.00	$ 6.00	$ 6.00