Trading Activities - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Average number of futures contracts traded	954	1,068	939	1,220
Average number of metals forward contracts traded	249	486	247	423
Average notional value of currency forward contracts	$ 243,218,252	$ 302,259,759	$ 238,229,528	$ 301,628,065