Fair Value Measurements - Assets and liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	$ 16,363,725	$ 2,409,346
Liabilities	1,050,898	1,116,103
Net fair value	15,312,827	1,293,243
U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	14,970,257
Future Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	408,200	873,317
Liabilities	145,676	134,615
Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	985,268	1,536,029
Liabilities	905,222	981,488
(Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	599,414	984,846
Liabilities	280,635	210,272
Net fair value	318,779	774,574
(Level 1) [Member] | Future Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	408,200	873,317
Liabilities	145,676	134,615
(Level 1) [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	191,214	111,529
Liabilities	134,959	75,657
(Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	15,764,311	1,424,500
Liabilities	770,263	905,831
Net fair value	14,994,048	518,669
(Level 2) [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	14,970,257
(Level 2) [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	794,054	1,424,500
Liabilities	$ 770,263	$ 905,831