Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a 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	$ 34,278,313	$ 9,574,552
Liabilities	2,972,297	3,112,070
Net Fair Value	31,306,016	6,462,482
U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	27,950,479
Future Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	5,256,807	7,228,527
Liabilities	1,610,752	1,519,724
Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	1,071,027	2,346,025
Liabilities	1,361,545	1,592,346
(Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	6,085,364	8,928,263
Liabilities	2,650,444	2,961,635
Net Fair Value	3,434,920	5,966,628
(Level 1) [Member] | Future Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	5,256,807	7,228,527
Liabilities	1,610,752	1,519,724
(Level 1) [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	828,557	1,699,736
Liabilities	1,039,692	1,441,911
(Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	28,192,949	646,289
Liabilities	321,853	150,435
Net Fair Value	27,871,096	495,854
(Level 2) [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	27,950,479
(Level 2) [Member] | Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets	242,470	646,289
Liabilities	$ 321,853	$ 150,435