Fair Value Measurements - Derivative Instruments Priced at Fair Value Using Unobservable Inputs (Detail) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Assets
Total assets	$ 18,455,361	$ 60,493,287
Liabilities
Total liabilities	2,004,367	3,556,814
Forward Contracts [Member]
Assets
Total assets	1,053,943	1,168,919
Liabilities
Total liabilities	731,337	1,125,088
U.S. Treasury Bills [Member]
Assets
Total assets	14,997,047	55,493,206
Futures Contracts [Member]
Assets
Total assets	2,404,371	3,831,162
Liabilities
Total liabilities	1,273,030	2,431,726
Level 1 [Member]
Assets
Total assets	2,918,736	4,572,104
Liabilities
Total liabilities	1,859,120	3,386,514
Level 1 [Member] | Forward Contracts [Member]
Assets
Total assets	514,365	740,942
Liabilities
Total liabilities	586,090	954,788
Level 1 [Member] | Futures Contracts [Member]
Assets
Total assets	2,404,371	3,831,162
Liabilities
Total liabilities	1,273,030	2,431,726
Level 2 [Member]
Assets
Total assets	15,536,625	55,921,183
Liabilities
Total liabilities	145,247	170,300
Level 2 [Member] | Forward Contracts [Member]
Assets
Total assets	539,578	427,977
Liabilities
Total liabilities	145,247	170,300
Level 2 [Member] | U.S. Treasury Bills [Member]
Assets
Total assets	$ 14,997,047	$ 55,493,206