Fair Value Measurements - Summary of Assets and Liabilities Measured at Fair Value (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Assets
Total assets	$ 851,529	$ 761,773
Liabilities
Total liabilities	757,896	545,665
Futures Contracts [Member]
Assets
Total assets	851,529	710,148
Liabilities
Total liabilities	757,896	522,665
Options Contracts [Member] | Long [Member]
Assets
Total assets		51,625
Options Contracts [Member] | Short [Member]
Liabilities
Total liabilities		23,000
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Assets
Total assets	851,529	761,773
Liabilities
Total liabilities	757,896	545,665
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Futures Contracts [Member]
Assets
Total assets	851,529	710,148
Liabilities
Total liabilities	$ 757,896	522,665
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Options Contracts [Member] | Long [Member]
Assets
Total assets		51,625
Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Options Contracts [Member] | Short [Member]
Liabilities
Total liabilities		$ 23,000