Fair Value Measurements - Schedule of the Summary of the Master Fund's Assets and Liabilities at Fair Value, Classified According to the Levels Used to Value Them (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Derivatives	$ 121,993,327	$ 136,007,920
U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	115,831,172	143,568,752
Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	6,162,155
Liability Derivatives	6,162,155	(7,560,832)
Quoted Prices in Active Market (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Derivatives	6,162,155	(7,560,832)
Quoted Prices in Active Market (Level 1) [Member] | Futures [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability Derivatives	6,162,155	(7,560,832)
Other Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Derivatives	115,831,172	143,568,752
Other Significant Observable Inputs (Level 2) [Member] | U.S. Treasuries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	$ 115,831,172	$ 143,568,752