Additional Valuation Information - Summary of the Tiered Valuation Input Levels (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
United States Treasury Obligations	$ 123,646,647	$ 409,384,745
Exchange-Traded Fund	79,893,780	79,818,080
Money Market Mutual Fund	25,736,227	22,398,721
Total Investments in Securities	229,276,654	511,601,546
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	(1,815,323)	(4,534,517)
Total Investments	227,461,331	507,067,029
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Exchange-Traded Fund	79,893,780	79,818,080
Money Market Mutual Fund	25,736,227	22,398,721
Total Investments in Securities	105,630,007	102,216,801
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	(1,815,323)	(4,534,517)
Total Investments	103,814,684	97,682,284
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
United States Treasury Obligations	123,646,647	409,384,745
Total Investments in Securities	123,646,647	409,384,745
Total Investments	$ 123,646,647	$ 409,384,745