Additional Valuation Information - Summary of the Tiered Valuation Input Levels (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
United States Treasury Obligations	$ 119,981,596	$ 123,646,647
Exchange-Traded Fund	80,037,610	79,893,780
Money Market Mutual Fund	540,851,203	25,736,227
Total Investments in Securities	740,870,409	229,276,654
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	1,174,619	(1,815,323)
Total Investments	742,045,028	227,461,331
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Exchange-Traded Fund	80,037,610	79,893,780
Money Market Mutual Fund	540,851,203	25,736,227
Total Investments in Securities	620,888,813	105,630,007
Commodity Futures Contracts, Unrealized Appreciation (Depreciation)	1,174,619	(1,815,323)
Total Investments	622,063,432	103,814,684
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
United States Treasury Obligations	119,981,596	123,646,647
Total Investments in Securities	119,981,596	123,646,647
Total Investments	$ 119,981,596	$ 123,646,647