XML 44 R31.htm IDEA: XBRL DOCUMENT v3.19.1
Derivative Instruments - Summary of Gross and Net Amounts of Offsetting Assets and Liabilities (Detail) - Morgan Stanley & Co. LLC [Member] - Commodity Futures Contract [Member] - USD ($)
Mar. 31, 2019
Dec. 31, 2018
Offsetting Assets And Liabilities [Line Items]    
Financial Derivative Assets, Futures Contracts $ 75,635,123 $ 222,631,350
Financial Derivative Liabilities, Futures Contracts (68,565,244) (253,228,835)
Net value of derivatives 7,069,879 (30,597,485)
Collateral (Received)/Pledged, Non-Cash   $ 30,597,485
Net amount $ 7,069,879