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Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($)
Jun. 30, 2020
Dec. 31, 2019
Investments in Securities, cost $ 101,267,073 $ 113,645,878
US Treasury Bill Securities [Member]    
Investments in Securities, cost 39,995,308 55,776,919
Affiliated Investments [Member]    
Affiliated Investments, at Cost $ 61,271,765 $ 57,868,959