XML 50 R34.htm IDEA: XBRL DOCUMENT v3.10.0.1
FAIR VALUE OF FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Detail) - USD ($)
Dec. 31, 2018
Dec. 31, 2017
Commodity Contracts [Member] | Assets [Member] | Future [Member]    
Derivatives Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments $ (194,392,958) $ 117,780,350