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Fair Value of Financial Instruments (Fair Value of Derivative Instruments) (Details) (Commodity Contracts, Futures, Assets, USD $)
Dec. 31, 2013
Dec. 31, 2012
Commodity Contracts | Futures | Assets
   
Derivatives, Fair Value [Line Items]    
Derivatives not Accounted for as Hedging Instruments $ 1,642,450 $ 1,556,910