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Fair Value Of Financial Instruments (Details 2) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Derivatives not Accounted for as Hedging Instruments Futures - Commodity Contracts    
Location of Gain or (Loss) on Derivatives Recognized in Income Change in unrealized gain (loss) on open positions    
Realized Gain or (Loss) on Derivatives Recognized in Income $ (19,750,710)us-gaap_DerivativeGainLossOnDerivativeNet $ 3,338,310us-gaap_DerivativeGainLossOnDerivativeNet $ 3,239,910us-gaap_DerivativeGainLossOnDerivativeNet
Change in Unrealized Gain or (Loss) on Derivatives Recognized in Income $ (6,375,760)us-gaap_UnrealizedGainLossOnDerivatives $ (710,660)us-gaap_UnrealizedGainLossOnDerivatives $ 1,655,900us-gaap_UnrealizedGainLossOnDerivatives
Commodity Contract [Member]      
Location of Gain or (Loss) on Derivatives Recognized in Income Realized gain (loss) on closed positions