Derivative and Hedging Financial Instruments - Summary of Realized and Unrealized Gains and Losses Related to Derivative Instrument (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Gain (Loss) on Investments [Abstract]
Realized gains (loss) on commodity derivative	$ 10,099,261	$ (189,506)	$ 12,129,437	$ (450,047)
Change in fair value of commodity derivative	(10,626,181)	(2,269,930)	(5,281,176)	(2,575,581)
Total realized and unrealized losses recorded	$ (526,920)	$ (2,459,436)	$ 6,848,261	$ (3,025,628)