Unproved Oil Gas and Mineral Properties - Additional Information (Detail) (USD $)	1 Months Ended	716 Months Ended	9 Months Ended
	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2012 MONTANA Transactions acre	Jul. 31, 2005 NORTH DAKOTA acre
Costs Incurred, Oil and Gas Property Acquisition, Exploration, and Development Activities [Line Items]
Write off of unproved properties	$ 2,832,519	$ 9,523,271	$ 2,832,519
Gas and oil lease area, undeveloped, net			32,313	21,688
Number of acquisitions between July 2005 and February 2006			3