Subsequent Events (Textuals) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Apr. 11, 2012 Paradox Basin [Member]	Apr. 30, 2012 Pending Acquisition of Thompson Field [Member]
Subsequent Event [Line Items]
Anticipated proceeds from sale of oil and natural gas properties			$ 75,000,000
Effective Date Of Transaction	Dec. 01, 2011		Jan. 01, 2012
Proceeds from Sale of Oil and Gas Property and Equipment	166,703,000	11,989,000	72,400,000
Net revenue interest acquired in purchase of oil and natural gas properties				84.70%
Anticipated Payments To Acquire Oil And Gas Property				$ 360,000,000
Net revenue interest retained by seller				5.00%
Gross oil production threshold				3,000
Anticipated Close Date				The acquisition is expected to close in June 2012