Income Taxes (Details Textual) (USD $)	3 Months Ended				6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2011	Jun. 30, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Texas [Member]	Dec. 31, 2011 Texas [Member]	Dec. 31, 2010 Texas [Member]	Dec. 31, 2009 Texas [Member]	Dec. 31, 2012 New Mexico [Member]	Dec. 31, 2011 New Mexico [Member]	Dec. 31, 2010 New Mexico [Member]	Dec. 31, 2009 New Mexico [Member]	Dec. 31, 2012 Louisiana [Member]	Dec. 31, 2011 Louisiana [Member]	Dec. 31, 2010 Louisiana [Member]	Dec. 31, 2009 Louisiana [Member]	Dec. 31, 2012 Internal Revenue Service (IRS) [Member]	Dec. 31, 2011 Internal Revenue Service (IRS) [Member]	Dec. 31, 2010 Internal Revenue Service (IRS) [Member]	Dec. 31, 2009 Internal Revenue Service (IRS) [Member]	Dec. 31, 2012 State and Local Jurisdiction [Member]	Dec. 31, 2012 State and Local Jurisdiction [Member] New Mexico [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards																						$ 123,300,000				$ 30,300,000
Operating loss carryforwards, expiration dates																						December 31, 2027				beginning in 2027	various dates beginning December 31, 2013
Open tax year										2012	2011	2010	2009	2012	2011	2010	2009	2012	2011	2010	2009	2012	2011	2010	2009
Income Taxes (Textual) [Abstract]
Net capitalized costs less related deferred income taxes exceeded the full-cost ceiling	17,300,000	2,300,000	21,300,000	23,000,000	21,300,000	2,300,000	17,300,000
Impairment charge of net capitalized costs				35,700,000	33,200,000	3,600,000	63,475,000	35,673,000	0
Deferred income tax credit				12,700,000	11,900,000	1,300,000	3,618,000,000	(24,375,000)	(9,156,000)
Increase in valuation allowance							7,900,000
Valuation allowance against net deferred tax assets	$ 10,300,000	$ 2,400,000				$ 2,400,000	$ 10,300,000