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Asset Retirement Obligations (Details) (USD $)
3 Months Ended
Mar. 31, 2012
Asset Retirement Obligations [Abstract]  
Balance at December 31, 2011 $ 13,075,000
Liabilities incurred during period 1,698,000
Liabilities settled during period   
Accretion expense during period 185,000 [1]
Revisions to estimates 984,000
Balance at March 31, 2012 15,942,000
Total asset retirement obligations, current portion $ 300,000
[1] Included in Depreciation, depletion and amortization on the Company's Condensed Consolidated Statement of Operations.