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Asset Retirement Obligations (Schedule Of Asset Retirement Obligations) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Asset Retirement Obligation Disclosure [Abstract]    
ARO liability, January 1: $ 100,567us-gaap_AssetRetirementObligation $ 133,657us-gaap_AssetRetirementObligation
Accretion of discount 932us-gaap_AssetRetirementObligationAccretionExpense 1,215us-gaap_AssetRetirementObligationAccretionExpense
Liability incurred 5,174us-gaap_AssetRetirementObligationLiabilitiesIncurred 635us-gaap_AssetRetirementObligationLiabilitiesIncurred
Liability settled (760)us-gaap_AssetRetirementObligationLiabilitiesSettled (548)us-gaap_AssetRetirementObligationLiabilitiesSettled
Liability sold (240)unt_AssetRetirementObligationLiabilitiesSold (459)unt_AssetRetirementObligationLiabilitiesSold
Revision of estimates (10,232)us-gaap_AssetRetirementObligationRevisionOfEstimate [1] (14,600)us-gaap_AssetRetirementObligationRevisionOfEstimate [1]
ARO liability, March 31: 95,441us-gaap_AssetRetirementObligation 119,900us-gaap_AssetRetirementObligation
Less current portion 3,467us-gaap_AssetRetirementObligationCurrent 2,961us-gaap_AssetRetirementObligationCurrent
Total long-term ARO $ 91,974us-gaap_AssetRetirementObligationsNoncurrent $ 116,939us-gaap_AssetRetirementObligationsNoncurrent
[1] Plugging liability estimates were revised in both 2015 and 2014 for updates in the cost of services used to plug wells over the preceding year. We had various upward and downward adjustments.