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ASSET RETIREMENT OBLIGATIONS (Reconciliations Of Asset Retirement Obligations) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Asset Retirement Obligations    
Balance at beginning of year $ 228,234 $ 150,072
Liabilities incurred 0 0
Liabilities settled (5,250) (1,292)
Accretion expense 2,940 2,006
Revisions up (down), net (93) 5,672
Balance at end of year $ 225,831 $ 156,458