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ASSET RETIREMENT OBLIGATIONS (Reconciliations Of Asset Retirement Obligations) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Asset Retirement Obligations      
Balance at beginning of year $ 150,072 $ 153,979  
Liabilities incurred 69,111 127  
Liabilities settled (16,203) (2,993)  
Accretion expense 10,685 7,956 8,195
Revisions up (down), net 14,569 (8,997)  
Balance at end of year $ 228,234 $ 150,072 $ 153,979