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Asset Retirement Obligation (Tables)
 12 Months Ended
Dec. 31, 2013
Asset Retirement Obligation  
Asset Retirement Obligation

 

 

(In thousands)
  Year Ended
December 31, 2013		  

Balance at beginning of period

   $ 67,016  

Liabilities incurred

     5,295  

Liabilities settled

     (762 )

Liabilities divested

     (6,400 )

Accretion expense

     3,691  

Change in estimate

     7,013  
       
​ ​ ​ ​ ​

Balance at end of period

   $ 75,853  
       
​ ​ ​ ​ ​
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