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Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2016
Asset Retirement Obligations  
Schedule of changes in asset retirement obligations

 

 

 

 

 

 

 

 

 

 

 

December 31,

 

 

 

2016

 

2015

 

 

 

(In thousands)

 

Asset retirement obligations:

 

 

 

 

 

 

 

Beginning asset retirement obligations

    

$
43,938

    

$
44,023

 

Liabilities incurred during period

 

 
14,235

 

 
3,818

 

Revisions in estimated retirement obligations

 

 

 —

 

 
(9,023)

 

Accretion expense

 

 
5,401

 

 
5,120

 

Ending asset retirement obligations

 

$
63,574

 

$
43,938