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ASSET RETIREMENT OBLIGATIONS (Tables)
 12 Months Ended
Dec. 31, 2017
ASSET RETIREMENT OBLIGATIONS [Abstract]  
Asset Retirement Obligations Operating Costs



 

 

 

 

 

 

 

 



 

 

 

 

 

 

 

 

in thousands

 2017 

 

 

 2016 

 

 

 2015 

 

ARO Operating Costs

 

 

 

 

 

 

 

 

Accretion

$        11,415 

 

 

$        11,059 

 

 

$       11,474 

 

Depreciation

 6,302 

 

 

 6,353 

 

 

 6,515 

 

Total

$        17,717 

 

 

$        17,412 

 

 

$       17,989 

 



Reconciliations of Asset Retirement Obligations



 

 

 

 

 



 

 

 

 

 

in thousands

 2017 

 

 

 2016 

 

Asset Retirement Obligations

 

 

 

 

 

Balance at beginning of year

$      223,872 

 

 

$      226,594 

 

  Liabilities incurred

 1,920 

 

 

 505 

 

  Liabilities settled

 (21,477)

 

 

 (17,114)

 

  Accretion expense

 11,415 

 

 

 11,059 

 

  Revisions, net

 2,387 

 

 

 2,828 

 

Balance at end of year

$      218,117 

 

 

$      223,872