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Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2013
Asset Retirement Obligations [Abstract]  
Schedule Of Change In Asset Retirement Obligation

 

 

 

 

Year Ended

 

 

December 31, 2013

 

December 31, 2012

 

Beginning of period

$
126,991 

 

$
92,561 

 

Assumed in acquisitions

 
13,409 

 

 
14,581 

 

Revisions to previous estimates (1)

 
12,911 

 

 
17,278 

 

Liabilities incurred

 
360 

 

 
1,185 

 

Liabilities settled

 
(5,806)

 

 
(4,262)

 

Accretion expense

 
7,456 

 

 
5,648 

 

End of period

$
155,321 

 

$
126,991 

 

Less: Current portion of asset retirement obligations

 
4,310 

 

 
1,426 

 

Asset retirement obligations - non current

$
151,011 

 

$
125,565 

 

 

(1)

In 2013 and 2012, we recorded an upward revision to previous estimates for our asset retirement obligations primarily due to changes in the estimated abandonment dates.