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Asset Retirement Obligations
 12 Months Ended
Dec. 31, 2018
Asset Retirement Obligation [Abstract]  
Asset Retirement Obligations ASSET RETIREMENT OBLIGATIONS:
The reconciliation of changes in asset retirement obligations at December 31, 2018 and 2017 is as follows:
 
 
As of December 31,
 
 
2018
 
2017
Balance at beginning of period
 
$
204,070

 
$
201,006

Obligations Divested (Note 6)
 
(196,643
)
 
(1,960
)
Accretion expense
 
9,874

 
5,760

Obligations Incurred
 
4,795

 
441

Obligations Settled
 
(5,323
)
 
(6,875
)
Revisions in estimated cash flows
 
21,781

 
5,698

Balance at end of period
 
$
38,554

 
$
204,070