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ASSET RETIREMENT OBLIGATIONS Asset Retirement Obligations (Tables)
 12 Months Ended
Dec. 31, 2016
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Change in Asset Retirement Obligation [Table Text Block]
The following table presents the changes in carrying amounts of the asset retirement obligations associated with our working interest in crude oil and natural gas properties:
 
2016
 
2015
 
(in thousands)
 
 
 
 
Balance at beginning of period
$
89,492

 
$
73,855

Obligations incurred with development activities and assumed with acquisitions
4,894

 
2,373

Accretion expense
7,080

 
6,293

Revisions in estimated cash flows
—

 
11,658

Obligations discharged with disposal of properties and asset retirements
(9,079
)
 
(4,687
)
Balance at end of period
92,387

 
89,492

Less current portion
(9,775
)
 
(5,460
)
Long-term portion
$
82,612

 
$
84,032