XML 35 R17.htm IDEA: XBRL DOCUMENT v3.10.0.1
Asset Retirement Obligations
 12 Months Ended
Dec. 31, 2018
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligations
Asset Retirement Obligations
The following table reconciles our AROs as of the dates presented, which are included in the “Other liabilities” caption on our Consolidated Balance Sheets: 
 
Year Ended December 31,
 
2018
 
2017
Balance at beginning of period
$
3,286

 
$
2,459

Changes in estimates
354

 
149

Liabilities incurred
335

 
118

Liabilities settled
(8
)
 
(139
)
Purchase of properties
385

 
494

Sale of properties
(310
)
 
—

Accretion expense
272

 
205

Balance at end of period
$
4,314

 
$
3,286