Asset Retirement Obligations (Tables)
6 Months Ended
Jun. 30, 2018
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Asset Retirement Obligations
The following table summarizes the changes in the Company’s asset retirement obligations (“ARO”) for the six months ended June 30, 2018 (in thousands):
Asset retirement obligations at January 1, 2018
$
12,161

Liabilities acquired
16

Liabilities incurred
670

Liabilities divested and settled
(556
)
Accretion expense
383

Revisions to estimated cash flows
(11
)
Asset retirement obligations at June 30, 2018
$
12,663