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Asset Retirement Obligations - Schedule of Asset Retirement Obligations (Detail)
$ in Thousands
6 Months Ended
Jun. 30, 2020
USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]  
As of December 31, 2019 $ 25,709
Liabilities incurred 488
Liabilities settled (766)
Disposition of properties (143)
Accretion expense 872
Revisions to estimate 409
As of June 30, 2020 26,569
Less: Current asset retirement obligations 2,619
Long-term asset retirement obligations $ 23,950