XML 112 R71.htm IDEA: XBRL DOCUMENT v3.19.3
Asset Retirement Obligations - Asset Retirement Obligations (Detail) - USD ($)
$ in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2019
Dec. 31, 2018
Asset Retirement Obligation [Abstract]    
Beginning of period $ 312,754 $ 276,855
Liabilities incurred 3,059 3,376
Acquisitions   13,438
Liabilities settled (5,091) (5,052)
Disposition of wells [1] (80,014) (13,332)
Accretion expense 12,289 25,456
Change in estimate (2,247) 12,013
End of period 240,750 312,754
Less current portion (5,485) (5,485)
Long-term asset retirement obligations $ 235,265 $ 307,269
[1] The nine months ended September 30, 2019 represents the completion of the sale of approximately 1,300 shallow, non-core wells in Pennsylvania.