Asset Retirement Obligations (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2019
USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]  
Asset retirement obligations as of January 1, 2019 $ 13,895
Liabilities incurred 264
Liabilities divested and settled (487)
Accretion expense 218
Asset retirement obligations as of March 31,2019 $ 13,890