Quarterly report pursuant to Section 13 or 15(d)

Asset Retirement Obligations (Details)

v3.19.1
Asset Retirement Obligations (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Asset retirement obligations at January 1, 2019 $ 14,292    
Accretion expense 241 $ 218  
Liabilities incurred 111    
Liabilities settled (618)    
Dispositions (87)    
Revisions to estimate 21    
Asset retirement obligations at end of period 13,960    
Less: Current asset retirement obligations (3,771)   $ (3,887)
Long-term asset retirement obligations at March 31, 2019 10,189   10,405
Restricted Investments      
Restricted investments $ 3,450   $ 3,424