Annual report pursuant to Section 13 and 15(d)

Asset Retirement Obligations (Details)

v3.10.0.1
Asset Retirement Obligations (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2018
USD ($)
item
Dec. 31, 2017
USD ($)
item
Dec. 31, 2016
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]          
Asset retirement obligations at beginning of period $ 6,020 $ 6,661      
Accretion expense 874 677 $ 958    
Liabilities incurred 1,543 278      
Liabilities settled (1,288) (711)      
Dispositions (614) 0      
Revisions to estimate 7,757 (885)      
Asset retirement obligations at end of period $ 6,020 $ 6,661 $ 6,661 $ 14,292 $ 6,020
Less: Current asset retirement obligations       (3,887) (1,295)
Long-term asset retirement obligations       10,405 4,725
Number of wells, plugging and abandonment, gross | item 26 18      
Restricted Investments          
Restricted investments       $ 3,424 $ 3,372