XML 51 R33.htm IDEA: XBRL DOCUMENT v3.20.1
Asset Retirement Obligation (Asset Retirement Obligation Transactions) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Asset Retirement Obligation [Abstract]    
Balance $ 1,998  
Accretion expense 31 $ 35
Liabilities incurred  
Liabilities settled (47)  
Liabilities relieved - sold properties  
Balance $ 1,982