Quarterly report pursuant to Section 13 or 15(d)

Asset Retirement Obligation (Details)

v3.20.2
Asset Retirement Obligation (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Mar. 31, 2017
Asset retirement obligation $ 814   $ 814   $ 790 $ 700
Accretion expense 12,000 $ 11,000 24,000 $ 23,000    
Other Assets            
Contributed to the Trust Fund $ 670,000   $ 670,000