Annual report pursuant to Section 13 and 15(d)

PROPERTY, PLANT AND EQUIPMENT - Additional Information (Details)

v3.20.4
PROPERTY, PLANT AND EQUIPMENT - Additional Information (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Sep. 10, 2019
Jun. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Property, Plant and Equipment [Abstract]          
Depreciation and depletion expense     $ 17,200 $ 20,400 $ 1,500
Asset Impairment Charges   $ 81,100 $ 81,065 $ 0 $ 4,513
Fair value of impaired assets   $ 28,700      
Proceeds from sale of subsidiary $ 14,800        
Gain on sale of subsidiary $ 4,200