v3.20.2
Inventories (Details) - USD ($)
$ in Thousands
Jun. 30, 2020
Dec. 31, 2019
Inventory Disclosure [Abstract]    
Finished goods $ 17,362 $ 17,612
Raw materials 177 243
Parts, supplies and other 29,129 30,441
Total inventories $ 46,668 $ 48,296