XML 36 R39.htm IDEA: XBRL DOCUMENT v3.20.1
Inventories - Schedule of Inventories (Detail) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Inventory [Line Items]    
Inventory, Net, Total $ 17,773 $ 21,415
Sand    
Inventory [Line Items]    
Raw material 587 527
Work in progress 10,862 14,173
Finished goods 3,445 4,097
Spare parts 2,879 2,618
Inventory, Net, Total $ 17,773 $ 21,415