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Inventory (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Inventory.    
Raw materials and supplies $ 34,689 $ 42,851
Work-in-process 4,584 3,492
Finished goods 3,015 2,433
Total inventory 42,288 48,776
Inventory held at service locations $ 4,700 $ 5,500