v3.8.0.1
Inventories (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Inventory, Net [Abstract]    
Raw materials $ 32,928 $ 23,144
Work-in-process 22,753 20,889
Finished goods 88,497 81,764
Total 144,178 125,797
Adjust to LIFO cost (51,813) (32,523)
Inventory $ 92,365 $ 93,274