Inventories - Inventories, Net of Reserves (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Raw materials	$ 66,359	$ 60,098
In-process and finished	112,507	115,874
Supplies	70,803	71,242
Total	$ 249,669	$ 247,214