Inventories, net - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 70,188	$ 85,684
Work in progress	65,382	81,645
Finished goods	239,083	233,732
Inventory, gross, Total	374,653	401,061
Less: allowance for obsolete and excess inventory	(83,566)	(45,648)
Total inventory	$ 291,087	$ 355,413