Inventories, net (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 50,775	$ 55,878
Work in progress	58,105	51,251
Finished goods	188,457	192,632
Inventory, gross, Total	297,337	299,761
Less: allowance for obsolete and excess inventory	(102,790)	(108,567)
Total inventory	$ 194,547	$ 191,194