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Inventories - Summary of Inventories (Detail) - USD ($)
$ in Thousands
Dec. 31, 2018
Dec. 31, 2017
Disclosure Of Inventories [Line Items]    
Inventories $ 83,925 $ 97,205
Gross carrying amount [Member]    
Disclosure Of Inventories [Line Items]    
Raw materials and supplies 25,717 32,278
Work in progress 15,598 14,240
Finished goods 46,592 53,051
Inventories 87,907 99,569
Accumulated impairment [Member]    
Disclosure Of Inventories [Line Items]    
Inventories $ (3,982) $ (2,364)