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Inventories - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2017
Inventory [Line Items]      
Percentage of LIFO inventories on total inventories 25.00%   39.00%
Increase in income due to effect of liquidations $ 0.2 $ 0.9  
Cost of Sales      
Inventory [Line Items]      
Increase in income due to effect of liquidations $ 0.3 $ 1.4