Inventories, Net - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory, Net [Abstract]
Percentage of LIFO inventory	19.90%	17.50%
Inventory, LIFO reserve	$ 13.6	$ 16.6
Effect of LIFO inventory liquidation on income	$ 1.4	$ 2.9	$ 1.5