Basis of Presentation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Incremental tax expense	$ 0.5		$ 0.8
Percentage inventory valued under LIFO	98.30%		98.30%	98.30%
Higher inventory if FIFO applied entirely	$ 158.1		$ 158.1	$ 147.9
Effect of LIFO inventory liquidation on income	$ (0.3)	$ 1.6	1.3
LIFO expense related to inflation increase in cost of sales			11.5
Increase in cost of sales due to LIFO accounting method			$ 10.2