Changes in Accounting Principles - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change In Accounting Principles [Line Items]
Increase decrease in the net income due to LIFO accounting method	$ 1.6	$ 6.7	$ 17.4
Change in Method of Accounting for Inventory Valuation [Member]
Change In Accounting Principles [Line Items]
Increase (decrease) in cost of goods sold due to LIFO accounting method		(4.2)
Increase decrease in the net income due to LIFO accounting method		$ 2.3
Increase decrease in the net income due to LIFO accounting method per diluted share		$ 0.06