New Accounting Pronouncements - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Item Effected [Line Items]
Net sales	$ 1,707.8	$ 1,658.9
Total gross profit	294.7	326.8
Inventories	(339.9)	(382.4)	$ (416.8)
Accrued liabilities	(349.2)		(447.5)
Stockholders equity	(202.8)		$ (217.6)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Item Effected [Line Items]
Net sales	5.2
Total gross profit	1.2
Inventories	67.6
Accrued liabilities	80.7
Stockholders equity	$ 14.0
Cost of Sales | Accounting Standards Update 2017 07
Item Effected [Line Items]
Operating change by adoption of new accounting standard		(1.0)
Selling, General and Administrative Expenses | Accounting Standards Update 2017 07
Item Effected [Line Items]
Operating change by adoption of new accounting standard		(3.1)
Investment And Other Expense Net | Accounting Standards Update 2017 07
Item Effected [Line Items]
Operating change by adoption of new accounting standard		$ 4.1