New Accounting Pronouncements - Narrative (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Item Effected [Line Items]
Total net sales	$ 1,649.5	$ 1,734.9	$ 5,036.8	$ 5,013.8
Total gross profit	315.4	323.5	900.7	952.3
Inventories	(361.8)		(361.8)		$ (416.8)
Accrued liabilities	(390.5)		(390.5)		(447.5)
Stockholders equity	(233.9)		(233.9)		$ (217.6)
Accounting Standards Update 2018 02
Item Effected [Line Items]
Expect to decrease accumulated deficit and increase accumulated other comprehensive loss			22.1
Accounting Standards Update 2017 07 | Cost of Sales
Item Effected [Line Items]
Operating change by adoption of new accounting standard		(0.9)		(3.0)
Accounting Standards Update 2017 07 | Selling, General and Administrative Expenses
Item Effected [Line Items]
Operating change by adoption of new accounting standard		(3.2)		(9.4)
Accounting Standards Update 2017 07 | Investment And Other Income Net
Item Effected [Line Items]
Operating change by adoption of new accounting standard		$ 4.1		$ 12.4
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Item Effected [Line Items]
Total net sales	3.7		9.6
Total gross profit	1.8		2.7
Inventories	71.9		71.9
Accrued liabilities	87.9		87.9
Stockholders equity	$ 15.6		$ 15.6