Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Deductions	$ (30.5)	$ (17.9)
Reserve For Doubtful Accounts And Cash Discounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	38.5	22.0	$ 25.3
Valuation Allowances and Reserves, Charged to Cost and Expense	132.0	125.9	41.4
Valuation Allowances and Reserves, Adjustments	2.9	(1.7)	0.2
Valuation Allowances and Reserves, Deductions	(111.6)	(107.7)	(44.9)
Valuation Allowances and Reserves, Ending Balance	61.8	38.5	22.0
Inventory Valuation Reserve [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Beginning Balance	45.9	32.9	32.6
Valuation Allowances and Reserves, Charged to Cost and Expense	19.1	33.0	23.3
Valuation Allowances and Reserves, Adjustments	5.0	(0.2)	0.5
Valuation Allowances and Reserves, Deductions	(18.5)	(19.8)	(23.5)
Valuation Allowances and Reserves, Ending Balance	$ 51.5	$ 45.9	$ 32.9