Summary of Activity for Valuation Allowances (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation And Qualifying Accounts Disclosure [Line Items]
Beginning balance, Accounts receivable allowance	$ (29.4)	$ (28.9)	$ (29.1)
Additions, Accounts receivable allowance	(9.0)	(8.9)	(8.0)
Write-offs and Adjustments, Accounts receivable allowance	10.9	8.4	8.2
Ending balance, Accounts receivable allowance	(27.5)	(29.4)	(28.9)
Beginning balance, Deferred tax assets valuation allowance	6.9	(8.4)	(15.2)
Additions, Deferred tax assets valuation allowance	2.4	0.5	4.7
Write-offs and Adjustments, Deferred tax assets valuation allowance	0.2	1.0	2.1
Ending balance, Deferred tax assets valuation allowance	$ 4.3	$ 6.9	$ (8.4)