Income Taxes - Schedule of Transactions Affecting Valuation Allowance on Deferred Tax Assets (Detail) - Valuation Allowance of Deferred Tax Assets - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Balance, beginning of year	$ 255.9	$ 238.3	$ 154.1
Current year expense-net	34.5	29.1	84.5
Write-offs	(50.1)	(0.2)	(6.8)
Foreign exchange and other	(2.8)	(11.3)	6.5
Balance, end of year	$ 237.5	$ 255.9	$ 238.3