Reconciliation of Beginning and Ending Amounts of Gross Uncertain Tax Positions (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits [Line Items]
Balance, beginning of the period	$ 21.7	$ 21.5	$ 18.5
Additions for current year tax positions	10.6	6.1	3.1
Additions for tax positions of prior years	2.3
Currency fluctuations		(0.1)	(0.1)
Settlements with taxing authorities		(5.8)
Balance, end of the period	$ 34.6	$ 21.7	$ 21.5