Fair Value of Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified			3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Other (Expenses) Income	Sep. 30, 2011 Other (Expenses) Income	Sep. 30, 2012 Other (Expenses) Income	Sep. 30, 2011 Other (Expenses) Income	Sep. 30, 2012 Other, Net	Sep. 30, 2011 Other, Net	Sep. 30, 2012 Accrued Expenses	Dec. 31, 2011 Accrued Expenses	Sep. 30, 2012 4.50% Senior Notes	Dec. 31, 2011 4.50% Senior Notes	Sep. 30, 2012 5.10% Senior Notes	Dec. 31, 2011 5.10% Senior Notes
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt instrument, interest rate											4.50%	4.50%	5.10%	5.10%
Foreign currency forward contracts, notional values	$ 192.8	$ 148.7
Fair value of foreign currency forward contracts, liabilities									0.4	0.9
Recognized gains (losses) of foreign currency forward contracts			3.0	(1.6)	(1.1)	4.1
Change in the fair value of foreign currency forward contracts							1.1	(4.1)
Cash settlements							$ (1.6)	$ 0.1