Financial Instruments - Additional Information (Detail) (USD $)			9 Months Ended			9 Months Ended
	Sep. 30, 2012 Year	Dec. 31, 2011	Sep. 30, 2012 Line of Credit Facility	Sep. 30, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 3	Dec. 31, 2011 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 3	Sep. 30, 2012 Interest rate swap contract
Derivative [Line Items]
Notional value of forward currency and option contracts	$ 165,500,000	$ 205,200,000
Fixed-rate notes interest percentage						2.875%
Fixed-rate notes due date						2016
Notional value of interest rate swap contract						250,000,000
Fair value of contingent consideration				73,000,000	77,100,000
Fair value of commercial paper borrowings	381,500,000	304,500,000
Line of credit facility, borrowing capacity	600,000,000
Line of credit facility, years	5
Line of credit facility, expiration date			2016-10
Fair value of long-term debt	$ 1,000,000,000	$ 1,000,000,000