Fair Value Measurements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Fair Value, Measurement Inputs, Disclosure [Line Items]
Maturity period limit of foreign currency exchange instruments (in months)	1 month
Net fair value gain on foreign exchange forward contracts	$ 1.5	$ 0.6
Difference between carrying amount and fair value of long-term debt	11		15
Other Income Expense Net
Fair Value, Measurement Inputs, Disclosure [Line Items]
Gain(loss) on foreign exchange forward contracts	15.9	(6.9)
Prepaid Expenses and Other Current Assets
Fair Value, Measurement Inputs, Disclosure [Line Items]
Net fair value gain on foreign exchange forward contracts	2.6	1.8
Other Accrued Liabilities
Fair Value, Measurement Inputs, Disclosure [Line Items]
Net fair value gain on foreign exchange forward contracts	(1.1)	(1.2)
Foreign Exchange Contract
Fair Value, Measurement Inputs, Disclosure [Line Items]
Notional amount of foreign exchange forward contracts not designated as hedging instruments	$ 421.1	$ 472.3