Financial Instruments - Valuation of Financial Instruments Recorded on Fair Value Basis (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Currency forward contracts	$ (0.1)	$ 1.8
Noncurrent marketable securities	27.7	21.6
Level 1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Currency forward contracts	(0.1)	1.8
Noncurrent marketable securities	27.7	21.6
Level 2 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Currency forward contracts
Noncurrent marketable securities
Level 3 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Currency forward contracts
Noncurrent marketable securities