Fair Value of Derivative Instruments (Detail) (USD $) In Millions	Jul. 31, 2011	Jan. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 6.9	$ 5.1
Derivative Liabilities	2.6	1.2
Designated as Hedging Instrument | Foreign exchange contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	6.9	5.1
Designated as Hedging Instrument | Foreign exchange contracts | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 2.6	$ 1.2