Information Regarding Operations by Geographic Area (Detail) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$ 546.3	$ 472.8	$ 1,074.6	$ 947.4
Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	191.1	168.4	372.5	329.6
Americas | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	151.4	136.1	294.9	266.6
Americas | Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	39.7	32.3	77.6	63.0
Europe, Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	211.9	188.8	426.9	387.4
Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	143.3	115.6	275.2	230.4
Asia Pacific | Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	58.2	46.6	118.9	100.2
Asia Pacific | Other Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$ 85.1	$ 69.0	$ 156.3	$ 130.2