Carrying Value of Goodwill, Intangible Assets, and Long-lived Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2012		Jan. 31, 2011		Jan. 31, 2010
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 527,102		$ 510,508		$ 458,313
Intangible assets, net	28,569		31,189
Purchased Technology And In Process Research And Development
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, net	14,023	[1]	17,852	[1]
Other Intangible Assets
Goodwill and Intangible Assets Disclosure [Line Items]
Intangible assets, net	$ 14,546	[2]	$ 13,337	[2]

[1] Includes accumulated amortization of $113,139 as of January 31, 2012 and $103,343 as of January 31, 2011.

[2] Includes accumulated amortization of $59,043 as of January 31, 2012 and $53,138 as of January 31, 2011.