Carrying Value of Goodwill, Intangible Assets, and Long-lived Assets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2012	Jan. 31, 2011
Purchased Technology And In Process Research And Development
Goodwill and Intangible Assets Disclosure [Line Items]
Accumulated amortization intangible assets	$ 113,139	$ 103,343
Other Intangible Assets
Goodwill and Intangible Assets Disclosure [Line Items]
Accumulated amortization intangible assets	$ 59,043	$ 53,138

The accumulated amount of amortization of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph a(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6905858&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant