Employee Stock and Savings Plans and Stockholders Equity Summary of Weighted Average Grant Date Fair Values (Details) (USD $)	12 Months Ended
Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value of options granted	$ 0.00	$ 7.18	$ 5.43
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 22.42	$ 16.74	$ 10.91
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 4.30	$ 3.82	$ 3.19

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration