Summary of Significant Accounting Policies Carrying Value of Goodwill, Intangible Assets, and Long-lived Assets (Parenthetical) (Details) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013	Jan. 31, 2012
Purchased Techonology and In Process Research and Development [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Intangible assets, accumulated amortization	$ 121,011	$ 113,139
Other Intangible Assets [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Intangible assets, accumulated amortization	$ 65,049	$ 59,043