Summary of Significant Accounting Policies Aggregate Amortization Expense Related to Purchased Technology and Other Intangible Assets (Details) (Purchased Technology and Other Intangible Asset [Member], USD $) In Thousands, unless otherwise specified	Jan. 31, 2013
Purchased Technology and Other Intangible Asset [Member]
Goodwill And Intangible Assets Disclosure [Line Items]
Expected Amortization Expense, 2014	$ 9,434
Expected Amortization Expense, 2015	7,233
Expected Amortization Expense, 2016	4,068
Expected Amortization Expense, 2017	859
Expected Amortization Expense, 2018	244
Finite-Lived Intangible Assets, Amortization Expense, Thereafter	0
Finite Lived Intangible Assets Future Amortization	$ 21,838