Summary of Significant Accounting Policies Purchased Technology and Other Intangible Asset Amortization Expenses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Schedule of Finite Lived Intangible Assets Amortization Expense
Amortization of intangible assets	$ 6,230	$ 5,915	$ 5,905
Purchased Technology and Other Intangible Asset
Schedule of Finite Lived Intangible Assets Amortization Expense
Amortization of intangible assets	$ 9,828	$ 13,716	$ 15,701