Employee Stock and Savings Plans Summary of Shares Issued Under ESPPs (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Employee Stock Purchase Plan [Line Items]
Shares issued under ESPPs	1,884	2,099	3,461
Cash received for the purchase of shares under the ESPPs	$ 22,645	$ 22,155	$ 19,019
Weighted average purchase price of shares issued under ESPPs	$ 12.02	$ 10.55	$ 5.50