Employee Stock and Savings Plans Summary of Weighted Average Grant Date Fair Values (Details) (USD $)	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 21.52	$ 22.42	$ 16.74
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value	$ 4.81	$ 4.30	$ 3.82
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Weighted average grant date fair value of options granted	$ 0.00	$ 0.00	$ 7.18