Business and Summary of Significant Accounting Policies Assumption Used to Estimate the Fair Value of Stock-Based Awards (Details)	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Stock Option Plans
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Expected dividends	0.00%	0.00%	0.00%
Employee Qualified Stock Purchase Plan 1998 ESP Plan
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Expected dividends	0.00%	0.00%	0.00%
Employee Qualified Stock Purchase Plan 1998 ESP Plan | Minimum
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Range of expected volatilities	41.00%	34.00%	33.00%
Range of expected lives (in years)	6 months	6 months	6 months
Range of risk-free interest rates	0.10%	0.10%	0.20%
Expected forfeitures	7.70%	7.80%	10.50%
Employee Qualified Stock Purchase Plan 1998 ESP Plan | Maximum
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Range of expected volatilities	44.00%	44.00%	47.00%
Range of expected lives (in years)	2 years	2 years	2 years
Range of risk-free interest rates	0.30%	0.80%	1.10%
Expected forfeitures	7.80%	10.50%	13.50%
Employee Stock Option Member | Minimum
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Range of expected volatilities	41.00%	40.00%	40.00%
Range of expected lives (in years)	3 years 7 months 6 days	2 years 7 months 6 days	2 years 7 months 6 days
Range of risk-free interest rates	0.50%	0.50%	0.80%
Expected forfeitures	7.70%	7.80%	10.50%
Employee Stock Option Member | Maximum
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Method Used [Line Items]
Range of expected volatilities	45.00%	49.00%	45.00%
Range of expected lives (in years)	4 years 7 months 6 days	4 years 9 months 18 days	2 years 7 months 6 days
Range of risk-free interest rates	0.80%	1.90%	1.90%
Expected forfeitures	7.80%	10.50%	13.50%