Employee Stock and Savings Plans - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 31, 2011
Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued vest from the original grant date	4 years
Options expiration period from the original grant date	10 years
Employee Stock Purchase Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan description	We have an employee stock purchase plan (ESPP) for U.S. employees and an ESPP for certain foreign subsidiary employees. The ESPPs provide for six month offerings commencing on January 1 and July 1 of each year with purchases on June 30 and December 31 of each year. Each eligible employee may purchase up to six thousand shares of stock on each purchase date (but no more than an annual offering date total fair market value of $25) at prices no less than 85% of the lesser of the fair market value of the shares on the offering date or on the purchase date.
Maximum number of shares that may be purchased by each eligible employee on each purchase dates	6
Eligible employee stock purchase price	85.00%
Eligible employee stock fair market value	25
Employee stock purchase plan expected offering term (Months)	6 months
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility for options, weighted percentages	35.00%
Expected volatility for options, weighted percentages	20.00%
Traded Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility for options, weighted percentages	30.00%
Expected volatility for options, weighted percentages	15.00%