Employee Stock and Savings Plans - Additional information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended				1 Months Ended	24 Months Ended	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2012 Omnibus Incentive Plan	Jan. 31, 2012 Acquired Company Options Exchange	Dec. 14, 2009 Restricted Stock Units (RSUs)	Jan. 31, 2012 Restricted Stock Units (RSUs) Year	Jan. 31, 2012 Employee Stock Purchase Plans	Jan. 31, 2012 Common Stock	Jan. 31, 2012 Traded Options	Jan. 31, 2012 Stock Option Plans Year	Jan. 31, 2012 Restricted Stock Year
Share based payment award vesting period			4 years	4 years
Options expiration period from the original grant date			10 years	10 years
Shares of common stock authorized and issued under the Valor plans				2,160
Shares of common stock available for future grant			7,299
Exercise price of options eligible for exchange					$ 11.00
Unrecognized compensation cost										$ 5,485	$ 30,528
Options exchanged		6,945				6,945
Restricted stock units						557
Incremental cost resulted from exchange options to restricted stock units						$ 491
Amortization period						2				1.3	1.7
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. Prior to July 1, 2010, the ESPPs generally provided for overlapping two-year offerings commencing on January 1 and July 1 of each year with purchases every six months during those offering periods. On July 1, 2010, the ESPPs were amended. Beginning July 1, 2010, 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 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. Offerings in process as of July 1, 2010 with two year terms extending beyond that date were replaced by the six month offering beginning on July 1, 2010. There was no incremental value associated with the replacement of unexpired ESPP purchase rights. As of January 31, 2012, 5,835 shares remain available for future purchase under the ESPPs.
Maximum number of shares that may be purchased by each eligible employee on each purchase dates							6
Eligible employee stock purchase price							85.00%
Employee stock purchase plan expected offering term (Months)							6 months
Shares remain available for future purchase under the ESPPs							5,835
Expected volatility for options, weighted percentages								35.00%	30.00%	53.00%
Expected volatility for options, weighted percentages								20.00%	15.00%
Eligible employee contribution	50.00%
Employee earnings maximum of employee's contribution	6.00%
Employer contribution, vest period	5 years
Employer contribution, percentage	20.00%