Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended				9 Months Ended
	Oct. 31, 2009	Oct. 31, 2013	Oct. 31, 2013 Time Based Options [Member]	Oct. 31, 2013 Performance Shares [Member]	Oct. 31, 2013 2006 Stock Incentive Plan [Member]	Oct. 31, 2013 Restricted Stock Units (RSUs) [Member]	Oct. 31, 2013 Minimum [Member]	Oct. 31, 2013 Minimum [Member] Performance Based Options [Member]	Oct. 31, 2013 Minimum [Member] Restricted Stock Units (RSUs) [Member]	Oct. 31, 2013 Maximum [Member]	Oct. 31, 2013 Maximum [Member] Performance Based Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Offer for eligible employees and independent directors to exchange ratio under Stock Incentive Plan	One-for-one basis
Awards vesting period			3 years	3 years
Expiration of granted option					10 years
Performance target for achievement								50.00%			150.00%
Stock expense expected to be recognized over the remaining future vesting period		$ 0.1
Unrecognized compensation costs recognition period							2 years	2 years	3 years	3 years	3 years
Unrecognized compensation costs		$ 1.8				$ 8.8