Stock-Based Compensation - Summary of Activity under Option and Stock Plans (Detail) (USD $)	9 Months Ended	12 Months Ended
	Oct. 31, 2013	Jan. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Outstanding, Beginning balance	926,224
Shares, Granted	228,000
Shares, Exercised	(220,224)
Shares, Outstanding, Ending balance	934,000	926,224
Shares, Exercisable	490,500	537,724
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 14.34
Weighted Average Exercise Price, Granted	$ 19.49
Weighted Average Exercise Price, Exercised	$ 11.26
Weighted Average Exercise Price, Outstanding, Ending balance	$ 16.32	$ 14.34
Weighted Average Exercise Price, Exercisable	$ 14.03	$ 12.16
Weighted Average Remaining Contract Term, Outstanding	6 years 3 months 18 days	5 years 4 months 21 days
Weighted Average Remaining Contract Term, Exercisable	4 years 7 months 24 days	4 years 5 months 16 days
Weighted Average Fair Value, Outstanding, Beginning balance	$ 5.93
Weighted Average Fair Value, Outstanding, Ending balance	$ 5.62	$ 5.93
Weighted Average Fair Value, Exercisable	$ 6.29	$ 6.12