Net Income Per Share - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Disclosure Net Income Loss Per Share Additional Information [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	73	1,205	1,238	2,626
Non-controlling interest adjustment to redemption value	$ (2,032)	$ 0	$ (3,913)	$ 0