Net Income Per Share - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Undistributed earnings, diluted									$ 2,075	$ 2,075	$ 2,075
Antidilutive securities excluded from computation of earnings per share									1,195	1,975	4,056
Non-controlling interest adjustment to redemption value	(573)	(2,032)	(2,349)	468	(5,272)	0	0	0	(4,486)	(5,272)	0
Retained Earnings
Adjustment of noncontrolling interest to redemption value									$ (4,486)	$ (3,590)	$ (1,682)