Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Reconciliation Of Unrecognized Tax Benefits [Line Items]
Beginning balance	$ 2,213	$ 2,007	$ 1,883
Additions based on tax positions related to the current year	325	311	244
Additions for tax positions of prior years	690	34	138
Reductions for tax positions of prior years	(210)	(139)	(258)
Ending balance	$ 3,018	$ 2,213	$ 2,007