Special Charges - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jul. 31, 2013		Jul. 31, 2012	Jul. 31, 2013		Jul. 31, 2012	Jan. 31, 2013
Disclosure Special Charges Additional Information [Abstract]
Percentage of termination benefit paid during the period				78.00%
Other charges litigation	$ 3,231		$ 1,236	$ 5,171		$ 1,777
Accrued special charges ending balance	7,128	[1]		7,128	[1]		5,541
Long-term portion of accrued lease termination fees and other facility costs, net of sublease income	998			998
Short-term portion of accrued special charges	$ 6,130			$ 6,130

[1] Of the $7,128 total accrued special charges as of July 31, 2013, $998 represents the long-term portion, which primarily includes accrued lease termination fees and other facility costs, net of sublease income and other long-term costs. The remaining balance of $6,130 represents the short-term portion of accrued special charges.