Special Charges - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Oct. 31, 2012		Oct. 31, 2011	Jan. 31, 2012
Disclosure Special Charges Additional Information [Abstract]
Percentage of termination benefit paid during the period	61.00%
Costs related to advisory fees			$ 3,967
Accrued special charges ending balance	4,755	[1]		6,479
Long-term portion of accrued lease termination fees and other facility costs, net of sublease income	2,299
Short-term portion of accrued special charges	$ 2,456

[1] Of the $4,755 total accrued special charges as of October 31, 2012, $2,299 represented the long-term portion, which primarily included accrued lease termination fees and other facility costs, net of sublease income and other long-term costs. The remaining balance of $2,456 represented the short-term portion of accrued special charges.