Special Charges - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2012		Apr. 30, 2011	Jan. 31, 2012
Disclosure Special Charges Additional Information [Abstract]
Percentage of termination benefit paid during the period	38.00%
Costs related to advisory fees			$ 3,102
Accrued special charges ending balance	5,165	[1]		6,479
Long-term portion of accrued lease termination fees and other facility costs, net of sublease income	2,101
Short-term portion of accrued special charges	$ 3,064

[1] Of the $5,165 total accrued special charges as of April 30, 2012, $2,101 represented the long-term portion of accrued lease termination fees and other facility costs, net of sublease income and other long-term costs. The remaining balance of $3,064 represented the short-term portion of accrued special charges.