Changes in Accrued Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 30, 2013		Apr. 30, 2012
Restructuring Cost and Reserve [Line Items]
Employee severance and related costs	$ 2,079		$ 988
Other costs	4		159
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance	4,917
Special charges	2,083		1,147
Payments	(1,875)
Accrued special charges ending balance	5,125	[1]
Employee severance and related costs
Restructuring Cost and Reserve [Line Items]
Employee severance and related costs	2,079
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance	2,028
Payments	(2,119)
Accrued special charges ending balance	1,988	[1]
Other costs
Restructuring Cost and Reserve [Line Items]
Other costs	4
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance	2,889
Payments	244
Accrued special charges ending balance	$ 3,137	[1]

[1] Of the $5,125 total accrued special charges as of April 30, 2013, $2,110 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 $3,015 represents the short-term portion of accrued special charges.