Changes in Accrued Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended					6 Months Ended
	Jul. 31, 2013		Apr. 30, 2013	Jul. 31, 2012	Apr. 30, 2012	Jul. 31, 2013		Jul. 31, 2012
Restructuring Cost and Reserve [Line Items]
Other charges litigation	$ 3,231			$ 1,236		$ 5,171		$ 1,777
Employee severance and related costs	631			1,029		2,710		2,017
Other costs	(3)			478		1		637
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance			5,541			5,541
Special charges	3,859		4,023	2,743	1,688	7,882		4,431
Payments						(6,295)
Accrued special charges ending balance	7,128	[1]				7,128	[1]
Employee severance and related costs
Restructuring Cost and Reserve [Line Items]
Employee severance and related costs						2,710
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance			2,028			2,028
Payments						(3,781)
Accrued special charges ending balance	957	[1]				957	[1]
Litigation costs
Restructuring Cost and Reserve [Line Items]
Other charges litigation						5,171
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance			624			624
Payments						(2,155)
Accrued special charges ending balance	3,640	[1]				3,640	[1]
Other costs
Restructuring Cost and Reserve [Line Items]
Other costs						1
Restructuring Reserve [Roll Forward]
Accrued special charges beginning balance			2,889			2,889
Payments						(359)
Accrued special charges ending balance	$ 2,531	[1]				$ 2,531	[1]

[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.