Summary of the Components of the Special Charges (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Disclosure Summary Of Components Of Special Charges [Abstract]
Special charges	$ 4,688	$ 1,975	$ 12,570	$ 6,406
Employee Severance [Member]
Disclosure Summary Of Components Of Special Charges [Abstract]
Employee severance and related costs	1,133	612	3,843	2,629
Litigation Costs [Member]
Disclosure Summary Of Components Of Special Charges [Abstract]
Litigation costs	3,046	829	8,217	2,606
Other Restructuring [Member]
Disclosure Summary Of Components Of Special Charges [Abstract]
Other costs	$ 509	$ 534	$ 510	$ 1,171