Change in Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jul. 31, 2013		Jul. 31, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	$ 5,331		$ 4,432
Charged to expense	(331)		32
Deductions	(186)	[1]	(145)	[1]
Ending balance	$ 4,814		$ 4,319

[1] Specific account write-offs and foreign exchange.