Change in Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Oct. 31, 2014	Jan. 31, 2014	Oct. 31, 2014 Allowance for Doubtful Accounts [Member]	Oct. 31, 2013 Allowance for Doubtful Accounts [Member]
Allowance for doubtful accounts receivable, beginning balance	$ 3,352	$ 5,469	$ 5,469	$ 5,331
Valuation Allowances and Reserves, Charged to Cost and Expense			(1,865)	(331)
Net Deductions Recoveries			(252)	(93)
Allowance for doubtful accounts receivable, ending balance	$ 3,352	$ 5,469	$ 3,352	$ 4,907