Change in Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified					6 Months Ended
	Jul. 31, 2014	Jan. 31, 2014	Jul. 31, 2013	Jan. 31, 2013	Jul. 31, 2014 Allowance for Doubtful Accounts [Member]	Jul. 31, 2013 Allowance for Doubtful Accounts [Member]
Allowance for doubtful accounts receivable, current	$ 3,294	$ 5,469	$ 4,814	$ 5,331
Valuation Allowances and Reserves, Charged to Cost and Expense					(1,951)	(331)
Net Deductions Recoveries					$ (224)	$ (186)