Change in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Allowance for doubtful accounts receivable, beginning balance	$ 4,217
Allowance for doubtful accounts receivable, ending balance	3,611
Allowance for Doubtful Accounts [Member]
Allowance for doubtful accounts receivable, beginning balance	4,217	$ 5,469
Valuation Allowances and Reserves, Charged to Cost and Expense	(597)	(1,951)
Valuation Allowances and Reserves, Adjustments	(9)	(224)
Allowance for doubtful accounts receivable, ending balance	$ 3,611	$ 3,294