Change in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015
Disclosure Change In Allowance For Doubtful Accounts [Abstract]
Allowance for doubtful accounts receivable, beginning balance	$ 3,826	$ 4,217
Valuation Allowances and Reserves, Period Increase (Decrease)	(611)	(522)
Valuation Allowances and Reserves, Adjustments	333	(42)
Allowance for doubtful accounts receivable, ending balance	$ 3,548	$ 3,653