Schedule II - Valuation and Qualifying Accounts (Detail) - Valuation Allowance for Deferred Tax Assets [Member] - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 19,962	$ 17,041	$ 305
Amounts Charged to Expense	1,967	2,921	17,041
Deductions From Allowance			(305)
Balance at End of Period	$ 21,929	$ 19,962	$ 17,041