Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Intangible Assets Net Excluding Goodwill [Abstract]
Amortization expense	$ 2.1	$ 1.1	$ 6.2	$ 2.2