Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 1.5	$ 1.0	$ 4.1	$ 2.5