Goodwill and Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill acquired	$ 0		$ 0
Amortization of intangible assets	$ 900,000	$ 1,500,000	$ 2,400,000	$ 2,700,000