Intangible Assets, Goodwill and Long-Lived Assets - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2017	Jan. 31, 2016	Apr. 30, 2017	Jul. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Pre-tax, non-cash goodwill impairment charge	$ 0	$ 9,113	$ 0	$ 9,113