Intangible Assets and Goodwill - Additional Information (Detail) - USD ($) $ in Thousands	Oct. 31, 2017	Jul. 31, 2017
Intangible Assets And Goodwill [Line Items]
Goodwill	$ 377,693	$ 377,693
Towables
Intangible Assets And Goodwill [Line Items]
Goodwill	334,822	334,822
Other
Intangible Assets And Goodwill [Line Items]
Goodwill	$ 42,871	$ 42,871