Components of Amortizable Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2017	Jul. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Cost	$ 572,327	$ 572,327
Accumulated Amortization	$ 142,419	128,861
Dealer Network/Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	16 years
Cost	$ 404,960	404,960
Accumulated Amortization	$ 113,181	101,795
Trademarks
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	18 years
Cost	$ 147,617	147,617
Accumulated Amortization	$ 19,361	17,570
Design Technology and Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	8 years
Cost	$ 19,300	19,300
Accumulated Amortization	$ 9,562	9,203
Non-Compete Agreements
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	2 years
Cost	$ 450	450
Accumulated Amortization	$ 315	$ 293