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Acquisition - Erwin Hymer Group - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended
	Feb. 01, 2019	Oct. 31, 2019	Oct. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments		$ 3,054
Goodwill		1,361,265	$ 377,693	$ 1,358,032	$ 377,693
Acquisition-related costs		$ 0	57,089
Other Expense
Business Acquisition [Line Items]
Acquisition-related costs			14,534
Trademarks
Business Acquisition [Line Items]
Weighted average remaining life		18 years
Erwin Hymer Group
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments		$ 3,054
Acquired finite-lived intangible assets, weighted average useful life	17 years
Goodwill	$ 1,011,526
Business acquisition, goodwill, expected tax deductible amount	$ 242,000
Erwin Hymer Group \| Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs		$ 57,089	57,089
Erwin Hymer Group \| Foreign Currency Contract Losses \| Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs			$ 42,555
Erwin Hymer Group \| Trademarks
Business Acquisition [Line Items]
Finite-lived intangible assets, amortization method	20 years
Erwin Hymer Group \| Technology assets
Business Acquisition [Line Items]
Finite-lived intangible assets, amortization method	10 years
Erwin Hymer Group \| Dealer network
Business Acquisition [Line Items]
Finite-lived intangible assets, amortization method	20 years
Erwin Hymer Group \| Backlog
Business Acquisition [Line Items]
Weighted average remaining life	5 months