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Acquisitions - Erwin Hymer Group - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Feb. 01, 2019	Apr. 30, 2020	Jan. 31, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019	Jul. 31, 2019	Jul. 31, 2018
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments					$ 1,282
Goodwill		$ 1,396,401		$ 1,350,187	1,396,401	$ 1,350,187	$ 1,358,032	$ 377,693
Acquisition-related costs		0		13,363	0	112,511
Impairment charges		0	$ 10,057	0	$ 10,057	0
North America
Business Acquisition [Line Items]
Impairment charges				0		52,501
Other Expense
Business Acquisition [Line Items]
Acquisition-related costs				16,293		41,734
Trademarks
Business Acquisition [Line Items]
Weighted average remaining life					17 years
Erwin Hymer Group
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments					$ 1,282
Acquired finite-lived intangible assets, weighted average useful life	17 years
Goodwill	$ 1,009,754
Business acquisition, goodwill, expected tax deductible amount	$ 311,000
Erwin Hymer Group \| Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs		$ 61,418		13,363		112,511
Erwin Hymer Group \| Acquisition costs \| Management Fees
Business Acquisition [Line Items]
Acquisition-related costs						1,684
Erwin Hymer Group \| Foreign Currency Contract Losses \| Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs				$ (2,930)		$ 70,777
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