Acquisition - Erwin Hymer Group - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Feb. 01, 2019	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019	Jul. 31, 2019	Jul. 31, 2018
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments				$ 5,087
Goodwill		$ 1,353,120	$ 377,693	1,353,120	$ 377,693	$ 1,358,032	$ 377,693
Acquisition-related costs		0	42,059	$ 0	99,148
Other Expense
Business Acquisition [Line Items]
Acquisition-related costs			10,907		25,441
Trademarks
Business Acquisition [Line Items]
Weighted average remaining life				17 years
Erwin Hymer Group
Business Acquisition [Line Items]
Goodwill, purchase accounting adjustments				$ 5,087
Acquired finite-lived intangible assets, weighted average useful life	17 years
Goodwill	$ 1,013,559
Business acquisition, goodwill, expected tax deductible amount	$ 242,000
Erwin Hymer Group | Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs		$ 42,059	42,059	$ 99,148	99,148
Erwin Hymer Group | Foreign Currency Contract Losses | Acquisition costs
Business Acquisition [Line Items]
Acquisition-related costs			$ 31,152		$ 73,707
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