SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail) $ in Thousands	12 Months Ended
	Jul. 31, 2020 USD ($) Segment shares	Jul. 31, 2019 USD ($) shares	Jul. 31, 2018 USD ($) shares	Aug. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | Segment	3
Cash and cash equivalents	$ 538,519	$ 425,615	$ 275,249
Depreciation	98,933	73,139	38,105
Advertising costs	$ 67,019	$ 38,643	$ 26,874
Maximum percentage of tax benefits realized upon ultimate settlement	50.00%
Operating lease right-of-use assets	$ 33,609
Total operating lease liabilities	$ 33,799
Restricted Stock Units (RSUs)
Summary Of Significant Accounting Policies [Line Items]
Stock-based compensation, requisite service period	3 years
Antidilutive restricted stock units and unvested restricted stock outstanding (in shares) | shares	0	233,395	0
Research and Development Expense
Summary Of Significant Accounting Policies [Line Items]
Research and development expense	$ 19,123	$ 9,381	$ 2,009
Continuing Operations | Selling, General and Administrative Expenses
Summary Of Significant Accounting Policies [Line Items]
Depreciation	$ 15,060	8,350	$ 5,035
Accounting Standards Update 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets				$ 33,000
Total operating lease liabilities				$ 33,000
Rental vehicles
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	6 years
Minimum | Non-Compete Agreements
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	2 years
Minimum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	15 years
Minimum | Dealer Network
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	12 years
Minimum | Building and Building Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	10 years
Minimum | Machinery and equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	3 years
Maximum | Non-Compete Agreements
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	15 years
Maximum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	25 years
Maximum | Dealer Network
Summary Of Significant Accounting Policies [Line Items]
Finite-lived intangible asset, useful life	20 years
Maximum | Building and Building Improvements
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	39 years
Maximum | Machinery and equipment
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	10 years
One US Financial Institution
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 963	61,057
Euro Financial Institutions One
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	174,077	115,168
Euro Financial Institutions Two
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	49,732	39,254
Held By One U.S. Financial Institution
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 260,876	$ 148,488