Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Jul. 31, 2019 USD ($) Segment shares	Jul. 31, 2018 USD ($) shares	Jul. 31, 2017 USD ($) shares	Aug. 01, 2019 USD ($)	Aug. 01, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | Segment	3
Cash and cash equivalents	$ 425,615	$ 275,249	$ 223,258
Depreciation	73,139	38,105	34,333
Advertising costs	$ 38,643	$ 26,874	$ 24,997
Maximum percentage of tax benefits realized upon ultimate settlement	50.00%
Antidilutive stock options, restricted stock units and unvested restricted stock outstanding | shares		0	0
Factored accounts receivable	$ 173,405	$ 0
Research and development	$ 9,381	2,009	$ 2,577
Restricted Stock Units (RSUs) [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock-based Compensation, requisite service period	3 years
Antidilutive stock options, restricted stock units and unvested restricted stock outstanding | shares	233,395
Restricted Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Antidilutive stock options, restricted stock units and unvested restricted stock outstanding | shares	0
Research and Development Expense [Member]
Summary Of Significant Accounting Policies [Line Items]
Increase In Research And Development Expense	$ 7,372
Research and Development Expense [Member] | European [Member] | Operating Segments
Summary Of Significant Accounting Policies [Line Items]
Increase In Research And Development Expense	7,244
Continuing Operations | Selling, General and Administrative Expenses
Summary Of Significant Accounting Policies [Line Items]
Depreciation	8,350	$ 5,035	$ 5,710
Accounting Standards Update 2014-09 | Retained Earnings
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax					$ (5,450)
Accounting Standards Update 2014-09 | Accrued Promotions and Rebates
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax					7,127
Cumulative effect of change on equity or net assets on pre-tax basis	$ 181
Accounting Standards Update 2014-09 | Deferred Income Tax Assets
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect of the change in accounting principle, net of tax					$ 1,677
Trademarks
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	18 years
Rental Vehicles
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	6 years
Minimum | Accounting Standards Update 2016-02 | Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Right of use assets				$ 30,000
Operating Lease Liability				30,000
Minimum | Design Technology Assets
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	2 years
Minimum | Non-Compete Agreements
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	2 years
Minimum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	15 years
Minimum | Dealer Network
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	12 years
Minimum | Other Intangible Assets
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	2 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
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents maturity period	3 months	3 months
Maximum | Accounting Standards Update 2016-02 | Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Right of use assets				40,000
Operating Lease Liability				$ 40,000
Maximum | Design Technology Assets
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	15 years
Maximum | Non-Compete Agreements
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	15 years
Maximum | Trademarks
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	25 years
Maximum | Dealer Network
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	20 years
Maximum | Backlog
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	5 months
Maximum | Other Intangible Assets
Summary Of Significant Accounting Policies [Line Items]
Intangible assets amortization period	15 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	$ 61,057
Euro Financial Institutions One
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	115,168
Euro Financial Institutions Two
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	39,254
Held By One U.S. Financial Institution
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 148,488	$ 254,701