Stock-based Compensation (Summary of Restricted Equity Awards Activity) (Details) $ / shares in Units, $ in Millions	9 Months Ended
May 02, 2020 USD ($) $ / shares shares
Market Based Restricted Equity Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding (in shares) \| shares	100,000
Weighted- Average Grant Date Fair Value Per Share
Awards outstanding (in dollars per share) \| $ / shares	$ 9.35
Total unrecognized compensation \| $	$ 0.9
Weighted-average years expected to be recognized	2 years
Service-based Restricted Equity Awards
Number of Shares
Nonvested at August 3, 2019 (in shares) \| shares	67,400
Granted (in shares) \| shares	0
Vested (in shares) \| shares	(28,600)
Cancelled/Forfeited (in shares) \| shares	(7,800)
Nonvested at February 1, 2020 (in shares) \| shares	31,000.0
Weighted- Average Grant Date Fair Value Per Share
Nonvested at August 3, 2019 (in dollars per share) \| $ / shares	$ 91.42
Granted (in dollars per share) \| $ / shares	0
Vested (in dollars per share) \| $ / shares	112.47
Cancelled/Forfeited (in dollars per share) \| $ / shares	88.68
Nonvested at February 1, 2020 (in dollars per share) \| $ / shares	$ 72.68
Total unrecognized compensation \| $	$ 0.4
Weighted-average years expected to be recognized	3 months 18 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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