Summary of Restricted Equity Awards Activity (Detail) (USD $)	3 Months Ended
Oct. 29, 2011 Service-based Restricted Equity Awards	Oct. 29, 2011 Performance-based Restricted Equity Awards	Oct. 29, 2011 Market-based Restricted Equity Awards	Jul. 30, 2011 Market-based Restricted Equity Awards
Number of Shares
Nonvested Number of shares at beginning of period	461,200	676,400	218,500	218,500
Granted	236,900	273,500
Vested	(58,100)
Cancelled/Forfeited	(58,100)
Nonvested Number of shares at end of period	581,900	949,900	218,500	218,500
Weighted-Average Grant Date Fair Value Per Share
Nonvested Weighted-Average Grant Date Fair Value at beginning of period	$ 25.27	$ 24.49	$ 24.68	$ 24.68
Granted	$ 26.72	$ 25.34
Vested	$ 24.01
Cancelled/Forfeited	$ 25.25
Nonvested Weighted-Average Grant Date Fair Value at end of period	$ 25.99	$ 24.71	$ 24.68	$ 24.68

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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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- Definition

The 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 during the reporting period as a result of the occurrence of a terminating event specified in the contractual agreement of the plan.

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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

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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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph A240

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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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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