Unrecognized cost of unvested share-based compensation awards.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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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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No definition available.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Net number of share options (or share units) granted during the period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

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No definition available.

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Share-based Compensation Expense - Additional Information (Detail) - USD ($) $ in Millions		12 Months Ended
	Nov. 04, 1985	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015	Jan. 21, 2014	Jan. 23, 2012	Jan. 29, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised		$ 2.2	$ 0.9	$ 4.3
Cash received from exercise of stock options		8.3	4.2	7.3
Total fair value of restricted stock grants vested in period		7.5	8.2	9.8
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit realized for tax deduction from option exercises		$ 0.1	$ 0.1	$ 0.1
Time Based Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vesting Period		3 years
Outstanding Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted		0	0
Total Shareholders Return Performance-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period		28,749	24,821	28,455
Non-GAAP EPS Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period		62,626	32,444	36,641
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized to be granted	700,000
Share-based compensation arrangement by share-based payment award, purchase price of common stock, percent	85.00%
2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares authorized to be granted					4,453,518	2,200,000	1,600,000
Remaining number of shares available for issuance		1,754,003
Stock Option and Restricted Stock Bonus Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested share-based compensation arrangements		$ 6.0
Unrecognized compensation cost related to non-vested share-based compensation arrangements, weighted average period		1 year