Share-based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Apr. 30, 2015	Apr. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted	0	78,846
Intrinsic value of options exercised	$ 2.5	$ 4.2
Total fair value of restricted stock units vested in period	1.1	6.5
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	12.7	12.7
Unrecognized compensation cost related to non-vested share-based compensation arrangements, weighted average period		1 year 4 months 24 days
Non-GAAP EPS Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period	265	36,641
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vested or expected to vest, shares	295,878	295,878
Stock options exercisable, shares	143,207	143,207
Stock options vested or expected to vest, weighted average exercise price	$ 68.50	$ 68.50
Stock options exercisable, weighted average exercise price	$ 63.52	$ 63.52
Stock options vested or expected to vest, aggregate intrinsic value	4.7	4.7
Stock options exercisable, aggregate intrinsic value	$ 3.0	$ 3.0
Stock options vested or expected to vest, weighted average remaining contractual term		5 years 26 days
Stock options exercisable, weighted average remaining contractual term		4 years 4 months 13 days
Total Shareholders Return Performance-based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, grants in period	206	28,455

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

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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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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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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.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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