Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award
Stock options, weighted average grant date fair value (in dollars per share)	$ 10.93	$ 12.27	$ 9.29
Intrinsic value of stock options exercised	$ 18.3	$ 30.3	$ 16.0
Shares reserved for outstanding options and future grants (in shares)	11,514,490
Intrinsic value of shares outstanding	$ 50.2
Intrinsic value of shares exercisable	49.3
Equity instruments other than options vested in period	$ 40.8	44.5	42.0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award
Stock options exercisable term (in years)	10 years
Stock option, award vesting period (in years)	3 years
Pre-tax compensation expense associated with stock options	$ 10.4	9.8	8.1
Tax benefit recorded resulting from stock option compensation expense recognized	1.7	2.0	1.9
Total unrecognized compensation expense related to non-vested stock options	7.2
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award
Total unrecognized compensation expense related to non-vested stock options	$ 2.9
Performance shares \| 2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Performance awards measurement period (in years)	3 years
Expiration period (in years)	3 years
Performance award expense	$ 3.4	$ 3.8	$ 7.5
Minimum \| Performance shares \| 2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Payout percentage based on target award	0.00%
Maximum \| Performance shares \| 2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Payout percentage based on target award	200.00%

Share-Based Compensation Arrange By Share-Based Payment Award, Award Target Payout, Percentage

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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 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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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Expected term of 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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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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