Stock-Based Compensation (Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 31, 2020	Oct. 31, 2019
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award
Pretax compensation expense associated with stock options	$ 5.1	$ 5.3
Tax benefits associated with stock options	0.6	1.1
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award
Pretax compensation expense associated with stock options	$ 0.9	$ 0.9

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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