Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Debt Instrument [Line Items]
Asset impairment charges	$ 0.0	$ 0.0	$ 0.0
Level 2 \| Long-term Debt
Debt Instrument [Line Items]
Long-term debt, fair value	330.6	394.4
Long-term debt, carrying value	325.0	375.0
Level 3
Debt Instrument [Line Items]
Carrying value of equity method investments	$ 19.0	$ 18.7

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2420-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02(22))
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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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