Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 31, 2018	Oct. 31, 2017	Jul. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Contract assets	$ 13.1
Contract liabilities	12.0		$ 10.5
Increase in net sales and cost of sales	238.4	$ 224.3
Calculated under Revenue Guidance in Effect before Topic 606 \| Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in net sales and cost of sales	$ 5.1

Amount, before allowance for credit loss, of right to consideration in exchange for good or service transferred to customer, when right is conditioned on something other than passage of time.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ References

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