Guarantees (Details) - USD ($) $ in Millions	3 Months Ended
Oct. 31, 2019	Oct. 31, 2018	Jul. 31, 2019
Guarantor Obligations [Line Items]
Contingent liability for standby letters of credit	$ 10.7		$ 11.0
Amounts drawn for letters of credit	0.0		0.0
Royalty income	672.7	$ 701.4
Advanced Filtration Systems, Inc.
Guarantor Obligations [Line Items]
Outstanding debt (the Company guarantees half)	40.0		$ 38.8
Advanced Filtration Systems, Inc.
Guarantor Obligations [Line Items]
Investment earnings (loss)	0.1	(0.3)
Advanced Filtration Systems, Inc. \| Royalty
Guarantor Obligations [Line Items]
Royalty income	$ 1.9	$ 1.7

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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.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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