Guarantees (Details) - USD ($) |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Apr. 30, 2019 |
Apr. 30, 2018 |
Apr. 30, 2019 |
Apr. 30, 2018 |
Jul. 31, 2018 |
|
| Guarantor Obligations [Line Items] | |||||
| Net sales | $ 712,800,000 | $ 700,000,000 | $ 2,117,900,000 | $ 2,009,500,000 | |
| Contingent liability for standby letters of credit, issued and outstanding | 11,200,000 | 11,200,000 | $ 8,200,000 | ||
| Amount drawn upon letters of credit | 0 | 0 | $ 0 | ||
| Advanced Filtration Systems, Inc. | |||||
| Guarantor Obligations [Line Items] | |||||
| Outstanding debt of joint venture | 38,200,000 | 38,200,000 | |||
| Advanced Filtration Systems, Inc. | |||||
| Guarantor Obligations [Line Items] | |||||
| Joint venture investment earnings (loss) | 400,000 | 600,000 | 100,000 | 1,100,000 | |
| Advanced Filtration Systems, Inc. | Royalty | |||||
| Guarantor Obligations [Line Items] | |||||
| Net sales | $ 1,500,000 | $ 1,700,000 | $ 4,800,000 | $ 5,300,000 | |