Revenue (Disaggregation of Revenue by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Disaggregation of Revenue [Line Items]
Total net sales	$ 712.8	$ 700.0	$ 2,117.9	$ 2,009.5
Engine Products segment
Disaggregation of Revenue [Line Items]
Total net sales	489.4	472.3	1,439.3	1,356.8
Engine Products segment | Off-Road
Disaggregation of Revenue [Line Items]
Total net sales	84.8	89.9	240.0	243.8
Engine Products segment | On-Road
Disaggregation of Revenue [Line Items]
Total net sales	46.9	42.2	135.6	110.7
Engine Products segment | Aftermarket
Disaggregation of Revenue [Line Items]
Total net sales	327.7	315.1	980.0	927.7
Engine Products segment | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	30.0	25.1	83.7	74.6
Industrial Products segment
Disaggregation of Revenue [Line Items]
Total net sales	223.4	227.7	678.6	652.7
Industrial Products segment | Industrial Filtration Solutions
Disaggregation of Revenue [Line Items]
Total net sales	155.2	152.2	469.2	431.8
Industrial Products segment | Gas Turbine Systems
Disaggregation of Revenue [Line Items]
Total net sales	27.5	32.1	80.5	91.4
Industrial Products segment | Special Applications
Disaggregation of Revenue [Line Items]
Total net sales	$ 40.7	$ 43.4	$ 128.9	$ 129.5