Revenue (Disaggregation of Revenue by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Disaggregation of Revenue [Line Items]
Total net sales	$ 703.7	$ 664.7	$ 1,405.1	$ 1,309.5
Engine Products segment
Disaggregation of Revenue [Line Items]
Total net sales	469.0	442.4	949.9	884.5
Engine Products segment | Off-Road
Disaggregation of Revenue [Line Items]
Total net sales	79.0	78.9	155.2	153.9
Engine Products segment | On-Road
Disaggregation of Revenue [Line Items]
Total net sales	42.8	35.2	88.7	68.5
Engine Products segment | Aftermarket
Disaggregation of Revenue [Line Items]
Total net sales	321.1	303.5	652.3	612.6
Engine Products segment | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Total net sales	26.1	24.8	53.7	49.5
Industrial Products segment
Disaggregation of Revenue [Line Items]
Total net sales	234.7	222.3	455.2	425.0
Industrial Products segment | Industrial Filtration Solutions
Disaggregation of Revenue [Line Items]
Total net sales	164.6	145.1	314.0	279.6
Industrial Products segment | Gas Turbine Systems
Disaggregation of Revenue [Line Items]
Total net sales	27.5	33.0	53.0	59.3
Industrial Products segment | Special Applications
Disaggregation of Revenue [Line Items]
Total net sales	$ 42.6	$ 44.2	$ 88.2	$ 86.1