Segment Reporting (Summary of Segment Detail) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2021	Oct. 31, 2020
Segment Reporting Information
Net sales	$ 760.9	$ 636.6
Earnings before income taxes	104.1	82.2
Operating Segments | Engine Products segment
Segment Reporting Information
Net sales	527.2	436.2
Earnings before income taxes	72.3	60.4
Operating Segments | Engine Products segment | Off-Road
Segment Reporting Information
Net sales	93.9	64.8
Operating Segments | Engine Products segment | On-Road
Segment Reporting Information
Net sales	31.5	32.0
Operating Segments | Engine Products segment | Aftermarket
Segment Reporting Information
Net sales	374.3	317.0
Operating Segments | Engine Products segment | Aerospace and Defense
Segment Reporting Information
Net sales	27.5	22.4
Operating Segments | Industrial Products segment
Segment Reporting Information
Net sales	233.7	200.4
Earnings before income taxes	38.3	27.5
Operating Segments | Industrial Products segment | Industrial Filtration Solutions
Segment Reporting Information
Net sales	165.5	135.6
Operating Segments | Industrial Products segment | Gas Turbine Systems
Segment Reporting Information
Net sales	16.6	23.0
Operating Segments | Industrial Products segment | Special Applications
Segment Reporting Information
Net sales	51.6	41.8
Corporate and unallocated
Segment Reporting Information
Earnings before income taxes	$ (6.5)	$ (5.7)