Segment Reporting (Summary of Segment Detail) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2021	Jan. 31, 2020
Segment Reporting Information
Net sales	$ 679.1	$ 662.0	$ 1,315.8	$ 1,334.7
Earnings before income taxes	73.9	82.8	156.1	169.5
Operating Segments | Engine Products segment
Segment Reporting Information
Net sales	462.4	435.6	898.6	894.7
Earnings before income taxes	61.3	53.3	121.7	115.7
Operating Segments | Engine Products segment | Off-Road
Segment Reporting Information
Net sales	77.9	67.5	142.6	136.1
Operating Segments | Engine Products segment | On-Road
Segment Reporting Information
Net sales	33.4	33.8	65.3	74.5
Operating Segments | Engine Products segment | Aftermarket
Segment Reporting Information
Net sales	330.2	308.1	647.4	627.5
Operating Segments | Engine Products segment | Aerospace and Defense
Segment Reporting Information
Net sales	20.9	26.2	43.3	56.6
Operating Segments | Industrial Products segment
Segment Reporting Information
Net sales	216.7	226.4	417.2	440.0
Earnings before income taxes	25.8	34.6	53.3	64.1
Operating Segments | Industrial Products segment | Industrial Filtration Solutions
Segment Reporting Information
Net sales	149.9	155.0	285.6	304.1
Operating Segments | Industrial Products segment | Gas Turbine Systems
Segment Reporting Information
Net sales	23.4	24.3	46.4	45.0
Operating Segments | Industrial Products segment | Special Applications
Segment Reporting Information
Net sales	43.4	47.1	85.2	90.9
Corporate and unallocated
Segment Reporting Information
Earnings before income taxes	$ (13.2)	$ (5.1)	$ (18.9)	$ (10.3)