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Segment Reporting (Summary of Segment Detail) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 662.0	$ 703.7	$ 1,334.7	$ 1,405.1
Earnings before income taxes	82.8	80.5	169.5	176.9
Engine Products segment
Segment Reporting Information [Line Items]
Net sales	435.6	469.0	894.7	949.9
Industrial Products segment
Segment Reporting Information [Line Items]
Net sales	226.4	234.7	440.0	455.2
Operating Segments \| Engine Products segment
Segment Reporting Information [Line Items]
Earnings before income taxes	53.3	53.2	115.7	117.1
Operating Segments \| Industrial Products segment
Segment Reporting Information [Line Items]
Earnings before income taxes	34.6	32.2	64.1	68.8
Corporate and Unallocated
Segment Reporting Information [Line Items]
Earnings before income taxes	(5.1)	(4.9)	(10.3)	(9.0)
Off-Road \| Engine Products segment
Segment Reporting Information [Line Items]
Net sales	67.5	79.0	136.1	155.2
On-Road \| Engine Products segment
Segment Reporting Information [Line Items]
Net sales	33.8	42.8	74.5	88.7
Aftermarket \| Engine Products segment
Segment Reporting Information [Line Items]
Net sales	308.1	321.1	627.5	652.3
Aerospace and Defense \| Engine Products segment
Segment Reporting Information [Line Items]
Net sales	26.2	26.1	56.6	53.7
Industrial Filtration Solutions \| Industrial Products segment
Segment Reporting Information [Line Items]
Net sales	155.0	164.6	304.1	314.0
Gas Turbine Systems \| Industrial Products segment
Segment Reporting Information [Line Items]
Net sales	24.3	27.5	45.0	53.0
Special Applications \| Industrial Products segment
Segment Reporting Information [Line Items]
Net sales	$ 47.1	$ 42.6	$ 90.9	$ 88.2