Business Segment Information - Schedule of Net Sales by Product Lines and Reportable Segments (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
		Mar. 31, 2021	Mar. 31, 2020		Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Revenues		$ 1,889.0	$ 1,796.7		$ 3,465.5	$ 3,491.8
Access Equipment
Segment Reporting Information [Line Items]
Revenues		736.6	693.0		1,299.0	1,410.9
Access Equipment | Aerial Work Platforms
Segment Reporting Information [Line Items]
Revenues		358.2	273.7		636.2	579.7
Access Equipment | Telehandlers
Segment Reporting Information [Line Items]
Revenues		175.2	217.6		298.1	419.0
Access Equipment | Other
Segment Reporting Information [Line Items]
Revenues		203.2	201.7		364.7	412.2
Defense
Segment Reporting Information [Line Items]
Revenues	[1]	614.3	626.1		1,164.3	1,126.0
Fire & Emergency
Segment Reporting Information [Line Items]
Revenues	[1]	308.7	241.9		578.5	494.6
Commercial
Segment Reporting Information [Line Items]
Revenues		228.8	235.0		423.0	458.9
Commercial | Concrete Placement
Segment Reporting Information [Line Items]
Revenues		97.3	89.7		165.0	165.4
Commercial | Refuse Collection
Segment Reporting Information [Line Items]
Revenues		104.4	115.2		206.7	231.1
Commercial | Other
Segment Reporting Information [Line Items]
Revenues		27.1	30.1		51.3	62.4
Corporate and Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	[1]	0.6	0.7		0.7	1.4
Operating Segments | Access Equipment
Segment Reporting Information [Line Items]
Revenues		738.2	693.0		1,301.9	1,410.9
Operating Segments | Access Equipment | Aerial Work Platforms
Segment Reporting Information [Line Items]
Revenues		358.2	273.7		636.2	579.7
Operating Segments | Access Equipment | Telehandlers
Segment Reporting Information [Line Items]
Revenues		175.2	217.6		298.1	419.0
Operating Segments | Access Equipment | Other
Segment Reporting Information [Line Items]
Revenues		204.8	201.7		367.6	412.2
Operating Segments | Defense
Segment Reporting Information [Line Items]
Revenues	[1]	614.7	631.0		1,165.0	1,131.4
Operating Segments | Fire & Emergency
Segment Reporting Information [Line Items]
Revenues	[1]	312.5	242.3		586.4	499.2
Operating Segments | Commercial
Segment Reporting Information [Line Items]
Revenues		230.0	236.7		425.7	460.9
Operating Segments | Commercial | Concrete Placement
Segment Reporting Information [Line Items]
Revenues		97.3	89.7		165.0	165.4
Operating Segments | Commercial | Refuse Collection
Segment Reporting Information [Line Items]
Revenues		104.4	115.2		206.7	231.1
Operating Segments | Commercial | Other
Segment Reporting Information [Line Items]
Revenues		28.3	31.8		54.0	64.4
Corporate, Non-segment | Corporate and Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	[1]	(6.4)	(6.3)		(13.5)	(10.6)
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues		(6.4)	(6.3)	[1]	(13.5)	(10.6)	[1]
Intersegment Eliminations | Access Equipment
Segment Reporting Information [Line Items]
Revenues		1.6			2.9
Intersegment Eliminations | Access Equipment | Other
Segment Reporting Information [Line Items]
Revenues		1.6			2.9
Intersegment Eliminations | Defense
Segment Reporting Information [Line Items]
Revenues	[1]	0.4	4.9		0.7	5.4
Intersegment Eliminations | Fire & Emergency
Segment Reporting Information [Line Items]
Revenues	[1]	3.8	0.4		7.9	4.6
Intersegment Eliminations | Commercial
Segment Reporting Information [Line Items]
Revenues		1.2	1.7		2.7	2.0
Intersegment Eliminations | Commercial | Other
Segment Reporting Information [Line Items]
Revenues		1.2	1.7		2.7	2.0
Intersegment Eliminations | Corporate and Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	[1]	$ (7.0)	$ (7.0)		$ (14.2)	$ (12.0)

[1] Results have been reclassified to reflect the move of the airport snow removal vehicle business from the Fire & Emergency segment to the Defense segment.