Business Segment Information (Details 2) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018	Sep. 30, 2018
Business Segment Information
Assets		$ 5,469.4		$ 5,469.4		$ 5,298.1	$ 5,294.2
Net sales:
Revenues		1,990.2	$ 1,886.4	3,793.6	$ 3,472.7
Operating income (loss) from continuing operations:
Operating income (loss):		175.6	156.4	336.1	230.9
Interest expense, net of interest income		(11.7)	(8.0)	(23.2)	(21.7)
Miscellaneous income (expense), net		1.2	(1.3)	0.0	(1.5)
Income before income taxes and earnings (losses) of unconsolidated affiliates		165.1	147.1	312.9	207.7
Access equipment
Net sales:
Revenues		987.6	927.9	1,814.1	1,556.1
Operating income (loss) from continuing operations:
Operating income (loss):		119.8	97.6	186.2	111.3
Access equipment | Aerial work platforms
Net sales:
Revenues		463.5	487.2	801.2	810.7
Access equipment | Telehandlers
Net sales:
Revenues		319.5	234.9	589.0	364.4
Access equipment | Other
Net sales:
Revenues		204.6	205.8	423.9	381.0
Defense
Net sales:
Revenues		486.2	427.8	950.0	921.0
Operating income (loss) from continuing operations:
Operating income (loss):		52.2	48.4	123.3	114.2
Fire & emergency
Net sales:
Revenues		279.0	269.1	570.2	494.0
Operating income (loss) from continuing operations:
Operating income (loss):		36.6	36.0	76.5	61.3
Commercial
Net sales:
Revenues		237.1	261.5	458.7	501.2
Operating income (loss) from continuing operations:
Operating income (loss):		7.8	16.4	26.5	24.7
Commercial | Concrete placement
Net sales:
Revenues		115.3	114.6	197.0	226.1
Commercial | Refuse collection
Net sales:
Revenues		92.0	117.8	201.2	219.0
Commercial | Other
Net sales:
Revenues		29.8	29.1	60.5	56.1
Intersegment eliminations
Net sales:
Revenues		0.3	0.1	0.6	0.4
Operating segments
Net sales:
Revenues		1,990.2	1,886.4	3,793.6	3,472.7
Operating segments | Access equipment
Business Segment Information
Assets		3,010.6		3,010.6			2,829.0
Net sales:
Revenues		987.6	927.9	1,814.1	1,556.1
Operating segments | Access equipment | Aerial work platforms
Net sales:
Revenues		463.5	487.2	801.2	810.7
Operating segments | Access equipment | Telehandlers
Net sales:
Revenues		319.5	234.9	589.0	364.4
Operating segments | Access equipment | Other
Net sales:
Revenues		204.6	205.8	423.9	381.0
Operating segments | Defense
Business Segment Information
Assets		836.4		836.4			829.3
Net sales:
Revenues		486.7	428.2	950.8	921.7
Operating segments | Fire & emergency
Net sales:
Revenues		283.2	273.1	578.7	502.2
Operating segments | Commercial
Business Segment Information
Assets		481.1		481.1			409.7
Net sales:
Revenues		237.9	263.9	460.1	505.3
Operating segments | Commercial | Concrete placement
Net sales:
Revenues		115.3	114.6	197.0	226.1
Operating segments | Commercial | Refuse collection
Net sales:
Revenues		92.0	117.8	201.2	219.0
Operating segments | Commercial | Other
Net sales:
Revenues		30.6	31.5	61.9	60.2
Operating segments | Intersegment eliminations
Net sales:
Revenues		(5.2)	(6.7)	(10.1)	(12.6)
Corporate, non-segment
Business Segment Information
Assets		591.7		591.7			661.3
Operating income (loss) from continuing operations:
Operating income (loss):		(40.8)	(42.0)	(76.4)	(80.6)
Intersegment eliminations
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Access equipment
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Access equipment | Aerial work platforms
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Access equipment | Telehandlers
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Access equipment | Other
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Defense
Net sales:
Revenues		0.5	0.4	0.8	0.7
Intersegment eliminations | Fire & emergency
Net sales:
Revenues		4.2	4.0	8.5	8.2
Intersegment eliminations | Commercial
Net sales:
Revenues		0.8	2.4	1.4	4.1
Intersegment eliminations | Commercial | Concrete placement
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Commercial | Refuse collection
Net sales:
Revenues		0.0	0.0	0.0	0.0
Intersegment eliminations | Commercial | Other
Net sales:
Revenues		0.8	2.4	1.4	4.1
Intersegment eliminations | Intersegment eliminations
Net sales:
Revenues		(5.5)	(6.8)	(10.7)	(13.0)
UNITED STATES | Operating segments | Access equipment
Business Segment Information
Assets		2,341.2		2,341.2			2,207.2
UNITED STATES | Operating segments | Defense
Business Segment Information
Assets		829.2		829.2			824.2
UNITED STATES | Operating segments | Fire & emergency
Business Segment Information
Assets		549.6		549.6			564.9
UNITED STATES | Operating segments | Commercial
Business Segment Information
Assets		434.4		434.4			364.3
UNITED STATES | Corporate, non-segment
Business Segment Information
Assets	[1]	481.5		481.5			548.6
Europe | Operating segments | Access equipment
Business Segment Information
Assets		415.0		415.0			406.6
Rest of the World
Net sales:
Revenues		116.4	88.1	197.1	162.1
Rest of the World | Access equipment
Net sales:
Revenues		100.4	67.9	167.0	121.4
Rest of the World | Defense
Net sales:
Revenues		0.1	0.1	0.1	0.1
Rest of the World | Fire & emergency
Net sales:
Revenues		8.3	13.1	19.8	25.5
Rest of the World | Commercial
Net sales:
Revenues		7.5	7.0	10.2	15.0
Rest of the World | Intersegment eliminations
Net sales:
Revenues		0.1	$ 0.0	0.0	$ 0.1
Rest of the World | Operating segments | Access equipment
Business Segment Information
Assets		254.4		254.4			215.2
Rest of the World | Operating segments | Defense
Business Segment Information
Assets		7.2		7.2			5.1
Rest of the World | Operating segments | Commercial
Business Segment Information
Assets		46.7		46.7			45.4
Rest of the World | Corporate, non-segment
Business Segment Information
Assets	[2]	$ 110.2		$ 110.2			$ 112.7

[1] Primarily includes cash and short-term investments.

[2] Primarily includes a corporate-led manufacturing facility that supports multiple operating segments.