Business Segment Information (Details 2) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Net sales:
Net sales	$ 1,886.4	$ 1,618.3	$ 3,472.7	$ 2,829.7
Operating income (loss) from continuing operations:
Operating income (loss):	155.9	80.4	229.7	116.6
Interest expense, net of interest income	(8.0)	(14.1)	(21.7)	(28.0)
Miscellaneous other income (expense)	(0.8)	1.2	(0.3)	2.5
Income before income taxes and earnings of unconsolidated affiliates	147.1	67.5	207.7	91.1
Access Equipment
Net sales:
Net sales	927.9	723.2	1,556.1	1,212.4
Operating income (loss) from continuing operations:
Operating income (loss):	97.7	42.1	111.5	66.5
Access Equipment | Aerial work platforms
Net sales:
Net sales	487.2	369.4	810.7	603.1
Access Equipment | Telehandlers
Net sales:
Net sales	234.9	161.6	364.4	254.9
Access Equipment | Other
Net sales:
Net sales	205.8	192.2	381.0	354.4
Defense
Net sales:
Net sales	427.8	445.7	921.0	739.9
Operating income (loss) from continuing operations:
Operating income (loss):	47.8	48.7	113.0	72.5
Fire & Emergency
Net sales:
Net sales	269.1	233.5	494.0	462.6
Operating income (loss) from continuing operations:
Operating income (loss):	36.0	21.8	61.1	38.8
Commercial
Net sales:
Net sales	261.5	214.1	501.2	412.2
Operating income (loss) from continuing operations:
Operating income (loss):	16.4	6.0	24.7	10.6
Commercial | Concrete placement
Net sales:
Net sales	114.6	112.7	226.1	197.1
Commercial | Refuse collection
Net sales:
Net sales	117.8	79.1	219.0	171.3
Commercial | Other
Net sales:
Net sales	29.1	22.3	56.1	43.8
Intersegment eliminations
Net sales:
Net sales	0.1	1.8	0.4	2.6
Operating segments
Net sales:
Net sales	1,886.4	1,618.3	3,472.7	2,829.7
Operating segments | Access Equipment
Net sales:
Net sales	927.9	723.2	1,556.1	1,212.4
Operating segments | Access Equipment | Aerial work platforms
Net sales:
Net sales	487.2	369.4	810.7	603.1
Operating segments | Access Equipment | Telehandlers
Net sales:
Net sales	234.9	161.6	364.4	254.9
Operating segments | Access Equipment | Other
Net sales:
Net sales	205.8	192.2	381.0	354.4
Operating segments | Defense
Net sales:
Net sales	428.2	446.1	921.7	740.6
Operating segments | Fire & Emergency
Net sales:
Net sales	273.1	237.5	502.2	470.0
Operating segments | Commercial
Net sales:
Net sales	263.9	216.0	505.3	415.2
Operating segments | Commercial | Concrete placement
Net sales:
Net sales	114.6	112.7	226.1	197.1
Operating segments | Commercial | Refuse collection
Net sales:
Net sales	117.8	79.1	219.0	171.3
Operating segments | Commercial | Other
Net sales:
Net sales	31.5	24.2	60.2	46.8
Operating segments | Intersegment eliminations
Net sales:
Net sales	(6.7)	(4.5)	(12.6)	(8.5)
Corporate, non-segment
Operating income (loss) from continuing operations:
Operating income (loss):	(42.0)	(38.2)	(80.6)	(71.8)
Intersegment eliminations
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Access Equipment
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Access Equipment | Aerial work platforms
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Access Equipment | Telehandlers
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Access Equipment | Other
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Defense
Net sales:
Net sales	0.4	0.4	0.7	0.7
Intersegment eliminations | Fire & Emergency
Net sales:
Net sales	4.0	4.0	8.2	7.4
Intersegment eliminations | Commercial
Net sales:
Net sales	2.4	1.9	4.1	3.0
Intersegment eliminations | Commercial | Concrete placement
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Commercial | Refuse collection
Net sales:
Net sales	0.0	0.0	0.0	0.0
Intersegment eliminations | Commercial | Other
Net sales:
Net sales	2.4	1.9	4.1	3.0
Intersegment eliminations | Intersegment eliminations
Net sales:
Net sales	$ (6.8)	$ (6.3)	$ (13.0)	$ (11.1)