Business Segment Information - Schedule of Income (Loss) from Continuing operations by Product Lines and Reportable Segments (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating income (loss):
Operating income (loss)		$ 203.8	$ 118.6	$ 440.5	$ 361.3
Interest expense, net of interest income		(11.7)	(11.7)	(34.3)	(44.2)
Miscellaneous other income (expense)		0.4	1.5	2.0	(4.7)
Income before income taxes and losses of unconsolidated affiliates		192.5	108.4	408.2	312.4
Operating Segments | Access Equipment
Operating income (loss):
Operating income (loss)	[1]	113.0	33.5	218.4	173.3
Operating Segments | Defense
Operating income (loss):
Operating income (loss)	[2]	59.8	41.4	148.1	132.1
Operating Segments | Fire & Emergency
Operating income (loss):
Operating income (loss)	[2]	44.5	46.2	127.0	96.1
Operating Segments | Commercial
Operating income (loss):
Operating income (loss)		29.6	23.8	60.3	49.7
Corporate, Non-segment
Operating income (loss):
Operating income (loss)		$ (43.1)	$ (26.3)	$ (113.3)	$ (89.9)

[1] Results for the three and nine months ended June 30, 2021 include a $0.2 million and $3.4 million charge for restructuring, respectively. The Company incurred additional charges of $1.1 million and $8.1 million of other costs related to restructuring plans in the three and nine months ended June 30, 2021, respectively.

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