Goodwill and Purchased Intangible Assets (Details) $ in Millions	6 Months Ended
	Mar. 31, 2018 USD ($)
Changes in goodwill
Net goodwill at the beginning of the period	$ 1,013.0
Foreign currency translation	7.4
Net goodwill at the end of the period	1,020.4
Access Equipment
Changes in goodwill
Net goodwill at the beginning of the period	885.9
Foreign currency translation	7.5
Net goodwill at the end of the period	893.4
Fire & Emergency
Changes in goodwill
Net goodwill at the beginning of the period	106.1
Foreign currency translation	0.0
Net goodwill at the end of the period	106.1
Commercial
Changes in goodwill
Net goodwill at the beginning of the period	21.0
Foreign currency translation	(0.1)
Net goodwill at the end of the period	$ 20.9