Other Income and Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Other Nonrecurring Expense	$ 0.9	$ 5.1
Research and Development Expense	15.0	14.3	$ 11.6
Advertising Expense	3.3	7.1	7.1
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.0	0.0	0.6
Interest Costs Capitalized	(0.3)	(3.0)	0.0
Interest Expense, Other	(0.3)	(0.2)	(0.6)
Interest Expense	26.6	23.3	25.3
Interest Income, Other	(1.1)	(3.5)	(4.4)
Interest expense, net	25.5	19.8	20.9
Amortization of Debt Issuance Costs	1.2	1.2	1.6
5.5% Senior Notes
Interest Expense, Debt	24.8	24.8	7.5
Secured Debt [Member]
Interest Expense, Debt	0.0	0.0	14.4
ABL Agreement
Interest Expense, Debt	0.6	0.6	$ 0.6
Project A [Member]
Restructuring Costs	0.5	$ 4.3
Project R [Member]
Restructuring Costs	$ 2.5