Income Taxes (Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Current:
Current Federal Tax Expense (Benefit)	$ 10.9	$ 11.6	$ 25.7
Current State and Local Tax Expense (Benefit)	2.7	3.9	7.1
Current Foreign Tax Expense (Benefit)	1.3	1.5	0.6
Current Income Tax Expense (Benefit)	14.9	17.0	33.4
Deferred:
Deferred Federal Income Tax Expense (Benefit)	5.6	2.5	(42.6)
Deferred State and Local Income Tax Expense (Benefit)	2.0	(0.4)	(1.0)
Deferred Foreign Income Tax Expense (Benefit)	(0.4)	(0.8)	0.3
Deferred Income Tax Expense (Benefit)	7.2	1.3	(43.3)
Income tax expense (benefit)	$ 22.1	$ 18.3	$ (9.9)