Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 0.7	$ 6.3	$ (12.1)	$ (5.7)
Net derivative gains and other costs arising during the period, net of tax expense of $0.7; $0.5; $1.1; and $0.5, respectively	[1]	1.9	1.6	2.8	1.3
Reclassification of losses into net income (loss), net of tax benefit (expense) of $0.1; $0.1; $0.0; and $(1.5), respectively		0.5	0.2	0.1	4.1
Other comprehensive income		2.4	1.8	2.9	5.4
Comprehensive income (loss)		$ 3.1	$ 8.1	$ (9.2)	$ (0.3)

[1] Other costs include the effects of foreign currency translation adjustments which were immaterial during the periods presented.