Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 10.8	$ 25.2	$ (1.3)	$ 19.5
Net derivative gains and other costs arising during the period, net of tax expense of $0.0; $0.3; $0.0; and $1.0, respectively	[1]	1.1	0.7	3.9	1.9
Reclassification of losses (gains) into net income (loss), net of tax benefit (expense) of $0.0; $(0.1); $0.0; and $1.4, respectively		(0.1)	(0.3)	(0.2)	(3.9)
Other comprehensive income		1.2	0.4	4.1	5.8
Comprehensive income		$ 12.0	$ 25.6	$ 2.8	$ 25.3

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