Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 41.7	$ 64.0	$ 118.3	$ 105.7
Other comprehensive gain/(loss), net of tax:
Foreign currency translation adjustment	3.2	1.2	11.4	(0.1)
Cash flow hedges	14.3	(18.1)	29.0	(18.2)
Total other comprehensive gain/(loss), net of tax	17.5	(16.9)	40.4	(18.3)
Comprehensive income	$ 59.2	$ 47.1	$ 158.7	$ 87.4