Revenue - Unearned Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021
Unearned Revenue (Details)
Unearned Revenue	$ 26.5	$ 22.6	$ 26.5	$ 22.6	$ 25.7	$ 21.6	$ 24.8	$ 15.5
Contract with Customer, Liability, Revenue Recognized	$ 6.7	$ 5.4	$ 18.9	$ 12.0