Summary of Significant Accounting Policies - Foreign Currency Translation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Gain (Loss), Foreign Currency Transaction, before Tax [Abstract]
Foreign currency transaction and remeasurement gains (losses)	$ 0.1	$ 0.3	$ (2.7)	$ (2.9)