Summary of Significant Accounting Policies - Schedule of Cash and Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 487.3	$ 447.1	$ 533.7	$ 452.6
Restricted cash	44.5	63.7	42.3	9.6
Cash, cash equivalents and restricted cash	$ 531.8	$ 510.8	$ 576.0	$ 462.2