Summary of Significant Accounting Polices - Cash Equivalents (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Cash Equivalents
Restricted cash	$ 27.3	$ 29.5

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Balance Type:	debit
Period Type:	instant