Acquisitions ICAP (Details) $ in Millions	12 Months Ended
Sep. 30, 2018 USD ($)
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	$ 1.4
ICAP [Member] [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	$ 6.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration