Restructuring and Severance Charges - Additional Information (Details) $ in Millions	3 Months Ended
Dec. 31, 2017 USD ($)
Employee Severance
Restructuring Cost and Reserve [Line Items]
Net provisions	$ 4.6
Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Net provisions	$ 0.6

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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration