Deferred Revenue and Related Customer Receivables (Details) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 30, 2017
Other Assets
Deferred Revenue and Financing Receivables [Line Items]
Billed but uncollected support and subscription related receivable	$ 108.7	$ 160.9

Amount, after allowance, receivable from customers, clients, or other third-parties, and receivables classified as other due within one year or the normal operating cycle, if longer.

No definition available.

Name:	us-gaap_AccountsAndOtherReceivablesNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant