Summary Of Significant Accounting Policies (Deferred Revenue) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 499,443	$ 458,907
Deferred Subscription Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	288,012	193,376
Deferred Support Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	196,684	256,999
Deferred License and Subscription Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	1,475	1,773
Deferred Professional Service Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	13,272	6,759
Other Current Assets [Member]
Deferred Revenue Arrangement [Line Items]
Billed but uncollected support and subscription-related revenue	$ 153,600	$ 160,900