Summary Of Significant Accounting Policies (Deferred Revenue) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 458,907	$ 413,657
Deferred Subscription Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	193,376	102,847
Deferred Support Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	256,999	297,684
Deferred License and Subscription Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	1,773	4,151
Deferred Professional Service Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	6,759	8,975
Other Current Assets [Member]
Deferred Revenue Arrangement [Line Items]
Billed but uncollected support and subscription-related revenue	$ 160,900	$ 126,300