Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Current Income Taxes [Abstract]
Federal			$ 29,832	$ (686)
State			10,290	18,293
Deferred Income Taxes [Abstract]
Federal			81,163	(184,419)
State			23,910	(84,829)
Income Tax Expense (Benefit)	$ 35,792	$ 8,740	145,195	(251,641)
Deferred Investment Tax Credit			(130)	(261)
Total Income Taxes			145,065	(251,902)
Presented as Follows [Abstract]
Other Income			(130)	(261)
Income Tax Expense (Benefit)	$ 35,792	$ 8,740	$ 145,195	$ (251,641)