Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Current Income Taxes [Abstract]
Federal	$ 8,245	$ (8,227)
State	3,335	3,890
Deferred Income Taxes [Abstract]
Federal	36,418	(97,705)
State	8,434	(42,308)
Income Tax Expense (Benefit)	56,432	(144,350)
Deferred Investment Tax Credit	(43)	(87)
Total Income Taxes	56,389	(144,437)
Presented as Follows [Abstract]
Other Income	(43)	(87)
Income Tax Expense (Benefit)	$ 56,432	$ (144,350)