Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Current Income Taxes [Abstract]
Federal	$ 25,064	$ 34,579	$ (632)
State	13,387	12,620	5,503
Deferred Income Taxes [Abstract]
Federal	(244,336)	116,143	130,318
State	(113,251)	26,272	37,569
Income Tax Expense	(319,136)	189,614	172,758
Deferred Investment Tax Credit	(414)	(434)	(426)
Total Income Taxes	(319,550)	189,180	172,332
Presented as Follows [Abstract]
Other Income	(414)	(434)	(426)
Income Tax Expense (Benefit)	$ (319,136)	$ 189,614	$ 172,758