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, 2016	Sep. 30, 2015	Sep. 30, 2014
Current Income Taxes [Abstract]
Federal	$ (6,658)	$ 25,064	$ 34,579
State	20,903	13,387	12,620
Deferred Income Taxes [Abstract]
Federal	(164,818)	(244,336)	116,143
State	(81,976)	(113,251)	26,272
Income Tax Expense (Benefit)	(232,549)	(319,136)	189,614
Deferred Investment Tax Credit	(348)	(414)	(434)
Total Income Taxes	(232,897)	(319,550)	189,180
Presented as Follows [Abstract]
Other Income	(348)	(414)	(434)
Income Tax Expense (Benefit)	$ (232,549)	$ (319,136)	$ 189,614