Income Taxes (Schedule Of Income Tax Reconciliation By Applying Federal Income Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
U.S. Income (Loss) Before Income Taxes	$ 443,991	$ (523,855)	$ (698,977)
Income Tax Expense (Benefit), Computed at U.S. Federal Statutory Rate of 35%	155,397	(183,349)	(244,642)
State Income Taxes (Benefit)	16,641	(39,697)	(64,912)
Federal Tax Credits	(6,679)	(3,262)	(732)
Miscellaneous	(4,850)	(6,589)	(9,264)
Total Income Taxes	$ 160,509	$ (232,897)	$ (319,550)
Federal Statutory Rate	35.00%	35.00%	35.00%