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, 2019	Sep. 30, 2018	Sep. 30, 2017
Current Income Taxes [Abstract]
Federal	$ (41,645)	$ 2,025	$ 32,034
State	4,601	8,634	10,673
Deferred Income Taxes [Abstract]
Federal	98,514	(38,927)	103,046
State	23,751	20,774	14,929
Income Tax Expense (Benefit)	85,221	(7,494)	160,682
Deferred Investment Tax Credit	(91)	(105)	(173)
Total Income Taxes	85,130	(7,599)	160,509
Presented as Follows [Abstract]
Other (Income) Deductions	(91)	(105)	(173)
Income Tax Expense (Benefit)	$ 85,221	$ (7,494)	$ 160,682