Income Taxes (Significant Components Of Deferred Tax Liabilities And Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred Tax Liabilities [Abstract]
Property, Plant and Equipment	$ 861,278	$ 770,794
Pension and Other Post-Retirement Benefit Costs	55,795	39,541
Other	54,486	49,734
Total Deferred Tax Liabilities	971,559	860,069
Deferred Tax Assets [Abstract]
Tax Loss and Credit Carryforwards	(175,542)	(214,128)
Pension and Other Post-Retirement Benefit Costs	(87,280)	(62,969)
Other	(55,355)	(75,286)
Total Gross Deferred Tax Assets	(318,177)	(352,383)
Valuation Allowance	0	5,000
Total Deferred Tax Assets	(318,177)	(347,383)
Total Net Deferred Income Taxes	$ 653,382	$ 512,686