Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at Beginning of Period	$ (30,123)	$ (5,640)
Other Comprehensive Gains and Losses Before Reclassifications	(3,173)	(30,988)
Amounts Reclassified From Other Comprehensive Loss	(7,623)	(18,231)
Balance at End of Period	(40,919)	(54,859)
Gains And Losses On Derivative Financial Instruments [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at Beginning of Period	20,801	64,782
Other Comprehensive Gains and Losses Before Reclassifications	(3,194)	(30,449)
Amounts Reclassified From Other Comprehensive Loss	(7,351)	(17,763)
Balance at End of Period	10,256	16,570
Gains And Losses On Securities Available For Sale [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at Beginning of Period	7,562	6,054
Other Comprehensive Gains and Losses Before Reclassifications	21	(539)
Amounts Reclassified From Other Comprehensive Loss	(272)	(468)
Balance at End of Period	7,311	5,047
Funded Status Of The Pension And Other Post-Retirement Benefit Plans [Member]
Accumulated Other Comprehensive Loss [Roll Forward]
Balance at Beginning of Period	(58,486)	(76,476)
Other Comprehensive Gains and Losses Before Reclassifications	0	0
Amounts Reclassified From Other Comprehensive Loss	0	0
Balance at End of Period	$ (58,486)	$ (76,476)