Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	$ 82,186	$ 126,689	$ 93,372	$ (3,979)
Other Comprehensive Gains and Losses Before Reclassification	(40,588)	(5,366)	23,251	170,690
Amounts Reclassified From Other Comprehensive Income (Loss)	(33,859)	(29,075)	(108,884)	(74,463)
Balance at End of Period	7,739	92,248	7,739	92,248
Gains And Losses On Derivative Financial Instruments [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	146,671	174,413	157,197	43,659
Other Comprehensive Gains and Losses Before Reclassification	(40,842)	(5,423)	23,432	170,719
Amounts Reclassified From Other Comprehensive Income (Loss)	(33,859)	(29,075)	(108,659)	(74,463)
Balance at End of Period	71,970	139,915	71,970	139,915
Gains And Losses On Securities Available For Sale [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	5,309	8,296	5,969	8,382
Other Comprehensive Gains and Losses Before Reclassification	254	57	(181)	(29)
Amounts Reclassified From Other Comprehensive Income (Loss)	0	0	(225)	0
Balance at End of Period	5,563	8,353	5,563	8,353
Funded Status Of The Pension And Other Post-Retirement Benefit Plans [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	(69,794)	(56,020)	(69,794)	(56,020)
Other Comprehensive Gains and Losses Before Reclassification	0	0	0	0
Amounts Reclassified From Other Comprehensive Income (Loss)	0	0	0	0
Balance at End of Period	$ (69,794)	$ (56,020)	$ (69,794)	$ (56,020)