Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	$ 93,372	$ (3,979)
Other Comprehensive Gains and Losses Before Reclassification	44,249	140,628
Amounts Reclassified From Other Comprehensive Income	(39,165)	(14,176)
Balance at End of Period	98,456	122,473
Gains And Losses On Derivative Financial Instruments [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	157,197	43,659
Other Comprehensive Gains and Losses Before Reclassification	44,696	140,880
Amounts Reclassified From Other Comprehensive Income	(39,165)	(14,176)
Balance at End of Period	162,728	170,363
Gains And Losses On Securities Available For Sale [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Balance at Beginning of Period	5,969	8,382
Other Comprehensive Gains and Losses Before Reclassification	(447)	(252)
Amounts Reclassified From Other Comprehensive Income	0	0
Balance at End of Period	5,522	8,130
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)
Other Comprehensive Gains and Losses Before Reclassification	0	0
Amounts Reclassified From Other Comprehensive Income	0	0
Balance at End of Period	$ (69,794)	$ (56,020)