Summary Of Significant Accounting Policies (Schedule Of Other Accruals And Current Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011
Segment Reporting Information [Line Items]
Accrued Capital Expenditures	$ 58,632	$ 118,624	$ 67,503	$ 125,115
Regulatory Liabilities	13,318		18,289
Reserve for Gas Replacement	(22,180)		(49,795)
Other	25,235		24,350
Total Other Accruals and Current Liabilities	109,933		79,099
Other Accruals [Member]
Segment Reporting Information [Line Items]
Accrued Capital Expenditures	49,348		36,460
Reserve For Gas Replacement [Member]
Segment Reporting Information [Line Items]
Reserve for Gas Replacement	$ 22,032		$ 0