Summary Of Significant Accounting Policies (Schedule Of Other Accruals And Current Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014
Summary Of Significant Accounting Policies [Line Items]
Regulatory Liabilities	$ 5,556	$ 18,072
Reserve for Gas Replacement	(16,506)	(39,422)
Other	27,494	32,454
Other Accruals and Current Liabilities	157,729	136,672
Accrued Capital Expenditures [Member]
Summary Of Significant Accounting Policies [Line Items]
Other	76,242	80,348
Reserve For Gas Replacement [Member]
Summary Of Significant Accounting Policies [Line Items]
Reserve for Gas Replacement	32,908	0
Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Payable	13,766	0
State [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Payable	$ 1,763	$ 5,798