Summary Of Significant Accounting Policies (Components Of Other Current Assets) (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Sep. 30, 2014
Summary Of Significant Accounting Policies [Line Items]
Prepayments		$ 10,743	$ 10,079
Prepaid Property and Other Taxes		13,709	13,743
Fair Values of Firm Commitments		15,775	0
Regulatory Assets	[1]	20,438	22,719
Other Current Assets		60,665	54,752
Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Receivable		$ 0	$ 8,211

[1] The Company recovers the cost of its regulatory assets but generally does not earn a return on them. There are a few exceptions to this rule. For example, the Company does earn a return on Unrecovered Purchased Gas Costs and, in the New York jurisdiction of its Utility segment, earns a return, within certain parameters, on the excess of cumulative funding to the pension plan over the cumulative amount collected in rates.