Summary Of Significant Accounting Policies (Components Of Other Current Assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Sep. 30, 2011
Summary Of Significant Accounting Policies [Line Items]
Prepayments	$ 8,316		$ 9,489
Prepaid Property and Other Taxes	14,455		13,240
Fair Values of Firm Commitments	1,291		9,096
Regulatory Assets	29,726	[1]	26,589	[1]
Other Current Assets	56,121		64,923
Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Receivable	268		385
State [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Receivable	$ 2,065		$ 6,124

[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.