Summary Of Significant Accounting Policies (Components Of Other Current Assets) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013
Summary Of Significant Accounting Policies [Line Items]
Prepayments	$ 10,609	$ 10,605
Prepaid Property and Other Taxes	11,008	13,079
Fair Values of Firm Commitments	0	1,829
Regulatory Assets	27,795	26,995
Other Current Assets	49,412	56,905
Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Receivable	0	1,122
State [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Taxes Receivable	$ 0	$ 3,275