Fair Value Measurements (Fair Value Measurements Using Unobservable Inputs (Level 3)) (Details) (Derivative Financial Instruments [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013
Derivative Financial Instruments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Balance, Beginning of Year	$ (5,190)	[1]	$ (19,664)	[1]
Total Gains/Losses, Realized and Included in Earnings	2,217	[1],[2]	13,408	[1],[3]
Total Gains/Losses, Unrealized and Included in Other Comprehensive Income (Loss)	4,341	[1]	1,066	[1]
Transfer In/(Out) of Level 3	0	[1]	0	[1]
Balance, End of Year	$ 1,368	[1]	$ (5,190)	[1]

[1] Derivative Financial Instruments are shown on a net basis.

[2] Amounts are reported in Operating Revenues in the Consolidated Statement of Income for the year ended September 30, 2014.

[3] Amounts are reported in Operating Revenues in the Consolidated Statement of Income for the year ended September 30, 2013.