Fair Value Measurements (Fair Value Measurements Using Unobservable Inputs (Level 3)) (Details) (Derivative Financial Instruments [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Roll Forward]
Beginning Balance	$ 1,368	[1]	$ (5,190)	[1]
Total Gains/Losses, Realized and Included in Earnings	(3,855)	[1],[2]	281	[1],[3]
Total Gains/Losses Unrealized and Included in Other Comprehensive Income (Loss)	7,824	[1]	3,067	[1]
Transfer In/Out of Level 3	0	[1]	0	[1]
Ending Balance	$ 5,337	[1]	$ (1,842)	[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 three months ended December 31, 2014

[3] Amounts are reported in Operating Revenues in the Consolidated Statement of Income for the three months ended December 31, 2013.