Disclosures About Derivative Instruments and Hedging Activities (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Derivatives, Fair Value [Line Items]
Total Derivatives Assets	$ 43	$ 5,468
Total Derivatives Liability	(6,677)	(39,959)
Interest rate contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Assets	0	0
Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Derivative Financial Instruments and Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Liability	0	(30,522)
Commodity contracts [Member] | Accounted for Under ASC 980 [Member] | Derivative Financial Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Assets	31	5,303
Commodity contracts [Member] | Accounted for Under ASC 980 [Member] | Derivative Financial Instruments and Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Liability	(6,677)	(9,437)
Commodity contracts [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Liability	0	0
Commodity contracts [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Derivative Financial Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Derivatives Assets	$ 12	$ 165