Derivative Instruments and Hedging Activities (Details 3) (Swap [Member], Fair Value Hedging [Member], Other Income Expense [Member], USD $) In Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Swap [Member] \| Fair Value Hedging [Member] \| Other Income Expense [Member]
Income Statement Classification
Gain/(Loss) on the hedged fixed rate debt attributable to changes in the market interest rates	$ 607	$ 3,061	$ (2,164)	$ 4,751

Amount of unrealized gain (loss) related to the fair value of interest rate derivatives designated as fair value hedging instruments. Recognized in earnings and offsets the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

Name:	us-gaap_IncreaseDecreaseInFairValueOfInterestRateFairValueHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration