Financial Instruments with Off-Balance Sheet Risk and Concentrations of Credit Risk Interest Rate Cash Flow Hedges (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 30, 2011	Sep. 30, 2012	Mar. 31, 2011	Dec. 31, 2010
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional Amount of Interest Rate Cash Flow Hedge Derivatives	$ 50
Accumulated other comprehensive, unrealized gain (loss) on cash flow interest rate swaps			0.6	0.2
Notional Amount of Interest Rate Derivatives	1,100.0	765.0
Cash Flow Hedge Loss Reclassified to Earnings	$ 0.3

The amount of loss reclassified into earnings in the period when cash flow hedge is discontinued because it is probable that the original forecasted transactions will not occur by the end of the original period or an additional two month time period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(4)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration