The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 470

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031897-161870

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Name:	us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Debt Convertible Senior Subordinated Notes Additional Information (Details) (Convertible Subordinated Debt [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Aug. 04, 2006 Senior Subordinated Notes [Member]	Aug. 01, 2011 Repurchased [Member] Senior Subordinated Notes [Member]	Sep. 30, 2011 Redeemed [Member] Senior Subordinated Notes [Member]
Convertible Senior Subordinated Notes [Line Items]
Repurchase of convertible senior subordinated debt			$ 184.8	$ 38.8
Estimated nonconvertible debt borrowing rate		7.38%
Debt Instrument, Convertible, Carrying Amount of Equity Component	$ 31.8