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

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) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 Convertible Subordinated Debt [Member]	Aug. 04, 2006 Convertible Subordinated Debt [Member] Senior Subordinated Notes [Member]	Aug. 01, 2011 Repurchased [Member]	Sep. 30, 2011 Redeemed [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