The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 21

-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Fair Value Measurements - (Other Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Stock Options [Member]	Feb. 14, 2007 Senior Notes [Member]	Dec. 31, 2012 Senior Notes [Member] Quoted Prices in Active Markets (Level 1) [Member]	Dec. 31, 2011 Senior Notes [Member] Quoted Prices in Active Markets (Level 1) [Member]	Dec. 31, 2012 Senior Notes and Notes Payable [Member] Fair Value [Member]	Dec. 31, 2011 Senior Notes and Notes Payable [Member] Fair Value [Member]	Dec. 31, 2012 Senior Notes and Notes Payable [Member] Book Value [Member]	Dec. 31, 2011 Senior Notes and Notes Payable [Member] Book Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross realized gains, sale proceeds	$ 0.2
Interest rate of senior notes		9.75%
Senior Notes and note payable, fair value			$ 274.6	$ 272.9	$ 274.6	$ 273.0	$ 275.0	$ 275.1