Fair Value Measurements (Carrying Amounts And Related Estimated Fair Value Of Debt Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-lived assets held and used	$ 3.2	$ 1.3	$ 0.9
Carrying Amount [Member] | Five Year 2.5% Unsecured Convertible Notes Due In 2013 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	278.7	346.9
Carrying Amount [Member] | Eight Year 6.75% Unsecured Note Payable Due In 2019 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	323.0	322.7
Carrying Amount [Member] | Secured Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	175.0
Carrying Amount [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	1.0	1.0
Fair Value [Member] | Five Year 2.5% Unsecured Convertible Notes Due In 2013 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	265.9	358.6
Fair Value [Member] | Eight Year 6.75% Unsecured Note Payable Due In 2019 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	198.3	281.4
Fair Value [Member] | Secured Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	175.0
Fair Value [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	1.0	1.0
Significant Other Observable Inputs (Level 2) [Member] | Five Year 2.5% Unsecured Convertible Notes Due In 2013 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	265.9	358.6
Significant Other Observable Inputs (Level 2) [Member] | Eight Year 6.75% Unsecured Note Payable Due In 2019 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	198.3	281.4
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-lived assets held and used	3.2	1.3	0.9
Significant Unobservable Inputs (Level 3) [Member] | Secured Term Loans [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	175.0
Significant Unobservable Inputs (Level 3) [Member] | Other [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair values of debt instruments	$ 1.0	$ 1.0