| **Fair Value Measurements - Table 2 (Details) (USD $)In Millions, unless otherwise specified** | Mar. 31, 2014 | Dec. 31, 2013 |
|------------------------------------------------------------------------------------------------|---------------|---------------|
| Revolving Credit Facility [Member] | Carrying Amount [Member]                                  |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Advances Under Revolving Credit Facility                                                       | $ 43.0        | $ 45.0        |
| Revolving Credit Facility [Member] | Estimated Fair Value [Member]                             |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Advances Under Revolving Credit Facility, Fair Value                                           | 43.0          | 45.0          |
| 7.25% Senior Notes due 2018 [Member] | Carrying Amount [Member]                                |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 272.4         | 272.4         |
| 7.25% Senior Notes due 2018 [Member] | Estimated Fair Value [Member]                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 288.0         | 291.4         |
| 8.125% Senior Notes due 2020 [Member] | Carrying Amount [Member]                               |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 286.7         | 286.6         |
| 8.125% Senior Notes due 2020 [Member] | Estimated Fair Value [Member]                          |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 315.0         | 319.4         |
| 7.75% Senior Notes due 2022 [Member] | Carrying Amount [Member]                                |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 252.5         | 252.5         |
| 7.75% Senior Notes due 2022 [Member] | Estimated Fair Value [Member]                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 276.2         | 275.0         |
| 5.75% Senior Notes Due 2024 [Member] | Carrying Amount [Member]                                |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 275.0         | 275.0         |
| 5.75% Senior Notes Due 2024 [Member] | Estimated Fair Value [Member]                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 282.6         | 273.6         |
| 2.00% Convertible Senior Subordinated Notes due 2043 [Member] | Carrying Amount [Member]       |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Convertible Subordinated Debt                                                                  | 251.6         | 249.5         |
| 2.00% Convertible Senior Subordinated Notes due 2043 [Member] | Estimated Fair Value [Member]  |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Convertible Debt, Fair Value                                                                   | 349.0         | 339.7         |
| Other Notes Payable [Member] | Carrying Amount [Member]                                        |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Other Notes Payable                                                                            | 46.3          | 47.6          |
| Other Notes Payable [Member] | Estimated Fair Value [Member]                                   |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Other Notes Payable, Fair Value                                                                | 46.3          | 47.6          |
| Letters of Credit [Member] | Carrying Amount [Member]                                          |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Letters of Credit                                                                              | 0             | 0             |
| Letters of Credit [Member] | Estimated Fair Value [Member]                                     |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Letters of Credit, Fair Value                                                                  | $ 37.3        | $ 36.5        |

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| - Definition
Carrying amount of letters of credit at balance sheet date.
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| X                                                                                                                                                                                                                                                                                     |
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| - Definition
Fair value of other notes payable at the balance sheet date.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
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| - Definition
Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, the carrying value of convertible subordinated debt, as of the balance sheet date, initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. This form of debt can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder, and places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.
+ References
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| X                                                                                                                                                                                                                                                                                                                                        |
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| - Definition
The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.
+ References
No definition available.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of notes payable.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, the carrying value of notes payable which were initially due after one year or beyond the normal operating cycle, if longer, and which are not otherwise defined in the taxonomy.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.
+ References
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