| **Fair Value Measurements - Table 2 (Details) (USD $)In Millions, unless otherwise specified** | Mar. 31, 2013 | Dec. 31, 2012 |
|------------------------------------------------------------------------------------------------|---------------|---------------|
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Advances Under Revolving Credit Facility                                                       | $ 122.0       | $ 0           |
| Other Notes Payable                                                                            | 42.3          | 36.8          |
| Revolving Credit Facility [Member] | Carrying Amount [Member]                                  |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Advances Under Revolving Credit Facility                                                       | 122.0         | 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                                           | 122.0         | 0             |
| 7.25% Senior Notes due 2018 [Member]                                                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 302.8         | 302.9         |
| 7.25% Senior Notes due 2018 [Member] | Carrying Amount [Member]                                |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 302.8         | 302.9         |
| 7.25% Senior Notes due 2018 [Member] | Estimated Fair Value [Member]                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 324.9         | 328.6         |
| 8.125% Senior Notes due 2020 [Member]                                                          |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 286.3         | 286.2         |
| 8.125% Senior Notes due 2020 [Member] | Carrying Amount [Member]                               |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 286.3         | 286.2         |
| 8.125% Senior Notes due 2020 [Member] | Estimated Fair Value [Member]                          |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 321.2         | 321.5         |
| 7.75% Senior Notes due 2022 [Member]                                                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 280.6         | 280.7         |
| 7.75% Senior Notes due 2022 [Member] | Carrying Amount [Member]                                |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 280.6         | 280.7         |
| 7.75% Senior Notes due 2022 [Member] | Estimated Fair Value [Member]                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes, Fair Value                                                                       | 303.4         | 306.5         |
| 5.75% Senior Notes Due 2024 [Member]                                                           |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Senior Notes                                                                                   | 275.0         | 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                                                                       | 277.0         | 277.1         |
| Other Notes Payable [Member] | Carrying Amount [Member]                                        |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Other Notes Payable                                                                            | 42.3          | 36.8          |
| Other Notes Payable [Member] | Estimated Fair Value [Member]                                   |          |          |
| **Carrying Amounts and Estimated Fair Values, Financial Instruments [Abstract]**               |          |          |
| Other Notes Payable, Fair Value                                                                | 42.3          | 36.8          |
| 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                                                                  | $ 35.9        | $ 39.5        |

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| X                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Carrying amount of letters of credit at balance sheet date.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value of other notes payable at the balance sheet date.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. Fair value of lines of credit at the balance sheet date.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents notes payable as of the balance sheet date.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -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.Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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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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