| **Long-term Debt - Textual (Details) $ in Millions**             |        |          |          | 1 Months Ended | 3 Months Ended | 6 Months Ended |        |        |         |         |        |          |
|------------------------------------------------------------------|--------|----------|----------|----------------|----------------|----------------|--------|--------|---------|---------|--------|----------|
||
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Repayments of Long-term Debt                                     |   |     |     |           |           |           |   |   | $ 112.8 | $ 546.1 |   |     |   |   |   |   |
| Loss on early extinguishment of debt                             |   |     |     |           |           | $ 2.4          | $ 2.4  | $ 18.8 | 4.8     | $ 20.0  |   |     |   |   |   |   |
| Other notes payable                                              |   |     |     |           |           | $ 43.3         |   |   | $ 43.3  |    |   |     |   |   |   | $ 39.2 |
| 7.75% Senior Notes Due 2022 [Member]                             |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Senior Notes, Portion of Principal Extinguished                  |   |     |     |           |           |           |   |   |    |    |   |     | $ 50.0 |   | $ 50.0 |   |
| Senior Note, redemption price                                    |   | 103.875% | 103.875% |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Repayments of Long-term Debt                                     |   | $ 52.0   | $ 52.0   |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Debt Instrument, Interest Rate, Stated Percentage                |   |     |     |           |           | 7.75%          |   |   | 7.75%   |    |   |     |   |   |   |   |
| 7.75% Senior Notes Due 2022 [Member] | Subsequent Event [Member] |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Senior Note, redemption price                                    |   |     |     |           |           |           |   |   |    |    |   | 102.583% |   |   |   |   |
| Senior Notes, Principal Extinguished                             |   |     |     |           |           |           |   |   |    |    |   | $ 76.0   |   |   |   |   |
| 5.125% Senior Notes Due 2023 [Member]                            |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Debt Instrument, Interest Rate, Stated Percentage                |   |     |     |           |           | 5.125%         |   |   | 5.125%  |    |   |     |   |   |   |   |
| 5.75% Senior Notes Due 2024 [Member]                             |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Debt Instrument, Interest Rate, Stated Percentage                |   |     |     |           |           | 5.75%          |   |   | 5.75%   |    |   |     |   |   |   |   |
| 5.75% Senior Notes Due 2025 [Member]                             |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Debt Instrument, Interest Rate, Stated Percentage                |   |     |     |           |           | 5.75%          |   |   | 5.75%   |    |   |     |   |   |   |   |
| 2.00% Convertible Senior Subordinated Notes due 2043 [Member]    |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Debt Instrument, Interest Rate, Stated Percentage                |   |     |     |           |           | 2.00%          |   |   | 2.00%   |    |   |     |   |   |   |   |
| Scenario, Forecast [Member]                                      |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Repayments of Long-term Debt                                     | $ 78.0 |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Loss on early extinguishment of debt                             |   |     |     |           | $ 3.0          |           |   |   |    |    |   |     |   |   |   |   |
| Corporate Office                                                 |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Lessee Leasing Arrangements, Operating Leases, Term of Contract  |   |     |     | 15 years       |           |           |   |   |    |    |   |     |   |   |   |   |
| Number of renewal options                                        |   |     |     |           |           |           |   |   |    |    |   |     |   | 4 |   |   |
| Lessee Leasing Arrangements, Operating Leases, Renewal Term      |   |     |     | 5 years        |           |           |   |   |    |    |   |     |   |   |   |   |
| Construction in Progress, Increase                               |   |     |     |           |           | $ 5.8          |   |   | $ 5.8   |    |   |     |   |   |   |   |
| Other notes payable                                              |   |     |     |           |           | $ 5.8          |   |   | $ 5.8   |    |   |     |   |   |   |   |
| Corporate Office | Scenario, Forecast [Member]                   |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| **Long Term Debt (Textual) [ Abstract]**                         |   |     |     |           |           |           |   |   |    |    |   |     |   |   |   |   |
| Financing Obligation                                             |   |     |     |           |           |           |   |   |    |    | $ 56.0 |     |   |   |   |   |

| X                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Financing obligation for construction in progress.
+ References
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| X                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Long Term Debt.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of renewal options as part of the development/lease agreement for the new corporate headquarters.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A portion of the principal amount of Senior Notes extinguished.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Gross principal amount of Senior Notes extinguished.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Price expressed as a percentage of principal amount at which the Company may redeem its senior notes during a specific time period in the future.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Term of the lessee's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Term of the lessee's leasing arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
No definition available.
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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
The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.
+ References
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