| **Financial Instruments (Carrying amounts and fair value of the financial instruments) (Details) (USD $)In Thousands, unless otherwise specified** | Jun. 30, 2014 | Dec. 31, 2013 |
|----------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Carrying Amount**                                                                                                                                |          |          |
| Current and long-term debt                                                                                                                         | $ 1,085,859   | $ 1,047,980   |
| **Fair Value**                                                                                                                                     |          |          |
| Current and long-term debt                                                                                                                         | $ 1,118,227   | $ 1,058,431   |
| Senior Notes Due 2021 [Member] | Line of Credit [Member]                                                                                           |          |          |
| **Fair Value**                                                                                                                                     |          |          |
| Debt percentage                                                                                                                                    | 6.75%         |          |
| Senior Notes Due 2019 [Member] | Line of Credit [Member]                                                                                           |          |          |
| **Fair Value**                                                                                                                                     |          |          |
| Debt percentage                                                                                                                                    | 8.63%         |          |

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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
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| X                                                                                                                                                                                                         |
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