| **Fair Value Measurements and Derivative Instruments (Carrying amounts and fair value of the financial instruments) (Details) - USD ($) $ in Thousands** | Sep. 30, 2016 | Dec. 31, 2015 |
|----------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Senior Notes Due 2021 | Senior Notes                                                                                                                     |          |          |
| **Debt Instrument [Line Items]**                                                                                                                         |          |          |
| Debt stated percentage                                                                                                                                   | 6.75%         |          |
| Senior Notes Due 2025 | Senior Notes                                                                                                                     |          |          |
| **Debt Instrument [Line Items]**                                                                                                                         |          |          |
| Debt stated percentage                                                                                                                                   | 6.875%        |          |
| Carrying Value [Member]                                                                                                                                  |          |          |
| **Debt Instrument [Line Items]**                                                                                                                         |          |          |
| Current and long-term debt                                                                                                                               | $ 1,333,535   | $ 1,348,106   |
| Fair Value [Member]                                                                                                                                      |          |          |
| **Debt Instrument [Line Items]**                                                                                                                         |          |          |
| Current and long-term debt                                                                                                                               | $ 1,392,626   | $ 1,390,743   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13476-108611
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contractual interest rate for funds borrowed, under the debt agreement.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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| X                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_DebtInstrumentLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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