| **Commitments and Contingencies (Summary of minimum future lease payments) (Details) (USD $)In Thousands, unless otherwise specified** | Dec. 31, 2013 |
|----------------------------------------------------------------------------------------------------------------------------------------|---------------|
| **Operating**                                                                                                                          |          |
| 2014                                                                                                                                   | $ 37,163      |
| 2015                                                                                                                                   | 31,358        |
| 2016                                                                                                                                   | 27,636        |
| 2017                                                                                                                                   | 22,120        |
| 2018                                                                                                                                   | 19,996        |
| 2019 and thereafter                                                                                                                    | 66,020        |
| Total minimum lease payments                                                                                                           | 204,293       |
| **Capital**                                                                                                                            |          |
| 2014                                                                                                                                   | 11,758        |
| 2015                                                                                                                                   | 11,734        |
| 2016                                                                                                                                   | 11,745        |
| 2017                                                                                                                                   | 11,723        |
| 2018                                                                                                                                   | 11,730        |
| 2019 and thereafter                                                                                                                    | 43,297        |
| Total minimum lease payments                                                                                                           | 101,987       |
| Less amount representing interest                                                                                                      | 27,381        |
| Less current maturity of obligations under capital leases                                                                              | 6,465         |
| Obligations under capital leases, excluding current maturities                                                                         | $ 68,141      |

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Amount of capital lease obligation due within one year or the normal operating cycle, if longer.
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