| **Financial Instruments (Tables)**                                               | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
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| **Financial Instruments [Abstract]**                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| Fair Value, by Balance Sheet Grouping [Table Text Block]                         |    March 31, December 31,   2013 2012   Carrying Amount Fair Value Carrying Amount Fair Value Current and long-term debt and  capital lease obligations$966,394 970,071 957,663 979,594 Other liabilities 25,675 24,850 25,511 24,766                                                                                                                                                                                                                                                                                                      |
| Fair Value Assets And Liabilities Measured On Recurring Basis [Table Text Block] |    Fair Value Measurement at Reporting Date Using March 31, 2013 Assets Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Deferred compensation plan assets  (mutual funds)$ 1,916  -  - Total assets at fair value$ 1,916  -  -         December 31, 2012 Assets       Deferred compensation plan assets  (mutual funds)$ 1,758  -  - Total assets at fair value$ 1,758  -  - |

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| - Definition
This element represents the disclosure related to assets and liabilities by class, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring and/or nonrecurring basis in periods after initial recognition (for example, impaired assets). The disclosures that may be required or desired include: (a) the fair value measurements recorded during the period and the reasons for the measurements and (b) the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.
+ References
No definition available.
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| - Definition
Tabular disclosure of the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments, assets, and liabilities. Such certain disclosures about the financial instruments, assets, and liabilities include: (1) the fair value of the required items together with their carrying amounts (as appropriate) and (2) the methodology and assumptions used in developing such estimates of fair value.
+ References
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