| **Receivables and Allowance for Doubtful Receivables (Tables)**                | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
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| **Receivables and Allowance for Doubtful Receivables [Abstract]**              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] |    2012 2011 Trade$ 148,902  140,533 Employee  703  720 Other  831  574 Total Receivables$ 150,436  141,827                                                                                                                                                                                                                                                                                                                 |
| Allowance For Doubtful Accounts Receivable Rollforward [Table Text Block]      |      Additions Deductions   Description Balance at beginning of year Charged to costs and expenses Charged to other accounts Write-offs net of recoveries Balance at end of year December 31, 2012$ 5,796  3,649  (2,261)  3,969  3,215 December 31, 2011$ 9,189  4,294  (29)  7,658  5,796 December 31, 2010$ 7,060  3,085  1,670  2,626  9,189 |

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| - Definition
No authoritative reference available.
+ References
No definition available.
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| - Definition
Tabular disclosure of the various types of trade accounts and notes receivable and for each the gross carrying value, allowance, and net carrying value as of the balance sheet date. Presentation is categorized by current, noncurrent and unclassified receivables.
+ 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 210.5-02.3,4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3, 4 -Article 5
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