| **Receivables and Allowance for Doubtful Receivables (Receivables by Type) (Details) (USD $)In Thousands, unless otherwise specified** | Dec. 31, 2012 | Dec. 31, 2011 |
|----------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Accounts Notes And Loans Receivable [Line Items]**                                                                                   |          |          |
| Receivables                                                                                                                            | $ 150,436     | $ 141,827     |
| Trade Accounts Receivable [Member]                                                                                                     |          |          |
| **Accounts Notes And Loans Receivable [Line Items]**                                                                                   |          |          |
| Receivables                                                                                                                            | 148,902       | 140,533       |
| Employee Receivable [Member]                                                                                                           |          |          |
| **Accounts Notes And Loans Receivable [Line Items]**                                                                                   |          |          |
| Receivables                                                                                                                            | 703           | 720           |
| Other Receivable [Member]                                                                                                              |          |          |
| **Accounts Notes And Loans Receivable [Line Items]**                                                                                   |          |          |
| Receivables                                                                                                                            | $ 831         | $ 574         |

| X                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_AccountsNotesAndLoansReceivableLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amounts due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer) for goods or services (including trade receivables) that have been delivered or sold in the normal course of business.
+ 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) -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 03 -Paragraph 3 -Subparagraph a, b -Article 5
+ Details**Name:**us-gaap_AccountsReceivableGrossCurrent**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |