Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) (USD $) In Thousands | Sep. 30, 2011 | Dec. 31, 2010 | ||||||
|---|---|---|---|---|---|---|---|---|
| Line of Credit Facility [Line Items] | ||||||||
| Unsecured Surety Bonds In Force | $ 142,336 | $ 120,109 | ||||||
Credit Facility [Member] | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Multicurrency revolving line of credit | 500,000 | [1] | 240,000 | [1] | ||||
| Line of Credit Facility, Amount Outstanding | (200,000) | [1] | 0 | [1] | ||||
| Standby letters of credit issued and outstanding | (35,872) | [1] | (43,540) | [1] | ||||
| Net available for additional borrowings and lines of credit | 264,128 | [1] | 196,460 | [1] | ||||
Unsecured Multicurrency Revolving Lines of Credit [Member] | ||||||||
| Line of Credit Facility [Line Items] | ||||||||
| Multicurrency revolving line of credit | 76,405 | 49,122 | ||||||
| Standby letters of credit issued and outstanding | (30,500) | (21,784) | ||||||
| Short-term borrowings | (901) | [2] | (66) | [2] | ||||
| Net available for additional borrowings and lines of credit | $ 45,004 | $ 27,272 | ||||||
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