Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Line of Credit Facility [Line Items]
Unsecured Surety Bonds In Force	$ 149,674		$ 139,954
Unsecured Multicurrency Revolving Lines of Credit [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	63,652		67,968
Standby letters of credit issued and outstanding	(29,684)		(28,733)
Short-term Debt	(310)	[1]	0	[1]
Net available for additional borrowings and lines of credit	33,658		39,235
Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	660,000	[2]	500,000	[2]
Line of Credit Facility, Amount Outstanding	(170,000)	[2]	(160,000)	[2]
Standby letters of credit issued and outstanding	(50,874)	[2]	(44,549)	[2]
Net available for additional borrowings and lines of credit	$ 439,126	[2]	$ 295,451	[2]

[1] Short-term borrowings are included in "Other current liabilities" on the Consolidated Balance Sheets.

[2] See Note 6 for details regarding our secured credit facilities.