Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Line of Credit Facility [Line Items]
Long-term borrowings	$ (125,000)
Standby LOCs issued and outstanding	(47,800)
Net available for additional borrowings and LOCs	487,200
Unsecured surety bonds in force	137,002		164,820
Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	660,000	[1]	660,000	[1]
Long-term borrowings	(125,000)	[1]	(140,000)	[1]
Standby LOCs issued and outstanding	(47,772)	[1]	(54,328)	[1]
Net available for additional borrowings and LOCs	487,228	[1]	465,672	[1]
Unsecured Multicurrency Revolving Lines of Credit [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	96,864		67,308
Standby LOCs issued and outstanding	(28,056)		(29,906)
Short-term borrowings(2)	(1,537)	[2]	(851)	[2]
Net available for additional borrowings and LOCs	$ 67,271		$ 36,551

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

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