Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	$ 660,000	[1]	$ 660,000	[1]
Long-term borrowings	(91,469)	[1]	(120,000)	[1]
Standby LOCs issued and outstanding	(50,399)	[1]	(49,491)	[1]
Net available for additional borrowings and LOCs	518,132	[1]	490,509	[1]
Unsecured Multicurrency Revolving Lines of Credit [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	106,855		115,269
Standby LOCs issued and outstanding	(28,636)		(31,714)
Short-term borrowings(2)	(4,282)	[2]	(4,252)	[2]
Net available for additional borrowings and LOCs	73,937		79,303
Surety Bond [Member]
Line of Credit Facility [Line Items]
Unsecured surety bonds in force	$ 116,306		$ 186,446

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

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