Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	$ 660,000
Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	660,000	[1]	660,000	[1]
Long-term Line of Credit	136,310	[1]	91,469	[1]
Standby LOCs issued and outstanding	(52,950)	[1]	(50,399)	[1]
Line of Credit Facility, Remaining Borrowing Capacity	470,740	[1]	518,132	[1]
Unsecured Multicurrency Revolving Lines of Credit [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	99,845		106,855
Standby LOCs issued and outstanding	(29,605)		(28,636)
Short-term borrowings(2)	(4,927)	[2]	(4,282)	[2]
Line of Credit Facility, Remaining Borrowing Capacity	65,313		73,937
Surety Bond [Member]
Line of Credit Facility [Line Items]
Unsecured surety bonds in force	$ 117,554		$ 116,306

[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.