Commitments and Contingencies Available Lines of Credit, Outstanding Standby Letter of Credits, and Bonds (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Jun. 23, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit			$ 500,000
Line of Credit Facility, Capacity remaining to support letters of credit		$ 250,168		$ 449,601
Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit	[1]	500,000		660,000
Long-term Line of Credit	[1]	147,958		91,469
Letters of Credit Outstanding, Amount	[1]	49,832		50,399
Unsecured Multicurrency Revolving Lines of Credit [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit		101,023		106,855
Letters of Credit Outstanding, Amount		31,743		28,636
Short-term borrowings(2)	[2]	(3,597)		(4,282)
Line of Credit Facility, Remaining Borrowing Capacity		65,683		73,937
Surety Bond [Member]
Line of Credit Facility [Line Items]
Unsecured surety bonds in force		72,951		116,306
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Multicurrency revolving line of credit		50,000
Long-term Line of Credit				91,469
Letters of Credit Outstanding, Amount		49,800
Line of Credit Facility, Remaining Borrowing Capacity		$ 244,472		$ 518,132	[1]

[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.