Segments and Geographic Area Analysis (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Revenues by geographic area, presented by attributing revenues to the individual country
Total revenues	$ 768,642	$ 806,389
United States [Member]
Revenues by geographic area, presented by attributing revenues to the individual country
Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Entity's Country of Domicile	46,606	50,274
South America [Member]
Revenues by geographic area, presented by attributing revenues to the individual country
Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries, Amount	375,845	444,103
Australia/Asia [Member]
Revenues by geographic area, presented by attributing revenues to the individual country
Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries, Amount	140,723	104,668
Europe/Africa/Mediterranean [Member]
Revenues by geographic area, presented by attributing revenues to the individual country
Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries, Amount	161,508	190,048
Mexico [Member]
Revenues by geographic area, presented by attributing revenues to the individual country
Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Individual Foreign Countries, Amount	$ 43,960	$ 17,296