Segments and Geographic Area Analysis (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues by geographic area, presented by attributing revenues to the individual country
Total revenues	$ 738,188	$ 889,496	$ 1,506,830	$ 1,695,885
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	49,960	101,221	96,566	151,495
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	347,748	441,221	723,593	885,324
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	126,667	118,454	267,390	223,122
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	160,397	209,102	321,905	399,150
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	$ 53,416	$ 19,498	$ 97,376	$ 36,794