Segments and Geographic Area Analysis (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
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									$ 2,999,038	$ 2,687,429	$ 2,398,344
Total revenues	748,357	878,177	889,496	806,389	840,966	799,724	822,603	859,681	3,322,419	3,322,974	3,631,284
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									323,381	635,545	1,232,940
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									1,736,798	1,308,641	716,448
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									451,364	641,372	717,658
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									749,128	601,122	641,180
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									$ 61,748	$ 136,294	$ 323,058