Segments and Geographic Area Analysis (Details 5)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Petroleo Brasileiro S.A. [Member]
Revenues from major customers that contributed more than 0.10 of total revenues
Percentage of revenues from major customers	35.00%	23.70%	15.00%
OGX Petroleo e Gas Ltda [Member]
Revenues from major customers that contributed more than 0.10 of total revenues
Percentage of revenues from major customers	14.10%	14.10%	1.40%