Geographic Areas (Narrative) (Detail)	12 Months Ended
	Dec. 31, 2012 Petrobras [Member]	Dec. 31, 2011 Petrobras [Member]	Dec. 31, 2010 Keppel Fels [Member]
Segment Reporting Information [Line Items]
Percentage of revenue accounted by one customer	12.00%	15.00%	13.00%