Significant Impact of Customers on Company Segments (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Asia Pacific | Exxon Mobil Corporation
Segment Reporting Information [Line Items]
Percentage of consolidated revenue	24.00%	36.00%	10.00%
Asia Pacific | BHP Billiton Petroleum Pty Ltd
Segment Reporting Information [Line Items]
Percentage of consolidated revenue	10.00%
Asia Pacific | Chevron Corporation
Segment Reporting Information [Line Items]
Percentage of consolidated revenue		10.00%	15.00%
Middle East | Saudi Aramco
Segment Reporting Information [Line Items]
Percentage of consolidated revenue	22.00%	24.00%	40.00%