Taxes - Net Operating Losses Available for Carryforward (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
United States [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 8,364
Net operating losses available for carryforward	Available for up to 20 years from 2012
Indonesia [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	54,435
Net operating losses available for carryforward	Available for up to 5 years from 2011
Gabon [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	23,268
Net operating losses available for carryforward	Available for up to 3 years from 2010
Oman [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	25,174
Net operating losses available for carryforward	Available for up to 5 years from 2009
The Netherlands [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	109,634
Net operating losses available for carryforward	Available for up to 9 years from 2007
Venezuela [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	3,043
Net operating losses available for carryforward	Available for up to 3 years from 2010
Colombia [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 1,214
Net operating losses available for carryforward	Available indefinitely