Commitments and Contingencies - Litigation (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Dec. 12, 2016 USD ($) item	Mar. 31, 2011 USD ($)	Dec. 31, 2016 USD ($) item	Dec. 31, 2009 USD ($)	Dec. 31, 2006 USD ($)	Mar. 19, 2012 USD ($)
Court of Ouargla Customs Infringement
Commitments and Contingencies, Disclosure
Litigation amount as per judgment			$ 3,600	$ 13,000
Litigation settlement fine (as percent)			50.00%
Additional amount to be recovered			$ 4,400
Amount paid to customs authority			3,100
Posted security paid			$ 1,330
Court of Ouargla Foreign Currency Controls
Commitments and Contingencies, Disclosure
Litigation amount as per judgment		$ 25,600
Payment of contract amount in foreign currency					$ 7,500
Payment of contract amount in domestic currency					$ 3,200
Approximate multiplier of the amount at issue for fines and penalties			4
Court of Ouargla Foreign Currency Controls | Maximum
Commitments and Contingencies, Disclosure
Potential judgment in excess of accrual			$ 17,600
NGH2L
Commitments and Contingencies, Disclosure
Escrow Deposit						$ 3,000
NGH2L | Maximum
Commitments and Contingencies, Disclosure
Monetary damages sought based on alleged breach of contract by NGH2L and alleged tortious interference with contractual relations by Parex			750,000
Potential recovery			$ 4,500
C J Energy And Subsidiaries
Commitments and Contingencies, Disclosure
Number of allowed unsecured claims | item	2		2
Maximum claim distribution to be received	$ 4,850		$ 4,850
Maximum obligation amount relating to tax matters	$ 11,500		$ 11,500
pro-rate share of warrant to acquire common equity percentage	2.00%		2.00%