Commitments and Contingencies (Details) $ in Thousands	1 Months Ended		3 Months Ended
	Jan. 31, 2017 USD ($)	Nov. 30, 2015 USD ($)	Mar. 31, 2017 USD ($) km² item	Mar. 31, 2016	Dec. 31, 2016 USD ($)
Commitments and contingencies
Interest accrual rate on line of credit receivable		7.875%
Long-term receivables - joint interest billings			$ 47,306		$ 45,663
Morocco
Commitments and contingencies
3 D seismic requirements (in square kilometers) | km²			3,000
Sao Tome and Principe
Commitments and contingencies
3 D seismic requirements (in square kilometers) | km²			4,750
Western Sahara
Commitments and contingencies
3 D seismic requirements (in square kilometers) | km²			5,000
Mauritania And Senegal Offshore Block | Maximum
Commitments and contingencies
Spending by third party for exploration and appraisal costs			$ 221,000
Timis Corporation
Commitments and contingencies
Line of credit receivable		$ 30,000
Long-term receivables - joint interest billings			1,600
Amount payable in settlement of line of credit and joint interest billing			16,000
Timis Corporation | Other noncurrent assets
Commitments and contingencies
Line of credit receivable amount outstanding			$ 14,500
Timis Corporation | Cayar Offshore Profond And Saint Louis Offshore Profond Blocks
Commitments and contingencies
Participating interests (as a percent)				30.00%
Number of Blocks | item			2
Operating leases
Future minimum rental commitments
2016			$ 3,963
2018			4,600
2019			3,940
2020			65
Total			12,568
Atwood Achiever drilling rig contract
Future minimum rental commitments
2016			133,875
Total			133,875
Atwood Achiever drilling rig contract | Kosmos Energy Ventures
Future minimum rental commitments
Recovery payment for reverting the rig rate back to original day rate			$ 48,100
Rig rate per day - subsidiary's revert option	$ 600