Suspended Well Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Capitalized Exploratory Well Costs Beginning Balance	$ 43,589	$ 34,527	$ 9,100
Capitalized Exploratory Well Cost, Additions Pending Determination of Proved Reserves	11,952	43,589	34,527
Capitalized Exploratory Well Cost, Divestitures	(809)	0	0
Reclassification to Well, Facilities, and Equipment Based on Determination of Proved Reserves	(18,485)	(33,340)	(9,100)
Capitalized Exploratory Well Cost, Charged to Expense	(24,295)	(1,187)	0
Capitalized Exploratory Well Costs Ending Balance	11,952	$ 43,589	$ 34,527
Capitalized Exploratory Well Costs that Have Been Capitalized for Period Greater than One Year	$ 0