Suspended Exploratory Well Costs - Additional Information (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Aug. 31, 2014 ft	Aug. 31, 2014 m Reservoirs	Nov. 30, 2013 Interval ft	Sep. 30, 2014 Miocene Exploratory Drilling Activities	Dec. 31, 2013 Miocene Exploratory Drilling Activities	Sep. 30, 2014 Pliocene Exploratory Drilling Activity
Costs Incurred Oil And Gas Property Acquisition Exploration And Development Activities [Line Items]
Suspended exploratory well cost				$ 26.5	$ 26.5	$ 6.5
Number of feet encountered by Hydrocarbons in three intervals, as interpreted by “LWD” data			65
Number of hydrocarbons Miocene formation intervals			3
Pliocene formation Eastern fault block vertical depth	6,059	1,847
Number of Pliocene formation Eastern fault block new oil and gas reservoirs	4	4
Hydrocarbons Pliocene formation Eastern fault block gross thickness	112	112