Note 6 - Property, Equipment and Construction in Progress (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 27, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Property, Plant and Equipment, Estimated Useful Lives				five
Ownership Percentage Sold	49.00%					49.00%
Capitalized Exploratory Well Costs		$ 6,600,000		$ 6,600,000		$ 6,600,000
Payments to Acquire Property, Plant, and Equipment				5,403,000	40,284,000
Interest Costs Capitalized		2,372,000	3,760,000	4,991,000	6,732,000
Capital And Exploratory Expenditures Funding Agreement	185,000,000			112,000,000		126,300,000
Development of Gas-Fired Power Generation Facility In Peru [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				5,400,000
Power Plant [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				4,200,000
Interest Costs Capitalized				3,900,000
Other Capitalized Property Plant and Equipment [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				1,200,000
Interest Costs Capitalized				1,100,000
Information Technology Investment [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				100,000
CX-15 Platform At The Corvina Field [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				11,200,000
Permanent Production Facilities [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Payments to Acquire Property, Plant, and Equipment				6,400,000
Block Z-1 [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Capital And Exploratory Expenditures Funding Agreement				20,800,000
Using Straight-Line Five Year Life [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Other Depreciation and Amortization		$ 300,000		$ 500,000
Block Z-1 [Member]
Note 6 - Property, Equipment and Construction in Progress (Details) [Line Items]
Ownership Percentage Sold		49.00%		49.00%		49.00%