Note 2 - Divestiture (Details) (USD $)	1 Months Ended		9 Months Ended	12 Months Ended				1 Months Ended
	Dec. 31, 2012	Apr. 27, 2012	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2012 Collection Of Revenue [Member]	Dec. 31, 2012 Payment Of Expenses [Member]	Dec. 31, 2012 Income Taxes [Member]	Apr. 27, 2012 Gross Sales Price [Member]	Apr. 27, 2012 Block Z-1 [Member]	Sep. 30, 2013 Block Z-1 [Member]	Sep. 30, 2012 Block Z-1 [Member]
Note 2 - Divestiture (Details) [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment		$ 150,000,000						$ 150,000,000	$ 85,000,000
Ownership Percentage Sold	49.00%	49.00%		49.00%						49.00%
Capital And Exploratory Expenditures Funding Agreement		185,000,000	101,600,000	126,300,000
Participating Interest Loans		65,000,000
Transaction Costs				5,700,000
Gain (Loss) on Disposition of Oil and Gas Property	26,900,000
Gain Loss On Sale Of Oil And Gas Property Net Of Tax	31,100,000
Sale Adjustments Prior To Closing	18,300,000			18,300,000	56,100,000	32,600,000	5,200,000
Other Liabilities, Current	21,792,000		20,588,000	21,792,000						19,900,000
Other Liabilities, Noncurrent	$ 20,755,000		$ 20,755,000	$ 20,755,000							$ 20,800,000