Note 1 - Organization and Accounting Policies - Average Brent Crude Oil Price (Details)	3 Months Ended
	Jun. 30, 2023 $ / item	Jun. 30, 2023 $ / bbl	Mar. 31, 2023 $ / bbl	Dec. 31, 2022 $ / bbl	Sep. 30, 2022 $ / bbl	Jun. 30, 2022 $ / bbl	Mar. 31, 2022 $ / bbl
Average sales price (in USD per Barrel of Oil)	78	77.99	81.07	88.72	100.71	113.84	100.87