Note 7 - Supplemental Information Relating to Oil and Gas Producing Activities (Unaudited) - Changes in the Standardized Measure of Discounted Future Net Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance, beginning of year	$ (8,564)	$ (2,502)
Revision of quantity estimates	12,040	(1,337)
Sales of crude oil and natural gas, net of production costs	(6,773)	(1,458)
Net change in income taxes	(194)	79
Net changes in prices and production costs	5,394	(7,748)
Accretion of discount	(856)	(250)
Other	5,729	4,652
Balance, end of year	$ 6,776	$ (8,564)