Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ / shares in Thousands	Jun. 30, 2024	Dec. 31, 2023
Allowance for doubtful accounts	$ 100,000	$ 100,000
Asser retirement obligations, non-related party	$ 271,000	$ 250,000
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, shares issued (in shares)	6,360,000	6,300,000
Common stock, shares outstanding (in shares)	6,360,000	6,300,000