Note 3 - Oil and Natural Gas Investments (Details Textual) $ in Millions	6 Months Ended	102 Months Ended
Jun. 30, 2026 USD ($)	Jun. 30, 2026 USD ($)
Oil and Gas, Cost Incurred, Development Cost	$ 1.4	$ 148.0
Wells Elected to Participate in Drilling		101

Amount of development cost incurred in oil- and gas-producing activities. Includes capitalized cost and cost charged to expense.

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