Note 7 - Oil and Gas Leases - Company's Royalty and Working Interests Share (Details)	12 Months Ended
	Dec. 31, 2019 Boe Mcfe	Dec. 31, 2018 Boe Mcfe
Natural Gas and Natural Gas Liquids [Member]
Net oil or gas produced (Thousand Cubic Foot Equivalent) | Mcfe	32,107	25,776
Crude Oil and Natural Gas Liquids (NGL) [Member]
Net oil or gas produced (Thousand Cubic Foot Equivalent) | Boe	6,272	6,956