Note 8 - Supplemental Information Relating to Oil and Gas Producing Activities (Unaudited) - Estimated Quantities of Proved Oil and Gas Reserves (Details)	12 Months Ended
	Dec. 31, 2018 bbl MMcf	Dec. 31, 2017 bbl MMcf
Oil [Member]
Beginning Balance (Barrel of Oil) | bbl	290,000	244,000
Extensions, discoveries and other additions (Barrel of Oil) | bbl		8,000
Production (Barrel of Oil) | bbl	(55,000)	(40,000)
Revision of previous estimates (Barrel of Oil) | bbl	151,000	78,000
Ending Balance (Barrel of Oil) | bbl	386,000	290,000
Natural Gas [Member]
Beginning Balance (Barrel of Oil) | MMcf	11,244,000	5,280,000
Extensions, discoveries and other additions (Barrel of Oil) | MMcf		17,000
Production (Barrel of Oil) | MMcf	(2,301,000)	(1,904,000)
Revision of previous estimates (Barrel of Oil) | MMcf	7,415,000	7,851,000
Ending Balance (Barrel of Oil) | MMcf	16,358,000	11,244,000