Note 16 - Subsequent Events (Details Textual) - Subsequent Event [Member]	1 Months Ended
	May 17, 2021 bbl
Crude Oil Marketing Contract, Barrels of Oil Per Day in First Year [Member]
Significant Supply Commitment, Minimum Volume Committed (Barrel of Oil)	5,000
Crude Oil Marketing Contract, Barrels of Oil Per Day in Second Year [Member]
Significant Supply Commitment, Minimum Volume Committed (Barrel of Oil)	7,500
Crude Oil Marketing Contract, Barrels of Oil Per Day in Remaining Eight Years [Member]
Significant Supply Commitment, Minimum Volume Committed (Barrel of Oil)	10,000