Note 15 - Subsequent Events - Derivative Contracts (Details) - Subsequent Event [Member]	Mar. 14, 2019 $ / bbl
Fixed Swap 2019 [Member]
Daily volume	1,156
Swap price (in USD per Barrel of Oil)	58.5
Fixed Swap 2020 [Member]
Daily volume	819
Swap price (in USD per Barrel of Oil)	57.65
Fixed Swap 2021 [Member]
Daily volume	236
Swap price (in USD per Barrel of Oil)	55.7