Note 19 - Supplemental Oil and Gas Disclosures - Schedule of Prices Weighted by Field Production Related to Proved Reserves (Details) - USD ($)  | 
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2020  | 
Dec. 31, 2019  | 
Dec. 31, 2018  | 
Dec. 31, 2017  | 
|
| Oil [Member] | ||||
| Weighted price | $ 37.78 | $ 58.11 | $ 65.21 | $ 46.58 | 
| Natural Gas Liquids [Member] | ||||
| Weighted price | 10.29 | 18.72 | 29.73 | 22.65 | 
| Natural Gas [Member] | ||||
| Weighted price | $ 2.05 | $ 2.63 | $ 3.13 | $ 2.86 | 
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- Definition Represents weighted average prices used to estimate reserve. No definition available. 
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