Note 11 - Major Customers (Details Textual)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Customer Concentration Risk [Member] \| Revenue Benchmark [Member] \| Lion Oil Trading and Transportation, LLC [Member]
Concentration Risk, Percentage	96.00%	88.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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