Note 4 - Revenue and Segment Information - Identifiable Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Identifiable assets	$ 110,818	$ 101,896
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Identifiable assets	5,363	5,996
Refinery Operations [Member] | Operating Segments [Member]
Identifiable assets	89,067	78,996
Tolling and Terminaling [Member] | Operating Segments [Member]
Identifiable assets	$ 16,388	$ 16,904