Note 4 - Revenue and Segment Information - Identifiable Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Identifiable assets	$ 102,283	$ 106,077
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Identifiable assets	4,812	3,048
Refinery Operations [Member] \| Operating Segments [Member]
Identifiable assets	79,891	86,565
Tolling and Terminaling [Member] \| Operating Segments [Member]
Identifiable assets	$ 17,580	$ 16,464

Amount of asset recognized for present right to economic benefit.

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+ Details