Note 4 - Revenue and Segment Information - Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Revenues from operations		$ 91,022	$ 116,661
Gross profit		11,830	20,504
Other operating and general and administrative expenses	[1]	(1,295)	(1,478)
Depreciation and amortization		(704)	(698)
Interest and other non-operating expenses, net		(1,366)	(1,330)
Income (loss) before income taxes		8,465	16,999
Income tax expense		(1,841)	(246)
Net income		6,624	16,753
Operating Segments [Member]
Revenues from operations		91,022	116,661
Operation costs and expenses	[2]	(79,192)	(96,157)
Gross profit		11,830	20,504
Consolidation, Eliminations [Member]
Revenues from operations	[3]	0	0
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Other operating and general and administrative expenses	[1]	(863)	(530)
Depreciation and amortization		(61)	(52)
Interest and other non-operating expenses, net		(136)	(183)
Income (loss) before income taxes		(1,060)	(764)
Refinery Operations [Member]
Revenues from operations		89,915	114,640
Refinery Operations [Member] | Operating Segments [Member]
Revenues from operations		89,915	114,640
Operation costs and expenses	[2]	(78,782)	(95,799)
Gross profit		10,630	18,265
Other operating and general and administrative expenses	[1]	(409)	(478)
Depreciation and amortization		(301)	(304)
Interest and other non-operating expenses, net		(734)	(677)
Income (loss) before income taxes		9,186	16,806
Refinery Operations [Member] | Consolidation, Eliminations [Member]
Revenues from operations	[3]	(503)	(576)
Tolling and Terminaling [Member]
Revenues from operations		1,107	2,021
Tolling and Terminaling [Member] | Operating Segments [Member]
Revenues from operations		1,107	2,021
Operation costs and expenses	[2]	(410)	(358)
Gross profit		1,200	2,239
Other operating and general and administrative expenses	[1]	(23)	(470)
Depreciation and amortization		(342)	(342)
Interest and other non-operating expenses, net		(496)	(470)
Income (loss) before income taxes		339	957
Tolling and Terminaling [Member] | Consolidation, Eliminations [Member]
Revenues from operations	[3]	$ 503	$ 576

[1] General and administrative expenses within refinery operations includes the LEH operating fee, related party, other operating expenses, and accretion of asset retirement obligations.

[2] Cost of goods sold within tolling and terminaling includes terminal operating expenses and an allocation of other costs (e.g., insurance and maintenance).

[3] Fees associated with an intercompany tolling agreement related to naphtha volumes.