Segment Reporting - Information Concerning Business Activities (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment				3
Number of operating segments | segment				3
Segment Reporting Information [Line Items]
Revenues	$ 992,050	$ 486,744		$ 1,766,295	$ 812,235
Segment operating earnings (losses)	2,960	6,335		11,108	10,186
Depreciation and amortization	5,088	4,801		10,101	9,854
Property and equipment additions	1,089	3,432		4,783	3,602
Crude Oil Marketing
Segment Reporting Information [Line Items]
Revenues	962,516	463,092		1,710,071	767,115
Depreciation and amortization	1,894	1,641		3,682	3,439
Property and equipment additions	884	492		4,008	702
Inventory liquidation gains (losses)	(1,500)	3,700		7,200	10,600
Transportation
Segment Reporting Information [Line Items]
Revenues	29,534	23,497		56,224	44,732
Depreciation and amortization	2,923	2,937		5,880	5,938
Property and equipment additions	159	2,761		694	2,703
Refund received			$ 300
Pipeline and storage
Segment Reporting Information [Line Items]
Revenues	0	155		0	388
Depreciation and amortization	271	223		539	477
Property and equipment additions	46	179		73	189
Operating segments
Segment Reporting Information [Line Items]
Revenues	994,197	487,278		1,770,589	812,988
Segment operating earnings (losses)	7,171	9,296		19,337	16,523
Operating segments | Crude Oil Marketing
Segment Reporting Information [Line Items]
Revenues	962,516	463,092		1,710,071	767,115
Segment operating earnings (losses)	5,111	8,370		15,231	15,388
Operating segments | Transportation
Segment Reporting Information [Line Items]
Revenues	29,621	23,535		56,398	44,803
Segment operating earnings (losses)	2,937	1,482		5,805	2,256
Operating segments | Pipeline and storage
Segment Reporting Information [Line Items]
Revenues	2,060	651		4,120	1,070
Segment operating earnings (losses)	(877)	(556)		(1,699)	(1,121)
Intersegment
Segment Reporting Information [Line Items]
Revenues	(2,147)	(534)		(4,294)	(753)
Intersegment | Crude Oil Marketing
Segment Reporting Information [Line Items]
Revenues	0	0		0	0
Intersegment | Transportation
Segment Reporting Information [Line Items]
Revenues	(87)	(38)		(174)	(71)
Intersegment | Pipeline and storage
Segment Reporting Information [Line Items]
Revenues	(2,060)	(496)		(4,120)	(682)
Other
Segment Reporting Information [Line Items]
Revenues	0	0		0	0
Segment operating earnings (losses)	0	0		0	0
Depreciation and amortization	0	0		0	0
Property and equipment additions	$ 0	$ 0		$ 8	$ 8