Segment Reporting - Identifiable Assets by Industry Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Segment Reconciliation [Abstract]
Total assets	$ 504,623	$ 374,703
Operating segments
Segment Reconciliation [Abstract]
Total assets	504,623	374,703
Operating segments | Crude Oil Marketing
Segment Reconciliation [Abstract]
Total assets	332,711	162,770
Operating segments | Transportation
Segment Reconciliation [Abstract]
Total assets	66,138	67,167
Operating segments | Pipeline and storage
Segment Reconciliation [Abstract]
Total assets	25,067	25,569
Cash and other
Segment Reconciliation [Abstract]
Total assets	$ 80,707	$ 119,197