Transactions with Related Parties (Narrative) (Details) - Affiliated Entity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Poseidon Oil Pipeline Company
Related Party Transaction [Line Items]
Net sales from related party	$ 13,846	$ 12,902	$ 12,669	[1]
Due from related parties	2,400	2,600
Costs charged by related party, included in operating costs	965	960	975	[1]
Poseidon Oil Pipeline Company | Asset Management Arrangement
Related Party Transaction [Line Items]
Net sales from related party	9,400	9,200	8,900
ANSAC
Related Party Transaction [Line Items]
Net sales from related party	280,935	236,408	367,133
Due from related parties	64,799	43,400
Costs charged by related party, included in operating costs	$ 1,213	$ 2,460	$ 4,446

[1] We own a 64% interest in Poseidon Oil Pipeline Company, LLC.