Overview (Details) bbl in Millions	12 Months Ended
	Dec. 31, 2017 a Pipelines Trucks mi Trailers bbl
Crude Transportation [Member]
Schedule Of Overview [Line Items]
Number of Trucks | Trucks	215
Number of Trailers | Trailers	210
HFOTCO LLC [Member]
Schedule Of Overview [Line Items]
Oil Storage Capacity | bbl	16.8
Acres | a	330
White Cliffs Pipeline, LLC [Member]
Schedule Of Overview [Line Items]
Equity method investment, ownership percentage	51.00%
White Cliffs Pipeline, LLC [Member] | Crude Transportation [Member]
Schedule Of Overview [Line Items]
Equity method investment, ownership percentage	51.00%
Ngl Energy Partners Lp [Member] | General Partner [Member]
Schedule Of Overview [Line Items]
Equity method investment, ownership percentage	11.78%
Gulf Coast [Member] | Crude Transportation [Member]
Schedule Of Overview [Line Items]
Number of Pipelines | Pipelines	3
Number of Miles | mi	106