Revenues (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Abstract]
Revenues by major source	$ 2,171,408,000	$ 2,838,399,000	$ 2,970,697,000
Revenue recognized	38,455,000	76,412,000
Marine Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	1,404,265,000	1,587,082,000	1,483,143,000
Marine Transportation [Member] | Inland Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	1,094,630,000	1,220,878,000	1,119,820,000
Marine Transportation [Member] | Coastal Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	309,635,000	366,204,000	363,323,000
Distribution and Services [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	767,143,000	1,251,317,000	1,487,554,000
Distribution and Services [Member] | Oil and Gas [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	200,817,000	659,364,000	1,010,410,000
Distribution and Services [Member] | Commercial and Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	$ 566,326,000	$ 591,953,000	$ 477,144,000