Contingencies and Commitments, Certain Significant Risks and Uncertainties (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) Customers Distributor	Dec. 31, 2019 Customers	Dec. 31, 2018 Customers
Guaranties [Abstract]
Issued guaranties	$ 23,180,000
Maximum [Member]
Guaranties [Abstract]
Guarantor obligations, expiration period	3 years
Performance Bonds [Member]
Guaranties [Abstract]
Issued guaranties	$ 9,594,000
Marine Transportation [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of inland revenue	65.00%
Marine Transportation [Member] | Minimum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	1 year
Marine Transportation [Member] | Maximum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	3 years
Marine Transportation [Member] | Customers [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of costal revenue	85.00%
Customer relationship period	40 years
Number of single customers accounting more than 10% of segment revenue | Customers	0	0	0
Distribution and Services [Member]
Certain Significant Risks and Uncertainties [Abstract]
Number of off-highway top distributors | Distributor	5
Distribution and Services [Member] | Minimum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Services segment's relationship term	50 years
Distribution and Services [Member] | Customers [Member]
Certain Significant Risks and Uncertainties [Abstract]
Number of single customers accounting more than 10% of segment revenue | Customers	0	0	0
Letters Of Credit [Member]
Guaranties [Abstract]
Issued guaranties	$ 13,586,000