Annual report pursuant to Section 13 and 15(d)

Operating Leases (Details)

v3.20.4
Operating Leases (Details)
12 Months Ended
Dec. 31, 2020
equipment
Petroleum and Chemical Carriers - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 2
Petroleum and Chemical Carriers - U.S.-flag | Minimum  
Operating Leases [Line Items]  
Sale Leaseback Transaction, Lease Terms 21
Petroleum and Chemical Carriers - U.S.-flag | Maximum  
Operating Leases [Line Items]  
Sale Leaseback Transaction, Lease Terms 68
Harbor Tugs - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Pure Car/Truck Carriers - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Inland River Dry-Cargo Barges  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 50
Inland River Towboats  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Inland River Harbor Boats  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 6
Other Equipment | Minimum  
Operating Leases [Line Items]  
Lessee, Operating Lease, Term of Contract 1 month
Other Equipment | Maximum  
Operating Leases [Line Items]  
Lessee, Operating Lease, Term of Contract 183 months
Bareboat Chartered, Petroleum and Chemical Carriers - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Bareboat Chartered, Ocean Liquid Tank Barges - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 5
Bareboat Chartered, Harbor Tugs - Foreign-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 6
Time Chartered, Petroleum and Chemical Carriers - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Time Chartered, PCTCs - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 4
Time Chartered, Inland River Towboats  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 8
Time Chartered, Offshore Tug - U.S.-flag  
Operating Leases [Line Items]  
Equipment Subject to Operating Lease, Number of Units 1