Annual report pursuant to Section 13 and 15(d)

Equipment Acquisitions And Dispositions (Major Equipment Additions) (Details)

v3.19.3.a.u2
Equipment Acquisitions And Dispositions (Major Equipment Additions) (Details)
12 Months Ended
Jul. 03, 2017
vessel
Dec. 31, 2019
equipment
Dec. 31, 2018
vessel
equipment
Dec. 31, 2017
equipment
Petroleum and chemical carriers - U.S.-flag        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   0 0 3
Harbor tugs - U.S.-flag        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   1 5 1
Harbor tugs - Foreign-flag        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   0 0 2
Short-sea container/RORO - Foreign-flag        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   0 2 0
Inland river liquid tank barges        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   0 0 2
Inland river towboats        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired   2 0 3
ISH | Bulk carriers - U.S.-flag        
Property, Plant and Equipment [Line Items]        
Number of equipment acquired | vessel 2   2