Annual report pursuant to Section 13 and 15(d)

Commitments And Contingencies (Capital Commitments and Narrative) (Details)

v3.20.4
Commitments And Contingencies (Capital Commitments and Narrative) (Details)
$ in Thousands
Feb. 25, 2021
USD ($)
claim
Aug. 02, 2016
claim
Dec. 31, 2020
USD ($)
equipment
claim
Feb. 16, 2016
claim
Commitments and Contingencies [Line Items]        
Unrecorded unconditional purchase obligation, due in 2021     $ 38,013  
Unrecorded unconditional purchase obligation, due in 2022     5,103  
Unrecorded unconditional purchase obligation     $ 43,116  
Deepwater Horizon Oil Spill Multi District Litigation        
Commitments and Contingencies [Line Items]        
Loss contingency, pending claims | claim       11
Loss Contingency, Claims Dismissed, Number | claim   11    
BP counter claims ORM and NRC        
Commitments and Contingencies [Line Items]        
Loss contingency, pending claims | claim     4  
BP counterclaims ORM's insurer        
Commitments and Contingencies [Line Items]        
Loss contingency, pending claims | claim     2  
Subsequent Event        
Commitments and Contingencies [Line Items]        
Unrecorded unconditional purchase obligation $ 200      
Subsequent Event | BELO/ORM        
Commitments and Contingencies [Line Items]        
Loss Contingency, Claims Dismissed, Number | claim 800      
Loss contingency, new claims filed | claim 2,400      
Subsequent Event | BELO/NRC        
Commitments and Contingencies [Line Items]        
Loss Contingency, Claims Dismissed, Number | claim 85      
Loss contingency, new claims filed | claim 230      
Ocean Services        
Commitments and Contingencies [Line Items]        
Unrecorded unconditional purchase obligation, due in 2021     $ 34,204  
Unrecorded unconditional purchase obligation, due in 2022     5,103  
Unrecorded unconditional purchase obligation     $ 39,307  
Ocean Services | Harbor Tugs - U.S.-flag        
Commitments and Contingencies [Line Items]        
Number of equipment committed to purchase | equipment     4  
Inland Services        
Commitments and Contingencies [Line Items]        
Unrecorded unconditional purchase obligation, due in 2021     $ 3,700  
Unrecorded unconditional purchase obligation, due in 2022     0  
Unrecorded unconditional purchase obligation     $ 3,700  
Inland Services | Inland river towboats        
Commitments and Contingencies [Line Items]        
Number of equipment committed to purchase | equipment     1  
Other        
Commitments and Contingencies [Line Items]        
Unrecorded unconditional purchase obligation, due in 2021     $ 109  
Unrecorded unconditional purchase obligation, due in 2022     0  
Unrecorded unconditional purchase obligation     $ 109