Investment in affiliates and available-for-sale securities - Navios Europe I and Navios Europe II (Details)
$ in Thousands
3 Months Ended 4 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2017
USD ($)
Apr. 21, 2020
USD ($)
Jun. 30, 2020
USD ($)
Jun. 30, 2019
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2015
USD ($)
Dec. 18, 2013
USD ($)
Feb. 18, 2015
USD ($)
Investments In And Advances To Affiliates [Line Items]                        
Long-term debt $ 1,591,781   $ 1,523,131     $ 1,591,781 $ 1,523,131          
Investments in affiliates 63,498   72,512     63,498 72,512 $ 64,352        
Proceeds From Related Party Debt           31,500 0          
Equity in net (losses)/ earnings of affiliated companies 9,445   (16,779)     $ 3,308 (12,502)          
Navios Europe I                        
Investments In And Advances To Affiliates [Line Items]                        
Number of vessels acquired                     10  
Difference between carrying amount of investment and underlying equity in net assets of equity method investee                     $ 6,763  
Investments in affiliates                     4,750  
Profit Sharing Arrangement           On an ongoing basis, Navios Europe I was required to distribute cash flows (after payment of operating expenses and amounts due pursuant to the terms of the Senior Loans I) according to a defined waterfall calculation.            
Proceeds From Related Party Debt               $ 13,420        
Equity in net (losses)/ earnings of affiliated companies 0   0     $ 0 0          
Navios Europe I | Navios Revolving Loans I | Navios Holdings, Navios Acquisition and Navios Partners                        
Investments In And Advances To Affiliates [Line Items]                        
Line of credit facility maximum borrowing capacity                     24,100  
Line of Credit Facility, Increase                 $ 30,000      
Navios Europe I | 10 vessels | Navios Holdings, Navios Acquisition and Navios Partners                        
Investments In And Advances To Affiliates [Line Items]                        
Long-term debt                     $ 10,000  
Navios Europe II                        
Investments In And Advances To Affiliates [Line Items]                        
Number of vessels acquired                   14    
Difference between carrying amount of investment and underlying equity in net assets of equity method investee                       $ 9,419
Investments in affiliates                       $ 6,650
Profit Sharing Arrangement           On an ongoing basis, Navios Europe II was required to distribute cash flows (after payment of operating expenses, amounts due pursuant to the terms of the Senior Loans II) according to a defined waterfall calculation.            
Unrealized Gain/ (Loss) On Ιnvestments   $ (6,650)                    
Equity in net (losses)/ earnings of affiliated companies $ 0   $ 591     $ 0 $ 1,151          
Navios Europe II | Navios Revolving Loans II | Navios Holdings, Navios Acquisition and Navios Partners                        
Investments In And Advances To Affiliates [Line Items]                        
Line of credit facility maximum borrowing capacity                   $ 43,500    
Line of Credit Facility, Increase       $ 14,000                
Debt Instrument, Decrease, Forgiveness         $ 5,000              
Navios Europe II | 14 Vessels | Navios Holdings, Navios Acquisition and Navios Partners                        
Investments In And Advances To Affiliates [Line Items]                        
Long-term debt                   $ 14,000