Investment in affiliates and available-for-sale securities - Navios Europe I and Navios Europe II (Details)
$ in Thousands
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2017
USD ($)
Jun. 30, 2019
USD ($)
Jun. 30, 2018
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 $ 1,790,805 $ 1,666,620   $ 1,790,805 $ 1,666,620        
Investments in affiliates 72,512 174,263   72,512 174,263 $ 91,111      
Portion of the carrying balance of related party loan 51,823     51,823   46,089      
Equity in net (losses)/ earnings of affiliated companies (16,779) (3,025)   (12,502) (9,489)        
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 3,019     3,019   3,357   $ 6,763  
Estimated maximum potential loss 41,538     41,538   35,069      
Investments in affiliates 4,750     $ 4,750   4,750   4,750  
Profit Sharing Arrangement       On an ongoing basis, Navios Europe I is 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.          
Equity in net (losses)/ earnings of affiliated companies 0 0   $ 0 0        
Navios Europe I | Navios Term Loans I                  
Investments In And Advances To Affiliates [Line Items]                  
Investents in affiliates including accrued interest 9,578     9,578   8,994      
Navios Europe I | Navios Revolving Loans I                  
Investments In And Advances To Affiliates [Line Items]                  
Portion of the carrying balance of related party loan 31,960     31,960   26,075      
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 5,598     5,598   6,069     $ 9,419
Estimated maximum potential loss 42,351     42,351   29,370      
Investments in affiliates 6,650     $ 6,650   6,650     $ 6,650
Profit Sharing Arrangement       On an ongoing basis, Navios Europe II is 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.          
Equity in net (losses)/ earnings of affiliated companies 591 $ 495   $ 1,151 $ 963        
Navios Europe II | Navios Term Loans II                  
Investments In And Advances To Affiliates [Line Items]                  
Investents in affiliates including accrued interest 13,583     13,583   12,432      
Navios Europe II | Navios Revolving Loans II                  
Investments In And Advances To Affiliates [Line Items]                  
Portion of the carrying balance of related party loan $ 28,768     $ 28,768   $ 16,938      
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            
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