Investments in affiliates and investments in 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, 2018
USD ($)
Jun. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
Jun. 30, 2018
USD ($)
Jun. 30, 2017
USD ($)
Dec. 31, 2015
USD ($)
Dec. 18, 2013
USD ($)
Dec. 31, 2017
USD ($)
Feb. 18, 2015
USD ($)
Investments In And Advances To Affiliates [Line Items]                  
Long-term debt $ 1,666,620 $ 1,646,270   $ 1,666,620 $ 1,646,270        
Investments in affiliates 174,263 189,195   174,263 189,195     $ 183,160  
Portion of the carrying balance of related party loan 31,588     31,588       30,112  
Equity in net earnings of affiliated companies (3,025) (3,775)   (9,489) 1,307        
Navios Europe I                  
Investments In And Advances To Affiliates [Line Items]                  
Difference between carrying amount of investment and underlying equity in net assets of equity method investee 3,696     3,696     $ 6,763 4,034  
Estimated maximum potential loss 25,383     25,383       23,838  
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 earnings of affiliated companies 0 (16)   $ 0 158        
Number of vessels acquired             10    
Navios Europe I | Navios Term Loans I                  
Investments In And Advances To Affiliates [Line Items]                  
Investents in affiliates including accrued interest 8,438     8,438       7,924  
Navios Europe I | Navios Revolving Loans I                  
Investments In And Advances To Affiliates [Line Items]                  
Portion of the carrying balance of related party loan 16,946     16,946       15,914  
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    
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]                  
Difference between carrying amount of investment and underlying equity in net assets of equity method investee 6,540     6,540       7,011 $ 9,419
Estimated maximum potential loss 23,425     23,425       22,463  
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 earnings of affiliated companies 495 $ 169   $ 963 $ 200        
Number of vessels acquired           14      
Navios Europe II | Navios Term Loans II                  
Investments In And Advances To Affiliates [Line Items]                  
Investents in affiliates including accrued interest 11,363     11,363       10,400  
Navios Europe II | Navios Revolving Loans II                  
Investments In And Advances To Affiliates [Line Items]                  
Portion of the carrying balance of related party loan $ 12,063     $ 12,063       $ 12,063  
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