Investments in affiliates and investments in available-for-sale securities - Navios Europe I and Navios Europe II (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 18, 2013
USD ($)
Feb. 18, 2015
USD ($)
Investments In And Advances To Affiliates [Line Items]            
Long-term debt   $ 1,682,488 $ 1,651,095 $ 1,581,308    
Investments in affiliates   183,160 160,071 381,746    
Portion of the carrying balance of related party loan   30,112 23,008      
Equity in net earnings of affiliated companies   4,399 (202,779) 61,484    
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   4,034 4,710   $ 6,763  
Estimated maximum potential loss   23,838 18,268      
Investments in affiliates   $ 4,750 5,967   $ 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   $ (1,089) 1,303 $ 1,293    
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   7,924 8,198      
Navios Europe I | Navios Revolving Loans I            
Investments In And Advances To Affiliates [Line Items]            
Portion of the carrying balance of related party loan   15,914 10,070      
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   7,011 7,953     $ 9,419
Estimated maximum potential loss   22,463 22,287      
Investments in affiliates   $ 6,650 5,894     $ 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   $ 2,456 (14)      
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   10,400 7,944      
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 $ 14,343      
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