Investment in Affiliates and Available-for-Sale Securities (Details) - USD ($)
$ / shares in Units, $ in Thousands
 2 Months Ended 3 Months Ended 6 Months Ended 7 Months Ended 8 Months Ended
Feb. 28, 2015
Feb. 28, 2014
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Jul. 31, 2015
Aug. 21, 2015
Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]                  
Payments to acquire common stock         $ 20,471 $ 2,233      
Common stock shares outstanding     107,835,547   107,835,547       105,831,718
Proceeds from issuance of common stock         $ 0 638      
Equity in net earnings of affiliated companies     $ 17,968 $ 7,079 31,880 29,497      
Investments in affiliates     $ 371,405 340,375 371,405 340,375     $ 344,453
Dividends received         $ 7,298 7,298      
Navios Partners                  
Schedule Of Equity Method Investments [Line Items]                  
General Partner Interest         2.00%        
Gain/(loss) from the sale of shares by the equity method         $ 0 11,230      
Common stock shares outstanding     15,344,310   15,344,310        
General partners units outstanding     1,695,509   1,695,509        
Ownership percentage     20.10%   20.10%        
Difference between carrying amount of investment and underlying equity in net assets of equity method investee     $ 34,507   $ 34,507       35,745
Equity in net earnings of affiliated companies     4,097 7,784 8,170 28,074      
Investments in affiliates     121,036   121,036       114,387
Dividends received     8,124 7,536 16,248 14,971   $ 8,124  
Market value of the investment     $ 182,326   $ 182,326        
Acropolis                  
Schedule Of Equity Method Investments [Line Items]                  
Ownership percentage     35.00%   35.00%        
Investments in affiliates     $ 682   $ 682       525
Dividends received     0 271 $ 0 271      
Profit Sharing Arrangement         Navios Holdings has a 50% interest in Acropolis, a brokerage firm for freight and shipping charters. Although Navios Holdings owns 50% of Acropolis' stock, Navios Holdings agreed with the other shareholder that the earnings and amounts declared by way of dividends will be allocated 35% to the Company with the balance to the other shareholder.        
Navios Acquisition                  
Schedule Of Equity Method Investments [Line Items]                  
Gain/(loss) from the sale of shares by the equity method     0 0 $ 0 6,193      
Difference between carrying amount of investment and underlying equity in net assets of equity method investee     1,777   1,777       1,293
Equity in net earnings of affiliated companies     13,426 (1,190) 22,961 619      
Investments in affiliates     240,245   240,245       $ 224,582
Dividends received     3,649 $ 3,649 7,298 $ 7,298 $ 3,649    
Market value of the investment     $ 261,988   $ 261,988        
Navios Partners                  
Schedule Of Equity Method Investments [Line Items]                  
Units issued in public offering 4,600,000 6,325,000              
Payments to acquire common stock   $ 2,233              
Unit price $ 13.09                
Proceeds from private placement of units to Navios Holdings $ 14,967                
Proceeds from issuance of common limited partners units   $ 60,214              
Ownership percentage     20.00%   20.00%        
Navios Partners | Common units                  
Schedule Of Equity Method Investments [Line Items]                  
Private placement of units to Navios Holdings 1,120,547                
Navios Partners | General partner units                  
Schedule Of Equity Method Investments [Line Items]                  
Private placement of units to Navios Holdings 22,868                
Navios Partners | Private placement                  
Schedule Of Equity Method Investments [Line Items]                  
Unit price $ 13.09                
Navios Acquisition                  
Schedule Of Equity Method Investments [Line Items]                  
Shares issued in public offering   14,950,000