Investment in affiliates and available-for-sale securities (Details) - USD ($)
$ in Thousands
1 Months Ended 2 Months Ended 3 Months Ended 5 Months Ended 6 Months Ended
Jan. 31, 2019
Feb. 28, 2019
Feb. 28, 2018
Jun. 30, 2020
Jun. 30, 2019
May 21, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Schedule Of Equity Method Investments [Line Items]                  
Equity in net (losses)/ earnings of affiliated companies       $ 9,445 $ (16,779)   $ 3,308 $ (12,502)  
Investments in affiliates       63,498 72,512   63,498 72,512 $ 64,352
Other than temporary impairment loss on investments       0 0   6,050 0  
Navios Partners                  
Schedule Of Equity Method Investments [Line Items]                  
Equity in net (losses)/ earnings of affiliated companies       $ 0 328   $ 0 656  
Partners capital account units acquisitions   518              
Payments to acquire investment   $ 8              
Navios Partners | Navios Holdings                  
Schedule Of Equity Method Investments [Line Items]                  
General partner interest of Navios Holdings   2.00%              
Navios Partners                  
Schedule Of Equity Method Investments [Line Items]                  
Private placement of units to directors and/or officers   25,396              
Stockholders' equity, Reverse stock split           1-for-15 reverse stock split      
Navios Partners | Share Repurchase Program                  
Schedule Of Equity Method Investments [Line Items]                  
Share repurchase program, Authorized amount $ 50,000                
Stock repurchase program period in force 2 years                
Number of shares repurchased             312,952    
Navios Acquisition | Share Repurchase Program                  
Schedule Of Equity Method Investments [Line Items]                  
Share repurchase program, Authorized amount     $ 25,000            
Stock repurchase program period in force     2 years            
Number of shares repurchased             735,251    
Navios Partners                  
Schedule Of Equity Method Investments [Line Items]                  
Common units held by Navios Holdings       2,070,216     2,070,216    
Difference between carrying amount of investment and underlying equity in net assets of equity method investee       $ 98,270     $ 98,270   101,492
Equity in net (losses)/ earnings of affiliated companies       $ (1,127) 902   $ (2,354) 3,153  
Ownership percentage of Navios Holdings       18.50%     18.50%    
Investments in affiliates       $ 31,520     $ 31,520   35,116
Dividends received       621 690   1,242 1,380  
Market value of the investment       20,102     20,102    
Navios Acquisition                  
Schedule Of Equity Method Investments [Line Items]                  
Difference between carrying amount of investment and underlying equity in net assets of equity method investee       73,605     73,605   79,477
Equity in net (losses)/ earnings of affiliated companies       $ 10,650 (4,728)   $ 12,207 (3,262)  
Ownership percentage of Navios Holdings       30.50%     30.50%    
Investments in affiliates       $ 29,182     $ 29,182   $ 19,894
Dividends received       1,460 2,766   2,919 $ 2,919  
Market value of the investment       $ 19,801     $ 19,801    
Other than temporary impairment loss on investments         $ 13,543