Investments in Affiliate Companies and Available-For-Sale Securities (Details Narrative)
$ in Thousands
 2 Months Ended 3 Months Ended 4 Months Ended 6 Months Ended 8 Months Ended 12 Months Ended
Feb. 18, 2015
USD ($)
Jun. 30, 2021
USD ($)
shares
Mar. 31, 2021
shares
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Mar. 31, 2017
USD ($)
Apr. 21, 2020
USD ($)
Jun. 30, 2021
USD ($)
shares
Jun. 30, 2020
USD ($)
Aug. 25, 2021
Dec. 31, 2020
USD ($)
shares
Dec. 31, 2021
Jan. 04, 2021
Schedule of Investments [Line Items]                          
Investments in affiliate companies   $ 97,351           $ 97,351     $ 56,988    
Equity in net earnings of affiliated companies   12,854   $ 9,445       40,594 $ 3,308        
Investment in available-for-sale-securities   364           364     222    
Available-for-sale Equity Securities, Gross Unrealized Gain   $ 101   5       $ 142 36        
Junior Loan II [Member]                          
Schedule of Investments [Line Items]                          
Repayments of Debt             $ 5,000            
Navios Partners [Member]                          
Schedule of Investments [Line Items]                          
Number of units held | shares   2,562,893           2,562,893          
Ownership percentage of Navios Holdings   9.70%           9.70%         12.60%
Difference between carrying amount of investment and underlying equity in net assets of equity method investee   $ 39,587           $ 39,587     77,904    
Investments in affiliate companies   80,632           80,632     39,133    
Equity in net earnings of affiliated companies   9,125   (1,227)       38,322 (2,354)        
Dividends received   128   621       232 1,242        
Market value of investment   $ 75,759           $ 75,759          
Navios Acquisition [Member]                          
Schedule of Investments [Line Items]                          
Ownership percentage of Navios Holdings   28.00%           28.00%          
Difference between carrying amount of investment and underlying equity in net assets of equity method investee   $ 75,408           $ 75,408     68,793    
Investments in affiliate companies   16,719           16,719     $ 15,033    
Equity in net earnings of affiliated companies   3,739   10,650       1,686 12,207        
Dividends received   0   $ 1,460       243 $ 2,919        
Market value of investment   16,590           $ 16,590          
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions               28.00%          
Navios Acquisition [Member] | Share Repurchase Program [Member]                          
Schedule of Investments [Line Items]                          
Stock Issued During Period, Shares, New Issues | shares               1,776,016     753,251    
Navios Europe II [Member]                          
Schedule of Investments [Line Items]                          
Ownership percentage of Navios Holdings       47.50%         47.50%        
Difference between carrying amount of investment and underlying equity in net assets of equity method investee $ 9,419                        
Investments in affiliate companies 6,650                        
Equity in net earnings of affiliated companies   $ 0   $ 0                  
Unrealized Gain (Loss) on Investments         $ 6,650                
Navios Europe II [Member] | Junior Loan II [Member]                          
Schedule of Investments [Line Items]                          
Repayments of Debt             $ 5,000            
Navios Europe II [Member] | Navios Revolving Loans 2 [Member]                          
Schedule of Investments [Line Items]                          
Loans and Leases Receivable, Related Parties 14,000                        
Revolving Credit Facility Maximum Borrowing Capacity $ 43,500                        
Line of Credit Facility, Increase (Decrease), Net           $ 14,000              
Navios Containers [Member]                          
Schedule of Investments [Line Items]                          
Ownership percentage of Navios Holdings   0.00% 3.90%         0.00%          
Equity in net earnings of affiliated companies   $ 0   $ 77       $ 596 $ 105        
Market value of investment   $ 2,812           $ 2,812          
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions                     3.90%    
Merger Agreement with Navios Partners II [Member]                          
Schedule of Investments [Line Items]                          
Shares conversion rate                   0.1275      
Merger Agreement with Navios Partners II [Member] | Navios Partners [Member]                          
Schedule of Investments [Line Items]                          
Ownership percentage of Navios Holdings                       10.30%  
Navios Holdings [Member] | Navios Partners [Member]                          
Schedule of Investments [Line Items]                          
General partner interest of Navios Holdings               2.00%          
Navios Partners [Member] | Merger Agreement With Navios Partners [Member]                          
Schedule of Investments [Line Items]                          
Number of units converted | shares               1,263,276          
Number of units held | shares   492,678           492,678          
Shares conversion rate     0.39                    
Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Issued | shares     8,133,452                    
Navios Partners [Member] | Continuous Offering Program Sales Agreement [Member] | General Partner [Member]                          
Schedule of Investments [Line Items]                          
Partners' Capital Account, Units, Sale of Units | shares               135,482     7,298    
Navios Partners [Member] | Common Stock [Member] | Continuous Offering Program Sales Agreement [Member]                          
Schedule of Investments [Line Items]                          
Partners' Capital Account, Units, Sale of Units | shares               6,638,503     357,508