Borrowings - Credit Facilities (Details)
$ in Thousands
 3 Months Ended 5 Months Ended 9 Months Ended 10 Months Ended 12 Months Ended
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
May 31, 2017
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Nov. 03, 2017
USD ($)
Oct. 31, 2016
USD ($)
Oct. 31, 2010
USD ($)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Sep. 30, 2010
USD ($)
Debt Instrument [Line Items]                        
Amount outstanding $ 167,393     $ 167,393         $ 219,856      
Repayment of debt                 48,600      
Payments related to installments for the current year                 25,707      
Payments related to installments for the next year                 7,286      
Total amount of prepayment to affiliate company                 (55,132) $ 50,000 $ 0  
Gain/ (Loss) on bond and debt extinguishment 6,464 $ 0   $ 6,464 $ 1,715       $ (981) 29,187 $ 0  
Navios Logistics                        
Debt Instrument [Line Items]                        
Variable rate basis       LIBOR                
Face amount at issuance date 166,853     $ 166,853                
Navios Logistics | Minimum                        
Debt Instrument [Line Items]                        
Loan margin percentage       3.15%                
Maturity date       Aug. 31, 2020                
Navios Logistics | Maximum                        
Debt Instrument [Line Items]                        
Loan margin percentage       4.75%                
Maturity date       Nov. 30, 2024                
Other long-term loans | Navios Logistics                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Oct. 29, 2009      
Maximum borrowing capacity                 $ 817      
Repayment frequency                 monthly      
Repayment installment                 $ 6      
Amount outstanding                 $ 253 321    
Fixed interest rate                 6.00%      
Repayment terms                 The loan facility bears interest at a fixed rate of 600 basis points. The loan is repayable in monthly installments of $6 each and the final repayment must occur prior to August 10, 2021.      
Line of Credit                        
Debt Instrument [Line Items]                        
Variable rate basis       LIBOR                
Line of Credit | Minimum                        
Debt Instrument [Line Items]                        
Loan margin percentage       2.75%                
Maturity date       Mar. 31, 2020                
Line of Credit | Maximum                        
Debt Instrument [Line Items]                        
Loan margin percentage       3.60%                
Maturity date       Nov. 30, 2022                
Navios Logistics Notes Payable                        
Debt Instrument [Line Items]                        
Maximum borrowing capacity                 $ 41,964      
Repayment installments                 16      
Repayment frequency                 semi-annual      
Interest Rate                 six-month LIBOR      
Debt finance costs                 $ 5,949      
Navios Logistics BBVA Loan Facility                        
Debt Instrument [Line Items]                        
Maximum borrowing capacity                 $ 25,000      
Loan margin percentage                 3.25%      
Repayment installments                 20      
Repayment frequency                 quarterly      
Interest Rate                 LIBOR (180 days) plus 325 basis points      
One of the secured credit facilities                        
Debt Instrument [Line Items]                        
Amount outstanding                 $ 17,332      
Repayment of debt                 15,607      
Gain/ (Loss) on bond and debt extinguishment                 $ 1,715      
Loan Facility Credit Agricole Bank ($40,000) to finance the construction of one newbuilding Capesize vessel                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Sep. 30, 2010      
Maximum borrowing capacity                 $ 40,000      
Loan margin percentage                 2.75%      
Interest rate description                 LIBOR plus 275 basis points      
Balloon payment on the last repayment date                 $ 6,810      
Amount outstanding                 $ 17,674 18,880    
Maturity date                 Aug. 31, 2021      
Loan Facility Credit Agricole Bank ($40,000) to finance the construction of one newbuilding Capesize vessel | First installment                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 2,411      
Loan Facility Credit Agricole Bank ($40,000) to finance the construction of one newbuilding Capesize vessel | From 2nd to 9th installment                        
Debt Instrument [Line Items]                        
Repayment installments                 7      
Repayment frequency                 semi-annual      
Repayment installment                 $ 1,205      
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one Panamax vessel                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Aug. 31, 2011      
Maximum borrowing capacity                 $ 23,000      
Loan margin percentage                 2.75%      
Interest rate description                 LIBOR plus 275 basis points      
Balloon payment on the last repayment date                 $ 7,264      
Amount outstanding                 $ 14,074 14,755    
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one Panamax vessel | First installment                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 681      
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one Panamax vessel | From 2nd to 10th installment                        
Debt Instrument [Line Items]                        
Repayment installments                 9      
Repayment frequency                 semi-annual      
Repayment installment                 $ 681      
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one newbuilding bulk carrier                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Dec. 31, 2011      
Maximum borrowing capacity                 $ 23,000      
Loan margin percentage                 3.25%      
Interest rate description                 LIBOR plus 325 basis points      
Balloon payment on the last repayment date                 $ 7,450      
Amount outstanding                 $ 14,450 15,150    
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one newbuilding bulk carrier | First installment                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 700      
Loan Facility Credit Agricole ($23,000) to partially finance the construction of one newbuilding bulk carrier | From 2nd to 10th installment                        
Debt Instrument [Line Items]                        
Repayment installments                 9      
Repayment frequency                 semi-annual      
Repayment installment                 $ 700      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Dec. 20, 2013      
Maximum borrowing capacity                 $ 22,500      
Loan margin percentage                 3.00%      
Interest rate description                 LIBOR plus 300 basis points      
Amount outstanding                 $ 15,188 16,313    
Number Of Loan Tranches                 2      
Maturity date                 Aug. 31, 2021      
Debt instrument collateral                 1 bulk carrier      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | Tranche A                        
Debt Instrument [Line Items]                        
Balloon payment on the last repayment date                 $ 2,812      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | Tranche B                        
Debt Instrument [Line Items]                        
Balloon payment on the last repayment date                 $ 2,812      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | First installment | Tranche A                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 563      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | First installment | Tranche B                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 1,125      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | From 2nd to 8th installment | Tranche A                        
Debt Instrument [Line Items]                        
Repayment installments                 7      
Repayment frequency                 semi-annual      
Repayment installment                 $ 563      
Loan Facility Credit Agricole ($22,500) to finance the acquisition of two Panamax Vessels | From 2nd to 8th installment | Tranche B                        
Debt Instrument [Line Items]                        
Repayment installments                 7      
Repayment frequency                 semi-annual      
Repayment installment                 $ 563      
Commerzbank A.G. to finance acquisition of one Capesize vessel and construction of three Capesize vessels                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Jun. 30, 2009      
Maximum borrowing capacity                 $ 240,000      
Amount outstanding                 $ 0 19,857    
Number Of Loan Tranches                 4      
Amount of each tranche                 $ 60,000      
Number of the cancellated tranches                       2
Commerzbank A.G. to finance acquisition of one Capesize vessel and construction of three Capesize vessels | Tranche A                        
Debt Instrument [Line Items]                        
Repayment of debt               $ 53,600        
Commerzbank A.G. to finance acquisition of one Capesize vessel and construction of three Capesize vessels | Tranche B                        
Debt Instrument [Line Items]                        
Repayment of debt               $ 54,500        
Commerzbank A.G. to finance acquisition of one Capesize vessel and construction of three Capesize vessels | Tranche C                        
Debt Instrument [Line Items]                        
Amount outstanding             $ 15,319          
Repayment of debt             $ 13,802          
Gain/ (Loss) on bond and debt extinguishment                   1,517    
Commerzbank A.G. to finance acquisition of one Capesize vessel and construction of three Capesize vessels | Tranche D                        
Debt Instrument [Line Items]                        
Amount outstanding     $ 17,322                  
Repayment of debt     $ 15,607                  
Gain/ (Loss) on bond and debt extinguishment                 $ 1,715      
HSH Nordbank A.G. ($15,300) to partially refinance the 4th tranche of the Commerzbank facility                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 May 23, 2017      
Maximum borrowing capacity                 $ 15,300      
Loan margin percentage                 3.00%      
Interest rate description                 LIBOR plus 300 basis points      
Repayment installments                 15      
Repayment frequency                 quarterly      
Repayment installment                 $ 383      
Balloon payment on the last repayment date                 $ 8,798      
Loan Facility DVB Bank SE ($72,000)                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Mar. 23, 2012      
Maximum borrowing capacity                 $ 42,000      
Amount outstanding                 $ 50,140 54,540    
Number Of Loan Tranches                 2      
Loan Facility DVB Bank SE ($72,000) | Tranche A                        
Debt Instrument [Line Items]                        
Loan margin percentage                 2.85%      
Interest rate description                 LIBOR plus 285 basis points      
Repayment installments                 9      
Repayment frequency                 quarterly      
Repayment installment                 $ 362      
Balloon payment on the last repayment date                 14,400      
Amount of each tranche                 $ 26,000      
Loan Facility DVB Bank SE ($72,000) | Tranche B                        
Debt Instrument [Line Items]                        
Loan margin percentage                 3.60%      
Interest rate description                 LIBOR plus 360 basis points      
Repayment installments                 10      
Repayment frequency                 quarterly      
Repayment installment                 $ 269      
Balloon payment on the last repayment date                 6,354      
Amount of each tranche                 $ 16,000      
Loan Facility DVB Bank SE ($72,000) | New Tranche June 2014                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Jun. 27, 2014      
Loan margin percentage                 2.75%      
Interest rate description                 LIBOR plus 275 basis points      
Repayment installments                 10      
Repayment frequency                 quarterly      
Repayment installment                 $ 469      
Balloon payment on the last repayment date                 18,750      
Amount of each tranche                 $ 30,000      
Loan Facility DVB Bank SE ($40,000) to finance the acquisition of four Panamax vessels                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Sep. 30, 2013      
Maximum borrowing capacity                 $ 40,000      
Loan margin percentage                 3.25%      
Interest rate description                 LIBOR plus 325 basis points      
Repayment installments                 15      
Repayment frequency                 quarterly      
Repayment installment                 $ 730      
Balloon payment on the last repayment date                 7,302      
Amount outstanding                 $ 18,254 28,000    
Maturity date                 Sep. 30, 2021      
Debt instrument collateral                 1 newbuilding Panamax and 1 newbuilding Capesize vessel      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Jan. 31, 2016      
Maximum borrowing capacity                 $ 41,000      
Loan margin percentage                 2.55%      
Interest rate description                 LIBOR plus 255 basis points      
Amount outstanding                 $ 33,816 37,293    
Number Of Loan Tranches                 2      
Amount drawn down                   39,900    
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | Tranche A                        
Debt Instrument [Line Items]                        
Balloon payment on the last repayment date                 $ 14,760      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | Tranche B                        
Debt Instrument [Line Items]                        
Balloon payment on the last repayment date                 $ 8,764      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | First installment | Tranche A                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 492      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | First installment | Tranche B                        
Debt Instrument [Line Items]                        
Repayment installments                 1      
Repayment frequency                 quarterly      
Repayment installment                 $ 377      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | From 2nd to 17th installment | Tranche A                        
Debt Instrument [Line Items]                        
Repayment installments                 16      
Repayment frequency                 quarterly      
Repayment installment                 $ 369      
Loan Facility DVB Bank SE ($41,000) to finance the acquisition of one newbuilding Panamax vessel and one newbuilding Capesize vessel | From 2nd to 17th installment | Tranche B                        
Debt Instrument [Line Items]                        
Repayment installments                 16      
Repayment frequency                 quarterly      
Repayment installment                 $ 220      
Alpha Bank A.E. ($31,000) to finance part of the acquisition of a Capesize vessel                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Nov. 06, 2014      
Maximum borrowing capacity                 $ 31,000      
Loan margin percentage                 3.00%      
Interest rate description                 LIBOR plus 300 basis points      
Repayment installments                 20      
Repayment frequency                 quarterly      
Repayment installment                 $ 450      
Balloon payment on the last repayment date                 16,600      
Amount outstanding                 $ 25,600 27,400    
Alpha Bank A.E. ($16,125) to refinance one Capesize vessel                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date                 Nov. 03, 2016      
Maximum borrowing capacity                 $ 16,125      
Loan margin percentage                 3.00%      
Interest rate description                 LIBOR plus 300 basis points      
Balloon payment on the last repayment date                 $ 10,725      
Amount outstanding                 $ 16,125 16,125    
Alpha Bank A.E. ($16,125) to refinance one Capesize vessel | First 4 installments                        
Debt Instrument [Line Items]                        
Repayment installments                 4      
Repayment frequency                 quarterly      
Repayment installment                 $ 250      
Alpha Bank A.E. ($16,125) to refinance one Capesize vessel | From 5th to 21rst installments                        
Debt Instrument [Line Items]                        
Repayment installments                 16      
Repayment frequency                 quarterly      
Repayment installment                 $ 275      
Navios Acquisition Loan                        
Debt Instrument [Line Items]                        
Line of credit facility issuance date       Sep. 19, 2016         Sep. 19, 2016      
Maximum borrowing capacity $ 70,000     $ 70,000         $ 70,000      
Amount outstanding                 $ 0 51,240    
Repayment of debt       60,716                
Payments related to installments for the current year       28,947                
Payments related to installments for the next year       $ 31,769                
Total amount of prepayment to affiliate company           $ (55,132)       $ 50,000    
Prepayment amount of loan to affiliate company, net           50,000            
Accrued interest           $ 5,132