Fair Value of Financial Instruments (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]      
Impairment loss $ 200,657 $ 50,565 $ 0
Loss on investments in Navios Partners 55,524    
One vessel      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]      
Impairment loss   $ 32,930  
Four vessels      
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]      
Impairment loss $ 179,186