Investment in affiliates and available-for-sale securities - Navios Containers (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Investments In And Advances To Affiliates [Line Items]        
Equity in net (losses)/ earnings of affiliated companies $ (16,779) $ (3,025) $ (12,502) $ (9,489)
Navios Containers        
Investments In And Advances To Affiliates [Line Items]        
Equity in net (losses)/ earnings of affiliated companies   $ 142   $ 244