Borrowings - Principal Payments (Table) (Details) - USD ($)
$ in Thousands
Jun. 30, 2017
Dec. 31, 2016
BORROWINGS [Abstract]    
June 30, 2018 $ 31,289  
June 30, 2019 400,167  
June 30, 2020 66,853  
June 30, 2021 32,420  
June 30, 2022 1,098,579  
June 30, 2023 and thereafter 38,748  
Total $ 1,668,056 $ 1,675,415