Fair Value of Financial Instruments - Non-Recurring Measurements (Table) (Details) - USD ($)
$ in Thousands
Jun. 30, 2020
Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash and cash equivalents $ 54,014 $ 77,991
Restricted cash 1,058 736
Investments in available-for-sale-securities 153 189
Loan receivable from affiliate companies 0 24,495
Long-term receivable from affiliate company 0 5,328
Senior and ship mortgage notes (780,814) (875,228)
Long-term debt, including current portion (312,667) (264,498)
Loan payable to affiliate companies, including current portion (129,224) (130,538)
Long-term payable to affiliate companies 0 (5,000)
Fair Value Measurements, Nonrecurring    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash and cash equivalents 54,014 77,991
Restricted cash 1,058 736
Investments in available-for-sale-securities 153 189
Loan receivable from affiliate companies [1]   24,495
Long-term receivable from affiliate company [1]   5,328
Senior and ship mortgage notes (780,814) (875,228)
Long-term debt, including current portion [2] (312,667) (264,498)
Loan payable to affiliate companies, including current portion [1] (129,224) (130,538)
Long-term payable to affiliate companies [1]   (5,000)
(Level I) | Fair Value Measurements, Nonrecurring    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash and cash equivalents 54,014 77,991
Restricted cash 1,058 736
Investments in available-for-sale-securities 153 189
Senior and ship mortgage notes (772,188) (866,602)
(Level II) | Fair Value Measurements, Nonrecurring    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Loan receivable from affiliate companies [1]   24,495
Long-term receivable from affiliate company [1]   5,328
Senior and ship mortgage notes (8,626) (8,626)
Long-term debt, including current portion [2] (312,667) (264,498)
Loan payable to affiliate companies, including current portion [1] $ (129,224) (130,538)
Long-term payable to affiliate companies [1]   $ (5,000)
[1] The fair value of the Company’s loan receivable from/ payable to affiliate companies and long-term receivable from/payable to affiliate companies is estimated based on currently available debt with similar contract terms, interest rate and remaining maturities as well as taking into account the counterparty’s creditworthiness.
[2] The fair value of the Company’s long-term debt is estimated based on currently available debt with similar contract terms, interest rates and remaining maturities, published quoted market prices as well as taking into account the Company’s creditworthiness.