Fair Value of Financial Instruments - Fair Value (Table) (Details) - USD ($)
$ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] |
|
|
|
|
| Cash and cash equivalents - Book Value |
$ 127,632
|
$ 135,992
|
$ 163,412
|
$ 247,556
|
| Cash and cash equivalents - Fair Value |
127,632
|
135,992
|
|
|
| Restricted cash - Book Value |
6,558
|
5,386
|
$ 13,480
|
|
| Restricted cash - Fair Value |
6,558
|
5,386
|
|
|
| Investments in available-for-sale securities - Book Value |
238
|
0
|
|
|
| Investments in available-for-sale securities - Fair Value |
238
|
0
|
|
|
| Loan receivable from affiliate companies - Book Value |
30,112
|
23,008
|
|
|
| Loan receivable from affiliate companies - Fair Value |
30,112
|
23,008
|
|
|
| Long-term receivable from affiliate companies - Book Value |
0
|
11,105
|
|
|
| Long-term receivable from affiliate companies - Fair Value |
0
|
11,105
|
|
|
| Capital lease obligations, including current portion - Book Value |
0
|
(17,617)
|
|
|
| Capital lease obligations, including current portion - Fair Value |
0
|
(17,617)
|
|
|
| Senior and ship mortgage notes, net - Book Value |
(1,301,999)
|
(1,296,537)
|
|
|
| Senior and ship mortgage notes, net - Fair Value |
(1,181,838)
|
(974,170)
|
|
|
| Long-term debt, including current portion - Book Value |
(380,489)
|
(304,682)
|
|
|
| Long-term debt, including current portion - Fair Value |
(389,332)
|
(308,080)
|
|
|
| Loan payable to affiliate company - Book Value |
0
|
(49,876)
|
|
|
| Loan payable to affiliate company - Fair Value |
0
|
(51,240)
|
|
|
| Long-term payable to affiliate companies - Book Value |
(76,872)
|
(6,399)
|
|
|
| Long-term payable to affiliate companies - Fair Value |
$ (76,872)
|
$ (6,399)
|
|
|