Deferred Charges, Net (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Changes in deferred charges, net    
Balance at the beginning of the period $ 67,949 $ 88,821
Additions 7,069 470
Written off amounts (341) (429)
Amortization (19,402) (20,913)
Balance at the end of the period 55,275 67,949
Drydocking and Special Survey Costs    
Changes in deferred charges, net    
Balance at the beginning of the period 4,041 9,669
Additions 6,887 283
Written off amounts (286) (429)
Amortization (4,387) (5,482)
Balance at the end of the period 6,255 4,041
Period of amortization for deferred costs 2 years 6 months  
Finance and other Costs    
Changes in deferred charges, net    
Balance at the beginning of the period 63,908 79,152
Additions 182 187
Written off amounts (55)  
Amortization (15,015) (15,431)
Balance at the end of the period $ 49,020 $ 63,908