| 
           Fair Value Measurements and Derivatives (Tables)
  
         | 
        9 Months Ended | 
      
      
        | 
           Sep. 30, 2013 
         | 
      
      
        | Derivatives Measured at Fair Value and Disclosed by Balance Sheet Location | 
        
 
 The following table sets forth the fair value of our derivatives
 including the balance sheet location (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
   | 
    | 
 Asset | 
   | 
    | 
 Liability | 
   | 
  
 
 |   | 
    | 
 
  Balance Sheet location 
  | 
    | 
 September 30, 
 2013 | 
   | 
    | 
 December 31, 
 2012 | 
   | 
    | 
 September 30, 
 2013 | 
   | 
    | 
 December 31, 
 2012 | 
   | 
  
 
 | 
  
 Fuel swaps designated as hedging instruments 
  | 
    | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Prepaid expenses and other assets 
  | 
    | 
 $ | 
 4,421 | 
    | 
    | 
 $ | 
 5,955 | 
    | 
    | 
 $ | 
 484 | 
    | 
    | 
 $ | 
 876 | 
    | 
  
 
  | 
    | 
 
  
 Other long-term assets 
  | 
    | 
   | 
 2,201 | 
    | 
    | 
   | 
 3,969 | 
    | 
    | 
   | 
 1,890 | 
   | 
    | 
   | 
 388 | 
    | 
  
 
  | 
    | 
 
  
 Accrued expenses and other liabilities 
  | 
    | 
   | 
 669 | 
    | 
    | 
   | 
 188 | 
    | 
    | 
   | 
 938 | 
    | 
    | 
   | 
 204 | 
    | 
  
 
  | 
    | 
 
  
 Other long-term liabilities 
  | 
    | 
   | 
 189 | 
    | 
    | 
   | 
 391 | 
    | 
    | 
   | 
 180 | 
    | 
    | 
   | 
 42 | 
    | 
  
 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Fuel collars designated as hedging instruments 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Prepaid expenses and other assets 
  | 
    | 
   | 
 614 | 
    | 
    | 
   | 
 1,615 | 
    | 
    | 
   | 
 322 | 
    | 
    | 
   | 
 530 | 
    | 
  
 
  | 
    | 
 
  
 Accrued expenses and other liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 51 | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 69 | 
    | 
  
 
  | 
    | 
 
  
 Other long-term liabilities 
  | 
    | 
   | 
 207 | 
    | 
    | 
   | 
 1,908 | 
    | 
    | 
   | 
 202 | 
    | 
    | 
   | 
 1,230 | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Fuel options not designated as hedging instruments 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Prepaid expenses and other assets 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 322 | 
    | 
    | 
   | 
 304 | 
    | 
  
 
  | 
    | 
 
  
 Other long-term liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 202 | 
    | 
    | 
   | 
 1,231 | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Foreign currency options designated as hedging instruments 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Accrued expenses and other liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 18,756 | 
    | 
    | 
   | 
 20,267 | 
    | 
  
 
  | 
    | 
 
  
 Other long-term liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 16,443 | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Foreign currency forward contracts designated as hedging
 instruments 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Prepaid expenses and other assets 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 11,685 | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Foreign currency collar designated as a hedging instrument 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Prepaid expenses and other assets 
  | 
    | 
   | 
 10,425 | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 30 | 
    | 
    | 
   | 
 —   | 
    | 
  
 
  | 
    | 
 
  
 Other long-term assets 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 9,765 | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 1,613 | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 Interest rate swaps designated as hedging instruments 
  | 
    | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
    | 
  | 
  | 
  | 
  
 
  | 
    | 
 
  
 Accrued expenses and other liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 898 | 
    | 
    | 
   | 
 —   | 
    | 
  
 
  | 
    | 
 
  
 Other long-term liabilities 
  | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 —   | 
    | 
    | 
   | 
 2,233 | 
   | 
    | 
   | 
 —   | 
    | 
  
  
  
 | 
      
      
        | Amounts Recognized Within Assets and Liabilities | 
        
 
 The following table discloses the amounts recognized within assets
 and liabilities (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 September 30, 2013 
  | 
    | 
 Gross Amounts | 
   | 
    | 
 Gross 
 Amounts 
 Offset | 
   | 
   | 
 Total Net 
 Amounts | 
   | 
    | 
 Gross 
 Amounts Not 
 Offset | 
   | 
   | 
 Net Amounts | 
   | 
  
 
 | 
  
 Assets 
  | 
    | 
 $ | 
 17,661 | 
    | 
    | 
 $ | 
 (3,048 | 
 )  | 
   | 
 $ | 
 14,613 | 
    | 
    | 
 $ | 
 —   | 
   | 
   | 
 $ | 
 14,613 | 
    | 
  
 
 | 
  
 Liabilities 
  | 
    | 
   | 
 23,409 | 
    | 
    | 
   | 
 (1,065 | 
 )  | 
   | 
   | 
 22,344 | 
    | 
    | 
   | 
 (21,887 | 
 )  | 
   | 
   | 
 457 | 
    | 
  
 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 | 
  
 December 31, 2012 
  | 
    | 
 Gross Amounts | 
   | 
    | 
 Gross 
 Amounts 
 Offset | 
   | 
   | 
 Total Net 
 Amounts | 
   | 
    | 
 Gross 
 Amounts Not 
 Offset | 
   | 
   | 
 Net Amounts | 
   | 
  
 
 | 
  
 Assets 
  | 
    | 
 $ | 
 32,989 | 
    | 
    | 
 $ | 
 (3,711 | 
 )  | 
   | 
 $ | 
 29,278 | 
    | 
    | 
 $ | 
 (11,685 | 
 )  | 
   | 
 $ | 
 17,593 | 
    | 
  
 
 | 
  
 Liabilities 
  | 
    | 
   | 
 39,486 | 
    | 
    | 
   | 
 (2,538 | 
 )  | 
   | 
   | 
 36,948 | 
    | 
    | 
   | 
 (36,710 | 
 )  | 
   | 
   | 
 238 | 
    | 
  
  
  
 | 
      
      
        | 
           Fuel Swaps 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the fuel
 swaps which were designated as cash flow hedges were as follows (in
 thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
   | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
   | 
 2013 | 
   | 
   | 
 2012 | 
   | 
  
 
 | 
  
 Gain recognized in other comprehensive loss – effective
 portion 
  | 
    | 
 $ | 
 13,500 | 
    | 
   | 
 $ | 
 30,848 | 
    | 
   | 
 $ | 
 132 | 
    | 
   | 
 $ | 
 23,029 | 
    | 
  
 
 | 
  
 Gain (loss) recognized in other income (expense) –
 ineffective portion 
  | 
    | 
   | 
 (83 | 
 )  | 
   | 
   | 
 157 | 
    | 
   | 
   | 
 (182 | 
 )  | 
   | 
   | 
 (473 | 
 )  | 
  
 
 | 
  
 Amount reclassified from accumulated comprehensive income (loss)
 into fuel expense 
  | 
    | 
   | 
 (2,081 | 
 )  | 
   | 
   | 
 (1,600 | 
 )  | 
   | 
   | 
 (5,080 | 
 )  | 
   | 
   | 
 (13,932 | 
 )  | 
  
  
  
 | 
      
      
        | 
           Fuel Options 
         | 
         
 | 
      
      
        | Effects of Derivatives Not Designated as Cash flow Hedges | 
        
 
 The effects on the consolidated financial statements of the fuel
 options which were not designated as hedging instruments were as
 follows (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
    | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 | 
  
 Gain recognized in other income (expense) 
  | 
    | 
 $ | 
 430 | 
   | 
    | 
 $ | 
 1,143 | 
    | 
    | 
 $ | 
 1,011 | 
    | 
    | 
 $ | 
 2,858 | 
    | 
  
  
  
 | 
      
      
        | 
           Fuel Collars 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the fuel
 collars which were designated as cash flow hedges were as follows
 (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
   | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
   | 
 2013 | 
   | 
   | 
 2012 | 
   | 
  
 
 | 
  
 Gain (loss) recognized in other comprehensive loss –
 effective portion 
  | 
    | 
 $ | 
 427 | 
    | 
   | 
 $ | 
 5,060 | 
    | 
   | 
 $ | 
 (1,108 | 
 )  | 
   | 
 $ | 
 2,441 | 
    | 
  
 
 | 
  
 Gain (loss) recognized in other income (expense) –
 ineffective portion 
  | 
    | 
   | 
 (51 | 
 )  | 
   | 
   | 
 479 | 
    | 
   | 
   | 
 (29 | 
 )  | 
   | 
   | 
 142 | 
    | 
  
 
 | 
  
 Amount reclassified from other comprehensive income (loss) into
 fuel expense 
  | 
    | 
   | 
 332 | 
    | 
   | 
   | 
 (1,107 | 
 )  | 
   | 
   | 
 1,150 | 
    | 
   | 
   | 
 (5,377 | 
 )  | 
  
  
  
 | 
      
      
        | 
           Foreign Exchange Option 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the foreign
 currency options which were designated as cash flow hedges were as
 follows (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months 
 Ended 
 September 30, | 
   | 
   | 
 Nine Months
 Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
   | 
 2013 | 
   | 
   | 
 2012 | 
   | 
  
 
 | 
  
 Gain (loss) recognized in other comprehensive loss –
 effective portion 
  | 
    | 
 $ | 
 1,179 | 
    | 
    | 
 $ | 
 (2,813 | 
 )  | 
   | 
 $ | 
 (3,174 | 
 )  | 
   | 
 $ | 
 (19,848 | 
 )  | 
  
 
 | 
  
 Gain (loss) recognized in other income (expense) –
 ineffective portion 
  | 
    | 
   | 
 13 | 
    | 
    | 
   | 
 (134 | 
 )  | 
   | 
   | 
 (307 | 
 )  | 
   | 
   | 
 (484 | 
 )  | 
  
 
 | 
  
 Amount reclassified from accumulated comprehensive income (loss)
 into depreciation and amortization expense 
  | 
    | 
   | 
 177 | 
    | 
    | 
   | 
 —   | 
    | 
   | 
   | 
 294 | 
    | 
   | 
   | 
 —   | 
    | 
  
  
  
 | 
      
      
        | 
           Foreign Exchange Forward 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the foreign
 currency forward contracts which were designated as cash flow
 hedges were as follows (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
    | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
  
 
 | 
  
 Gain (loss) recognized in other comprehensive loss –
 effective portion 
  | 
    | 
 $ | 
 —   | 
    | 
   | 
 $ | 
 2,609 | 
    | 
    | 
 $ | 
 (7,886 | 
 )  | 
   | 
 $ | 
 4,332 | 
    | 
  
 
 | 
  
 Gain recognized in other income (expense) – ineffective
 portion 
  | 
    | 
   | 
 —   | 
    | 
   | 
   | 
 —   | 
    | 
    | 
   | 
 66 | 
    | 
   | 
   | 
 —   | 
    | 
  
 
 | 
  
 Amount reclassified from accumulated comprehensive income (loss)
 into depreciation and amortization expense 
  | 
    | 
   | 
 (32 | 
 ) | 
   | 
   | 
 —   | 
    | 
    | 
   | 
 (52 | 
 )  | 
   | 
   | 
 —   | 
    | 
  
  
  
 | 
      
      
        | Effects of Derivatives Not Designated as Cash flow Hedges | 
        
 
 As of September 30, 2013, the effects on the consolidated
 financial statements of the foreign currency forward contracts
 which were not designated as hedging instruments were as follows
 (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
    | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 | 
  
 Gain recognized in other income (expense) 
  | 
    | 
 $ | 
 —   | 
    | 
    | 
 $ | 
 —   | 
    | 
    | 
 $ | 
 20 | 
    | 
    | 
 $ | 
 —   | 
    | 
  
  
  
 | 
      
      
        | 
           Foreign Currency Collar 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the foreign
 currency collar which was designated as a cash flow hedge was as
 follows (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
    | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
    | 
 2013 | 
   | 
    | 
 2012 | 
   | 
  
 
 | 
  
 Gain recognized in other comprehensive income – effective
 portion 
  | 
    | 
 $ | 
 4,518 | 
    | 
    | 
 $ | 
 5,156 | 
   | 
    | 
 $ | 
 2,243 | 
    | 
    | 
 $ | 
 5,156 | 
   | 
  
  
  
 | 
      
      
        | 
           Interest Rate Swap 
         | 
         
 | 
      
      
        | Effects of Derivatives Designated as Cash Flow Hedges | 
        
 
 The effects on the consolidated financial statements of the
 interest rates swaps which were designated as cash flow hedges were
 as follows (in thousands): 
 
   
 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  
 
 |   | 
    | 
 Three Months Ended 
 September 30, | 
   | 
    | 
 Nine Months Ended 
 September 30, | 
   | 
  
 
 |   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
    | 
 2013 | 
   | 
   | 
 2012 | 
   | 
  
 
 | 
  
 Loss recognized in other comprehensive loss – effective
 portion 
  | 
    | 
 $ | 
 (2,826 | 
 )  | 
   | 
 $ | 
 
 —   | 
    | 
    | 
 $ | 
 (2,826 | 
 )  | 
   | 
 $ | 
 
 —   | 
    | 
  
 
 | 
  
 Loss recognized in other income (expense) – ineffective
 portion 
  | 
    | 
   | 
 (334 | 
 )  | 
   | 
   | 
 
 —   | 
    | 
    | 
   | 
 (334 | 
 )  | 
   | 
   | 
 
 —   | 
    | 
  
 
 | 
  
 Amount reclassified from other comprehensive income (loss) into
 interest expense, net 
  | 
    | 
   | 
 65 | 
    | 
   | 
   | 
 
 —   | 
    | 
    | 
   | 
 65 | 
    | 
   | 
   | 
 
 —   | 
    | 
  
  
  
 |