Fair Value Measurements and Derivatives (Tables)
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9 Months Ended | 
Sep. 30, 2019  | 
| Derivative Instruments And Hedging Activities Disclosure [Abstract] | 
 
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| Schedule of derivatives measured at fair value and disclosed by balance sheet location | 
  
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Assets  | 
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Liabilities  | 
 
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September 30,   | 
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December 31,   | 
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September 30,   | 
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December 31,   | 
 
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Balance Sheet Location  | 
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2019  | 
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2018  | 
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2019  | 
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2018  | 
 
Derivative Contracts Designated as Hedging Instruments  | 
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Fuel contracts  | 
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Prepaid expenses and other assets  | 
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$  | 
 50  | 
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$  | 
 2,583  | 
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$  | 
 346  | 
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$  | 
 1  | 
 
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Other long-term assets  | 
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 53  | 
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 197  | 
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 —  | 
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 29  | 
 
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Accrued expenses and other liabilities  | 
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   | 
 17  | 
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 1,173  | 
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 35,439  | 
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 19,547  | 
 
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Other long-term liabilities  | 
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 261  | 
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 933  | 
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 36,233  | 
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 51,184  | 
 
Foreign currency contracts  | 
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Prepaid expenses and other assets  | 
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   | 
 —  | 
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 5,285  | 
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 —  | 
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 1,497  | 
 
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Other long-term assets  | 
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   | 
 —  | 
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 3,514  | 
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 —  | 
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 —  | 
 
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Accrued expenses and other liabilities  | 
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 —  | 
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 112  | 
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 97,524  | 
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 5,145  | 
 
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Other long-term liabilities  | 
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 —  | 
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 2,874  | 
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 156,339  | 
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 40,476  | 
 
Interest rate contracts  | 
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Prepaid expenses and other assets  | 
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   | 
 —  | 
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 519  | 
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 —  | 
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 —  | 
 
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Other long-term assets  | 
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 —  | 
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 27  | 
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 —  | 
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 —  | 
 
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Accrued expenses and other liabilities  | 
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   | 
 —  | 
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 —  | 
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 2,984  | 
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 —  | 
 
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Other long-term liabilities  | 
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 —  | 
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 —  | 
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 3,284  | 
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 —  | 
 
Total derivatives designated as hedging instruments  | 
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$  | 
 381  | 
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$  | 
 17,217  | 
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$  | 
 332,149  | 
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$  | 
 117,879  | 
 
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Derivative Contracts Not Designated as Hedging Instruments  | 
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Fuel contracts  | 
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Prepaid expenses and other assets  | 
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$  | 
 667  | 
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$  | 
 —  | 
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$  | 
 —  | 
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$  | 
 —  | 
 
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Accrued expenses and other liabilities  | 
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 495  | 
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 —  | 
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 —  | 
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 —  | 
 
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Total derivatives not designated as hedging instruments  | 
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$  | 
 1,162  | 
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$  | 
 —  | 
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$  | 
 —  | 
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$  | 
 —  | 
 
Total derivatives  | 
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$  | 
 1,543  | 
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$  | 
 17,217  | 
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$  | 
 332,149  | 
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$  | 
 117,879  | 
 
 
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| Schedule of gross and net amounts recognized within assets and liabilities | 
  
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Gross   | 
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Gross  | 
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Gross   | 
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Amounts   | 
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Total Net  | 
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Amounts   | 
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September 30, 2019  | 
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Amounts  | 
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Offset  | 
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Amounts  | 
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Not Offset  | 
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Net Amounts  | 
 
Assets  | 
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$  | 
 770  | 
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$  | 
 (346)  | 
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$  | 
 424  | 
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$  | 
 —  | 
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$  | 
 424  | 
 
Liabilities  | 
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 331,803  | 
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 (773)  | 
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 331,030  | 
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 (260,131)  | 
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 70,899  | 
 
 
 
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Gross   | 
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Gross   | 
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Gross   | 
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Amounts   | 
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Total Net   | 
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Amounts   | 
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December 31, 2018  | 
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Amounts  | 
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Offset  | 
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Amounts  | 
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Not Offset  | 
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Net Amounts  | 
 
Assets  | 
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$  | 
 12,125  | 
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$  | 
 (1,527)  | 
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$  | 
 10,598  | 
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$  | 
 (6,872)  | 
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$  | 
 3,726  | 
 
Liabilities  | 
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 116,352  | 
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 (5,092)  | 
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 111,260  | 
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 (35,718)  | 
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 75,542  | 
 
 
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| Schedule of cash flow hedge accounting on accumulated other comprehensive income (loss) | 
  
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Location of Gain  | 
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(Loss) Reclassified  | 
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from Accumulated  | 
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Amount of Gain (Loss) Reclassified  | 
 
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Amount of Gain (Loss)  | 
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Other Comprehensive  | 
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from Accumulated Other  | 
 
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Recognized in Other  | 
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Income (Loss) into  | 
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Comprehensive  | 
 
Derivatives  | 
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Comprehensive Income  | 
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Income  | 
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Income (Loss) into Income  | 
 
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Three Months  | 
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Three Months  | 
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Three Months  | 
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Three Months  | 
 
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Ended  | 
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Ended  | 
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Ended  | 
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Ended  | 
 
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      | 
September 30, 2019  | 
      | 
September 30, 2018  | 
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      | 
September 30, 2019  | 
      | 
September 30, 2018  | 
 
Fuel contracts  | 
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$  | 
 (65,726)  | 
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$  | 
 24,439  | 
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Fuel  | 
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$  | 
 1,657  | 
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$  | 
 11,595  | 
 
Foreign currency contracts  | 
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 (142,627)  | 
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 (10,062)  | 
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Depreciation and amortization  | 
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 (703)  | 
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   | 
 (703)  | 
 
Interest rate contracts  | 
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 (1,158)  | 
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 988  | 
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Interest expense, net  | 
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 (506)  | 
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 (186)  | 
 
Total gain (loss) recognized in other comprehensive income  | 
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$  | 
 (209,511)  | 
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$  | 
 15,365  | 
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$  | 
 448  | 
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$  | 
 10,706  | 
 
 
 
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Location of Gain  | 
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(Loss) Reclassified  | 
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from Accumulated  | 
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Amount of Gain (Loss) Reclassified  | 
 
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Amount of Gain (Loss)  | 
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Other Comprehensive  | 
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from Accumulated Other  | 
 
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Recognized in Other  | 
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Income (Loss) into  | 
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Comprehensive  | 
 
Derivatives  | 
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Comprehensive Income  | 
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Income  | 
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Income (Loss) into Income  | 
 
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Nine Months  | 
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Nine Months  | 
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Nine Months  | 
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Nine Months  | 
 
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Ended  | 
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Ended  | 
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Ended  | 
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Ended  | 
 
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      | 
September 30, 2019  | 
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September 30, 2018  | 
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September 30, 2019  | 
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September 30, 2018  | 
 
Fuel contracts  | 
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$  | 
 14,205  | 
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$  | 
 88,935  | 
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Fuel  | 
   | 
$  | 
 19,060  | 
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$  | 
 23,024  | 
 
Foreign currency contracts  | 
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 (218,724)  | 
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   | 
 (43,951)  | 
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Depreciation and amortization  | 
   | 
   | 
 (2,108)  | 
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   | 
 (2,761)  | 
 
Interest rate contracts  | 
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 (7,029)  | 
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   | 
 3,063  | 
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Interest expense, net  | 
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   | 
 (230)  | 
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   | 
 (1,049)  | 
 
Total gain (loss) recognized in other comprehensive income  | 
   | 
$  | 
 (211,548)  | 
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$  | 
 48,047  | 
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    | 
   | 
$  | 
 16,722  | 
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$  | 
 19,214  | 
 
 
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| Schedule of cash flow hedge accounting on the consolidated financial statements of operations | 
  
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Three Months Ended September 30, 2019  | 
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Three Months Ended September 30, 2018  | 
 
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Depreciation  | 
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Depreciation  | 
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  | 
  | 
  | 
  | 
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and    | 
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Interest   | 
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  | 
  | 
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and  | 
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Interest   | 
 
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      | 
Fuel  | 
      | 
Amortization  | 
      | 
 Expense, net  | 
      | 
Fuel  | 
      | 
Amortization  | 
      | 
Expense, net  | 
 
Total amounts of income and expense line items presented in the consolidated statements of operations in which the effects of cash flow hedges are recorded  | 
  | 
$  | 
 98,943  | 
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$  | 
 156,215  | 
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$  | 
 60,188  | 
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$  | 
 99,643  | 
  | 
$  | 
 143,700  | 
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$  | 
 69,540  | 
 
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Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into income  | 
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Fuel contracts  | 
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  | 
 1,657  | 
  | 
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 —  | 
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 —  | 
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 11,595  | 
  | 
  | 
 —  | 
  | 
  | 
 —  | 
 
Foreign currency contracts  | 
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  | 
 —  | 
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 (703)  | 
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  | 
 —  | 
  | 
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 —  | 
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 (703)  | 
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  | 
 —  | 
 
Interest rate contracts  | 
  | 
  | 
 —  | 
  | 
  | 
 —  | 
  | 
  | 
 (506)  | 
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  | 
 —  | 
  | 
  | 
 —  | 
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  | 
 (186)  | 
 
 
 
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Nine Months Ended September 30, 2019  | 
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Nine Months Ended September 30, 2018  | 
 
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Depreciation   | 
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Depreciation   | 
  | 
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  | 
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and   | 
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Interest   | 
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and   | 
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Interest   | 
 
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      | 
Fuel  | 
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Amortization  | 
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Expense, net  | 
      | 
Fuel  | 
      | 
Amortization  | 
      | 
Expense, net  | 
 
Total amounts of income and expense line items presented in the consolidated statements of operations in which the effects of cash flow hedges are recorded  | 
  | 
$  | 
 297,727  | 
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$  | 
 482,227  | 
  | 
$  | 
 199,660  | 
  | 
$  | 
 288,286  | 
  | 
$  | 
 415,648  | 
  | 
$  | 
 202,226  | 
 
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    | 
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Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into income  | 
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   | 
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    | 
   | 
  | 
    | 
   | 
  | 
    | 
 
Fuel contracts  | 
   | 
  | 
 19,060  | 
   | 
  | 
 —  | 
   | 
  | 
 —  | 
   | 
  | 
 23,024  | 
   | 
  | 
 —  | 
   | 
  | 
 —  | 
 
Foreign currency contracts  | 
   | 
  | 
 —  | 
  | 
  | 
 (2,108)  | 
   | 
  | 
 —  | 
   | 
  | 
 —  | 
   | 
  | 
 (2,761)  | 
   | 
  | 
 —  | 
 
Interest rate contracts  | 
   | 
  | 
 —  | 
   | 
  | 
 —  | 
   | 
  | 
 (230)  | 
   | 
  | 
 —  | 
   | 
  | 
 —  | 
   | 
  | 
 (1,049)  | 
 
 
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