Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements and Derivatives - Derivatives Measured at Fair Value and Disclosed by Balance Sheet Location (Details)

v3.4.0.3
Fair Value Measurements and Derivatives - Derivatives Measured at Fair Value and Disclosed by Balance Sheet Location (Details) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 70,316 $ 3,446
Designated as Hedging Instrument | Fuel Swaps | Prepaid expenses and other assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 6,283
Derivative liabilities, fair value 256
Designated as Hedging Instrument | Fuel Swaps | Other long-term assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 3,534
Derivative liabilities, fair value $ 43
Designated as Hedging Instrument | Fuel Swaps | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 117,016 $ 128,740
Designated as Hedging Instrument | Fuel Swaps | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 1,241
Derivative liabilities, fair value 132,656 $ 132,494
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Prepaid expenses and other assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 671
Derivative liabilities, fair value
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other long-term assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 59,812 $ 3,446
Derivative liabilities, fair value $ 2,953 $ 1,370
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 138 $ 8,737
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 1,397 551
Derivative liabilities, fair value $ 5,390 $ 24,181
Designated as Hedging Instrument | Interest Rate Swap | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 3,882 $ 4,079
Designated as Hedging Instrument | Interest Rate Swap | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 4,490 $ 3,395
Not Designated as Hedging Instrument | Fuel Swaps | Prepaid expenses and other assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 16
Derivative liabilities, fair value
Not Designated as Hedging Instrument | Fuel Swaps | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 1,545
Not Designated as Hedging Instrument | Foreign Currency Collar | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 29,368 $ 42,993