Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements and Derivatives - Derivatives measured at fair value and disclosed by balance sheet location (Details)

v3.6.0.2
Fair Value Measurements and Derivatives - Derivatives measured at fair value and disclosed by balance sheet location (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 20,302 $ 3,446
Derivative liabilities, fair value 238,069 344,619
Designated as Hedging Instrument | Fuel Swaps | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value  
Derivative liabilities, fair value 44,271 128,740
Designated as Hedging Instrument | Fuel Swaps | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 13,237
Derivative liabilities, fair value 38,608 132,494
Designated as Hedging Instrument | Fuel Swaps | Prepaid expenses and other assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 20,288
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 14 3,446
Derivative liabilities, fair value 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 61,788 8,737
Designated as Hedging Instrument | Foreign currency forward contracts | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 551
Derivative liabilities, fair value 88,920 24,181
Designated as Hedging Instrument | Interest rates swaps | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value 3,331 4,079
Designated as Hedging Instrument | Interest rates swaps | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value 1,151 3,395
Not Designated as Hedging Instrument | Foreign currency forward contracts    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 42,993