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)

v3.7.0.1
Fair Value Measurements and Derivatives - Derivatives Measured at Fair Value and Disclosed by Balance Sheet Location (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Dec. 31, 2016
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value $ 11,855 $ 20,302
Derivative liabilities, fair value 223,492 238,069
Designated as Hedging Instrument | Fuel Swaps | Prepaid expenses and other assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 11,630 20,288
Derivative liabilities, fair value
Designated as Hedging Instrument | Fuel Swaps | Accrued expenses and other liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 622
Derivative liabilities, fair value 45,690 44,271
Designated as Hedging Instrument | Fuel Swaps | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 7,827 13,237
Derivative liabilities, fair value 42,130 38,608
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other long-term assets    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value 225 14
Derivative liabilities, fair value
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 54,086 61,788
Designated as Hedging Instrument | Foreign Currency Forward Contracts | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value 78,247 88,920
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 2,886 3,331
Designated as Hedging Instrument | Interest Rate Swap | Other long-term liabilities    
Derivatives, Fair Value [Line Items]    
Derivative assets, fair value
Derivative liabilities, fair value $ 453 $ 1,151