Fair Value Measurements and Derivative Instruments - Recurring (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Assets:
Derivative financial instruments		$ 104,193	$ 0
Liabilities:
Derivative financial instruments		72,098	346,887
Fair Value, Measurements, Recurring | Level 1
Assets:
Derivative financial instruments	[1],[2]	0	0
Investments	[2],[3]	3,237	3,576
Total Assets	[2]	3,237	3,576
Liabilities:
Derivative financial instruments	[2],[4]	0	0
Total Liabilities	[2]	0	0
Fair Value, Measurements, Recurring | Level 2
Assets:
Derivative financial instruments	[1],[5]	221,258	19,397
Investments	[3],[5]	0	0
Total Assets	[5]	221,258	19,397
Liabilities:
Derivative financial instruments	[4],[5]	189,163	373,497
Total Liabilities	[5]	189,163	373,497
Fair Value, Measurements, Recurring | Level 3
Assets:
Derivative financial instruments	[1],[6]	0	0
Investments	[3],[6]	0	0
Total Assets	[6]	0	0
Liabilities:
Derivative financial instruments	[4],[6]	0	0
Total Liabilities	[6]	0	0
Total | Fair Value, Measurements, Recurring
Assets:
Derivative financial instruments	[1]	221,258	19,397
Investments	[3]	3,237	3,576
Total Assets		224,495	22,973
Liabilities:
Derivative financial instruments	[4]	189,163	373,497
Total Liabilities		$ 189,163	$ 373,497

[1] Consists of foreign currency forward contracts, interest rate swaps and fuel swaps. Please refer to the “Fair Value of Derivative Instruments” table for breakdown by instrument type.

[2] Inputs based on quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Valuation of these items does not entail a significant amount of judgment.

[3] Consists of exchange-traded equity securities and mutual funds reported within Other assets in our consolidated balance sheets.

[4] Consists of foreign currency forward contracts, interest rate swaps and fuel swaps. Please refer to the “Fair Value of Derivative Instruments” table for breakdown by instrument type.

[5] Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. For foreign currency forward contracts, interest rate swaps, cross currency swaps and fuel swaps, fair value is derived using valuation models that utilize the income valuation approach. These valuation models take into account the contract terms, such as maturity, as well as other inputs, such as foreign exchange rates and curves, fuel types, fuel curves and interest rate yield curves. Fair value for foreign currency collar options is determined by using standard option pricing models with inputs based on the options’ contract terms, such as exercise price and maturity, and readily available public market data, such as foreign exchange curves, foreign exchange volatility levels and discount rates. All derivative instrument fair values take into account the creditworthiness of the counterparty and the Company.

[6] Inputs that are unobservable. The Company did not use any Level 3 inputs as of September 30, 2017 and December 31, 2016.