Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 8

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-Name Accounting Standards Codification

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-Section 50

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-Name Accounting Standards Codification

-Topic 815

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Fair value of asset after deduction of liability.

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Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Assets (Liabilties) at Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets (liabilities) at fair value	$ 17,660	$ 7,745	$ (4,627)
Assets (Liabilties) at Fair Value \| Other current assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded assets	17,660	10,070
Assets (Liabilties) at Fair Value \| Other current assets \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets		10,215
Gross amounts offset in the balance sheets		(145)
Assets (Liabilties) at Fair Value \| Other current assets \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets	25,052
Gross amounts offset in the balance sheets	(73)
Assets (Liabilties) at Fair Value \| Other current assets \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets	(7,319)
Assets (Liabilties) at Fair Value \| Investments & other assets, net
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded assets			417
Assets (Liabilties) at Fair Value \| Investments & other assets, net \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets			2,146
Gross amounts offset in the balance sheets			(1,936)
Assets (Liabilties) at Fair Value \| Investments & other assets, net \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets			373
Gross amounts offset in the balance sheets			(166)
Assets (Liabilties) at Fair Value \| Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded liabilities		2,325	(5,044)
Assets (Liabilties) at Fair Value \| Accrued liabilities \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets		(14,103)	2,937
Gross amounts of recognized liabilities		438	(6,978)
Assets (Liabilties) at Fair Value \| Accrued liabilities \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets		15,990	317
Gross amounts of recognized liabilities			(1,158)
Assets (Liabilties) at Fair Value \| Accrued liabilities \| Derivatives not designated as hedging instruments \| 30-day euro forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized liabilities			(162)
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets (liabilities) at fair value	17,660	7,745	(4,627)
Level 2 \| Other current assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded assets	17,660	10,070
Level 2 \| Other current assets \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets		10,215
Gross amounts offset in the balance sheets		(145)
Level 2 \| Other current assets \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets	25,052
Gross amounts offset in the balance sheets	(73)
Level 2 \| Other current assets \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets	(7,319)
Level 2 \| Investments & other assets, net
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded assets			417
Level 2 \| Investments & other assets, net \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets			2,146
Gross amounts offset in the balance sheets			(1,936)
Level 2 \| Investments & other assets, net \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized assets			373
Gross amounts offset in the balance sheets			(166)
Level 2 \| Accrued liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net amount of recorded liabilities		(2,325)	(5,044)
Level 2 \| Accrued liabilities \| Designated as cash flow hedges \| Currency hedge portfolio
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets		(14,103)	2,937
Gross amounts of recognized liabilities		438	(6,978)
Level 2 \| Accrued liabilities \| Designated as cash flow hedges \| Bunker fuel forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts offset in the balance sheets		15,990	317
Gross amounts of recognized liabilities			(1,158)
Level 2 \| Accrued liabilities \| Derivatives not designated as hedging instruments \| 30-day euro forward contracts
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross amounts of recognized liabilities			$ (162)