Fair Value Measurements (Details) (USD $) | Sep. 30, 2013 | Dec. 31, 2012 | Sep. 30, 2012 |
In Thousands, unless otherwise specified |
Assets (Liabilties) at Fair Value | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Assets (liabilities) at fair value | ($10,051) | | ($13,005) | | $2,936 | |
Assets (Liabilties) at Fair Value | Other current assets | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded assets | ' | | 1,636 | | 5,853 | |
Available-for-sale investment | ' | | 1,668 | | ' | |
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 | ' | | 192 | | 1,725 | |
Gross amounts offset in the balance sheets | ' | | -2,550 | | -4,963 | |
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 of recognized assets | ' | | 4,001 | [1] | 9,105 | [1] |
Assets (Liabilties) at Fair Value | Other current assets | Not designated as hedging instruments | 30-day euro forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts of recognized assets | ' | | 4 | | ' | |
Gross amounts offset in the balance sheets | ' | | -11 | | -14 | |
Assets (Liabilties) at Fair Value | Investments & other assets, net | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded assets | 61 | | 830 | | 1,007 | |
Available-for-sale investment | ' | | ' | | 5,566 | |
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 | 515 | | ' | | 522 | |
Gross amounts offset in the balance sheets | -465 | | ' | | -1,152 | |
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 | 196 | [1] | 1,889 | [1] | 1,760 | [1] |
Gross amounts offset in the balance sheets | -137 | [1] | -1,059 | [1] | -123 | [1] |
Assets (Liabilties) at Fair Value | Investments & other assets, net | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts of recognized assets | 22 | [2] | ' | | ' | |
Gross amounts offset in the balance sheets | -70 | [2] | ' | | ' | |
Assets (Liabilties) at Fair Value | Accrued liabilities | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded liabilities | -9,161 | | -17,139 | | -7,104 | |
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 | 1,163 | | 1,992 | | 2,960 | |
Gross amounts of recognized liabilities | -10,913 | | -22,849 | | -12,217 | |
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 | 1,212 | [1] | 3,741 | [1] | 2,202 | [1] |
Gross amounts of recognized liabilities | -611 | [1] | ' | | ' | |
Assets (Liabilties) at Fair Value | Accrued liabilities | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 282 | [2] | ' | | ' | |
Gross amounts of recognized liabilities | -203 | [2] | ' | | ' | |
Assets (Liabilties) at Fair Value | Accrued liabilities | Not designated as hedging instruments | 30-day euro forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 17 | | 1 | | ' | |
Gross amounts of recognized liabilities | -108 | | -24 | | -49 | |
Assets (Liabilties) at Fair Value | Other liabilities | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded liabilities | -951 | | ' | | -2,386 | |
Assets (Liabilties) at Fair Value | Other 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 | 196 | | ' | | 2,133 | |
Gross amounts of recognized liabilities | -233 | | ' | | -4,626 | |
Assets (Liabilties) at Fair Value | Other 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 | 145 | [1] | ' | | 1,203 | [1] |
Gross amounts of recognized liabilities | -835 | [1] | ' | | -1,096 | [1] |
Assets (Liabilties) at Fair Value | Other liabilities | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 12 | [2] | ' | | ' | |
Gross amounts of recognized liabilities | -236 | [2] | ' | | ' | |
Level 1 | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Assets (liabilities) at fair value | ' | | 1,668 | | 5,566 | |
Level 1 | Other current assets | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Available-for-sale investment | ' | | 1,668 | | ' | |
Level 1 | Investments & other assets, net | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Available-for-sale investment | ' | | ' | | 5,566 | |
Level 2 | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Assets (liabilities) at fair value | -10,051 | | -14,673 | | -2,630 | |
Level 2 | Other current assets | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded assets | ' | | 1,636 | | 5,853 | |
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 | ' | | 192 | | 1,725 | |
Gross amounts offset in the balance sheets | ' | | -2,550 | | -4,963 | |
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 of recognized assets | ' | | 4,001 | [1] | 9,105 | [1] |
Level 2 | Other current assets | Not designated as hedging instruments | 30-day euro forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts of recognized assets | ' | | 4 | | ' | |
Gross amounts offset in the balance sheets | ' | | -11 | | -14 | |
Level 2 | Investments & other assets, net | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded assets | 61 | | 830 | | 1,007 | |
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 | 515 | | ' | | 522 | |
Gross amounts offset in the balance sheets | -465 | | ' | | -1,152 | |
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 | 196 | [1] | 1,889 | [1] | 1,760 | [1] |
Gross amounts offset in the balance sheets | -137 | [1] | -1,059 | [1] | -123 | [1] |
Level 2 | Investments & other assets, net | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts of recognized assets | 22 | [2] | ' | | ' | |
Gross amounts offset in the balance sheets | -70 | [2] | ' | | ' | |
Level 2 | Accrued liabilities | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded liabilities | -9,161 | | -17,139 | | -7,104 | |
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 | 1,163 | | 1,992 | | 2,960 | |
Gross amounts of recognized liabilities | -10,913 | | -22,849 | | -12,217 | |
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 | 1,212 | [1] | 3,741 | [1] | 2,202 | [1] |
Gross amounts of recognized liabilities | -611 | [1] | ' | | ' | |
Level 2 | Accrued liabilities | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 282 | [2] | ' | | ' | |
Gross amounts of recognized liabilities | -203 | [2] | ' | | ' | |
Level 2 | Accrued liabilities | Not designated as hedging instruments | 30-day euro forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 17 | | 1 | | ' | |
Gross amounts of recognized liabilities | -108 | | -24 | | -49 | |
Level 2 | Other liabilities | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Net amount of recorded liabilities | -951 | | ' | | -2,386 | |
Level 2 | Other 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 | 196 | | ' | | 2,133 | |
Gross amounts of recognized liabilities | -233 | | ' | | -4,626 | |
Level 2 | Other 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 | 145 | [1] | ' | | 1,203 | [1] |
Gross amounts of recognized liabilities | -835 | [1] | ' | | -1,096 | [1] |
Level 2 | Other liabilities | Not designated as hedging instruments | Bunker fuel forward contracts | ' | | ' | | ' | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ' | | ' | | ' | |
Gross amounts offset in the balance sheets | 12 | [2] | ' | | ' | |
Gross amounts of recognized liabilities | ($236) | [2] | ' | | ' | |
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[1] | Bunker fuel forward contracts designated as cash flow hedges. |
[2] | Bunker fuel forward contracts not designated as hedging instruments. |