Fair Value of Financial Instruments (Details) (USD $) | 3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | Dec. 31, 2010 | |
| Fair value of assets and liabilities measured on recurring basis | |||||
| Marketable securities, current | $ 79,146,000 | $ 79,146,000 | $ 193,279,000 | ||
| Marketable securities, noncurrent | 293,969,000 | 293,969,000 | 279,080,000 | ||
| Proceeds from the sale of available-for-sale securities | 143,000,000 | 103,000,000 | 372,000,000 | 344,000,000 | |
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Cash and cash equivalents | 147,520,000 | 147,520,000 | 20,498,000 | ||
| Deferred compensation trusts | 74,964,000 | 74,964,000 | 73,916,000 | ||
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Cash and cash equivalents | 23,296,000 | ||||
| Marketable securities, current | 58,154,000 | 58,154,000 | 141,192,000 | ||
| Marketable securities, noncurrent | 293,969,000 | 293,969,000 | 279,080,000 | ||
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Commodity Swap Forward Contracts | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Derivative assets | 3,693,000 | 3,693,000 | 5,138,000 | ||
| Derivative liabilities | 65,000 | 65,000 | 64,000 | ||
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign currency contracts. | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Derivative assets | 17,173,000 | 17,173,000 | 731,000 | ||
| Derivative liabilities | 8,636,000 | 8,636,000 | 2,527,000 | ||
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Cash and cash equivalents | |||||
Fair Value, Measurements, Recurring | Fair Value | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Cash and cash equivalents | 147,520,000 | 147,520,000 | 43,794,000 | ||
| Marketable securities, current | 58,154,000 | 58,154,000 | 141,192,000 | ||
| Deferred compensation trusts | 74,964,000 | 74,964,000 | 73,916,000 | ||
| Marketable securities, noncurrent | 293,969,000 | 293,969,000 | 279,080,000 | ||
Fair Value, Measurements, Recurring | Fair Value | Commodity Swap Forward Contracts | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Derivative assets | 3,693,000 | 3,693,000 | 5,138,000 | ||
| Derivative liabilities | 65,000 | 65,000 | 64,000 | ||
Fair Value, Measurements, Recurring | Fair Value | Foreign currency contracts. | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Derivative assets | 17,173,000 | 17,173,000 | 731,000 | ||
| Derivative liabilities | 8,636,000 | 8,636,000 | 2,527,000 | ||
Fair Value, Measurements, Recurring | Money market funds | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | 148,000,000 | 148,000,000 | 20,000,000 | ||
Fair Value, Measurements, Recurring | U.S. agency securities | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | 123,000,000 | 123,000,000 | 155,000,000 | ||
Fair Value, Measurements, Recurring | U.S. Treasury securities | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | 51,000,000 | 51,000,000 | 59,000,000 | ||
Fair Value, Measurements, Recurring | Corporate debt securities | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | 170,000,000 | 170,000,000 | 196,000,000 | ||
Fair Value, Measurements, Recurring | Commercial paper | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | 26,000,000 | ||||
Fair Value, Measurements, Recurring | Other securities | |||||
| Fair value of assets and liabilities measured on recurring basis | |||||
| Available-for-sale securities | $ 8,000,000 | $ 8,000,000 | $ 48,000,000 | ||