Marketable Securities, Available-for-sale (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Contractual maturity:
Marketable securities, available-for-sale	$ 347,016	$ 437,795
Total debt securities
Contractual maturity:
Maturing in one year or less	167,413	22,244
Maturing after one year through three years	120,952	299,381
Maturing after three years	32,876	11,006
Marketable securities, available-for-sale	321,241	332,631
Time deposits and short-term pooled investments
Contractual maturity:
Marketable securities, available-for-sale	$ 25,775	$ 105,164

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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+ Details

- Definition

This item represents the fair value of debt securities which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details