Cash and Cash Equivalents and Investments (Details 1) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Gross unrealized gains and (losses) aggregated by investment category
Cost	$ 426,781	$ 323,620
Gross Unrealized Gains	44	42
Gross Unrealized (Losses)	(17)	(35)
Estimated Fair Value	426,808	323,627
Cash and Cash Equivalents and Investments (Textuals) [Abstract]
Cash	107,678	107,815
Fair value of short-term trading securities, Equity mutual funds	613	491
Time deposits and drafts [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	32,239	18,554
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	0	0
Estimated Fair Value	32,239	18,554
Money market funds [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	75,794	7,032
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	0	0
Estimated Fair Value	75,794	7,032
U.S. treasury and agency obligations [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	318,748	298,034
Gross Unrealized Gains	44	42
Gross Unrealized (Losses)	(17)	(35)
Estimated Fair Value	318,775	298,041
Cash and cash equivalents [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	108,433	54,664
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	0	(3)
Estimated Fair Value	108,433	54,661
Short-term investments [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	309,086	268,956
Gross Unrealized Gains	43	42
Gross Unrealized (Losses)	(14)	(32)
Estimated Fair Value	309,115	268,966
Long-term marketable securities [Member]
Gross unrealized gains and (losses) aggregated by investment category
Cost	9,262
Gross Unrealized Gains	1
Gross Unrealized (Losses)	(3)
Estimated Fair Value	$ 9,260

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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+ Details

- Definition

For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.

+ References

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

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+ Details

- Definition

Financial instruments that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time, usually less than one year or the normal operating cycle, whichever is longer) or for debt and equity securities formerly categorized as available-for-sale or held-to-maturity which the entity held as of the date it opted to account for such securities at fair value. An enterprise may also categorize such a security as trading without the intent to sell it in the near term assuming the decision to categorize the security as trading occurred at acquisition.

+ References

+ Details