Marketable Securities and Time Deposits (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Amortized cost of short-term deposits and available-for-sale debt securities
Amortized cost	$ 89,734	$ 100,701
Unrealized gains (losses), Gains	412
Unrealized gains (losses), Losses	(521)
Estimated fair value	89,625
Due in one year or less [Member]
Amortized cost of short-term deposits and available-for-sale debt securities
Amortized cost	18,791
Unrealized gains (losses), Gains	43
Unrealized gains (losses), Losses	(2)
Estimated fair value	18,832
Due after one year to five years [Member]
Amortized cost of short-term deposits and available-for-sale debt securities
Amortized cost	70,943
Unrealized gains (losses), Gains	369
Unrealized gains (losses), Losses	(519)
Estimated fair value	$ 70,793

Amount of debt securities categorized neither as held-to-maturity nor trading.

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Statement of Financial Accounting Standard (FAS)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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

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-Name Statement of Financial Accounting Standard (FAS)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 10: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details