Short-Term Investments And Fair Value Measurement (Estimated Fair Value Of Short-Term Investments By Contractual Maturity) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Short-Term Investments And Fair Value Measurement [Abstract]
Due within one year	$ 96,056
Due after one year and through 5 years	109,488
Due after 5 years and through 10 years
Due after 10 years	1,029
Total short-term investments	$ 206,573	$ 155,888

Investments in debt and equity securities which are categorized neither as trading securities nor held-to-maturity securities and which are intended be sold or mature within one year from the balance sheet date or the normal operating cycle, whichever is longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

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-Name Accounting Standards Codification

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-Name Accounting Research Bulletin (ARB)

-Number 43

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