Stockholders' Equity (Details 1) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Components of Comprehensive income
Net income, as reported	$ 22,344	$ 28,110	$ 45,621	$ 52,303
Other comprehensive income (loss):
Foreign currency translation adjustment	845	(1,497)	3,173	(4,350)
Change in net unrealized gain on available-for-sale securities during the period	(6,767)	(1,004)	(10,180)	(3,653)
Reclassification adjustments:
Realized gain on available-for-sale securities, net of tax	(1,372)	1,206	(1,142)	2,654
Total other comprehensive income (loss), net	(7,294)	(1,295)	(8,149)	(5,349)
Comprehensive income	$ 15,050	$ 26,815	$ 37,472	$ 46,954

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A5
-Appendix A

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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
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This element represents Other Comprehensive Income (Loss), Net of Tax, for the period. Includes deferred gains (losses) on qualifying hedges, unrealized holding gains (losses) on available-for-sale securities, minimum pension liability, and cumulative translation adjustment.

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Reclassification adjustment for unrealized gains or losses realized upon the sale of securities, after tax.

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