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Cash and Cash Equivalents and Short-term Investments (Details 2) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 31, 2012 | Jun. 30, 2013
Cash and cash equivalents and short-term investments |  |
Cash and cash equivalents, fair value | $ 524,922 | $ 508,128
Short-term investments: |  |
Trading equity securities, fair value | 52,705 |
Trading equity securities, gross unrealized holding gains | 46,981 |
Available-for-sale equities securities |  |
Available-for-sale equity securities, fair value | 200,577 | 99,832
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 25,967 | 21,170
Available-for-sale securities, gross unrealized holding gains | 139,205 | 54,564
Available-for-sale securities, gross unrealized holding losses | (1,225) | (91)
Total short-term investments | 253,282 | 99,832
Total cash, cash equivalents and short-term investments, fair value | 778,204 | 607,960
Total cash, cash equivalents and short-term investments, gross unrealized gains | 186,186 | 54,564
Total cash, cash equivalents and short-term investments, gross unrealized losses | (1,225) | (91)
Available-for-sale equity securities |  |
Available-for-sale equities securities |  |
Available-for-sale equity securities, fair value | 174,610 | 78,662
Available-for-sale debt securities: |  |
Available-for-sale securities, gross unrealized holding gains | 137,282 | 50,115
Available-for-sale securities, gross unrealized holding losses | (1,030) |
Available-for-sale debt securities |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 25,967 | 21,170
Available-for-sale securities, gross unrealized holding gains | 1,923 | 4,449
Available-for-sale securities, gross unrealized holding losses | (195) | (91)
Commercial paper and CDs |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 206 |
Corporate debt securities |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 23,399 | 19,685
Available-for-sale securities, gross unrealized holding gains | 1,870 | 4,432
Mortgage-backed debt securities |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 244 | 216
Available-for-sale securities, gross unrealized holding gains | 15 | 13
Mortgage-CMO debt securities |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 523 | 209
Available-for-sale securities, gross unrealized holding gains | 10 | 4
Available-for-sale securities, gross unrealized holding losses | (3) | (3)
Asset-backed debt securities |  |
Available-for-sale debt securities: |  |
Total available-for-sale debt securities, fair value | 1,595 | 1,060
Available-for-sale securities, gross unrealized holding gains | 28 |
Available-for-sale securities, gross unrealized holding losses | (192) | (88)
Short-term Investments |  |
Available-for-sale debt securities: |  |
Total short-term investments | 253,282 | 99,832
Total short-term investments, gross unrealized gains | 186,186 | 54,564
Total short-term investments, gross unrealized holding losses | $ (1,225) | $ (91)

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- Definition Total of debt securities categorized neither as held-to-maturity nor trading which are intended be sold or mature within one year from the balance sheet date or the normal operating cycle, whichever is longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15C -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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph b -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 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 16 -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 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 22 -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 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15D -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 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26626-111562 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Section A -Paragraph 4, 5 -Chapter 3 -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 -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13, 17 -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 -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 15E -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. + Details
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- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph b -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 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 + Details
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