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Investments Marketable Equity Securities Gains (Losses) (Details) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2021 | Mar. 31, 2020
Marketable Equity Securities Gains (Losses) [Abstract] |  |
Marketable equity securities gains (losses), net | $ 16,011 | $ (51,408)
Less net gains recognized on marketable equity securities sold | 263 | 323
Unrealized gains (losses) recognized on marketable equity securities held | $ 15,748 | $ (51,731)

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- Definition Marketable Equity Securities Gains (Losses) [Abstract] + References No definition available. + Details
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- Definition Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
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- Definition Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
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- Definition Amount of unrealized gain (loss) on investment in marketable security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
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