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Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017
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Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | $ 259,011 | $ 1,470,729
Available-for-sale marketable securities, Unrealized Gain | 592 | 6,582
Available-for-sale marketable securities, Unrealized (Loss) | (2,967) | (3,406)
Available-for-sale marketable securities, Fair Market Value | 256,636 | 1,473,905
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 191,978 | 1,350,896
Marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 190,100 | 1,349,970
Available-for-sale marketable securities, Unrealized Gain | 88 | 38
Available-for-sale marketable securities, Unrealized (Loss) | (92) | (2,029)
Available-for-sale marketable securities, Fair Market Value | 190,096 | 1,347,979
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 140,262 | 1,288,844
Long-term marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 68,911 | 120,759
Available-for-sale marketable securities, Unrealized Gain | 504 | 6,544
Available-for-sale marketable securities, Unrealized (Loss) | (2,875) | (1,377)
Available-for-sale marketable securities, Fair Market Value | 66,540 | 125,926
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | $ 51,716 | $ 62,052

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References No definition available. + Details
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References No definition available. + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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