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Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
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Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | $ 487,503 | $ 259,011
Available-for-sale marketable securities, Unrealized Gain | 1,569 | 592
Available-for-sale marketable securities, Unrealized (Loss) | (1,347) | (2,967)
Available-for-sale marketable securities, Fair Market Value | 487,725 | 256,636
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 120,039 | 191,978
Marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 421,024 | 190,100
Available-for-sale marketable securities, Unrealized Gain | 126 | 88
Available-for-sale marketable securities, Unrealized (Loss) | (62) | (92)
Available-for-sale marketable securities, Fair Market Value | 421,088 | 190,096
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | 91,100 | 140,262
Long-term marketable securities |  |
Schedule of Available-for-sale Securities |  |
Available-for-sale marketable securities, Cost | 66,479 | 68,911
Available-for-sale marketable securities, Unrealized Gain | 1,443 | 504
Available-for-sale marketable securities, Unrealized (Loss) | (1,285) | (2,875)
Available-for-sale marketable securities, Fair Market Value | 66,637 | 66,540
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses | $ 28,939 | $ 51,716

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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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