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Schedule of Reported Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	$ 601,976	$ 211,596
Available-for-sale marketable securities, Unrealized Gain	9,077	4,687
Available-for-sale marketable securities, Unrealized (Loss)	(213)	(262)
Available-for-sale marketable securities, Fair Market Value	610,840	216,021
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	70,418	23,999
Marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	522,228	137,144
Available-for-sale marketable securities, Unrealized Gain	92	160
Available-for-sale marketable securities, Unrealized (Loss)	(40)	(1)
Available-for-sale marketable securities, Fair Market Value	522,280	137,303
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	61,806	2,922
Long-term marketable securities
Schedule of Available-for-sale Securities
Available-for-sale marketable securities, Cost	79,748	74,452
Available-for-sale marketable securities, Unrealized Gain	8,985	4,527
Available-for-sale marketable securities, Unrealized (Loss)	(173)	(261)
Available-for-sale marketable securities, Fair Market Value	88,560	78,718
Available-for-sale marketable securities, Fair Market Value of Investments with Unrealized Losses	$ 8,612	$ 21,077

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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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=121645371&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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