FINANCIAL INSTRUMENTS - Realized and Unrealized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Adjustments to Carrying Value of Non-Marketable Equity Securities [Abstract]
Upward adjustments (gross unrealized gains)	$ 0	$ 128,786	$ 0	$ 128,786
Downward adjustments including impairment (gross unrealized losses)	(500)	(2,396)	(650)	(2,588)
Total	(500)	126,390	(650)	126,198
Adjustments to Carrying Value of Non-Marketable Equity Securities [Abstract]
Realized gains, net, for equity securities sold	2,066	27,275	2,144	27,172
Unrealized gains, net, on equity securities held	29,369	126,414	29,247	126,559
Total gains recognized, net, in other income, net	$ 31,435	$ 153,689	$ 31,391	$ 153,731

Equity Securities without Readily Determinable Fair Value, Annual Amount

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of loss from downward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117539-209714

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Amount of gain from upward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117539-209714

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