FINANCIAL INSTRUMENTS - Narrative (Details) - USD ($)	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Investments [Line Items]
Carrying value of investments in equity securities without readily determinable fair value	$ 14,200,000		$ 5,100,000
Gross unrealized losses of downward adjustments to the carrying value of equity securities without readily determinable fair values	6,100,000
Impairment charge on equity securities without readily determinable fair value	0	$ 0
Trade Name \| United Kingdom
Schedule of Investments [Line Items]
Impairment of intangible assets	$ 4,600,000

Amount of investment in equity security without readily determinable fair value.

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Amount of impairment loss on investment in equity security without readily determinable fair value.

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