FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS - Equity Investment in InCarda (Details)		3 Months Ended		12 Months Ended
	Oct. 06, 2020 USD ($)	Sep. 30, 2021	Sep. 30, 2020 USD ($) shares	Dec. 31, 2021 USD ($) Director $ / shares	Dec. 31, 2020 USD ($)
Equity Investment
Equity and long-term investments				$ 483,845,000	$ 438,258,000
InCarda
Equity Investment
Number of Investee's Board members currently representing the Company | Director				1
Number of the Investee's Board members | Director				8
Equity investment ownership percentage				13.00%	13.40%
InCarda | Series C preferred stock and warrants
Equity Investment
Securities Purchase Agreement, Amount	$ 15,800,000
Amount of securities purchase agreement	$ 15,800,000
Unrealized gain from fair value changes in equity investments					$ 1,100,000
InCarda | Series C preferred stock
Equity Investment
Number of shares to be purchased under the securities purchase agreement | shares			20,469,432
Securities Purchase Agreement, Amount			$ 800,000
Amount of securities purchase agreement			$ 800,000
Equity and long-term investments				$ 15,800,000	15,800,000
Unrealized loss from fair value changes in equity investments				(700,000)
Impairment of equity investments				$ 0	0
InCarda | Warrants
Equity Investment
Maximum number of additional shares into which warrants may be converted under the securities purchase agreement | shares			5,117,358
Exercise price of warrants | $ / shares				$ 0.7328
Extended Expiration Date		Mar. 31, 2022
Equity and long-term investments at fair value				$ 400,000	$ 1,100,000