FAIR VALUE MEASURES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill impairment	$ 48,671	$ 48,700	$ 63,000	$ 48,671	$ 63,000
Impairment of long-lived assets	12,438
Performance Materials
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill impairment	48,671		$ 63,000	$ 48,671	63,000
Impairment of long-lived assets	$ 12,438	$ 12,400			$ 1,200