BASIS OF FINANCIAL STATEMENT PRESENTATION - Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 21, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Common stock, par value (in usd per share)	$ 0.01			$ 0.01
Non-cash capital expenditures	$ 4,200,000	$ 2,700,000
Proportion of trade receivables in cash at time of sale (as a percent)	90.00%
Proportion of trade receivables in cash when customer pays (as a percent)	10.00%
Maximum amount subject to Receivables Purchases Agreements for a certain customer	$ 10,000,000.0
Maximum amount subject to Receivables Purchases Agreements in aggregate	$ 50,000,000.0
Merger Agreement | Unifrax Holding Co.
Restructuring Cost and Reserve [Line Items]
Common stock, par value (in usd per share)			$ 0.01
Right to receive cash per share			$ 62.10