SEGMENT INFORMATION - Net Sales by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net Sales		$ 764,041	$ 837,398	$ 785,897
Long-Lived Assets		243,354	252,851	222,041
Impairment of goodwill and other long-lived assets	$ 61,109	61,109	64,206	0
Restructuring charges		15,903	767	2,297
Intangible assets amortization		20,800	21,500	9,300
Reduction-in-force severance expenses			1,900
Operating lease right-of-use assets		22,243	23,116
Increase (decrease) in AP capex		100	600	1,700
Accounting Standards Update 2016-02
Segment Reporting Information [Line Items]
Operating lease right-of-use assets			23,100
Thermal Acoustical Solutions Segment
Segment Reporting Information [Line Items]
Impairment of goodwill and other long-lived assets	0
Performance Materials Segment
Segment Reporting Information [Line Items]
Impairment of goodwill and other long-lived assets	61,109
Technical Nonwovens Segment
Segment Reporting Information [Line Items]
Impairment of goodwill and other long-lived assets	$ 0
Restructuring charges			800	2,300
Operating Segments | Thermal Acoustical Solutions Segment
Segment Reporting Information [Line Items]
Net Sales		294,807	361,577	365,427
Reduction-in-force severance expenses		500
Operating Segments | Performance Materials Segment
Segment Reporting Information [Line Items]
Net Sales		264,645	245,480	169,217
Intercompany sales		3,300	4,000	3,500
Impairment of goodwill and other long-lived assets		61,100	64,200
Restructuring charges		15,500
Intangible assets amortization		15,800	16,200	3,500
Purchase accounting adjustments related to inventory step-up				2,000
Operating Segments | Technical Nonwovens Segment
Segment Reporting Information [Line Items]
Net Sales		222,340	255,346	277,071
Intercompany sales		14,500	21,000	22,200
Restructuring charges			800	2,300
Intangible assets amortization		4,800	5,100	5,600
Corporate
Segment Reporting Information [Line Items]
Restructuring charges		400
CEO Transition Expenses			2,300
Strategic initiative expenses		3,100	1,500	3,600
United States
Segment Reporting Information [Line Items]
Net Sales		420,129	478,720	422,222
Long-Lived Assets		131,992	138,265	136,448
France
Segment Reporting Information [Line Items]
Net Sales		79,343	75,313	66,579
Long-Lived Assets		22,289	13,723	13,219
Germany
Segment Reporting Information [Line Items]
Net Sales		112,466	124,402	125,796
Long-Lived Assets		33,827	44,116	25,873
United Kingdom
Segment Reporting Information [Line Items]
Net Sales		22,144	26,556	27,156
Long-Lived Assets		5,598	5,981	4,844
Canada
Segment Reporting Information [Line Items]
Net Sales		74,347	76,535	87,622
Long-Lived Assets		31,293	29,667	25,614
China
Segment Reporting Information [Line Items]
Net Sales		48,586	54,036	54,198
Long-Lived Assets		16,597	17,888	11,958
Other
Segment Reporting Information [Line Items]
Net Sales		7,026	1,836	2,324
Long-Lived Assets		$ 1,758	$ 3,211	$ 4,085