Segment Information (Detail) T in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) T	Sep. 30, 2020 USD ($) T	Sep. 30, 2021 USD ($) T	Sep. 30, 2020 USD ($) T
Segment Reporting Information [Line Items]
Net sales	$ 279,651	$ 233,473	$ 750,236	$ 681,216
Costs of products sold	241,294	195,222	637,029	574,100
Gross profit	38,357	38,251	113,207	107,116
SG&A	26,066	24,635	77,877	72,707
Gains on dispositions of plant, equipment and timberlands, net	(2,235)	(413)	(4,638)	(1,010)
Operating income	14,526	14,029	39,968	35,419
Non-operating expense	(2,916)	(3,888)	(7,261)	(14,992)
Income from continuing operations before income taxes	$ 11,610	$ 10,141	$ 32,707	$ 20,427
Supplementary Data
Net tons sold | T	76,263	69,761	208,053	203,092
Depreciation, depletion and amortization	$ 15,710	$ 13,702	$ 44,176	$ 43,310
Capital expenditures	7,308	8,154	18,519	20,165
Composite Fibers
Segment Reporting Information [Line Items]
Net sales	138,118	132,419	420,965	387,267
Airlaid Materials
Segment Reporting Information [Line Items]
Net sales	141,533	101,054	329,271	293,949
Operating Segments | Composite Fibers
Segment Reporting Information [Line Items]
Net sales	138,118	132,419	420,965	387,267
Costs of products sold	121,028	112,031	354,629	319,403
Gross profit	17,090	20,388	66,336	67,864
SG&A	11,278	9,924	33,396	30,811
Gains on dispositions of plant, equipment and timberlands, net	0	0	0	0
Operating income	5,812	10,464	32,940	37,053
Non-operating expense	0	0	0	0
Income from continuing operations before income taxes	$ 5,812	$ 10,464	$ 32,940	$ 37,053
Supplementary Data
Net tons sold | T	32,737	35,009	101,348	100,024
Depreciation, depletion and amortization	$ 6,904	$ 6,755	$ 20,885	$ 19,652
Capital expenditures	2,585	3,060	8,240	9,121
Operating Segments | Airlaid Materials
Segment Reporting Information [Line Items]
Net sales	141,533	101,054	329,271	293,949
Costs of products sold	121,102	83,699	283,825	243,526
Gross profit	20,431	17,355	45,446	50,423
SG&A	5,689	4,438	15,076	13,192
Gains on dispositions of plant, equipment and timberlands, net	0	0	0	0
Operating income	14,742	12,917	30,370	37,231
Non-operating expense	0	0	0	0
Income from continuing operations before income taxes	$ 14,742	$ 12,917	$ 30,370	$ 37,231
Supplementary Data
Net tons sold | T	43,526	34,752	106,705	103,068
Depreciation, depletion and amortization	$ 7,763	$ 5,674	$ 20,378	$ 16,598
Capital expenditures	2,926	2,791	5,962	6,606
Other and Unallocated
Segment Reporting Information [Line Items]
Net sales			0	0
Costs of products sold			(1,425)	11,171
Gross profit			1,425	(11,171)
SG&A			29,405	28,704
Gains on dispositions of plant, equipment and timberlands, net			(4,638)	(1,010)
Operating income			(23,342)	(38,865)
Non-operating expense			(7,261)	(14,992)
Income from continuing operations before income taxes			$ (30,603)	$ (53,857)
Supplementary Data
Net tons sold | T			0	0
Depreciation, depletion and amortization			$ 2,913	$ 7,060
Capital expenditures			$ 4,317	$ 4,438
Other and Unallocated | Other and Unallocated
Segment Reporting Information [Line Items]
Net sales	0	0
Costs of products sold	(836)	(508)
Gross profit	836	508
SG&A	9,099	10,273
Gains on dispositions of plant, equipment and timberlands, net	(2,235)	(413)
Operating income	(6,028)	(9,352)
Non-operating expense	(2,916)	(3,888)
Income from continuing operations before income taxes	$ (8,944)	$ (13,240)
Supplementary Data
Net tons sold | T	0	0
Depreciation, depletion and amortization	$ 1,043	$ 1,273
Capital expenditures	$ 1,797	$ 2,303