Segment Information - Schedule of Financial and Other Information by Business Unit (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) T	Sep. 30, 2016 USD ($) T	Sep. 30, 2017 USD ($) T	Sep. 30, 2016 USD ($) T
Segment Reporting Information [Line Items]
Net sales	$ 413,325	$ 405,301	$ 1,191,380	$ 1,213,932
Energy and related sales, net	1,236	1,346	3,346	4,013
Total revenues	414,561	406,647	1,194,726	1,217,945
Cost of products sold	359,826	345,477	1,052,626	1,056,209
Gross profit	54,735	61,170	142,100	161,736
SG&A	33,399	35,747	100,484	104,796
(Gains) losses on dispositions of plant, equipment and timberlands, net	(24)	5	(50)	31
Operating income	21,360	25,418	41,666	56,909
Non-operating expense	(4,974)	(4,416)	(13,728)	(12,716)
Income before income taxes	$ 16,386	$ 21,002	$ 27,938	$ 44,193
Supplementary Data
Net tons sold | T	267,100	261,500	779,500	788,500
Depreciation, depletion and amortization	$ 21,400	$ 16,300	$ 56,343	$ 49,725
Capital expenditures	31,100	36,600	102,200	116,900
Composite Fibers [Member]
Segment Reporting Information [Line Items]
Net sales	142,300	131,700	400,600	391,600
Total revenues	142,300	131,700	400,600	391,600
Cost of products sold	115,000	105,800	322,200	316,000
Gross profit	27,300	25,900	78,400	75,600
SG&A	10,900	11,900	32,900	35,100
Operating income	16,400	14,000	45,500	40,500
Income before income taxes	$ 16,400	$ 14,000	$ 45,500	$ 40,500
Supplementary Data
Net tons sold | T	43,800	39,100	124,500	116,700
Depreciation, depletion and amortization	$ 7,100	$ 6,900	$ 20,900	$ 21,200
Capital expenditures	3,800	5,100	10,600	13,700
Advanced Airlaid Materials [Member]
Segment Reporting Information [Line Items]
Net sales	67,800	61,900	190,400	183,400
Total revenues	67,800	61,900	190,400	183,400
Cost of products sold	57,200	53,500	160,700	157,500
Gross profit	10,600	8,400	29,700	25,900
SG&A	2,400	2,000	6,900	6,200
Operating income	8,200	6,400	22,800	19,700
Income before income taxes	$ 8,200	$ 6,400	$ 22,800	$ 19,700
Supplementary Data
Net tons sold | T	26,200	25,200	76,600	74,100
Depreciation, depletion and amortization	$ 2,500	$ 2,400	$ 7,100	$ 7,000
Capital expenditures	12,600	4,300	36,100	25,000
Specialty Papers [Member]
Segment Reporting Information [Line Items]
Net sales	203,200	211,800	600,300	638,900
Energy and related sales, net	1,200	1,300	3,300	4,000
Total revenues	204,400	213,100	603,600	642,900
Cost of products sold	179,700	180,100	555,700	574,100
Gross profit	24,700	33,000	47,900	68,800
SG&A	12,200	14,300	36,000	40,900
Operating income	12,500	18,700	11,900	27,900
Income before income taxes	$ 12,500	$ 18,700	$ 11,900	$ 27,900
Supplementary Data
Net tons sold | T	197,100	197,300	578,400	597,700
Depreciation, depletion and amortization	$ 8,000	$ 6,400	$ 22,900	$ 19,700
Capital expenditures	10,200	26,700	44,200	77,400
Other and Unallocated [Member]
Segment Reporting Information [Line Items]
Cost of products sold	7,900	6,100	14,000	8,600
Gross profit	(7,900)	(6,100)	(14,000)	(8,600)
SG&A	7,900	7,500	24,700	22,600
Operating income	(15,800)	(13,600)	(38,700)	(31,200)
Non-operating expense	(5,000)	(4,400)	(13,700)	(12,700)
Income before income taxes	(20,800)	(18,000)	(52,400)	(43,900)
Supplementary Data
Depreciation, depletion and amortization	3,800	600	5,400	1,800
Capital expenditures	$ 4,500	$ 500	$ 11,300	$ 800