Segment Information - Schedule of Financial and Other Information by Business Unit (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 T	Jun. 30, 2013 T	Jun. 30, 2014 T	Jun. 30, 2013 T
Segment Reporting Information [Line Items]
Net sales	$ 445,341	$ 425,967	$ 901,062	$ 831,156
Energy and related sales, net	790	424	6,052	1,525
Total revenue	446,131	426,391	907,114	832,681
Cost of products sold	404,694	385,551	810,637	734,466
Gross profit (loss)	41,437	40,840	96,477	98,215
SG&A	32,314	34,528	65,865	68,015
Gains on dispositions of plant, equipment and timberlands, net	(1,482)	(19)	(2,291)	(92)
Total operating income (loss)	10,605	6,331	32,903	30,292
Non-operating expense	(4,649)	(4,293)	(9,189)	(7,785)
Income (loss) before income taxes	5,956	2,038	23,714	22,507
Supplementary Data
Net tons sold	254,800	254,400	522,100	503,200
Depreciation, depletion and amortization	18,300	16,700	36,893	32,024
Capital expenditures	15,700	29,400	30,200	60,800
Composite Fibers [Member]
Segment Reporting Information [Line Items]
Net sales	157,000	142,600	315,600	254,400
Total revenue	157,000	142,600	315,600	254,400
Cost of products sold	126,900	114,600	252,900	205,000
Gross profit (loss)	30,100	27,900	62,700	49,400
SG&A	12,800	11,500	26,100	21,300
Total operating income (loss)	17,300	16,400	36,600	28,100
Income (loss) before income taxes	17,300	16,400	36,600	28,100
Supplementary Data
Net tons sold	39,400	35,000	79,400	57,600
Depreciation, depletion and amortization	7,600	5,900	15,300	10,600
Capital expenditures	5,400	18,800	11,400	36,200
Advanced Airlaid Materials [Member]
Segment Reporting Information [Line Items]
Net sales	70,500	66,400	141,800	132,700
Total revenue	70,500	66,400	141,800	132,700
Cost of products sold	62,000	58,800	125,100	118,400
Gross profit (loss)	8,500	7,600	16,700	14,300
SG&A	2,300	2,400	4,700	4,500
Total operating income (loss)	6,200	5,200	12,000	9,800
Income (loss) before income taxes	6,200	5,200	12,000	9,800
Supplementary Data
Net tons sold	24,600	23,700	49,700	47,600
Depreciation, depletion and amortization	2,300	2,200	4,600	4,400
Capital expenditures	1,400	1,900	2,900	4,000
Specialty Papers [Member]
Segment Reporting Information [Line Items]
Net sales	217,900	217,000	443,700	444,100
Energy and related sales, net	800	400	6,100	1,500
Total revenue	218,700	217,400	449,800	445,600
Cost of products sold	214,100	207,900	429,100	403,400
Gross profit (loss)	4,600	9,500	20,700	42,300
SG&A	11,800	13,400	25,500	27,900
Total operating income (loss)	(7,200)	(3,900)	(4,800)	14,400
Income (loss) before income taxes	(7,200)	(3,900)	(4,800)	14,400
Supplementary Data
Net tons sold	190,700	195,700	392,900	398,000
Depreciation, depletion and amortization	7,900	8,300	16,100	16,600
Capital expenditures	8,600	8,200	14,800	16,800
Other and Unallocated [Member]
Segment Reporting Information [Line Items]
Cost of products sold	1,700	4,200	3,500	7,700
Gross profit (loss)	(1,700)	(4,200)	(3,500)	(7,700)
SG&A	5,400	7,300	9,600	14,300
Gains on dispositions of plant, equipment and timberlands, net	(1,500)		(2,300)	(100)
Total operating income (loss)	(5,600)	(11,500)	(10,800)	(21,900)
Non-operating expense	(4,600)	(4,300)	(9,200)	(7,800)
Income (loss) before income taxes	(10,200)	(15,800)	(20,000)	(29,700)
Supplementary Data
Depreciation, depletion and amortization	500	200	900	400
Capital expenditures	$ 300	$ 600	$ 1,100	$ 3,800