Discontinued Operations - Summary of Discontinued Operations included in Condensed Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Non-operating income (expense)
Income (loss) before income taxes	$ (114,656)	$ 9,661	$ (128,714)	$ 14,422
Income tax provision (benefit)	(19,530)	2,601	(28,361)	5,515
Income (loss) from discontinued operations	(95,126)	7,060	(100,353)	8,907
Specialty Papers [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Total revenues	202,132	204,442	593,974	603,692
Costs of products sold	181,628	188,076	572,820	569,840
Gross profit	20,504	16,366	21,154	33,852
Selling, general and administrative expenses	6,058	5,997	18,566	17,971
(Gains) losses on dispositions of plant, equipment and timberlands, net	3	70	(440)	118
Operating income	14,443	10,299	3,028	15,763
Non-operating income (expense)
Interest expense	(2,281)	(1,221)	(6,017)	(3,005)
Other, net	(1,174)	583	(81)	1,664
Impairment charge	(125,644)		(125,644)
Income (loss) before income taxes	(114,656)	9,661	(128,714)	14,422
Income tax provision (benefit)	(19,530)	2,601	(28,361)	5,515
Income (loss) from discontinued operations	(95,126)	7,060	(100,353)	8,907
Specialty Papers [Member] \| Product [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Total revenues	201,288	203,206	590,757	600,346
Specialty Papers [Member] \| Energy and Related Sales Net [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Total revenues	$ 844	$ 1,236	$ 3,217	$ 3,346

Disposal group including discontinued operation gain loss on dispositions of plant equipment and timberlands net.

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Amount of operating income (loss) attributable to disposal group, including, but not limited to, discontinued operation.

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