Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 232,515	$ 209,855	$ 696,701	$ 636,806
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Costs of products sold	$ 194,494	$ 179,983	$ 585,563	$ 537,073
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Gross profit	$ 38,021	$ 29,872	$ 111,138	$ 99,733
Selling, general and administrative expenses	23,721	25,799	71,143	81,915
Gains on dispositions of plant, equipment and timberlands, net	(235)	(249)	(1,327)	(1,939)
Operating income	14,535	4,322	41,322	19,757
Non-operating income (expense)
Interest expense	(1,902)	(3,965)	(8,513)	(11,237)
Interest income	185	147	931	227
Other, net	(1,034)	2,253	(3,547)	1,131
Total non-operating expense	(2,751)	(1,565)	(11,129)	(9,879)
Income from continuing operations before income taxes	11,784	2,757	30,193	9,878
Income tax provision	3,141	3,462	10,654	7,037
Income (loss) from continuing operations	8,643	(705)	19,539	2,841
Discontinued operations:
Income (loss) before income taxes	1,062	(114,656)	1,291	(128,714)
Income tax benefit	(2,519)	(19,530)	(2,511)	(28,361)
Income (loss) from discontinued operations	3,581	(95,126)	3,802	(100,353)
Net income (loss)	$ 12,224	$ (95,831)	$ 23,341	$ (97,512)
Basic earnings per share
Income (loss) from continuing operations	$ 0.19	$ (0.02)	$ 0.44	$ 0.06
Income (loss) from discontinued operations	0.09	(2.17)	0.09	(2.29)
Basic earnings (loss) per share	0.28	(2.19)	0.53	(2.23)
Diluted earnings (loss) per share
Income (loss) from continuing operations	0.19	(0.02)	0.44	0.06
Income (loss) from discontinued operations	0.09	(2.17)	0.09	(2.29)
Diluted earnings (loss) per share	0.28	(2.19)	0.53	(2.23)
Cash dividends declared per common share	$ 0.13	$ 0.13	$ 0.39	$ 0.39
Weighted average shares outstanding
Basic	44,171	43,792	44,113	43,754
Diluted	44,442	43,792	44,405	43,754