Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 784,459	$ 761,608	$ 735,994
Cost of Goods and Services Sold	538,877	520,803	508,677
Gross profit	245,582	240,805	227,317
Selling, general and administrative expenses	199,906	177,187	172,271
Goodwill and Intangible Asset Impairment	50,307	0	10,039
Impairment of Long-Lived Assets to be Disposed of	36,285	0	0
Costs of Transition Services Agreement	12,515	4,673	0
Cost of Acquired Retention Plans [Line Items]	22,814	0	0
Restructuring costs (Note 5)	8,359	1,558	7,353
Gain (Loss) on Disposition of Business	(493)	3,739	(5,722)
Net loss (gain) on sale of assets	200	237	(1,031)
Operating (loss) income	(84,311)	53,411	32,963
Interest expense, net	19,270	17,202	20,046
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	(16,250)	(396)	(12,127)
Income from transition services agreement	(8,439)	(3,673)	0
Other income, net	(728)	(309)	(92)
(Loss) earnings from continuing operations before income taxes	(78,164)	40,587	25,136
Income tax (benefit) expense	(7,730)	(15,859)	9,259
Net earnings	(70,434)	56,446	15,877
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax	0	29,027	38,292
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	692	124,356	0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	692	153,383	38,292
Net earnings	$ (69,742)	$ 209,829	$ 54,169
Earnings per share:
Income (Loss) from Continuing Operations, Per Basic Share	$ (2.54)	$ 2.02	$ 0.57
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.02	5.49	1.37
Earnings Per Share, Basic (in dollars per share)	(2.52)	7.51	1.94
Income (Loss) from Continuing Operations, Per Diluted Share	(2.54)	2.01	0.56
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic and Diluted Share	0.02	5.46	1.36
Diluted earnings per share (in dollars per share)	$ (2.52)	$ 7.47	$ 1.92
Weighted average shares outstanding:
Basic (in shares)	27,723	27,936	27,945
Diluted (in shares)	27,723	28,092	28,223