Discontinued Operations and Divestitures (Summary of the Major Classes of Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Total current assets held for sale	$ 0	$ 58,171
Total noncurrent assets held for sale	0	107,240
Current liabilities
Total current liabilities held for sale	0	24,551
Total noncurrent liabilities held for sale	$ 0	3,367
Discontinued Operations, Disposed of by Sale
Current assets
Cash and cash equivalents		11,471
Accounts receivable - net		24,346
Inventories - net		14,272
Other current assets		8,082
Total current assets held for sale		58,171
Property, plant and equipment - net		59,703
Other intangible assets - net		46,829
Other assets - net		708
Total noncurrent assets held for sale		107,240
Total assets held for sale		165,411
Current liabilities
Current portion of long-term debt		857
Accounts payable		17,076
Accrued compensation and employee benefits		2,498
Other current liabilities		4,120
Total current liabilities held for sale		24,551
Long-term debt		1,143
Deferred income taxes		112
Other long-term liabilities		2,112
Total noncurrent liabilities held for sale		3,367
Total liabilities held for sale		27,918
Discontinued Operations, Disposed of by Sale | North American Fiber Solutions
Current assets
Cash and cash equivalents		11,712
Accounts receivable - net		19,234
Inventories - net		8,120
Other current assets		6,615
Total current assets held for sale		45,681
Property, plant and equipment - net		43,960
Other intangible assets - net		20,083
Other assets - net		316
Total noncurrent assets held for sale		64,359
Total assets held for sale		110,040
Current liabilities
Current portion of long-term debt		857
Accounts payable		12,199
Accrued compensation and employee benefits		2,087
Other current liabilities		3,358
Total current liabilities held for sale		18,501
Long-term debt		1,143
Deferred income taxes		112
Other long-term liabilities		1,022
Total noncurrent liabilities held for sale		2,277
Total liabilities held for sale		20,778
Discontinued Operations, Disposed of by Sale | Metalex
Current assets
Cash and cash equivalents		(241)
Accounts receivable - net		5,112
Inventories - net		6,152
Other current assets		1,467
Total current assets held for sale		12,490
Property, plant and equipment - net		15,743
Other intangible assets - net		26,746
Other assets - net		392
Total noncurrent assets held for sale		42,881
Total assets held for sale		55,371
Current liabilities
Current portion of long-term debt		0
Accounts payable		4,877
Accrued compensation and employee benefits		411
Other current liabilities		762
Total current liabilities held for sale		6,050
Long-term debt		0
Deferred income taxes		0
Other long-term liabilities		1,090
Total noncurrent liabilities held for sale		1,090
Total liabilities held for sale		$ 7,140