Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 769,970	$ 723,530		$ 705,030
Operating Profit (loss)	(88,290)	91,220		108,810
Capital Expenditures	40,480	29,670		23,420
Depreciation and Amortization	49,770	43,500		40,490
Assets	1,193,880	1,192,700		1,100,520
Packaging [Member]
Segment Reporting Information [Line Items]
Net sales	488,340	392,340		368,200
Operating Profit (loss)	93,990	80,770		84,590
Capital Expenditures	30,730	16,400		13,590
Depreciation and Amortization	27,600	24,650		21,620
Assets	721,440	546,950		435,140
Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales	167,740	194,110		185,920
Operating Profit (loss)	(133,440)	28,950		27,290
Capital Expenditures	5,770	8,110		1,190
Depreciation and Amortization	18,130	15,090		15,190
Assets	348,190	393,260		392,140
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales	113,890	137,080		150,910
Operating Profit (loss)	4,350	16,000		20,990
Capital Expenditures	3,890	5,090		3,750
Depreciation and Amortization	3,910	3,480		3,400
Assets	65,520	77,250		82,610
Corporate [Member]
Segment Reporting Information [Line Items]
Operating Profit (loss)	(53,190)	(34,500)		(24,060)
Capital Expenditures	90	70	[1]	4,890	[1]
Depreciation and Amortization	130	280		280
Assets	58,730	175,240		95,260
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Assets	1,193,880	1,192,700		1,005,150
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Assets	$ 0	$ 0		$ 95,370

[1] (a) Corporate capital expenditures for the year ended December 31, 2018 are primarily related to purchases of machinery and equipment formerly held under operating leases. These purchased assets were subsequently transferred from Corporate to the segment utilizing the assets.