Business Segments (Schedule Of Depreciation And Amortization, Capital Expenditures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Depreciation and Amortization	$ 23,784	$ 31,957	$ 44,284
Capital Expenditures	27,361	23,355	50,864
Capital Expenditure, Discontinued Operations	0	1,912	15,353
PE Films [Member]
Segment Reporting Information [Line Items]
Depreciation and Amortization	6,263	6,762	5,860
Capital Expenditures	2,997	6,024	8,567
Flexible Packaging Films [Member] [Domain]
Segment Reporting Information [Line Items]
Depreciation and Amortization	1,988	1,761	1,517
Capital Expenditures	5,603	4,959	8,866
Aluminum Extrusions
Segment Reporting Information [Line Items]
Depreciation and Amortization	15,326	17,403	26,759
Capital Expenditures	18,914	10,260	17,855
Subtotal
Segment Reporting Information [Line Items]
Depreciation and Amortization	23,577	25,926	34,136
Capital Expenditures	27,514	21,243	35,288
General Corporate
Segment Reporting Information [Line Items]
Depreciation and Amortization	207	520	186
Capital Expenditures	$ (153)	$ 200	$ 223