Business Segments (Schedule Of Net Sales By Geographic Area) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1],[2]	$ 936,295	$ 1,029,444	$ 927,647
United States
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	638,815	691,232	584,066
Exports From The United States | Asia
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	82,829	75,904	84,846
Exports From The United States | Canada
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	16,846	51,984	46,505
Exports From The United States | Europe
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	6,091	6,203	8,505
Exports From The United States | Latin America
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	13,735	12,106	15,199
Operations Outside The United States | Brazil
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	111,246	101,217	87,155
Operations Outside The United States | The Netherlands
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	35,871	45,667	54,380
Operations Outside The United States | Hungary
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	25,530	33,512	24,727
Operations Outside The United States | China
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	225	7,814	12,199
Operations Outside The United States | India
Segment Reporting Information [Line Items]
Net Sales by Geographic Area, Total	[1]	$ 5,107	$ 3,805	$ 10,065

[1] Information on exports and foreign operations are provided on the previous page. Cash and cash equivalents includes funds held in locations outside the U.S. of $23.0 million and $31.1 million at December 31, 2019 and 2018, respectively. Export sales relate almost entirely to PE Films. Operations outside the U.S. in The Netherlands, Hungary, China and India also relate to PE Films. Operations in Brazil are primarily related to Flexible Packaging Films, but also include PE Films operations. Sales from locations in The Netherlands and Hungary are primarily to customers located in Europe. Sales from locations in China (Guangzhou and Shanghai) are primarily to customers located in China, but also include other customers in Asia.

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