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Business Segments (Schedule Of Segment Reporting Information By Segment) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales | [1],[2] |  |  |  |  |  |  |  |  |  |  | $ 936,295 |  | $ 1,029,444 |  | $ 927,647 |
Goodwill, Impairment Loss |  |  |  |  |  |  |  |  |  |  |  | 0 |  | (46,792) |  | 0 |
Total |  |  |  |  |  |  |  |  |  |  |  | 74,284 |  | 41,439 |  | (11,608) |
Interest income |  |  |  |  |  |  |  |  |  |  |  | 296 |  | 369 |  | 209 |
Interest expense |  |  |  |  |  |  |  |  |  |  |  | 4,051 |  | 5,702 |  | 6,170 |
Gain (loss) on investment accounted for under the fair value method |  |  |  |  |  |  |  |  |  |  |  | 10,900 |  | 30,600 |  | 33,800 |
Stock option-based compensation expense |  |  |  |  |  |  |  |  |  |  |  | 4,209 |  | 1,221 |  | 264 |
Corporate expenses, net | [3] |  |  |  |  |  |  |  |  |  |  | 36,630 |  | 28,893 |  | 30,879 |
Income (loss) before income taxes |  |  |  |  |  |  |  |  |  |  |  | 58,172 |  | 36,368 |  | (14,912) |
Income tax expense (benefit) | [3] |  |  |  |  |  |  |  |  |  |  | 9,913 |  | 11,526 |  | (53,163) |
Net income |  | $ (3,135) |  | $ 17,133 | $ 14,477 | $ 19,785 | $ 26,157 |  | $ (34,201) | $ 14,722 | $ 18,165 | 48,259 |  | 24,842 |  | 38,251 |
Cash and cash equivalents |  | 31,422 | [1] |  |  |  | 34,397 | [1] |  |  |  | 31,422 | [1] | 34,397 | [1] | 36,491 | $ 29,511
Sales |  | 232,427 |  | $ 243,217 | $ 248,248 | $ 248,466 | 275,707 |  | $ 267,294 | $ 263,759 | $ 258,711 | 972,358 |  | 1,065,471 |  | 961,330 |
Foreign Country |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | 23,000 |  |  |  |  | 31,100 |  |  |  |  | 23,000 |  | 31,100 |  |  |
Pension Benefits |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Defined benefit pension plan net liability |  | $ (100,434) |  |  |  |  | $ (81,873) |  |  |  |  | (100,434) |  | (81,873) |  |  |
kaleo |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on investment accounted for under the fair value method | [3] |  |  |  |  |  |  |  |  |  |  | 28,482 |  | 30,600 |  | 33,800 |
Alleghany and Bath County, Virginia |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on investment accounted for under the fair value method |  |  |  |  |  |  |  |  |  |  |  | 0 |  | (186) |  | 0 |
Gain (Loss) on Disposition of Assets |  |  |  |  |  |  |  |  |  |  |  | 0 |  | (38) |  | 0 |
Unrealized Gain (Loss) on Investment Property |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 186 |  | 0 |
PE Films [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  |  |  |  | 272,758 |  | 332,488 |  | 352,459 |
segment EBITDA |  |  |  |  |  |  |  |  |  |  |  | 37,803 |  | 51,058 |  | 55,889 |
Depreciation, Amortization and Accretion, Net |  |  |  |  |  |  |  |  |  |  |  | (14,627) |  | (14,877) |  | (14,343) |
segment EBIT |  |  |  |  |  |  |  |  |  |  |  | 23,176 |  | 36,181 |  | 41,546 |
Plant shutdowns, asset impairments, restructurings and other | [3] |  |  |  |  |  |  |  |  |  |  | (475) |  | (5,905) |  | (4,905) |
Goodwill, Impairment Loss |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 46,792 |  |  |
Personal Care Materials [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Goodwill, Impairment Loss |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 46,792 |  |  |
Aluminum Extrusions |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  |  |  |  | 529,602 |  | 573,126 |  | 466,833 |
segment EBITDA |  |  |  |  |  |  |  |  |  |  |  | 65,683 |  | 65,479 |  | 58,524 |
Depreciation, Amortization and Accretion, Net |  |  |  |  |  |  |  |  |  |  |  | (16,719) |  | (16,866) |  | (15,070) |
segment EBIT |  |  |  |  |  |  |  |  |  |  |  | 48,964 |  | 48,613 |  | 43,454 |
Plant shutdowns, asset impairments, restructurings and other | [3] |  |  |  |  |  |  |  |  |  |  | (561) |  | (505) |  | 321 |
Trade Name Accelerated Amortization |  |  |  |  |  |  |  |  |  |  |  | (10,040) |  | 0 |  | 0 |
Goodwill, Impairment Loss |  |  |  |  |  |  |  |  |  |  |  | 0 |  |  |  |  |
Flexible Packaging Films [Member] [Domain] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total net sales |  |  |  |  |  |  |  |  |  |  |  | 133,935 |  | 123,830 |  | 108,355 |
segment EBITDA |  |  |  |  |  |  |  |  |  |  |  | 14,737 |  | 11,154 |  | 7,817 |
Depreciation, Amortization and Accretion, Net |  |  |  |  |  |  |  |  |  |  |  | (1,517) |  | (1,262) |  | (10,443) |
segment EBIT |  |  |  |  |  |  |  |  |  |  |  | 13,220 |  | 9,892 |  | (2,626) |
Plant shutdowns, asset impairments, restructurings and other | [3] |  |  |  |  |  |  |  |  |  |  | 0 |  | (45) |  | (89,398) |
Shipping and Handling [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other Cost of Operating Revenue |  |  |  |  |  |  |  |  |  |  |  | 36,063 |  |  |  |  |
Cost of Goods and Services Sold |  |  |  |  |  |  |  |  |  |  |  | $ 36,063 |  | $ 36,027 |  | $ 33,683 |
[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.
[2] | {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOjQ4ZmFiYTVhZGM5MDRlMDZhZmZmMzZjZTZjMjVjMWM1fFRleHRTZWxlY3Rpb246NUZENkVBRjFFN0NFQzk2QjhFRTA2M0QxNDU5NUQ0QUYM}
[3] | See Notes 1, 3, 4 and 17 for more information on losses associated with plant shutdowns, asset impairments and restructurings, unusual items, gains or losses from sale of assets, gains or losses on an investment accounted for under the fair value method and other items.

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