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Retirement Plans And Other Postretirement Benefits (Narrative) (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2018 USD ($) employee | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |  |
Pension and other postretirement liabilities | $ 88,124 | $ 98,837 |
Percentage of change in health care cost trend rate assumptions would be immaterial | 1.00% |  |
Expected pension expense for next twelve months | $ 9,600 |  |
Term of estimated benefit payments for fixed income securities, minimum | 1 year |  |
Term of estimated benefit payments for fixed income securities, maximum | 2 years |  |
Defined benefit, average remaining duration of benefit payments for pension plans | 11 years |  |
Unfunded Non-Qualified Supplemental Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Projected benefit obligation to unfunded plan | $ 2,000 | 2,200 |
Pension Cost (Reversal of Cost) | $ 100 | 100 | $ 100
Films Manufacturing Facility In Kerkrade | Multiemployer Plans, Pension |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Number of employees participating in pension plan | employee | 72 |  |
Multi-employer pension plan, pension expenses | $ 400 | 400 | 400
Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Prior service cost (benefit) | 0 |  |
Projected benefit obligation to unfunded plan | 287,240 | 318,123 | 303,126
Multi-employer pension plan, pension expenses | 10,342 | $ 10,134 | $ 10,886
Credit Spread Over London Interbank Offered Rate Basis Points | $ 8,100 |  |

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