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Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Mar. 01, 2007 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Retirement Benefits [Abstract] |  |  |  |
Employees contribution |  | 100.00% |  |
Corporation matching contribution, percent |  | 100.00% |  |
Employee contribution, percent |  | 5.00% |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |  |
Performance bonus expense |  | $ 1,070 | $ 500 | $ 454
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement |  | (128) | (269) | (235)
Plan expenses |  | 764 | 743 | 713
Highest consecutive years of compensation | 5 years |  |  |
Years of service | 10 years |  |  |
Accumulated other comprehensive income includes net unrecognized pension cost before income taxes |  | 3,412 |  |
Accumulated other comprehensive income expected to be amortized into benefit cost |  | 23 |  |
Allocated Share-based Compensation Expense |  | 171 | 45 | 38
Corporation self-funded medical plan |  | 75 |  |
Medical expenses |  | 2,445 | 2,695 | 2,324
Other Postretirement Benefits Plan [Member] |  |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |  |
Plan expenses |  | $ 355 | $ 356 | $ 473
Safe Harbor 401(k) [Member] |  |  |  |
Defined Contribution Plan Disclosure [Line Items] |  |  |  |
Vesting percentage |  | 100.00% |  |
Fixed Income Funds [Member] |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Investment allocation in securities |  | 50.00% |  |
Equity Collective Trust [Member] |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Investment allocation in securities |  | 50.00% |  |

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