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Postretirement Benefit Plans (Narrative) (Details) - USD ($) |  | 12 Months Ended
--- | --- | ---
Jan. 01, 2008 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Settlement gains recognized |  | $ 3,000 | $ 34,000 |  |
Postretirement Life Insurance [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, minimum service period requirement |  | 20 years |  |  | 10 years
Defined benefit plan, minimum retirement age |  | 55 years |  |  |
Defined benefit plan, benefit description, until age 65 |  | The insurance amount will be $50,000 until age 65. |  |  |
Life insurance coverage amount until age 65 |  | $ 50,000 |  |  |
Defined benefit plan, benefit description, after age 65 |  | After age 65, the insurance amount will decrease by $5,000 per year until age 74. |  |  |
Decrease in coverage amount after age 65 |  | $ 5,000 |  |  |
Life insurance coverage amount |  | $ 5,000 |  |  |
Defined Benefit Postretirement Health and Life Benefit Plan [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, minimum service period requirement | 10 years | 20 years |  |  |
Defined benefit plan, minimum retirement age |  | 55 years |  |  |
Percentage increase in postretirement benefit health insurance reimbursable premium |  | 36.79% |  |  |
Defined benefit plan, coverage period |  | 5 years |  |  |
Defined Benefit Postretirement Health and Life Benefit Plan [Member] | Maximum [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Postretirement benefit health insurance reimbursable premium |  | $ 5,000 |  |  |
Post-Retirement Health Benefit Plan [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, minimum service period requirement |  | 20 years |  |  |
Defined benefit plan, coverage period |  | 5 years |  |  |
Defined benefit plan, minimum retirement age |  | Employees who had achieved ten years of service as of January 1, 2008 and subsequently retire after at least 20 years of service are eligible for reimbursement of major medical insurance premiums up to $5,000, if the employee has not yet reached age 65. |  |  |
Post-Retirement Health Benefit Plan [Member] | Maximum [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Postretirement benefit health insurance reimbursable premium |  | $ 5,000 |  |  |
Defined Benefit Postretirement Health And Life Coverage [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, accumulated benefit obligation |  | 342,000 | 404,000 |  |
Defined benefit plan, amount to be amortized from accumulated other comprehensive income (loss) next fiscal year |  | 25,000 |  |  |
Director's Retirement Plan [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, accumulated benefit obligation |  | 1,142,000 | 1,077,000 |  |
Defined benefit plan, amount to be amortized from accumulated other comprehensive income (loss) next fiscal year |  | 0 |  |  |
Unrecognized prior service cost credit generated by adoption of plan |  |  |  |  | $ 274,000
Recognized prior service cost credit and fully amortized |  |  |  | $ 22,000 |
Cash surrender value of bank owned life insurance |  | 3,987,000 | 3,921,000 |  |
Scottdale Defined Benefit Pension Plan [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Defined benefit plan, accumulated benefit obligation |  | 5,401,000 | 5,587,000 |  |
Settlement gains recognized |  | (85,000) | (91,000) |  |
Scottdale Defined Benefit Pension Plan [Member] | Scottdale Bank and Trust Company [Member] | Other Income [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Settlement gains recognized |  | $ 3,000 | $ 34,000 |  |
Scottdale Defined Benefit Pension Plan [Member] | Maximum [Member] | Scottdale Bank and Trust Company [Member] | Cash [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of target portfolio allocation |  | 20.00% |  |  |
Scottdale Defined Benefit Pension Plan [Member] | Maximum [Member] | Scottdale Bank and Trust Company [Member] | Fixed Income Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of target portfolio allocation |  | 50.00% |  |  |
Scottdale Defined Benefit Pension Plan [Member] | Maximum [Member] | Scottdale Bank and Trust Company [Member] | Equity Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of target portfolio allocation |  | 60.00% |  |  |
Scottdale Defined Benefit Pension Plan [Member] | Minimum [Member] | Scottdale Bank and Trust Company [Member] | Fixed Income Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of target portfolio allocation |  | 30.00% |  |  |
Scottdale Defined Benefit Pension Plan [Member] | Minimum [Member] | Scottdale Bank and Trust Company [Member] | Equity Securities [Member] |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |
Percentage of target portfolio allocation |  | 40.00% |  |  |

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