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Employee Benefit Plans (Details Textual) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
National Bancshares Corporation |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
(Benefit) expense under the plan | $ 180 | $ 136 | $ (19)
Liability under the Plan | $ 1,100 | 1,000 |
Director age for eligibility for annual retirement benefit plan | 70 years |  |
Maximum years for benefit payment under the plan | 15 years |  |
Retirement Savings Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employees who have completed no days of service | 90 days |  |
Percentage of matching contribution by company | 50.00% |  |
(Benefit) expense under the plan | $ 665 | 708 | 573
Retirement Savings Plan | Maximum |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of the participants' voluntary contributions of gross wages | 6.00% |  |
Profit Sharing Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
(Benefit) expense under the plan | $ 195 | $ 95 | $ 78
Annual compensation for associates, Percent | 2.00% | 1.00% | 1.00%
Deferred Compensation Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
(Benefit) expense under the plan | $ 7 | $ 7 | $ 8
Liability under the Plan | 105 | 115 |
Deferred compensation plan asset recorded | 1,900 | 1,300 |
Deferred compensation plan liability recorded | $ 1,900 | $ 1,300 |

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