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Regulatory Matters (Details Textual) - USD ($) | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
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Regulatory Matters (Additional Textual) [Abstract] |  |  |
Common equity tier 1 capital to risk-weighted assets, capital conservation buffer ratio |  | 2.50% |
Tier 1 capital to risk-weighted assets, capital conservation buffer ratio |  | 2.50% |
Total capital to risk-weighted assets, capital conservation buffer ratio |  | 2.50% |
Capital conservation buffer ratio |  | 1.875% | 1.25%
Capital conservation buffer, additional capital amount required |  | $ 34,400,000 | $ 21,000,000
Minimum ratio of common equity tier 1 capital to risk-weighted assets |  | 4.50% | 4.50%
Minimum ratio of tier 1 capital to risk-weighted assets |  | 6.00% | 6.00%
Minimum ratio of total capital to risk-weighted assets |  | 8.00% | 8.00%
Minimum leverage ratio |  | 4.00% | 4.00%
Farmers National Banc Corp |  |  |
Regulatory Matters (Additional Textual) [Abstract] |  |  |
Minimum ratio of common equity tier 1 capital to risk-weighted assets |  | 4.50% | 4.50%
Minimum ratio of tier 1 capital to risk-weighted assets |  | 6.00% | 6.00%
Minimum ratio of total capital to risk-weighted assets |  | 8.00% | 8.00%
Minimum leverage ratio |  | 4.00% | 4.00%
Farmers National Banc Corp | Scenario, Forecast |  |  |
Regulatory Matters (Additional Textual) [Abstract] |  |  |
Dividends that can be declared without prior approval | $ 39,000,000 |  |
Farmers Trust Company | Scenario, Forecast |  |  |
Regulatory Matters (Additional Textual) [Abstract] |  |  |
Minimum capital maintained by trust | 3,000,000 |  |
Dividends that can be declared without prior approval | $ 603,000 |  |

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- Definition Capital required for capital adequacy to risk weighted assets capital conservation buffer ratio. + References No definition available. + Details
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- Definition Tier one risk based capital required for capital adequacy to risk weighted assets capital conservation buffer ratio. + References No definition available. + Details
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- Definition Tier one risk based common capital required for capital adequacy to risk weighted assets. + References No definition available. + Details
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- Definition The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84167132&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=84167132&loc=SL5958570-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=84167132&loc=d3e65071-112826 + Details
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- Definition Minimum amount of net capital required to be maintained by the entity to engage in securities transactions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher SEC -Name Rule 15c3-1 -Number 240 -Section 15c3-1 + Details
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- Definition Amount of dividends that can be declared or paid without approval of regulatory agency. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(e)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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