Regulatory Matters (Details Textual) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
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	2.50%	2.50%
Capital conservation buffer, additional capital amount required	$ 52,900,000	$ 47,800,000
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	0.060	0.060
Minimum ratio of total capital to risk-weighted assets	0.080	0.080
Minimum leverage ratio	0.040	0.040
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	0.060	0.060
Minimum ratio of total capital to risk-weighted assets	0.080	0.080
Minimum leverage ratio	0.040	0.040
Dividends that can be declared without prior approval	$ 12,800,000
Farmers Trust Company
Regulatory Matters (Additional Textual) [Abstract]
Minimum capital maintained by trust	3,000,000
Dividends that can be declared without prior approval	$ 206,000