Parent Company Only Condensed Financial Information - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets:
Other investments	$ 600	$ 0
TOTAL ASSETS	4,082,200	4,142,749
Liabilities:
Other liabilities	44,926	35,324
Subordinated debentures	73,895	73,770
TOTAL LIABILITIES	3,789,905	3,670,317
Total stockholders' equity	292,295	472,432	$ 350,097	$ 299,309
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	4,082,200	4,142,749
Farmers National Banc Corp
Assets:
Cash	104,497	92,076
TOTAL ASSETS	383,048	562,026
Liabilities:
Other liabilities	2,542	1,836
Subordinated debentures	88,211	87,758
TOTAL LIABILITIES	90,753	89,594
Total stockholders' equity	292,295	472,432
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	383,048	562,026
Farmers National Banc Corp | Bank Segment
Assets:
Investment in subsidiaries	261,631	453,695
Farmers National Banc Corp | Farmers Trust
Assets:
Investment in subsidiaries	13,598	13,667
Farmers National Banc Corp | Captive Insurance
Assets:
Investment in subsidiaries	$ 2,722	$ 2,588