PARENT COMPANY ONLY - Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
ASSETS
Other assets	$ 51,135	$ 46,681
TOTAL ASSETS	2,610,653	2,515,584
LIABILITIES AND STOCKHOLDERS' EQUITY
Senior notes, net	14,899	14,831
Subordinated debt, net	24,831	24,717
Accrued interest and other liabilities	33,791	26,638
Stockholders' equity	275,284	262,381	$ 249,325	$ 301,405
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	2,610,653	2,515,584
Parent Company
ASSETS
Cash	16,013	14,822
Other assets	136	200
TOTAL ASSETS	315,186	302,128
LIABILITIES AND STOCKHOLDERS' EQUITY
Senior notes, net	14,899	14,831
Subordinated debt, net	24,831	24,717
Accrued interest and other liabilities	172	199
Stockholders' equity	275,284	262,381
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	315,186	302,128
Subsidiaries [Member] | Citizens and Northern Bank [Member]
ASSETS
Investment in subsidiaries	285,465	272,286
Subsidiaries [Member] | Citizens and Northern Investment Corporation [Member]
ASSETS
Investment in subsidiaries	9,768	11,087
Subsidiaries [Member] | Bucktail Life Insurance Company [Member]
ASSETS
Investment in subsidiaries	$ 3,804	$ 3,733