LOANS AND ALLOWANCE FOR CREDIT LOSSES - Classes of loan portfolio summarized by risk rating and year of origination and year-to-date gross charge-offs (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	$ 23,563,000		$ 123,180,000
2025/2024	123,438,000		106,185,000
2024/2023	99,900,000		119,577,000
2023/2022	116,657,000		153,340,000
2022/2021	147,980,000		123,935,000
Prior	420,082,000		320,444,000
Subtotal: Total Loans	931,620,000		946,661,000
Financing Receivable, Total	931,620,000	$ 964,181,000	946,661,000
Gross Charge Offs:
2026/2025			1,000
2025/2024			8,000
2024/2023			459,000
2023/2022			2,503,000
2022/2021			2,000
Prior			21,000
Total Gross Charge Offs	34,000	371,000	2,994,000
Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	23,303,000		122,237,000
2025/2024	123,144,000		105,792,000
2024/2023	99,507,000		117,572,000
2023/2022	105,979,000		149,669,000
2022/2021	144,410,000		121,871,000
Prior	396,769,000		300,729,000
Subtotal: Total Loans	893,112,000		917,870,000
Special Mention
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			863,000
2025/2024	214,000		393,000
2024/2023	393,000		1,995,000
2023/2022	10,678,000		282,000
2022/2021	280,000		804,000
Prior	784,000		13,000
Subtotal: Total Loans	12,349,000		4,350,000
Substandard
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	260,000		80,000
2025/2024	80,000
2024/2023			10,000
2023/2022			3,389,000
2022/2021	3,290,000		1,260,000
Prior	22,529,000		19,702,000
Subtotal: Total Loans	26,159,000		24,441,000
Real Estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	20,909,000		106,328,000
2025/2024	107,185,000		98,110,000
2024/2023	92,598,000		102,580,000
2023/2022	100,022,000		147,191,000
2022/2021	142,038,000		107,764,000
Prior	376,487,000		291,695,000
Subtotal: Total Loans	839,239,000		853,668,000
Financing Receivable, Total	839,239,000	863,664,000	853,668,000
Gross Charge Offs:
2024/2023			10,000
2023/2022			2,000,000
Prior			7,000
Total Gross Charge Offs			2,017,000
Real Estate | Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	20,659,000		105,385,000
2025/2024	106,891,000		98,017,000
2024/2023	92,505,000		100,585,000
2023/2022	98,037,000		143,520,000
2022/2021	138,468,000		105,700,000
Prior	353,184,000		272,003,000
Subtotal: Total Loans	809,744,000		825,210,000
Real Estate | Special Mention
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			863,000
2025/2024	214,000		93,000
2024/2023	93,000		1,995,000
2023/2022	1,985,000		282,000
2022/2021	280,000		804,000
Prior	784,000
Subtotal: Total Loans	3,356,000		4,037,000
Real Estate | Substandard
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	250,000		80,000
2025/2024	80,000
2023/2022			3,389,000
2022/2021	3,290,000		1,260,000
Prior	22,519,000		19,692,000
Subtotal: Total Loans	26,139,000		24,421,000
Agricultural
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			24,000
2025/2024	116,000		168,000
2024/2023	162,000		151,000
2023/2022	223,000		24,000
2022/2021	23,000
Prior	706,000		617,000
Subtotal: Total Loans	1,230,000		984,000
Financing Receivable, Total	1,230,000	1,117,000	984,000
Agricultural | Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			24,000
2025/2024	116,000		168,000
2024/2023	162,000		151,000
2023/2022	223,000		24,000
2022/2021	23,000
Prior	706,000		617,000
Subtotal: Total Loans	1,230,000		984,000
Commercial and Industrial
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	2,020,000		14,374,000
2025/2024	13,943,000		6,597,000
2024/2023	6,015,000		15,050,000
2023/2022	14,734,000		4,414,000
2022/2021	4,271,000		3,303,000
Prior	25,204,000		23,186,000
Subtotal: Total Loans	66,187,000		66,924,000
Financing Receivable, Total	66,187,000	68,223,000	66,924,000
Gross Charge Offs:
2024/2023			442,000
2023/2022			500,000
Total Gross Charge Offs		361,000	942,000
Commercial and Industrial | Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	2,010,000		14,374,000
2025/2024	13,943,000		6,297,000
2024/2023	5,715,000		15,040,000
2023/2022	6,041,000		4,414,000
2022/2021	4,271,000		3,303,000
Prior	25,204,000		23,186,000
Subtotal: Total Loans	57,184,000		66,614,000
Commercial and Industrial | Special Mention
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2025/2024			300,000
2024/2023	300,000
2023/2022	8,693,000
Subtotal: Total Loans	8,993,000		300,000
Commercial and Industrial | Substandard
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	10,000
2024/2023			10,000
Subtotal: Total Loans	10,000		10,000
Consumer
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	634,000		1,593,000
2025/2024	1,298,000		1,310,000
2024/2023	1,125,000		657,000
2023/2022	545,000		337,000
2022/2021	274,000		340,000
Prior	1,005,000		716,000
Subtotal: Total Loans	4,881,000		4,953,000
Financing Receivable, Total	4,881,000	6,544,000	4,953,000
Gross Charge Offs:
2026/2025			1,000
2025/2024			8,000
2024/2023	17,000		7,000
2023/2022	6,000		3,000
2022/2021			2,000
Prior	11,000		14,000
Total Gross Charge Offs	34,000	10,000	35,000
Consumer | Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025	634,000		1,593,000
2025/2024	1,298,000		1,310,000
2024/2023	1,125,000		657,000
2023/2022	545,000		337,000
2022/2021	274,000		340,000
Prior	995,000		693,000
Subtotal: Total Loans	4,871,000		4,930,000
Consumer | Special Mention
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Prior			13,000
Subtotal: Total Loans			13,000
Consumer | Substandard
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Prior	10,000		10,000
Subtotal: Total Loans	10,000		10,000
State and Political Subdivisions
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			861,000
2025/2024	896,000
2024/2023			1,139,000
2023/2022	1,133,000		1,374,000
2022/2021	1,374,000		12,528,000
Prior	16,680,000		4,230,000
Subtotal: Total Loans	20,083,000		20,132,000
Financing Receivable, Total	20,083,000	$ 24,633,000	20,132,000
State and Political Subdivisions | Pass
LOANS AND ALLOWANCE FOR CREDIT LOSSES
2026/2025			861,000
2025/2024	896,000
2024/2023			1,139,000
2023/2022	1,133,000		1,374,000
2022/2021	1,374,000		12,528,000
Prior	16,680,000		4,230,000
Subtotal: Total Loans	$ 20,083,000		$ 20,132,000