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		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Loans
2025/2024	$ 93,450,000		$ 93,450,000		$ 115,236,000
2024/2023	108,695,000		108,695,000		133,644,000
2023/2022	123,980,000		123,980,000		184,275,000
2022/2021	164,672,000		164,672,000		138,658,000
2021/2020	129,231,000		129,231,000		109,010,000
Prior	336,984,000		336,984,000		266,003,000
Financing Receivable, Total	957,012,000		957,012,000		946,826,000
Gross Charge Offs:
2024/2023			8,000		15,000
2023/2022			443,000		29,000
2022/2021			3,000		31,000
2021/2020			2,000		8,000
Prior			16,000		855,000
Total Gross Charge Offs	31,000	$ 750,000	472,000	$ 783,000	938,000
Pass
Loans
2025/2024	92,625,000		92,625,000		115,236,000
2024/2023	108,286,000		108,286,000		133,224,000
2023/2022	121,851,000		121,851,000		179,670,000
2022/2021	159,767,000		159,767,000		137,865,000
2021/2020	126,896,000		126,896,000		104,905,000
Prior	315,769,000		315,769,000		248,092,000
Financing Receivable, Total	925,194,000		925,194,000		918,992,000
Special Mention
Loans
2025/2024	825,000		825,000
2024/2023	409,000		409,000
2023/2022	2,129,000		2,129,000		76,000
2022/2021	339,000		339,000		225,000
2021/2020	1,045,000		1,045,000
Prior	1,212,000		1,212,000		1,239,000
Financing Receivable, Total	5,959,000		5,959,000		1,540,000
Substandard
Loans
2024/2023					420,000
2023/2022					4,529,000
2022/2021	4,566,000		4,566,000		568,000
2021/2020	1,290,000		1,290,000		4,105,000
Prior	20,003,000		20,003,000		16,672,000
Financing Receivable, Total	25,859,000		25,859,000		26,294,000
Real Estate
Loans
2025/2024	83,088,000		83,088,000		103,734,000
2024/2023	100,187,000		100,187,000		114,225,000
2023/2022	106,287,000		106,287,000		171,887,000
2022/2021	157,648,000		157,648,000		120,199,000
2021/2020	112,150,000		112,150,000		105,841,000
Prior	306,785,000		306,785,000		234,770,000
Financing Receivable, Total	866,145,000		866,145,000		850,656,000
Gross Charge Offs:
2023/2022			10,000
Prior			7,000		345,000
Total Gross Charge Offs		237,000	17,000	237,000	345,000
Real Estate | Pass
Loans
2025/2024	82,263,000		82,263,000		103,734,000
2024/2023	100,093,000		100,093,000		114,225,000
2023/2022	104,158,000		104,158,000		167,282,000
2022/2021	152,743,000		152,743,000		119,406,000
2021/2020	109,815,000		109,815,000		101,748,000
Prior	285,612,000		285,612,000		216,890,000
Financing Receivable, Total	834,684,000		834,684,000		823,285,000
Real Estate | Special Mention
Loans
2025/2024	825,000		825,000
2024/2023	94,000		94,000
2023/2022	2,129,000		2,129,000		76,000
2022/2021	339,000		339,000		225,000
2021/2020	1,045,000		1,045,000
Prior	1,183,000		1,183,000		1,239,000
Financing Receivable, Total	5,615,000		5,615,000		1,540,000
Real Estate | Substandard
Loans
2023/2022					4,529,000
2022/2021	4,566,000		4,566,000		568,000
2021/2020	1,290,000		1,290,000		4,093,000
Prior	19,990,000		19,990,000		16,641,000
Financing Receivable, Total	25,846,000		25,846,000		25,831,000
Agricultural
Loans
2025/2024	26,000		26,000		59,000
2024/2023	222,000		222,000		223,000
2023/2022	158,000		158,000		43,000
2022/2021	26,000		26,000
Prior	639,000		639,000		611,000
Financing Receivable, Total	1,071,000		1,071,000		936,000
Agricultural | Pass
Loans
2025/2024	26,000		26,000		59,000
2024/2023	222,000		222,000		223,000
2023/2022	158,000		158,000		43,000
2022/2021	26,000		26,000
Prior	639,000		639,000		611,000
Financing Receivable, Total	1,071,000		1,071,000		936,000
Commercial and Industrial
Loans
2025/2024	8,872,000		8,872,000		8,481,000
2024/2023	6,607,000		6,607,000		16,672,000
2023/2022	15,561,000		15,561,000		8,888,000
2022/2021	5,187,000		5,187,000		4,544,000
2021/2020	3,544,000		3,544,000		3,098,000
Prior	24,217,000		24,217,000		25,023,000
Financing Receivable, Total	63,988,000		63,988,000		66,706,000
Gross Charge Offs:
2023/2022			426,000
2022/2021					20,000
Prior					504,000
Total Gross Charge Offs	20,000	504,000	426,000	504,000	524,000
Commercial and Industrial | Pass
Loans
2025/2024	8,872,000		8,872,000		8,481,000
2024/2023	6,292,000		6,292,000		16,252,000
2023/2022	15,561,000		15,561,000		8,888,000
2022/2021	5,187,000		5,187,000		4,544,000
2021/2020	3,544,000		3,544,000		3,086,000
Prior	24,214,000		24,214,000		24,998,000
Financing Receivable, Total	63,670,000		63,670,000		66,249,000
Commercial and Industrial | Special Mention
Loans
2024/2023	315,000		315,000
Financing Receivable, Total	315,000		315,000
Commercial and Industrial | Substandard
Loans
2024/2023					420,000
2021/2020					12,000
Prior	3,000		3,000		25,000
Financing Receivable, Total	3,000		3,000		457,000
Consumer
Loans
2025/2024	1,400,000		1,400,000		2,962,000
2024/2023	1,679,000		1,679,000		1,292,000
2023/2022	779,000		779,000		718,000
2022/2021	437,000		437,000		577,000
2021/2020	382,000		382,000		71,000
Prior	769,000		769,000		770,000
Financing Receivable, Total	5,446,000		5,446,000		6,390,000
Gross Charge Offs:
2024/2023			8,000		15,000
2023/2022			7,000		29,000
2022/2021			3,000		11,000
2021/2020			2,000		8,000
Prior			9,000		6,000
Total Gross Charge Offs	11,000	$ 9,000	29,000	$ 42,000	69,000
Consumer | Pass
Loans
2025/2024	1,400,000		1,400,000		2,962,000
2024/2023	1,679,000		1,679,000		1,292,000
2023/2022	779,000		779,000		718,000
2022/2021	437,000		437,000		577,000
2021/2020	382,000		382,000		71,000
Prior	730,000		730,000		764,000
Financing Receivable, Total	5,407,000		5,407,000		6,384,000
Consumer | Special Mention
Loans
Prior	29,000		29,000
Financing Receivable, Total	29,000		29,000
Consumer | Substandard
Loans
Prior	10,000		10,000		6,000
Financing Receivable, Total	10,000		10,000		6,000
State and Political Subdivisions
Loans
2025/2024	64,000		64,000
2024/2023					1,232,000
2023/2022	1,195,000		1,195,000		2,739,000
2022/2021	1,374,000		1,374,000		13,338,000
2021/2020	13,155,000		13,155,000
Prior	4,574,000		4,574,000		4,829,000
Financing Receivable, Total	20,362,000		20,362,000		22,138,000
State and Political Subdivisions | Pass
Loans
2025/2024	64,000		64,000
2024/2023					1,232,000
2023/2022	1,195,000		1,195,000		2,739,000
2022/2021	1,374,000		1,374,000		13,338,000
2021/2020	13,155,000		13,155,000
Prior	4,574,000		4,574,000		4,829,000
Financing Receivable, Total	$ 20,362,000		$ 20,362,000		$ 22,138,000