SEGMENT INFORMATION - Segment income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
INTEREST INCOME
Total interest income	$ 3,828	$ 3,437
INTEREST EXPENSE
Total interest expense	1,384	1,309
Net interest income	2,444	2,128
Provision for credit losses loans receivable	120	110
Net interest income after provision for credit losses	2,324	2,018
NONINTEREST INCOME
Gain on sale of fixed assets	6
Earnings on deferred compensation plan assets	33	26
Net gains on sale of residential mortgage loans	24	33
Total noninterest income	604	486
NONINTEREST EXPENSE
Compensation and employee benefits	1,579	1,286
Core processing	463	335
Premises and equipment	310	223
Professional fees	174	57
Postage and office supplies	24	43
FDIC premiums	55	33
Advertising	92	98
Director fees	46	48
Intangible asset amortization	39	39
Other	189	165
Total noninterest expense	2,971	2,327
(Loss) Income before provision for income taxes	(43)	177
PROVISION FOR INCOME TAXES	7	29
Net (loss) income	(50)	148
Service fees
NONINTEREST INCOME
Non-interest income	35	32
Income from financial services
NONINTEREST INCOME
Non-interest income	262	224
Fee income
NONINTEREST INCOME
Non-interest income	244	171
Operating Segments | Seneca Savings
INTEREST INCOME
Total interest income	3,828	3,437
INTEREST EXPENSE
Total interest expense	1,384	1,309
Net interest income	2,444	2,128
Provision for credit losses loans receivable	120	110
Net interest income after provision for credit losses	2,324	2,018
NONINTEREST INCOME
Gain on sale of fixed assets	6
Earnings on deferred compensation plan assets	33	26
Net gains on sale of residential mortgage loans	24	33
Total noninterest income	334	254
NONINTEREST EXPENSE
Compensation and employee benefits	1,439	1,170
Core processing	463	335
Premises and equipment	304	217
Professional fees	159	57
Postage and office supplies	24	43
FDIC premiums	55	33
Advertising	91	96
Director fees	46	48
Other	172	153
Total noninterest expense	2,753	2,152
(Loss) Income before provision for income taxes	(95)	120
PROVISION FOR INCOME TAXES	7	29
Net (loss) income	(102)	91
Operating Segments | Seneca Savings | Service fees
NONINTEREST INCOME
Non-interest income	35	32
Operating Segments | Seneca Savings | Fee income
NONINTEREST INCOME
Non-interest income	236	163
Operating Segments | Financial Quest
NONINTEREST INCOME
Total noninterest income	270	232
NONINTEREST EXPENSE
Compensation and employee benefits	140	116
Premises and equipment	6	6
Professional fees	15
Advertising	1	2
Intangible asset amortization	39	39
Other	17	12
Total noninterest expense	218	175
(Loss) Income before provision for income taxes	52	57
Net (loss) income	52	57
Operating Segments | Financial Quest | Income from financial services
NONINTEREST INCOME
Non-interest income	262	224
Operating Segments | Financial Quest | Fee income
NONINTEREST INCOME
Non-interest income	$ 8	$ 8