SEGMENT INFORMATION - Segment income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
INTEREST INCOME
Total interest income	$ 3,595	$ 3,336	$ 7,032	$ 6,475
INTEREST EXPENSE
Total interest expense	1,364	1,365	2,673	2,610
Net interest income	2,231	1,971	4,359	3,865
Provision for credit losses loans receivable	511		621	15
Net interest income after provision for credit losses	1,720	1,971	3,738	3,850
NONINTEREST INCOME
Gain on sale of fixed assets			(1)	6
Earnings on bank-owned life insurance	26	11	52	22
Net gain/(loss) on sales of available-for-sale securities			1
Net gains on sale of residential mortgage loans	32	20	65	22
Total noninterest income	531	463	1,017	875
NONINTEREST EXPENSE
Compensation and employee benefits	1,387	1,180	2,673	2,395
Core processing	375	366	711	730
Premises and equipment	222	173	445	381
Professional fees	106	109	163	131
Postage & office supplies	29	20	58	56
FDIC premiums	34	31	67	60
Advertising	85	93	183	180
Director fees	37	40	85	88
Other	207	209	424	372
Total noninterest expense	2,482	2,221	4,809	4,393
Income before provision for income taxes	(231)	213	(54)	332
PROVISION FOR INCOME TAXES	(35)	37	(6)	50
Net income (loss)	(196)	176	(48)	282
Service fees
NONINTEREST INCOME
Non-interest income	33	30	65	61
Income from financial services
NONINTEREST INCOME
Non-interest income	240	218	464	423
Fee income
NONINTEREST INCOME
Non-interest income	226	195	370	341
Operating Segments | Seneca Savings
INTEREST INCOME
Total interest income	3,595	3,336	7,032	6,475
INTEREST EXPENSE
Total interest expense	1,364	1,365	2,673	2,610
Net interest income	2,231	1,971	4,359	3,865
Provision for credit losses loans receivable	511		621	15
Net interest income after provision for credit losses	1,720	1,971	3,738	3,850
NONINTEREST INCOME
Gain on sale of fixed assets				6
Earnings on bank-owned life insurance			52	22
Net gain/(loss) on sales of available-for-sale securities			1
Net gains on sale of residential mortgage loans	32	20	65	22
Total noninterest income	283	236	537	436
NONINTEREST EXPENSE
Compensation and employee benefits	1,268	1,075	2,438	2,188
Core processing	375	366	711	730
Premises and equipment	216	167	433	369
Professional fees	106	109	163	131
Postage & office supplies	29	19	57	55
FDIC premiums	34	31	67	60
Advertising	82	88	179	175
Director fees	37	38	84	85
Other	155	158	322	273
Total noninterest expense	2,302	2,051	4,454	4,066
Income before provision for income taxes	(299)	156	(179)	220
PROVISION FOR INCOME TAXES	(35)	37	(6)	50
Net income (loss)	(264)	119	(173)	170
Operating Segments | Seneca Savings | Service fees
NONINTEREST INCOME
Non-interest income	33	30	65	61
Operating Segments | Seneca Savings | Fee income
NONINTEREST INCOME
Non-interest income	218	186	354	325
Operating Segments | Financial Quest
NONINTEREST INCOME
Total noninterest income	248	227	480	439
NONINTEREST EXPENSE
Compensation and employee benefits	119	105	235	207
Premises and equipment	6	6	12	12
Postage & office supplies		1	1	1
Advertising	3	5	4	5
Director fees		2	1	3
Other	52	51	102	99
Total noninterest expense	180	170	355	327
Income before provision for income taxes	68	57	125	112
Net income (loss)	68	57	125	112
Operating Segments | Financial Quest | Income from financial services
NONINTEREST INCOME
Non-interest income	240	218	464	423
Operating Segments | Financial Quest | Fee income
NONINTEREST INCOME
Non-interest income	$ 8	$ 9	$ 16	$ 16