LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES - Components of Loans receivable net (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	$ 134,439	$ 132,835
Net Deferred Loan Fees	495	483
Net Discounts on Purchased Loans	(689)	(714)
Allowance for Credit Losses	(1,112)	(1,100)	$ (1,059)	$ (1,063)
Loans Receivable, Net	133,133	131,504
Real Estate Loan [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	128,212	126,081
Home Equity
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	2,294	2,142
Commercial Non-Mortgage
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	2,310	2,408
Automobile
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	1,579	1,849
Passbook
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	353	368
Consumer
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	1,985	2,129
Residential Portfolio Segment [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	116,735	115,134
Allowance for Credit Losses	(864)	(859)	(805)	(799)
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	111,341	109,700
Residential Portfolio Segment [Member] \| Construction - Residential
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	3,100	3,292
Residential Portfolio Segment [Member] \| Home Equity
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	2,294	2,142
Commercial Portfolio Segment [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	11,477	10,947
Allowance for Credit Losses	(160)	(148)	(152)	(156)
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	11,337	10,807
Commercial Portfolio Segment [Member] \| Construction - Commercial
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	140	140
Consumer Portfolio Segment [Member]
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	3,917	4,346
Allowance for Credit Losses	(50)	(54)	$ (65)	$ (68)
Consumer Portfolio Segment [Member] \| Commercial Non-Mortgage
LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Total Loans	$ 2,310	$ 2,408

Gouverneur Bancorp, Inc./MD/ 10-Q