PARENT COMPANY ONLY FINANCIAL INFORMATION - Parent Only Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Interest income:
Total interest income	$ 14,627	$ 13,364
Non-interest expenses:
Professional fees	426	232
Other non-interest expense	847	569
Total noninterest expense	10,083	8,878
Income before provision for income taxes	181	816
Income tax benefit	(9)	(104)
Net income	172	712
Seneca Financial Corp (Parent Company)
Interest income:
Income on ESOP loan	23	28
Total interest income	23	28
Non-interest expenses:
Professional fees	268	152
Other non-interest expense	119	75
Total noninterest expense	387	227
Income before provision for income taxes	(364)	(199)
Income tax benefit		42
Earnings before equity in undistributed earnings of Bank	(364)	(157)
Equity in undistributed net income of bank subsidiary	536	869
Net income	$ 172	$ 712