BORROWED FUNDS - Subordinated and Junior Subordinated Borrowings (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Nov. 26, 2019
BORROWED FUNDS
Net loans	$ 3,118,352	$ 3,571,807	$ 3,118,352
Maximum borrowing capacity		259,100
Repayments of subordinated debt			20,000
Asset Pledged as Collateral | FHLB stock
BORROWED FUNDS
Net loans	781,200	$ 740,700	$ 781,200
Financial guarantee
BORROWED FUNDS
Interest rate margin		2.79%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
NHTB Capital Trust II and NHTB Capital Trust III | Financial guarantee
BORROWED FUNDS
Debentures issued by variable interest entities		$ 20,600
Subordinated borrowings
BORROWED FUNDS
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Subordinated borrowings private placement
BORROWED FUNDS
Principal amount of debt issued				$ 40,000
Fixed interest rate				4.63%
Interest rate margin		3.27%
Repayments of subordinated debt	$ 20,000
Outstanding subordinated debt		$ 20,000
Acquired subordinated notes
BORROWED FUNDS
Principal amount of debt issued		13,000
Fair value		$ 12,200
Interest rate margin		4.82%
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration]		us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Effective interest rate		4.875%