REGULATORY CAPITAL REQUIREMENTS Regulatory Capital Requirements (Narrative) (Details) $ in Thousands	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2006 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.1050	0.1050
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	7.00%	7.00%
Banking Regulation, Tier One Leverage Capital Ratio, Capital Adequacy, Minimum	0.0400	0.0400
Value Of Trust Preferred Securities Included In Tier One Capital	$ 63,000	$ 43,000
Subordinated Debt	61,365	$ 44,331	$ 44,300
Northway Financial, Inc "NFI"
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Subordinated Debt	$ 20,600
Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.080
Banking Regulation, Tier One Risk-Based Capital Ratio, Capital Adequacy, Minimum	0.060
Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%
Banking Regulation, Tier One Leverage Capital Ratio, Capital Adequacy, Minimum	0.040

Common Equity Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets

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Value of trust preferred securities included in Tier I Capital.

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Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework.

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Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

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