SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]
PRINCIPLES OF CONSOLIDATION	The consolidated financial statements include the accounts of the Company, the Bank and other wholly-owned subsidiaries, except subsidiaries that are not deemed necessary to be consolidated. All significant intercompany balances and transactions have been eliminated in consolidation. The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company would consolidate voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities ("VIEs") are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company also owns the common stock of various trusts which have issued trust preferred securities. These trusts are VIEs in which the Company is not the primary beneficiary and, therefore, are not consolidated. The trust's only assets are junior subordinated debentures issued by the Company, which were acquired by the trust using the proceeds from the issuance of the trust preferred securities and common stock. The junior subordinated debentures are included in long-term debt and the Company’s equity interest in the trust is included in other assets in the accompanying Consolidated Balance Sheets. Interest expense on the junior subordinated debentures is reported in interest expense on long-term debt in the accompanying Consolidated Statements of Income.
RECLASSIFICATION	Reclassification Certain previously reported amounts have been reclassified to conform to the current year’s presentation.
USE OF ESTIMATES	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could vary from these estimates. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of the allowance for expected credit losses on loans held for investment, income taxes, valuation and allowance for expected credit losses on investment securities, and the valuation of goodwill and other intangible assets and their respective analyses of impairment.
SIGNIFICANT CONCENTRATIONS OF CREDIT RISK	Concentrations of Credit Risk The vast majority of the Bank’s lending activities are conducted in New England. The Bank originates commercial and industrial loans, commercial and residential real estate loans, including construction loans, small business loans, home equity loans, and other consumer loans for its portfolio. The Bank tracks concentrations of credit across numerous categories and segments based on aggregate credit exposure, which includes direct, indirect or contingent obligations to a borrower or group of borrowers engaged in one industry and by property type. The Bank considers a concentration to exist when aggregate credit exposure of a category or segment exceeds 25% of the Bank's total risk-based capital (inclusive of Tier 2 capital instruments).
CASH AND CASH EQUIVALENTS	Cash and Cash Equivalents For purposes of reporting cash flows, cash and cash equivalents may include cash on hand, amounts due from banks, inclusive of interest-earning deposits held at banks, and federal funds sold. Generally, federal funds are sold for up to two week periods.
SECURITIES	Securities Investment securities are classified at the time of purchase as available for sale, held to maturity, trading, or equity. Classification is constantly re-evaluated for consistency with corporate goals and objectives. Trading and equity securities are recorded at fair value with subsequent changes in fair value recorded in earnings. Debt securities that management has the positive intent and ability to hold to maturity are classified as held to maturity and recorded at amortized cost. Securities not classified as held to maturity or trading are classified as available for sale and recorded at fair value, with changes in fair value excluded from earnings and reported in other comprehensive income, net of related tax. Purchase premiums and discounts are recognized in interest income, using the interest method, to arrive at periodic interest income at a constant effective yield, thereby reflecting the securities market yield. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. Such gains and losses are recognized within non-interest income or non-interest expense within the consolidated statements of income. Accrued interest receivable balances are excluded from the amortized cost of held to maturity securities and the fair value of available for sale securities and are included within other assets on the Consolidated Balance Sheets. Management has elected not to measure an allowance for credit losses on these balances as the Company employs a timely write-off policy. It is the Company's policy that a security is placed on nonaccrual status at the time any principal or interest payments become 90 days delinquent, and interest earned but not collected for a security placed on non-accrual is reversed against interest income. Allowance for Credit Losses - Available for Sale Securities The Company's available for sale securities are carried at fair value and assessed for estimated credit losses in accordance with the current expected credit loss ("CECL") methodology. For available for sale securities in an unrealized loss position, management will first evaluate whether there is intent to sell, or if it is more likely than not that the Company will be required to sell a security prior to anticipated recovery of its amortized cost basis. If either of these criteria are met, the Company will record a write-down of the security's amortized cost basis to fair value through income. For those available for sale securities which do not meet the intent or requirement to sell criteria, management will evaluate whether the decline in fair value is a result of credit related matters or other factors. In performing this assessment, management considers the creditworthiness of the issuer including whether the security is guaranteed by the U.S. Federal Government or other government agency, the extent to which fair value is less than amortized cost, and changes in credit rating during the period, among other factors. If this assessment indicates the existence of credit losses, the security will be written down to fair value, as determined by a discounted cash flow analysis. To the extent the estimated cash flows do not support the amortized cost, the deficiency is considered to be due to credit loss and is recognized in earnings. Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense. Losses are charged against the allowance when the uncollectibility of a security is confirmed, or when either of the aforementioned criteria surrounding intent or requirement to sell have been met. Allowance for Credit Losses - Held to Maturity Securities The Company measures expected credit losses on held to maturity securities on a collective basis by major security type in accordance with the CECL methodology. Management classifies the held to maturity portfolio into the following major security types: U.S. Government Agency, U.S. Treasury, Agency Mortgage-Backed Securities, Agency Collateralized Mortgage Obligations, Small Business Administration Pooled Securities, and Single Issuer Trust Preferred Securities. Securities in the Company's held to maturity portfolio are primarily guaranteed by either the U.S. Federal Government or other government sponsored agencies with a long history of no credit losses. As a result, management has determined these securities to have a zero loss expectation and therefore does not estimate an allowance for credit losses on these securities.
LOANS HELD FOR SALE	Loans Held for Sale The Bank may choose to classify new residential real estate mortgage loans as held for sale based on intent, which is determined when loans are underwritten. Residential real estate mortgage loans not designated as held for sale are retained based upon available liquidity, for interest rate risk management and other business purposes. The Company has elected the fair value option to account for originated closed loans intended for sale. Accordingly, changes in fair value relating to loans intended for sale are recorded in earnings and are offset by changes in fair value relating to interest rate lock commitments and forward sales commitments. Gains and losses on residential loan sales (sales proceeds minus carrying amount) are recorded in mortgage banking income. Upfront costs and fees related to items for which the fair value option is elected are recognized in earnings as incurred and are not deferred.
Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts	Allowance for Credit Losses - Loans Held for Investment The allowance for credit losses is established based upon the Company's current estimate of expected lifetime credit losses on loans measured at amortized cost, also referred to as the CECL methodology. Credit losses are charged against the allowance when management's assessments confirm that the Company will not collect the full amortized cost basis of a loan. Subsequent recoveries, if any, are credited to the allowance. Under the CECL methodology, the Company estimates credit losses for financial assets on a collective basis for loans sharing similar risk characteristics using a quantitative model combined with an assessment of certain qualitative factors designed to address forecast risk and model risk inherent in the quantitative model output. The quantitative model utilizes a factor based approach to estimate expected credit losses using Probability of Default ("PD"), Loss Given Default ("LGD") and Exposure at Default ("EAD"), which are derived from internal historical default and loss experience. The model estimates expected credit losses using loan level data over the estimated life of the exposure, considering the effect of prepayments. Economic forecasts are incorporated into the estimate over a reasonable and supportable forecast period, beyond which is a reversion to the Company's historical long-run average. Management has determined a reasonable and supportable period of 12 months, and a straight line reversion period of 6 months, to be appropriate for purposes of estimating expected credit losses. The qualitative risk factors impacting the expected risk of loss within the portfolio include the following: •Lending policies and procedures •Economic and business conditions •Nature and volume of loans •Changes in management •Changes in credit quality •Changes in loan review system •Changes to underlying collateral values •Concentrations of credit risk •Model imprecision •Other external factors Loans that do not share similar risk characteristics with any pools of assets are subject to individual evaluation and are removed from the collectively assessed pools to avoid double counting. For the loans that are individually evaluated, the Company uses either a discounted cash flow (“DCF”) approach or a fair value of collateral approach. The latter approach is used for loans deemed to be collateral dependent or when foreclosure is probable. Loan modifications made to borrowers experiencing financial difficulty are evaluated on a collective basis with loans sharing similar risk characteristics in accordance with the CECL methodology. Under previously applicable accounting guidance, the Company determined the amount of allowance for credit losses on TDRs using a discounted cash flow analysis or a fair value of collateral approach if the loan was determined to be individually evaluated. This change in methodology did not have a material impact on the Company's allowance for credit loss estimate. Accrued interest receivable amounts are excluded from balances of loans held at amortized cost and are included within other assets on the consolidated balance sheets. Management has elected not to measure an allowance for credit losses on these amounts as the Company employs a timely write-off policy. Consistent with the Company's policy for nonaccrual loans, accrued interest receivable is typically written off when loans reach 90 days past due and are placed on nonaccrual status. In the ordinary course of business, the Company enters into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for credit losses. The reserve for unfunded lending commitments is included in other liabilities on the Consolidated Balance Sheets.
ACQUIRED LOANS	Acquired Loans Loans acquired through purchase or a business combination are recorded at their fair value at the acquisition date. The Company performs an assessment of acquired loans to first determine if such loans have experienced a more than insignificant deterioration in credit quality since their origination and thus should be classified and accounted for as PCD loan. For loans that have not experienced a more than insignificant deterioration in credit quality since origination, referred to as non-PCD loans, the Company records such loans at fair value, with any resulting discount or premium accreted or amortized into interest income over the remaining life of the loan using the interest method. Additionally, upon the purchase or acquisition of non-PCD loans, the Company measures and records a reserve for credit losses based on the Company’s methodology for determining the allowance under CECL. The allowance for non-PCD loans is recorded through a charge to provision for credit losses in the period in which the loans were purchased or acquired. Acquired loans that are classified as PCD are acquired at fair value, including any resulting discounts or premiums. Discounts and premiums are accreted or amortized into interest income over the remaining life of the loan using the interest method. In contrast to non-PCD loans, the initial allowance for credit losses on PCD loans is established through an adjustment to the acquired loan balance, rather than through a charge to provision for credit losses, in the period in which the loans were acquired. The allowance for PCD loans is determined based upon the Company's methodology for estimating the allowance under CECL, and is recorded as an adjustment to the acquired loan balance on the date of acquisition. The Company evaluates acquired loans for deterioration in credit quality based on a variety of characteristics, including, but not limited to non-accrual and delinquency status, downgrades in credit quality since origination, loans that have been modified, along with any other factors identified by the Company through its initial analysis of acquired loans which may indicate there has been a more than insignificant deterioration in credit quality since origination. At the acquisition date, an estimate of expected credit losses is made for groups of PCD loans with similar risk characteristics and individual PCD loans without similar risk characteristics, if applicable. Subsequent to acquisition, the allowance for credit losses for both non-PCD and PCD loans are determined with the use of the Company’s allowance methodology under CECL, in the same manner as all other loans. Transfers and Servicing of Financial Assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. Loans held for sale are generally sold with servicing rights released, however if rights are retained, servicing assets are recognized as separate assets. Servicing rights are originally recorded at fair value within other assets, but subsequently are amortized in proportion to and over the period of estimated net servicing income, and are assessed for impairment at each reporting date. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds, default rates and losses. Impairment is determined by stratifying the rights based on predominant characteristics, such as interest rate, loan type and investor type. Impairment is recognized through a valuation allowance, to the extent that fair value is less than the capitalized amount. If the Company later determines that all or a portion of the impairment no longer exists, a reduction of the allowance may be recorded as an increase to income. Servicing fee income is recorded for fees earned for servicing loans for investors. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan, and are recorded as income when earned. The amortization of mortgage servicing rights is recorded as a reduction of loan servicing fee income. The Company is also a party to certain instruments with off-balance-sheet risk including certain residential loans sold to investors with recourse. The Company's policy is to record such instruments when funded.
FEDERAL HOME LOAN BANK STOCK	Federal Home Loan Bank Stock The Company, as a member of the Federal Home Loan Bank ("FHLB") of Boston, is required to maintain an investment in capital stock of the FHLB. Based on redemption provisions, the stock has no quoted market value and is carried at cost. The Company continually reviews its investment to determine if impairment exists. The Company reviews recent public filings, rating agency analysis and other factors when making its determination.
BANK PREMISES AND EQUIPMENT	Bank Premises and Equipment Land is carried at cost. Bank premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line convention method over the estimated useful lives of the assets. Leasehold improvements are amortized over the shorter of the lease terms or the estimated useful lives of the improvements. Expected terms include lease option periods to the extent that the exercise of such options is reasonably assured, not to exceed fifteen years. Leases The Company leases office space, space for ATM and parking locations, and certain branch locations under noncancelable operating leases, several of which have renewal options to extend lease terms. Upon commencement of a new lease, the Company will recognize a right of use ("ROU") asset and corresponding lease liability. The Company makes the decision on whether to renew an option to extend a lease by considering various factors. The Company will recognize an adjustment to its ROU asset and lease liability when lease agreements are amended and executed, or in an event where the Company is reasonably certain that a renewal option will be exercised. The discount rate used in determining the present value of lease payments is based on the Company's incremental borrowing rate for borrowings with terms similar to each lease at commencement date. The Company has lease agreements with lease and non-lease components, which are generally accounted for separately. For real estate leases, non-lease components and other non-components, such as common area maintenance charges, real estate taxes, and insurance, are not included in the measurement of the lease liability since they are generally able to be segregated. The Company has elected the short-term lease recognition exemption for all leases that qualify. The Company may also assume lease obligations in connection with its acquisition activities, which may result in a market-based favorable or unfavorable lease position, resulting in an intangible lease asset. These intangible lease assets are amortized over the estimated remaining lease term. The Company is a party to certain equipment lease transactions where it has assumed the role of lessor for purchased assets. These lease transactions are classified by the Company as either operating leases or direct financing leases for accounting purposes, depending upon the nature of the underlying lease agreements. Under operating lease arrangements, the leased asset value is recorded within fixed assets and the Company recognizes rental income over the life of the lease. Under direct financing lease arrangements, the leased asset value is de-recognized and offset with the recognition of a lease receivable that is evaluated for impairment in a manner similar to loans.
GOODWILL AND IDENTIABLE INTANGIBLE ASSETS	Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price over the net fair value of acquired businesses. Goodwill is not amortized and is assigned to one reporting unit. Goodwill is evaluated for impairment at least annually, or more often if warranted. In assessing for impairment, the Company has the option to first perform a qualitative analysis to determine whether the existence of events or circumstances leads to a determination that it is more-likely-than-not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of such events and circumstances, the Company determines it is more-likely-than-not that the fair value is less than carrying value, a quantitative impairment test is performed to compare carrying value to the fair value of the reporting unit. The Company also has an unconditional option to bypass the assessment of qualitative factors for any period and proceed directly to the quantitative goodwill impairment test. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss will be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit. Other intangible assets subject to amortization consist of core deposit intangibles, customer lists, and non-compete agreements that are amortized over the estimated lives of the intangibles using a method that approximates the amount of economic benefits that are realized by the Company. Other intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable.
IMPAIRMENT OF LONG-LIVED ASSETS OTHER THAN GOODWILL	Impairment of Long-Lived Assets Other Than Goodwill The Company reviews long-lived assets, including premises and equipment, for impairment whenever events or changes in business circumstances indicate that the remaining useful life may warrant revision or that the carrying amount of the long-lived asset may not be fully recoverable. The Company performs an undiscounted cash flow analysis to determine if impairment exists. When impairment is determined to exist, the related impairment loss is calculated based on fair value. Impairment losses on assets to be disposed of are based on the estimated proceeds to be received, less costs of disposal.
CASH SURRENDER VALUE OF LIFE INSURANCE POLICIES	Cash Surrender Value of Life Insurance Policies Increases in the cash surrender value ("CSV") of life insurance policies, as well as benefits received net of any CSV, are recorded in other noninterest income, and are generally not subject to income taxes. The CSV of the policies is recorded as an asset of the Bank, with liabilities recognized for any split dollar arrangements associated with the policies. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. Regulatory requirements limit the total amount of CSV to be held with any individual carrier to 15% of Tier 1 capital (as defined for regulatory purposes) and the total CSV of all life insurance policies is limited to 25% of Tier 1 capital.
OTHER REAL ESTATE OWNED AND OTHER FORECLOSED ASSETS	Other Real Estate Owned and Other Foreclosed Assets Real estate properties and other assets, which have served as collateral to secure loans, are held for sale and are initially recorded at fair value less estimated costs to sell at the date control is established, resulting in a new cost basis. The amount by which the recorded investment in the loan exceeds the fair value (net of estimated costs to sell) of the foreclosed asset is charged to the allowance for credit losses. Subsequent declines in the fair value of the foreclosed asset below the new cost basis are recorded through the use of a valuation allowance. Subsequent increases in the fair value are recorded as reductions in the valuation allowance, but not below zero. Upon a sale of a foreclosed asset, any excess of the carrying value over the sale proceeds is recognized as a loss on sale. Any excess of sale proceeds over the carrying value of the foreclosed asset is first applied as a recovery to the valuation allowance, if any, with the remainder being recognized as a gain on sale. Operating expenses and changes in the valuation allowance relating to foreclosed assets are recorded in other noninterest expense.
DERIVATIVES	Derivatives Derivative instruments are carried at fair value in the Company’s financial statements. The accounting for changes in the fair value of a derivative instrument is determined by whether it has been designated and qualifies as part of a hedging relationship, and further, by the type of hedging relationship. At the inception of a hedge, the Company documents certain items, including but not limited to the following: the relationship between hedging instruments and hedged items, the Company's risk management objectives, hedging strategies, and the evaluation of hedge transaction effectiveness. Documentation includes linking all derivatives designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific forecasted transactions. For those derivative instruments that are designated and qualify for special hedge accounting, the Company designates the hedging instrument, based upon the exposure being hedged, as either a fair value hedge or a cash flow hedge. For derivative instruments that are designated and qualify as a cash flow hedge (i.e., hedging the exposure to variability in expected future cash flows that is attributable to a particular risk), the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income, net of related tax. The Company considers any economic mismatch between the hedging instrument and the hedged transaction in its ongoing assessment of hedge effectiveness. If the hedging instrument is not highly effective at achieving offsetting cash flows attributable to the revised contractually specified interest rate(s), hedge accounting will be discontinued. At that time, accumulated other comprehensive income would be frozen and amortized, as long as the forecasted transactions are still probable of occurring. For derivative instruments designated and qualifying as a fair value hedge (i.e., hedging the exposure to changes in the fair value of an asset or liability or an identified portion thereof that is attributable to the hedged risk), the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item attributable to the hedged risk, are recognized in current earnings during the period of the change in fair values. Hedge accounting is discontinued prospectively when (1) a derivative is no longer highly effective in offsetting changes in the fair value or cash flow of a hedged item, (2) a derivative expires or is settled, (3) it is no longer likely that a forecasted transaction associated with the hedge will occur, or (4) it is determined that designation of a derivative as a hedge is no longer appropriate. To the extent the Company enters into new or re-designates existing hedging relationships, it is the Company's policy to include the Overnight Index Swap Rate based on the Fed Funds Effective Rate and the Overnight Index Swap Rate based on the Secured Overnight Financing Rate in the spectrum of available benchmark interest rates for hedge accounting. For derivative instruments not designated as hedging instruments, such as loan level derivatives, foreign exchange contracts, risk participation agreements and mortgage derivatives, changes in fair value are recognized in other noninterest income during the period of change and are included in changes in other assets or other liabilities on the Company's consolidated statement of cash flows.
RETIREMENT PLANS	Retirement Plans The Company has various retirement plans in place for current and former employees, including postretirement benefit plans, supplemental executive retirement plans, frozen multiemployer pension plans, deferred compensation plans, as well as other benefits. The postretirement benefit plans and the supplemental executive retirement plans are unfunded and therefore have no plan assets. The actuarial cost method used to compute the benefit liabilities and related expense is the projected unit credit method. The projected benefit obligation is principally determined based on the present value of the projected benefit distributions at an assumed discount rate. The discount rate which is utilized is based on the investment yield of high quality corporate bonds available in the market place with maturities approximately equal to projected cash flows of future benefit payments as of the measurement date. Periodic benefit expense (or income) includes service costs and interest costs based on the assumed discount rate, amortization of prior service costs due to plan amendments and amortization of actuarial gains and losses. Service costs are included in salaries and employee benefits and all other costs are included in other noninterest expense. The amortization of actuarial gains and losses is determined using the 10% corridor minimum amortization approach and is taken over the average remaining future working lifetime of the plan participants. The underfunded status of the plans is recorded as a liability on the balance sheet. The multiemployer pension plans' assets are determined based on fair value, generally representing observable market prices. The actuarial cost method used to compute the pension liabilities and related expense is the unit credit method. The pension expense is equal to the plan contribution requirement of the Company for the plan year. In conjunction with the acquisition of Blue Hills Bancorp, Inc., parent of Blue Hills Bank (collectively "BHB") the Company acquired BHB's defined benefit pension plan, which is administered by the Savings Banks Employees Retirement Association. The Company accounts for the plan using an actuarial model that allocates pension costs over the service period of employees in the plan. The Company accounts for the over-funded or under-funded status of the plan as an asset or liability on its consolidated balance sheets and recognizes changes in the funded status that are not reflected in net periodic pension cost as other comprehensive income or loss. BHB amended its defined benefit pension plan in 2013 freezing the plan to new participants and subsequently amended the plan and froze it for all participants effective October 31, 2014. The Director Deferred Compensation Plan allows directors to invest their funds into a diversified investment portfolio and the 401(k) Restoration Plan allows employees to invest their funds in both Company stock and other investment alternatives offered by the Plan. All funds under both of these plans are held in a rabbi trust. The plans do not permit diversification after initial election and therefore elections made to defer into Company stock result in both the investment and obligation recognized within Stockholders' Equity. Alternatively, investments not in Company stock are included in trading securities, with the correlating obligation classified as a liability. The Company has obligations with various individuals related to certain post-retirement benefits. The obligations are based on the individual's service through retirement, with the associated cost recognized over the requisite service period. The accrual methodology results in an accrued amount at the full eligibility date equal to the then present value of all of the future benefits expected to be paid.
STOCK-BASED COMPENSATION	Stock-Based Compensation The Company recognizes stock-based compensation based on the grant-date fair value of the award, with no adjustment for estimated forfeitures, as forfeitures are recognized when they occur. For restricted stock awards and units, the Company recognizes compensation expense ratably over the vesting period for the fair value of the award, measured at the grant date. For stock option awards, the Company values awards granted using the Black-Scholes option-pricing model. The Company recognizes compensation expense for these awards on a straight-line basis over the requisite service period for the entire award (straight-line attribution method), ensuring that the amount of compensation cost recognized at any date at least equals the portion of the grant-date fair value of the award that is vested at that time. The Company recognizes excess tax benefits on certain stock compensation transactions. The excess tax benefits are recorded through earnings as a discrete item within the Company’s effective tax rate during the period of the transaction.
INCOME TAXES	Income Taxes Deferred income tax assets and liabilities are determined using the asset and liability (or balance sheet) method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. If current available information raises doubt as to the realization of the deferred tax assets, a valuation allowance is established. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in enacted tax rates is recognized in income in the period that includes the enactment date. Income taxes are allocated to each entity in the consolidated group based on its share of taxable income. Management exercises significant judgment in evaluating the amount and timing of recognition of the resulting tax liabilities and assets, including projections of future taxable income. Additionally, a liability for unrecognized tax benefits is recorded for uncertain tax positions taken by the Company on its tax returns for which there is less than a 50% likelihood of being recognized upon a tax examination.
Low Income Housing Tax Credits Policy Text Block [Policy Text Block]	Low Income Housing Tax Credits The Company accounts for its investments in qualified affordable housing projects using the proportional amortization method. Under the proportional amortization method the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received, and recognizes the net investment benefit as a component of income tax expense (benefit).
ASSETS UNDER ADMININSTRATION	Assets Under Administration Assets held in a fiduciary or agency capacity for customers are not included in the accompanying consolidated balance sheet, as such assets are not assets of the Company. Revenue from administrative and management activities associated with these assets is recorded on an accrual basis.
Extinguishment of Debt [Policy Text Block]	Extinguishment of Debt Upon extinguishment of an outstanding debt, the Company records the difference between the exit price and the net carrying amount of the debt as a gain or loss on the extinguishment. The gain or loss is recorded as a component of other noninterest income or other noninterest expense, respectively.
EARNINGS PER SHARE	Earnings Per Share Basic earnings per share is calculated using the two-class method. The two-class method is an earnings allocation formula under which earnings per share is calculated from common stock and participating securities according to dividends declared and participation rights in undistributed earnings. Under this method, all earnings, distributed and undistributed, are allocated to participating securities and common shares based on their respective rights to receive dividends. Unvested share-based payment awards that contain nonforfeitable rights to dividends are considered participating securities, not subject to performance based measures (i.e. unvested time-vested restricted stock). Basic earnings per share is calculated by dividing net income by the weighted average number of common shares outstanding (inclusive of participating securities). Diluted earnings per share have been calculated in a manner similar to that of basic earnings per share except that the weighted average number of common shares outstanding is increased to include the number of additional common shares that would have been outstanding if all potentially dilutive common shares (such as those resulting from the exercise of stock options or the attainment of performance measures) were issued during the period, computed using the treasury stock method.
COMPREHENSIVE INCOME	Comprehensive Income Comprehensive income consists of net income and other comprehensive income. Other comprehensive income includes unrealized gains and losses on securities available for sale, unrealized losses related to factors other than credit on debt securities, if applicable, unrealized gains and losses on cash flow hedges, deferred gains on hedge accounting transactions, and changes in the funded status of the Company’s postretirement and supplemental retirement plans.
FAIR VALUE MEASUREMENTS	Fair Value Measurements In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and the Company’s creditworthiness, among other things, as well as unobservable parameters.
Lessee, Leases [Policy Text Block]
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Standards FASB ASC Topic 740 "Income Taxes" Update No. 2023-09. Update No. 2023-09 was issued in December 2023 and aims to enhance the transparency and decision usefulness of income tax disclosures by requiring disaggregated information related to the effective tax rate reconciliation as well as information on income taxes paid. This standard is effective for annual periods beginning after December 15, 2024 and requires prospective application with the option to apply retrospectively. The adoption of this standard will not have an impact on the Company's financial statements.
Policy Loans Receivable, Policy	Loans Held for Investment Loans that the Company has the intent and ability to hold until maturity or payoff are carried at amortized cost (net of the allowance for credit losses). Amortized cost is the principal amount outstanding, adjusted by partial charge-offs and net of deferred loan costs or fees. For originated loans, loan fees and certain direct origination costs are deferred and amortized into interest income over the expected term of the loan using the level-yield method. When a loan is paid off, the unamortized portion is recognized in interest income. Interest income on loans is accrued based upon the daily principal amount outstanding except for loans on nonaccrual status. As a general rule, loans 90 days or more past due with respect to principal or interest are classified as nonaccrual loans, or sooner if management considers such action to be prudent. However, loans that are 90 days or more past due may be kept on an accruing status if the loan is well secured and in the process of collection. Income accruals are suspended on all nonaccrual loans in a timely manner and all previously accrued and uncollected interest is reversed against current income. A loan remains on nonaccrual status until it becomes current with respect to principal and interest and remains current for a minimum period of six months, the loan is liquidated, or when the loan is determined to be uncollectible and is charged-off against the allowance for credit losses. When doubt exists as to the collectability of a loan, any payments received are applied to reduce the amortized cost of the loan to the extent necessary to eliminate such doubt. For all loan portfolios, a charge-off occurs when the Company determines that a specific loan, or portion thereof, is uncollectible. This determination is made based on management's review of specific facts and circumstances of the individual loan, including assessing the viability of the customer’s business or project as a going concern, the expected cash flows to repay the loan, the value of the collateral and the ability and willingness of any guarantors to perform. In the course of resolving problem loans, the Company may choose to modify the contractual terms of certain loans. The Company attempts to work out an alternative payment schedule with the borrower in order to avoid or cure a default. Terms may be modified to fit the ability of the borrower to repay in line with its current financial status and may include adjustments to term extensions, interest rates, other than insignificant payment delays and/or a combination thereof. These actions are intended to minimize economic loss and avoid foreclosure or repossession of collateral. If such efforts by the Bank do not result in satisfactory performance, the loan is referred to legal counsel, at which time foreclosure proceedings are initiated. At any time prior to a sale of the property at foreclosure, the Bank may terminate foreclosure proceedings if the borrower is able to work out a satisfactory payment plan. Any loans that are modified are reviewed by the Company to determine whether the modification is the direct result of a borrower experiencing financial difficulty, as the Company adopted the accounting and disclosure requirements for loan modifications made to borrowers experiencing financial difficulty and ceased to recognize troubled debt restructurings ("TDRs") effective January 1, 2023. Prior to this adoption, the Company would classify loans as TDRs in cases where a borrower was experiencing financial difficult and where the Company made certain concessionary modifications to contractual terms. Modifications included adjustments to interest rates, extensions of maturity, consumer loans where the borrower's obligations had been effectively discharged through Chapter 7 Bankruptcy and the borrower had not reaffirmed the debt to the Bank, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. Under the previously applicable guidance, loans classified as TDRs would have remained classified as such for the life of the loan, except in limited circumstances, when it was determined that the borrower was performing under the modified terms and the restructuring agreement specified an interest rate greater than or equal to an acceptable market rate for a comparable new loan at the time of the restructuring.
Credit Loss, Financial Instrument	Commercial Portfolio •Commercial and Industrial: Consists of revolving, non-revolving, and term loan obligations extended to business and corporate enterprises for the purpose of financing working capital and/or capital investment. Collateral generally consists of accounts receivable, inventory, plant and equipment, real estate, or other business assets. The primary source of repayment is operating cash flow and, secondarily, liquidation of assets. •Commercial Real Estate: Consists of mortgage loans to finance investment in real property such as multi-family residential, commercial/retail, office, industrial, hotels, educational and healthcare facilities, as well as other specific use properties and is inclusive of owner-occupied commercial properties. Loans are typically written with amortizing payment structures. Collateral values are determined based upon third party appraisals and evaluations. Permissible loan to value ratios at origination are governed by Company policy and regulatory guidelines. The primary source of repayment is cash flow from operating leases and rents and, secondarily, liquidation of assets. •Commercial Construction: Consists of short-term construction loans, revolving and nonrevolving credit lines and construction/permanent loans to finance the acquisition, development and construction or rehabilitation of real property. Project types include residential land development, one-to-four family, condominium, and multi-family home construction, commercial/retail, office, industrial, hotels, educational and healthcare facilities as well as other specific use properties. Loans may be written with nonamortizing or hybrid payment structures depending upon the type of project. Collateral values are determined based upon third party appraisals and evaluations. Permissible loan to value ratios at origination are governed by Company policy and regulatory guidelines. Repayment sources vary depending upon the type of project and may consist of proceeds from the sale or lease of units, operating cash flows or liquidation of other assets. •Small Business: Consists of revolving, term loan and mortgage obligations extended to sole proprietors and small businesses for purposes of financing working capital and/or capital investment. Collateral generally consists of pledges of business assets including, but not limited to, accounts receivable, inventory, plant and equipment, or real estate if applicable. The primary source of repayment is operating cash flows and, secondarily, liquidation of assets. For the commercial portfolio the Company typically obtains personal guarantees for payment from individuals holding material ownership interests in the borrowing entities. Consumer Portfolio •Residential Real Estate: Residential mortgage loans held in the Company’s portfolio are made to borrowers who demonstrate the ability to make scheduled payments with full consideration to underwriting factors such as current and expected income, employment status, current assets, other financial resources, credit history and the value of the collateral. Collateral consists of mortgage liens on one-to-four family residential properties. Residential mortgage loans also include loans to construct owner-occupied one-to-four family residential properties. •Home Equity: Home equity loans and credit lines are made to qualified individuals and are primarily secured by senior or junior mortgage liens on one-to-four family homes, condominiums or vacation homes. Each home equity loan has a fixed rate and is billed in equal payments comprised of principal and interest. The majority of home equity lines of credit have a variable rate and are billed in interest-only payments during the draw period. At the end of the draw period, the home equity line of credit is billed as a percentage of the then outstanding principal balance plus all accrued interest over a predetermined repayment period, as set forth in the note. Additionally, the Company has the option of renewing each line of credit for additional draw periods. Borrower qualifications include favorable credit history combined with supportive income requirements and combined loan to value ratios within established policy guidelines. •Other Consumer: Other consumer loan products include personal lines of credit and amortizing loans made to qualified individuals for various purposes such as debt consolidation, personal expenses or overdraft protection. Borrower qualifications include favorable credit history combined with supportive income and collateral requirements within established policy guidelines. These loans may be secured or unsecured. Credit Quality

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)

12 Months Ended

Dec. 31, 2023

The consolidated financial statements include the accounts of the Company, the Bank and other wholly-owned subsidiaries, except subsidiaries that are not deemed necessary to be consolidated. All significant intercompany balances and transactions have been eliminated in consolidation.

The Company determines whether it has a controlling financial interest in an entity by first evaluating whether the entity is a voting interest entity or a variable interest entity under GAAP. Voting interest entities are entities in which the total equity investment at risk is sufficient to enable the entity to finance itself independently and provides the equity holders with the obligation to absorb losses, the right to receive residual returns and the right to make decisions about the entity’s activities. The Company would consolidate voting interest entities in which it has all, or at least a majority of, the voting interest. As defined in applicable accounting standards, variable interest entities ("VIEs") are entities that lack one or more of the characteristics of a voting interest entity. A controlling financial interest in a VIE is present when the Company has both the power and ability to direct the activities of the VIE that most significantly impact the VIE's economic performance and an obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE.

The Company also owns the common stock of various trusts which have issued trust preferred securities. These trusts are VIEs in which the Company is not the primary beneficiary and, therefore, are not consolidated. The trust's only assets are junior subordinated debentures issued by the Company, which were acquired by the trust using the proceeds from the issuance of the trust preferred securities and common stock. The junior subordinated debentures are included in long-term debt and the Company’s equity interest in the trust is included in other assets in the accompanying Consolidated Balance Sheets. Interest expense on the junior subordinated debentures is reported in interest expense on long-term debt in the accompanying Consolidated Statements of Income.

RECLASSIFICATION

Reclassification

Certain previously reported amounts have been reclassified to conform to the current year’s presentation.

USE OF ESTIMATES

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could vary from these estimates. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of the allowance for expected credit losses on loans held for investment, income taxes, valuation and allowance for expected credit losses on investment securities, and the valuation of goodwill and other intangible assets and their respective analyses of impairment.

SIGNIFICANT CONCENTRATIONS OF CREDIT RISK

Concentrations of Credit Risk

The vast majority of the Bank’s lending activities are conducted in New England. The Bank originates commercial and industrial loans, commercial and residential real estate loans, including construction loans, small business loans, home equity loans, and other consumer loans for its portfolio. The Bank tracks concentrations of credit across numerous categories and segments based on aggregate credit exposure, which includes direct, indirect or contingent obligations to a borrower or group of borrowers engaged in one industry and by property type. The Bank considers a concentration to exist when aggregate credit exposure of a category or segment exceeds 25% of the Bank's total risk-based capital (inclusive of Tier 2 capital instruments).

CASH AND CASH EQUIVALENTS

Cash and Cash Equivalents

For purposes of reporting cash flows, cash and cash equivalents may include cash on hand, amounts due from banks, inclusive of interest-earning deposits held at banks, and federal funds sold. Generally, federal funds are sold for up to two week periods.

SECURITIES

Securities

Investment securities are classified at the time of purchase as available for sale, held to maturity, trading, or equity. Classification is constantly re-evaluated for consistency with corporate goals and objectives. Trading and equity securities are recorded at fair value with subsequent changes in fair value recorded in earnings. Debt securities that management has the positive intent and ability to hold to maturity are classified as held to maturity and recorded at amortized cost. Securities not classified as held to maturity or trading are classified as available for sale and recorded at fair value, with changes in fair value excluded from earnings and reported in other comprehensive income, net of related tax. Purchase premiums and discounts are recognized in interest income, using the interest method, to arrive at periodic interest income at a constant effective yield, thereby reflecting the securities market yield. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. Such gains and losses are recognized within non-interest income or non-interest expense within the consolidated statements of income.

Accrued interest receivable balances are excluded from the amortized cost of held to maturity securities and the fair value of available for sale securities and are included within other assets on the Consolidated Balance Sheets. Management has elected not to measure an allowance for credit losses on these balances as the Company employs a timely write-off policy. It is the Company's policy that a security is placed on nonaccrual status at the time any principal or interest payments become 90 days delinquent, and interest earned but not collected for a security placed on non-accrual is reversed against interest income.

Allowance for Credit Losses - Available for Sale Securities

The Company's available for sale securities are carried at fair value and assessed for estimated credit losses in accordance with the current expected credit loss ("CECL") methodology. For available for sale securities in an unrealized loss position, management will first evaluate whether there is intent to sell, or if it is more likely than not that the Company will be required to sell a security prior to anticipated recovery of its amortized cost basis. If either of these criteria are met, the Company will record a write-down of the security's amortized cost basis to fair value through income. For those available for sale securities which do not meet the intent or requirement to sell criteria, management will evaluate whether the decline in fair value is a result of credit related matters or other factors. In performing this assessment, management considers the

creditworthiness of the issuer including whether the security is guaranteed by the U.S. Federal Government or other government agency, the extent to which fair value is less than amortized cost, and changes in credit rating during the period, among other factors. If this assessment indicates the existence of credit losses, the security will be written down to fair value, as determined by a discounted cash flow analysis. To the extent the estimated cash flows do not support the amortized cost, the deficiency is considered to be due to credit loss and is recognized in earnings.

Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense. Losses are charged against the allowance when the uncollectibility of a security is confirmed, or when either of the aforementioned criteria surrounding intent or requirement to sell have been met.

Allowance for Credit Losses - Held to Maturity Securities

The Company measures expected credit losses on held to maturity securities on a collective basis by major security type in accordance with the CECL methodology. Management classifies the held to maturity portfolio into the following major security types: U.S. Government Agency, U.S. Treasury, Agency Mortgage-Backed Securities, Agency Collateralized Mortgage Obligations, Small Business Administration Pooled Securities, and Single Issuer Trust Preferred Securities. Securities in the Company's held to maturity portfolio are primarily guaranteed by either the U.S. Federal Government or other government sponsored agencies with a long history of no credit losses. As a result, management has determined these securities to have a zero loss expectation and therefore does not estimate an allowance for credit losses on these securities.

LOANS HELD FOR SALE

Loans Held for Sale

The Bank may choose to classify new residential real estate mortgage loans as held for sale based on intent, which is determined when loans are underwritten. Residential real estate mortgage loans not designated as held for sale are retained based upon available liquidity, for interest rate risk management and other business purposes.

The Company has elected the fair value option to account for originated closed loans intended for sale. Accordingly, changes in fair value relating to loans intended for sale are recorded in earnings and are offset by changes in fair value relating to interest rate lock commitments and forward sales commitments. Gains and losses on residential loan sales (sales proceeds minus carrying amount) are recorded in mortgage banking income. Upfront costs and fees related to items for which the fair value option is elected are recognized in earnings as incurred and are not deferred.

Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts

Allowance for Credit Losses - Loans Held for Investment

The allowance for credit losses is established based upon the Company's current estimate of expected lifetime credit losses on loans measured at amortized cost, also referred to as the CECL methodology. Credit losses are charged against the allowance when management's assessments confirm that the Company will not collect the full amortized cost basis of a loan. Subsequent recoveries, if any, are credited to the allowance.

Under the CECL methodology, the Company estimates credit losses for financial assets on a collective basis for loans sharing similar risk characteristics using a quantitative model combined with an assessment of certain qualitative factors designed to address forecast risk and model risk inherent in the quantitative model output. The quantitative model utilizes a factor based approach to estimate expected credit losses using Probability of Default ("PD"), Loss Given Default ("LGD") and Exposure at Default ("EAD"), which are derived from internal historical default and loss experience. The model estimates expected credit losses using loan level data over the estimated life of the exposure, considering the effect of prepayments. Economic forecasts are incorporated into the estimate over a reasonable and supportable forecast period, beyond which is a reversion to the Company's historical long-run average. Management has determined a reasonable and supportable period of 12 months, and a straight line reversion period of 6 months, to be appropriate for purposes of estimating expected credit losses. The qualitative risk factors impacting the expected risk of loss within the portfolio include the following:

•Lending policies and procedures

•Economic and business conditions

•Nature and volume of loans

•Changes in management

•Changes in credit quality

•Changes in loan review system

•Changes to underlying collateral values

•Concentrations of credit risk

•Model imprecision

•Other external factors

Loans that do not share similar risk characteristics with any pools of assets are subject to individual evaluation and are removed from the collectively assessed pools to avoid double counting. For the loans that are individually evaluated, the Company uses either a discounted cash flow (“DCF”) approach or a fair value of collateral approach. The latter approach is used for loans deemed to be collateral dependent or when foreclosure is probable.

Loan modifications made to borrowers experiencing financial difficulty are evaluated on a collective basis with loans sharing similar risk characteristics in accordance with the CECL methodology. Under previously applicable accounting guidance, the Company determined the amount of allowance for credit losses on TDRs using a discounted cash flow analysis or a fair value of collateral approach if the loan was determined to be individually evaluated. This change in methodology did not have a material impact on the Company's allowance for credit loss estimate.

Accrued interest receivable amounts are excluded from balances of loans held at amortized cost and are included within other assets on the consolidated balance sheets. Management has elected not to measure an allowance for credit losses on these amounts as the Company employs a timely write-off policy. Consistent with the Company's policy for nonaccrual loans, accrued interest receivable is typically written off when loans reach 90 days past due and are placed on nonaccrual status.

In the ordinary course of business, the Company enters into commitments to extend credit, commercial letters of credit, and standby letters of credit. Such financial instruments are recorded in the financial statements when they become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for credit losses. The reserve for unfunded lending commitments is included in other liabilities on the Consolidated Balance Sheets.

ACQUIRED LOANS

Acquired Loans

Loans acquired through purchase or a business combination are recorded at their fair value at the acquisition date. The Company performs an assessment of acquired loans to first determine if such loans have experienced a more than insignificant deterioration in credit quality since their origination and thus should be classified and accounted for as PCD loan. For loans that have not experienced a more than insignificant deterioration in credit quality since origination, referred to as non-PCD loans, the Company records such loans at fair value, with any resulting discount or premium accreted or amortized into interest income over the remaining life of the loan using the interest method. Additionally, upon the purchase or acquisition of non-PCD loans, the Company measures and records a reserve for credit losses based on the Company’s methodology for determining the allowance under CECL. The allowance for non-PCD loans is recorded through a charge to provision for credit losses in the period in which the loans were purchased or acquired.

Acquired loans that are classified as PCD are acquired at fair value, including any resulting discounts or premiums. Discounts and premiums are accreted or amortized into interest income over the remaining life of the loan using the interest method. In contrast to non-PCD loans, the initial allowance for credit losses on PCD loans is established through an adjustment to the acquired loan balance, rather than through a charge to provision for credit losses, in the period in which the loans were acquired. The allowance for PCD loans is determined based upon the Company's methodology for estimating the allowance under CECL, and is recorded as an adjustment to the acquired loan balance on the date of acquisition. The Company evaluates acquired loans for deterioration in credit quality based on a variety of characteristics, including, but not limited to non-accrual and delinquency status, downgrades in credit quality since origination, loans that have been modified, along with any other factors identified by the Company through its initial analysis of acquired loans which may indicate there has been a more than insignificant deterioration in credit quality since origination. At the acquisition date, an estimate of expected credit losses is made for groups of PCD loans with similar risk characteristics and individual PCD loans without similar risk characteristics, if applicable.

Subsequent to acquisition, the allowance for credit losses for both non-PCD and PCD loans are determined with the use of the Company’s allowance methodology under CECL, in the same manner as all other loans.

Transfers and Servicing of Financial Assets

Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.

Loans held for sale are generally sold with servicing rights released, however if rights are retained, servicing assets are recognized as separate assets. Servicing rights are originally recorded at fair value within other assets, but subsequently are amortized in proportion to and over the period of estimated net servicing income, and are assessed for impairment at each reporting date. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds, default rates and losses. Impairment is determined by stratifying the rights based on predominant characteristics, such as interest rate, loan type and investor type. Impairment is recognized through a valuation allowance, to the extent that fair value is less than the capitalized amount. If the Company later determines that all or a portion of the impairment no longer exists, a reduction of the allowance may be recorded as an increase to income.

Servicing fee income is recorded for fees earned for servicing loans for investors. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan, and are recorded as income when earned. The amortization of mortgage servicing rights is recorded as a reduction of loan servicing fee income.

The Company is also a party to certain instruments with off-balance-sheet risk including certain residential loans sold to investors with recourse. The Company's policy is to record such instruments when funded.

FEDERAL HOME LOAN BANK STOCK

Federal Home Loan Bank Stock

The Company, as a member of the Federal Home Loan Bank ("FHLB") of Boston, is required to maintain an investment in capital stock of the FHLB. Based on redemption provisions, the stock has no quoted market value and is carried at cost. The Company continually reviews its investment to determine if impairment exists. The Company reviews recent public filings, rating agency analysis and other factors when making its determination.

BANK PREMISES AND EQUIPMENT

Bank Premises and Equipment

Land is carried at cost. Bank premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line convention method over the estimated useful lives of the assets. Leasehold improvements are amortized over the shorter of the lease terms or the estimated useful lives of the improvements. Expected terms include lease option periods to the extent that the exercise of such options is reasonably assured, not to exceed fifteen years.

Leases

The Company leases office space, space for ATM and parking locations, and certain branch locations under noncancelable operating leases, several of which have renewal options to extend lease terms. Upon commencement of a new lease, the Company will recognize a right of use ("ROU") asset and corresponding lease liability. The Company makes the decision on whether to renew an option to extend a lease by considering various factors. The Company will recognize an adjustment to its ROU asset and lease liability when lease agreements are amended and executed, or in an event where the Company is reasonably certain that a renewal option will be exercised. The discount rate used in determining the present value of lease payments is based on the Company's incremental borrowing rate for borrowings with terms similar to each lease at commencement date. The Company has lease agreements with lease and non-lease components, which are generally accounted for separately. For real estate leases, non-lease components and other non-components, such as common area maintenance charges, real estate taxes, and insurance, are not included in the measurement of the lease liability since they are generally able to be segregated. The Company has elected the short-term lease recognition exemption for all leases that qualify. The Company may also assume lease obligations in connection with its acquisition activities, which may result in a market-based favorable or unfavorable lease position, resulting in an intangible lease asset. These intangible lease assets are amortized over the estimated remaining lease term.

The Company is a party to certain equipment lease transactions where it has assumed the role of lessor for purchased assets. These lease transactions are classified by the Company as either operating leases or direct financing leases for accounting purposes, depending upon the nature of the underlying lease agreements. Under operating lease arrangements, the leased asset value is recorded within fixed assets and the Company recognizes rental income over the life of the lease. Under direct financing lease arrangements, the leased asset value is de-recognized and offset with the recognition of a lease receivable that is evaluated for impairment in a manner similar to loans.

GOODWILL AND IDENTIABLE INTANGIBLE ASSETS

Goodwill and Other Intangible Assets

Goodwill represents the excess of the purchase price over the net fair value of acquired businesses. Goodwill is not amortized and is assigned to one reporting unit. Goodwill is evaluated for impairment at least annually, or more often if warranted. In assessing for impairment, the Company has the option to first perform a qualitative analysis to determine whether the existence of events or circumstances leads to a determination that it is more-likely-than-not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of such events and circumstances, the Company determines it is more-likely-than-not that the fair value is less than carrying value, a quantitative impairment test is performed to compare carrying value to the fair value of the reporting unit. The Company also has an unconditional option to bypass the assessment of qualitative factors for any period and proceed directly to the quantitative goodwill impairment test. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss will be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit.

Other intangible assets subject to amortization consist of core deposit intangibles, customer lists, and non-compete agreements that are amortized over the estimated lives of the intangibles using a method that approximates the amount of economic benefits that are realized by the Company. Other intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable.

IMPAIRMENT OF LONG-LIVED ASSETS OTHER THAN GOODWILL

Impairment of Long-Lived Assets Other Than Goodwill

The Company reviews long-lived assets, including premises and equipment, for impairment whenever events or changes in business circumstances indicate that the remaining useful life may warrant revision or that the carrying amount of the long-lived asset may not be fully recoverable. The Company performs an undiscounted cash flow analysis to determine if impairment exists. When impairment is determined to exist, the related impairment loss is calculated based on fair value. Impairment losses on assets to be disposed of are based on the estimated proceeds to be received, less costs of disposal.

CASH SURRENDER VALUE OF LIFE INSURANCE POLICIES

Cash Surrender Value of Life Insurance Policies

Increases in the cash surrender value ("CSV") of life insurance policies, as well as benefits received net of any CSV, are recorded in other noninterest income, and are generally not subject to income taxes. The CSV of the policies is recorded as an asset of the Bank, with liabilities recognized for any split dollar arrangements associated with the policies. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. Regulatory requirements limit the total amount of CSV to be held with any individual carrier to 15% of Tier 1 capital (as defined for regulatory purposes) and the total CSV of all life insurance policies is limited to 25% of Tier 1 capital.

OTHER REAL ESTATE OWNED AND OTHER FORECLOSED ASSETS

Other Real Estate Owned and Other Foreclosed Assets

Real estate properties and other assets, which have served as collateral to secure loans, are held for sale and are initially recorded at fair value less estimated costs to sell at the date control is established, resulting in a new cost basis. The amount by which the recorded investment in the loan exceeds the fair value (net of estimated costs to sell) of the foreclosed asset is charged to the allowance for credit losses. Subsequent declines in the fair value of the foreclosed asset below the new cost basis are recorded through the use of a valuation allowance. Subsequent increases in the fair value are recorded as reductions in the valuation allowance, but not below zero. Upon a sale of a foreclosed asset, any excess of the carrying value over the sale proceeds is recognized as a loss on sale. Any excess of sale proceeds over the carrying value of the foreclosed asset is first applied as a recovery to the valuation allowance, if any, with the remainder being recognized as a gain on sale. Operating expenses and changes in the valuation allowance relating to foreclosed assets are recorded in other noninterest expense.

DERIVATIVES

Derivatives

Derivative instruments are carried at fair value in the Company’s financial statements. The accounting for changes in the fair value of a derivative instrument is determined by whether it has been designated and qualifies as part of a hedging relationship, and further, by the type of hedging relationship. At the inception of a hedge, the Company documents certain items, including but not limited to the following: the relationship between hedging instruments and hedged items, the Company's risk management objectives, hedging strategies, and the evaluation of hedge transaction effectiveness. Documentation includes linking all derivatives designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific forecasted transactions.

For those derivative instruments that are designated and qualify for special hedge accounting, the Company designates the hedging instrument, based upon the exposure being hedged, as either a fair value hedge or a cash flow hedge. For derivative instruments that are designated and qualify as a cash flow hedge (i.e., hedging the exposure to variability in expected future cash flows that is attributable to a particular risk), the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income, net of related tax. The Company considers any economic mismatch between the hedging instrument and the hedged transaction in its ongoing assessment of hedge effectiveness. If the hedging instrument is not highly effective at achieving offsetting cash flows attributable to the revised contractually specified interest rate(s), hedge accounting will be discontinued. At that time, accumulated other comprehensive income would be frozen and amortized, as long as the forecasted transactions are still probable of occurring. For derivative instruments designated and qualifying as a fair value hedge (i.e., hedging the exposure to changes in the fair value of an asset or liability or an identified portion thereof that is attributable to the hedged risk), the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item attributable to the hedged risk, are recognized in current earnings during the period of the change in fair values. Hedge accounting is discontinued prospectively when (1) a derivative is no longer highly effective in offsetting changes in the fair value or cash flow of a hedged item, (2) a derivative expires or is settled, (3) it is no longer likely that a forecasted transaction associated with the hedge will occur, or (4) it is determined that designation of a derivative as a hedge is no longer appropriate.

To the extent the Company enters into new or re-designates existing hedging relationships, it is the Company's policy to include the Overnight Index Swap Rate based on the Fed Funds Effective Rate and the Overnight Index Swap Rate based on the Secured Overnight Financing Rate in the spectrum of available benchmark interest rates for hedge accounting.

For derivative instruments not designated as hedging instruments, such as loan level derivatives, foreign exchange contracts, risk participation agreements and mortgage derivatives, changes in fair value are recognized in other noninterest income during the period of change and are included in changes in other assets or other liabilities on the Company's consolidated statement of cash flows.

RETIREMENT PLANS

Retirement Plans

The Company has various retirement plans in place for current and former employees, including postretirement benefit plans, supplemental executive retirement plans, frozen multiemployer pension plans, deferred compensation plans, as well as other benefits.

The postretirement benefit plans and the supplemental executive retirement plans are unfunded and therefore have no plan assets. The actuarial cost method used to compute the benefit liabilities and related expense is the projected unit credit method. The projected benefit obligation is principally determined based on the present value of the projected benefit distributions at an assumed discount rate. The discount rate which is utilized is based on the investment yield of high quality corporate bonds available in the market place with maturities approximately equal to projected cash flows of future benefit payments as of the measurement date. Periodic benefit expense (or income) includes service costs and interest costs based on the assumed discount rate, amortization of prior service costs due to plan amendments and amortization of actuarial gains and losses. Service costs are included in salaries and employee benefits and all other costs are included in other noninterest expense. The amortization of actuarial gains and losses is determined using the 10% corridor minimum amortization approach and is taken over the average remaining future working lifetime of the plan participants. The underfunded status of the plans is recorded as a liability on the balance sheet.

The multiemployer pension plans' assets are determined based on fair value, generally representing observable market prices. The actuarial cost method used to compute the pension liabilities and related expense is the unit credit method. The pension expense is equal to the plan contribution requirement of the Company for the plan year.

In conjunction with the acquisition of Blue Hills Bancorp, Inc., parent of Blue Hills Bank (collectively "BHB") the Company acquired BHB's defined benefit pension plan, which is administered by the Savings Banks Employees Retirement Association. The Company accounts for the plan using an actuarial model that allocates pension costs over the service period of employees in the plan. The Company accounts for the over-funded or under-funded status of the plan as an asset or liability on its consolidated balance sheets and recognizes changes in the funded status that are not reflected in net periodic pension cost as other comprehensive income or loss. BHB amended its defined benefit pension plan in 2013 freezing the plan to new participants and subsequently amended the plan and froze it for all participants effective October 31, 2014.

The Director Deferred Compensation Plan allows directors to invest their funds into a diversified investment portfolio and the 401(k) Restoration Plan allows employees to invest their funds in both Company stock and other investment alternatives offered by the Plan. All funds under both of these plans are held in a rabbi trust. The plans do not permit

diversification after initial election and therefore elections made to defer into Company stock result in both the investment and obligation recognized within Stockholders' Equity. Alternatively, investments not in Company stock are included in trading securities, with the correlating obligation classified as a liability.

The Company has obligations with various individuals related to certain post-retirement benefits. The obligations are based on the individual's service through retirement, with the associated cost recognized over the requisite service period. The accrual methodology results in an accrued amount at the full eligibility date equal to the then present value of all of the future benefits expected to be paid.

STOCK-BASED COMPENSATION

Stock-Based Compensation

The Company recognizes stock-based compensation based on the grant-date fair value of the award, with no adjustment for estimated forfeitures, as forfeitures are recognized when they occur. For restricted stock awards and units, the Company recognizes compensation expense ratably over the vesting period for the fair value of the award, measured at the grant date. For stock option awards, the Company values awards granted using the Black-Scholes option-pricing model. The Company recognizes compensation expense for these awards on a straight-line basis over the requisite service period for the entire award (straight-line attribution method), ensuring that the amount of compensation cost recognized at any date at least equals the portion of the grant-date fair value of the award that is vested at that time. The Company recognizes excess tax benefits on certain stock compensation transactions. The excess tax benefits are recorded through earnings as a discrete item within the Company’s effective tax rate during the period of the transaction.

INCOME TAXES

Income Taxes

Deferred income tax assets and liabilities are determined using the asset and liability (or balance sheet) method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. If current available information raises doubt as to the realization of the deferred tax assets, a valuation allowance is established. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in enacted tax rates is recognized in income in the period that includes the enactment date. Income taxes are allocated to each entity in the consolidated group based on its share of taxable income. Management exercises significant judgment in evaluating the amount and timing of recognition of the resulting tax liabilities and assets, including projections of future taxable income. Additionally, a liability for unrecognized tax benefits is recorded for uncertain tax positions taken by the Company on its tax returns for which there is less than a 50% likelihood of being recognized upon a tax examination.

Low Income Housing Tax Credits Policy Text Block [Policy Text Block]

Low Income Housing Tax Credits

The Company accounts for its investments in qualified affordable housing projects using the proportional amortization method. Under the proportional amortization method the Company amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits received, and recognizes the net investment benefit as a component of income tax expense (benefit).

ASSETS UNDER ADMININSTRATION

Assets Under Administration

Assets held in a fiduciary or agency capacity for customers are not included in the accompanying consolidated balance sheet, as such assets are not assets of the Company. Revenue from administrative and management activities associated with these assets is recorded on an accrual basis.

Extinguishment of Debt [Policy Text Block]

Extinguishment of Debt

Upon extinguishment of an outstanding debt, the Company records the difference between the exit price and the net carrying amount of the debt as a gain or loss on the extinguishment. The gain or loss is recorded as a component of other noninterest income or other noninterest expense, respectively.

EARNINGS PER SHARE

Earnings Per Share

Basic earnings per share is calculated using the two-class method. The two-class method is an earnings allocation formula under which earnings per share is calculated from common stock and participating securities according to dividends

declared and participation rights in undistributed earnings. Under this method, all earnings, distributed and undistributed, are allocated to participating securities and common shares based on their respective rights to receive dividends. Unvested share-based payment awards that contain nonforfeitable rights to dividends are considered participating securities, not subject to performance based measures (i.e. unvested time-vested restricted stock). Basic earnings per share is calculated by dividing net income by the weighted average number of common shares outstanding (inclusive of participating securities). Diluted earnings per share have been calculated in a manner similar to that of basic earnings per share except that the weighted average number of common shares outstanding is increased to include the number of additional common shares that would have been outstanding if all potentially dilutive common shares (such as those resulting from the exercise of stock options or the attainment of performance measures) were issued during the period, computed using the treasury stock method.

COMPREHENSIVE INCOME

Comprehensive Income

Comprehensive income consists of net income and other comprehensive income. Other comprehensive income includes unrealized gains and losses on securities available for sale, unrealized losses related to factors other than credit on debt securities, if applicable, unrealized gains and losses on cash flow hedges, deferred gains on hedge accounting transactions, and changes in the funded status of the Company’s postretirement and supplemental retirement plans.

FAIR VALUE MEASUREMENTS

Fair Value Measurements

In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and the Company’s creditworthiness, among other things, as well as unobservable parameters.

Lessee, Leases [Policy Text Block]

New Accounting Pronouncements, Policy [Policy Text Block]

Recent Accounting Standards

FASB ASC Topic 740 "Income Taxes" Update No. 2023-09. Update No. 2023-09 was issued in December 2023 and aims to enhance the transparency and decision usefulness of income tax disclosures by requiring disaggregated information related to the effective tax rate reconciliation as well as information on income taxes paid. This standard is effective for annual periods beginning after December 15, 2024 and requires prospective application with the option to apply retrospectively. The adoption of this standard will not have an impact on the Company's financial statements.

Policy Loans Receivable, Policy

Loans Held for Investment

Loans that the Company has the intent and ability to hold until maturity or payoff are carried at amortized cost (net of the allowance for credit losses). Amortized cost is the principal amount outstanding, adjusted by partial charge-offs and net of deferred loan costs or fees. For originated loans, loan fees and certain direct origination costs are deferred and amortized into interest income over the expected term of the loan using the level-yield method. When a loan is paid off, the unamortized portion is recognized in interest income. Interest income on loans is accrued based upon the daily principal amount outstanding except for loans on nonaccrual status.

As a general rule, loans 90 days or more past due with respect to principal or interest are classified as nonaccrual loans, or sooner if management considers such action to be prudent. However, loans that are 90 days or more past due may be kept on an accruing status if the loan is well secured and in the process of collection. Income accruals are suspended on all nonaccrual loans in a timely manner and all previously accrued and uncollected interest is reversed against current income. A loan remains on nonaccrual status until it becomes current with respect to principal and interest and remains current for a minimum period of six months, the loan is liquidated, or when the loan is determined to be uncollectible and is charged-off against the allowance for credit losses. When doubt exists as to the collectability of a loan, any payments received are applied to reduce the amortized cost of the loan to the extent necessary to eliminate such doubt. For all loan portfolios, a charge-off occurs when the Company determines that a specific loan, or portion thereof, is uncollectible. This determination is made based on management's review of specific facts and circumstances of the individual loan, including assessing the viability of the customer’s business or project as a going concern, the expected cash flows to repay the loan, the value of the collateral and the ability and willingness of any guarantors to perform.

In the course of resolving problem loans, the Company may choose to modify the contractual terms of certain loans. The Company attempts to work out an alternative payment schedule with the borrower in order to avoid or cure a default. Terms may be modified to fit the ability of the borrower to repay in line with its current financial status and may include adjustments to term extensions, interest rates, other than insignificant payment delays and/or a combination thereof. These actions are intended to minimize economic loss and avoid foreclosure or repossession of collateral. If such efforts by the Bank

do not result in satisfactory performance, the loan is referred to legal counsel, at which time foreclosure proceedings are initiated. At any time prior to a sale of the property at foreclosure, the Bank may terminate foreclosure proceedings if the borrower is able to work out a satisfactory payment plan. Any loans that are modified are reviewed by the Company to determine whether the modification is the direct result of a borrower experiencing financial difficulty, as the Company adopted the accounting and disclosure requirements for loan modifications made to borrowers experiencing financial difficulty and ceased to recognize troubled debt restructurings ("TDRs") effective January 1, 2023. Prior to this adoption, the Company would classify loans as TDRs in cases where a borrower was experiencing financial difficult and where the Company made certain concessionary modifications to contractual terms. Modifications included adjustments to interest rates, extensions of maturity, consumer loans where the borrower's obligations had been effectively discharged through Chapter 7 Bankruptcy and the borrower had not reaffirmed the debt to the Bank, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. Under the previously applicable guidance, loans classified as TDRs would have remained classified as such for the life of the loan, except in limited circumstances, when it was determined that the borrower was performing under the modified terms and the restructuring agreement specified an interest rate greater than or equal to an acceptable market rate for a comparable new loan at the time of the restructuring.

Credit Loss, Financial Instrument

Commercial Portfolio

•Commercial and Industrial: Consists of revolving, non-revolving, and term loan obligations extended to business and corporate enterprises for the purpose of financing working capital and/or capital investment. Collateral generally consists of accounts receivable, inventory, plant and equipment, real estate, or other business assets. The primary source of repayment is operating cash flow and, secondarily, liquidation of assets.

•Commercial Real Estate: Consists of mortgage loans to finance investment in real property such as multi-family residential, commercial/retail, office, industrial, hotels, educational and healthcare facilities, as well as other specific use properties and is inclusive of owner-occupied commercial properties. Loans are typically written with amortizing payment structures. Collateral values are determined based upon third party appraisals and evaluations. Permissible loan to value ratios at origination are governed by Company policy and regulatory guidelines. The primary source of repayment is cash flow from operating leases and rents and, secondarily, liquidation of assets.

•Commercial Construction: Consists of short-term construction loans, revolving and nonrevolving credit lines and construction/permanent loans to finance the acquisition, development and construction or rehabilitation of real property. Project types include residential land development, one-to-four family, condominium, and multi-family home construction, commercial/retail, office, industrial, hotels, educational and healthcare facilities as well as other specific use properties. Loans may be written with nonamortizing or hybrid payment structures depending upon the type of project. Collateral values are determined based upon third party appraisals and evaluations. Permissible loan to value ratios at origination are governed by Company policy and regulatory guidelines. Repayment sources vary depending upon the type of project and may consist of proceeds from the sale or lease of units, operating cash flows or liquidation of other assets.

•Small Business: Consists of revolving, term loan and mortgage obligations extended to sole proprietors and small businesses for purposes of financing working capital and/or capital investment. Collateral generally consists of pledges of business assets including, but not limited to, accounts receivable, inventory, plant and equipment, or real estate if applicable. The primary source of repayment is operating cash flows and, secondarily, liquidation of assets.

For the commercial portfolio the Company typically obtains personal guarantees for payment from individuals holding material ownership interests in the borrowing entities.

Consumer Portfolio

•Residential Real Estate: Residential mortgage loans held in the Company’s portfolio are made to borrowers who demonstrate the ability to make scheduled payments with full consideration to underwriting factors such as current and expected income, employment status, current assets, other financial resources, credit history and the value of the collateral. Collateral consists of mortgage liens on one-to-four family residential properties. Residential mortgage loans also include loans to construct owner-occupied one-to-four family residential properties.

•Home Equity: Home equity loans and credit lines are made to qualified individuals and are primarily secured by senior or junior mortgage liens on one-to-four family homes, condominiums or vacation homes. Each home equity loan has a fixed rate and is billed in equal payments comprised of principal and interest. The majority of home equity lines of credit have a variable rate and are billed in interest-only payments during the draw period. At the end of the draw period, the home equity line of credit is billed as a percentage of the then outstanding principal balance plus all accrued interest over a predetermined repayment period, as set forth in the note. Additionally, the Company has the option of renewing each line of credit for additional draw periods. Borrower qualifications include favorable credit history combined with supportive income requirements and combined loan to value ratios within established policy guidelines.

•Other Consumer: Other consumer loan products include personal lines of credit and amortizing loans made to qualified individuals for various purposes such as debt consolidation, personal expenses or overdraft protection. Borrower qualifications include favorable credit history combined with supportive income and collateral requirements within established policy guidelines. These loans may be secured or unsecured.

Credit Quality