Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company’s Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and its Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) as well as the rules and interpretive releases of the U.S. Securities and Exchange Commission (“SEC”) under the authority of federal securities laws. The Consolidated Financial Statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which it holds a controlling financial interest through being the primary beneficiary or through holding a majority of the voting interest. All intercompany accounts and transactions have been eliminated in consolidation. Certain previously reported amounts have been reclassified to conform to the current period’s presentation. In addition, as a result of the decision to sell substantially all of the assets and transfer substantially all of the liabilities of Eastern Insurance Group, the Company reclassified certain amounts previously reported including: •certain components of noninterest income and noninterest expense previously reported in the insurance agency business were reclassified to net income from discontinued operations on the Consolidated Statements of Income; and •certain operating, investing, and financing cash flows previously reported on their applicable lines within the Consolidated Statements of Cash Flows were reclassified to cash flows used in/provided by operating activities of, investment activities of and financing activities of discontinued operations, respectively. The accompanying Consolidated Balance Sheet as of March 31, 2024, the Consolidated Statements of Income and Comprehensive Income and of Changes in Shareholders’ Equity for the three months ended March 31, 2024 and 2023 and Statements of Cash Flows for the three months ended March 31, 2024 and 2023 are unaudited. The Consolidated Balance Sheet as of December 31, 2023 was derived from the Audited Consolidated Financial Statements as of that date. The interim Consolidated Financial Statements and the accompanying notes should be read in conjunction with the annual Consolidated Financial Statements and the accompanying notes contained within the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (“2023 Form 10-K”), as filed with the SEC. In the opinion of management, the Company’s Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, any other interim periods, or any future year or period.
Use of Estimates	Use of Estimates In preparing the Consolidated Financial Statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheets and income and expenses for the periods reported. Actual results could differ from those estimates based on changing conditions, including economic conditions and future events. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, valuation and fair value measurements, the liabilities for benefit obligations (particularly pensions), the provision for income taxes and impairment of goodwill and other intangibles.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Relevant standards that were recently issued but not yet adopted as of March 31, 2024: In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements–Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”). The amendments in this update modify the disclosure or presentation requirements for a variety of topics in the codification. Certain amendments represent clarifications to or technical corrections of the current requirements. The following is a summary of the topics included in the update and which pertain to the Company: 1.Statement of cash flows (Topic 230): Requires an accounting policy disclosure in annual periods of where cash flows associated with derivative instruments and their related gains and loses are presented in the statement of cash flows; 2.Accounting changes and error corrections (Topic 250): Requires that when there has been a change in the reporting entity, the entity disclose any material prior-period adjustment and the effect of the adjustment on retained earnings in interim financial statements; 3.Earnings per share (Topic 260): Requires disclosure of the methods used in the diluted earnings-per-share computation for each dilutive security and clarifies that certain disclosures should be made during interim periods, and amends illustrative guidance to illustrate disclosure of the methods used in the diluted earnings per share computation; 4.Commitments (Topic 440): Requires disclosure of assets mortgaged, pledged, or otherwise subject to lien and the obligations collateralized; and 5.Debt (Topic 470): Requires disclosure of amounts and terms of unused lines of credit and unfunded commitments and the weighted-average interest rate on outstanding short-term borrowings. For public business entities, the amendments in ASU 2023-06 are effective on the date which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the related amendment will be removed from the codification and will not become effective for any entity. Early adoption is not permitted and the amendments are required to be applied on a prospective basis. The Company expects the adoption of this standard will not have a material impact on its Consolidated Financial Statements. In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in this update are intended to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. The amendments in this update: 1.Require that a public entity disclose, on an annual and interim basis, significant segment expenses that are regularly provided to the chief operating decision-maker (“CODM”) and included within each reported measure of segment profit or loss (collectively referred to as the “significant expense principle”). 2.Require that a public entity disclose, on an annual and interim basis, an amount for other segment items by reportable segment and a description of its composition. The other segment items category is the difference between segment revenue less the segment expenses disclosed under the significant expense principle and each reported measure of segment profit or loss. 3.Require that a public entity provide all annual disclosures about a reportable segment’s profit or loss and assets currently required by ASC 280, Segment Reporting in interim periods. 4.Clarify that if the CODM uses more than one measure of a segment’s profit or loss in assessing segment performance and deciding how to allocate resources, a public entity may report one or more of those additional measures of segment profit. However, at least one of the reported segment profit or loss measures (or the single reported measure, if only one is disclosed) should be the measure that is most consistent with the measurement principles used in measuring the corresponding amounts in the public entity’s consolidated financial statements. In other words, in addition to the measure that is most consistent with the measurement principles under U.S. GAAP, a public entity is not precluded from reporting additional measures of a segment’s profit or loss that are used by the CODM in assessing segment performance and deciding how to allocate resources. 5.Require that a public entity disclose the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources. 6.Require that a public entity that has a single reportable segment provide all the disclosures required by the amendments in this update and all existing segment disclosures in Topic 280. For public business entities, the amendments in ASU 2023-07 are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted and adoption is required to be done on a retrospective basis. The Company expects the adoption of this standard will not have a material impact on its Consolidated Financial Statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this update are intended to improve income tax disclosure requirements, primarily through enhanced disclosures related to the existing requirements to disclose a rate reconciliation, income taxes paid and certain other required disclosures. Specifically, the amendments in this update: 1.Require that a public entity disclose, on an annual basis: (1) specific categories in the rate reconciliation and (2) additional information for reconciling items that meet a quantitative threshold. The update requires disclosure of such reconciling items according to requirements indicated in the update. 2.Require that all entities disclose certain disaggregated information regarding income taxes paid. 3.Require that all entities disclose certain disaggregated information regarding income tax expense. 4.Eliminate the requirement to: (1) disclose the nature and estimate of the range of reasonably possible changes in the unrecognized tax benefits balance in the next 12 months or (2) make a statement that an estimate of the range cannot be made. 5.Remove the requirement to disclose the cumulative amount of each type of temporary difference when a deferred tax liability is not recognized because of exceptions to comprehensive recognition of deferred taxes related to subsidiaries and corporate joint ventures. For public business entities, the amendments in ASU 2023-09 are effective for annual periods beginning after December 15, 2024. Adoption should be done on a prospective basis and retrospective application is permitted. Relevant standards that were adopted during the three months ended March 31, 2024: In March 2023, the FASB issued ASU 2023-02, Investments–Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Tax Credit Structures Using the Proportional Amortization Method (“ASU 2023-02”). This update permits reporting entities to elect to account for their tax equity investments, regardless of the tax credit program from which the income tax credits are received, using the proportional amortization method if the following conditions are met: 1.It is probable that the income tax credits allocable to the tax equity investor will be available. 2.The tax equity investor does not have the ability to exercise significant influence over the operating and financial policies of the underlying project. 3.Substantially all of the projected benefits are from income tax credits and other income tax benefits. Projected benefits include income tax credits, other income tax benefits, and other non-income-tax-related benefits. The projected benefits are determined on a discounted basis, using a discount rate that is consistent with the cash flow assumptions used by the tax equity investor in making its decision to invest in the project. 4.The tax equity investor’s projected yield based solely on the cash flows from the income tax credits and other income tax benefits is positive. 5.The tax equity investor is a limited liability investor in the limited liability entity for both legal and tax purposes, and the tax equity investor’s liability is limited to its capital investment. Under existing accounting standards, the proportional amortization method is allowable only for equity investments in low-income-housing tax credit structures. Under the proportional amortization method, an entity amortizes the initial cost of the investment in proportion to the income tax credits and other income tax benefits received and recognizes the net amortization and income tax credits and other income tax benefits in the income statement as a component of income tax expense (benefit). Updates made by ASU 2023-02 allow a reporting entity to make an accounting policy election to apply the proportional amortization method on a tax-credit-program-by-tax-credit-program basis. The Company had previously made an accounting policy election to account for its investments in low-income-housing tax credit investments using the proportional amortization method. This election was made upon the Company’s adoption of ASU 2014-01, Investments–Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects, which introduced the option to apply proportional amortization to low-income-housing tax credit investments. The Company adopted this standard on January 1, 2024 and such adoption did not have a material impact on its Consolidated Financial Statements.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2024

The Company’s Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”) as set forth by the Financial Accounting Standards Board (“FASB”) and its Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) as well as the rules and interpretive releases of the U.S. Securities and Exchange Commission (“SEC”) under the authority of federal securities laws.

The Consolidated Financial Statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which it holds a controlling financial interest through being the primary beneficiary or through holding a majority of the voting interest. All intercompany accounts and transactions have been eliminated in consolidation.

Certain previously reported amounts have been reclassified to conform to the current period’s presentation. In addition, as a result of the decision to sell substantially all of the assets and transfer substantially all of the liabilities of Eastern Insurance Group, the Company reclassified certain amounts previously reported including:

•certain components of noninterest income and noninterest expense previously reported in the insurance agency business were reclassified to net income from discontinued operations on the Consolidated Statements of Income; and

•certain operating, investing, and financing cash flows previously reported on their applicable lines within the Consolidated Statements of Cash Flows were reclassified to cash flows used in/provided by operating activities of, investment activities of and financing activities of discontinued operations, respectively.

The accompanying Consolidated Balance Sheet as of March 31, 2024, the Consolidated Statements of Income and Comprehensive Income and of Changes in Shareholders’ Equity for the three months ended March 31, 2024 and 2023 and Statements of Cash Flows for the three months ended March 31, 2024 and 2023 are unaudited. The Consolidated Balance Sheet as of December 31, 2023 was derived from the Audited Consolidated Financial Statements as of that date. The interim Consolidated Financial Statements and the accompanying notes should be read in conjunction with the annual Consolidated Financial Statements and the accompanying notes contained within the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (“2023 Form 10-K”), as filed with the SEC. In the opinion of management, the Company’s Consolidated Financial Statements reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The results for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, any other interim periods, or any future year or period.

Use of Estimates

In preparing the Consolidated Financial Statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheets and income and expenses for the periods reported. Actual results could differ from those estimates based on changing conditions, including economic conditions and future events. Material estimates that are particularly susceptible to change relate to the determination of the allowance for credit losses, valuation and fair value measurements, the liabilities for benefit obligations (particularly pensions), the provision for income taxes and impairment of goodwill and other intangibles.

Recent Accounting Pronouncements

Relevant standards that were recently issued but not yet adopted as of March 31, 2024:

In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements–Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (“ASU 2023-06”). The amendments in this update modify the disclosure or presentation requirements for a variety of topics in the codification. Certain amendments represent clarifications to or technical corrections of the current requirements. The following is a summary of the topics included in the update and which pertain to the Company:

1.Statement of cash flows (Topic 230): Requires an accounting policy disclosure in annual periods of where cash flows associated with derivative instruments and their related gains and loses are presented in the statement of cash flows;

2.Accounting changes and error corrections (Topic 250): Requires that when there has been a change in the reporting entity, the entity disclose any material prior-period adjustment and the effect of the adjustment on retained earnings in interim financial statements;

3.Earnings per share (Topic 260): Requires disclosure of the methods used in the diluted earnings-per-share computation for each dilutive security and clarifies that certain disclosures should be made during interim periods, and amends illustrative guidance to illustrate disclosure of the methods used in the diluted earnings per share computation;

4.Commitments (Topic 440): Requires disclosure of assets mortgaged, pledged, or otherwise subject to lien and the obligations collateralized; and

5.Debt (Topic 470): Requires disclosure of amounts and terms of unused lines of credit and unfunded commitments and the weighted-average interest rate on outstanding short-term borrowings.

For public business entities, the amendments in ASU 2023-06 are effective on the date which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective. If by June 30, 2027, the SEC has not removed the applicable requirement from Regulation S-X or Regulation S-K, the pending content of the related amendment will be removed from the codification and will not become effective for any entity. Early adoption is not permitted and the amendments are required to be applied on a prospective basis. The Company expects the adoption of this standard will not have a material impact on its Consolidated Financial Statements.

In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. The amendments in this update are intended to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. The amendments in this update:

1.Require that a public entity disclose, on an annual and interim basis, significant segment expenses that are regularly provided to the chief operating decision-maker (“CODM”) and included within each reported measure of segment profit or loss (collectively referred to as the “significant expense principle”).

2.Require that a public entity disclose, on an annual and interim basis, an amount for other segment items by reportable segment and a description of its composition. The other segment items category is the difference between segment revenue less the segment expenses disclosed under the significant expense principle and each reported measure of segment profit or loss.

3.Require that a public entity provide all annual disclosures about a reportable segment’s profit or loss and assets currently required by ASC 280, Segment Reporting in interim periods.

4.Clarify that if the CODM uses more than one measure of a segment’s profit or loss in assessing segment performance and deciding how to allocate resources, a public entity may report one or more of those additional measures of segment profit. However, at least one of the reported segment profit or loss measures (or the single reported measure, if only one is disclosed) should be the measure that is most consistent with the measurement principles used in measuring the corresponding amounts in the public entity’s consolidated financial statements. In other words, in

addition to the measure that is most consistent with the measurement principles under U.S. GAAP, a public entity is not precluded from reporting additional measures of a segment’s profit or loss that are used by the CODM in assessing segment performance and deciding how to allocate resources.

5.Require that a public entity disclose the title and position of the CODM and an explanation of how the CODM uses the reported measure(s) of segment profit or loss in assessing segment performance and deciding how to allocate resources.

6.Require that a public entity that has a single reportable segment provide all the disclosures required by the amendments in this update and all existing segment disclosures in Topic 280.

For public business entities, the amendments in ASU 2023-07 are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted and adoption is required to be done on a retrospective basis. The Company expects the adoption of this standard will not have a material impact on its Consolidated Financial Statements.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in this update are intended to improve income tax disclosure requirements, primarily through enhanced disclosures related to the existing requirements to disclose a rate reconciliation, income taxes paid and certain other required disclosures. Specifically, the amendments in this update:

1.Require that a public entity disclose, on an annual basis: (1) specific categories in the rate reconciliation and (2) additional information for reconciling items that meet a quantitative threshold. The update requires disclosure of such reconciling items according to requirements indicated in the update.

2.Require that all entities disclose certain disaggregated information regarding income taxes paid.

3.Require that all entities disclose certain disaggregated information regarding income tax expense.

4.Eliminate the requirement to: (1) disclose the nature and estimate of the range of reasonably possible changes in the unrecognized tax benefits balance in the next 12 months or (2) make a statement that an estimate of the range cannot be made.

5.Remove the requirement to disclose the cumulative amount of each type of temporary difference when a deferred tax liability is not recognized because of exceptions to comprehensive recognition of deferred taxes related to subsidiaries and corporate joint ventures.

For public business entities, the amendments in ASU 2023-09 are effective for annual periods beginning after December 15, 2024. Adoption should be done on a prospective basis and retrospective application is permitted.

Relevant standards that were adopted during the three months ended March 31, 2024:

In March 2023, the FASB issued ASU 2023-02, Investments–Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Tax Credit Structures Using the Proportional Amortization Method (“ASU 2023-02”). This update permits reporting entities to elect to account for their tax equity investments, regardless of the tax credit program from which the income tax credits are received, using the proportional amortization method if the following conditions are met:

1.It is probable that the income tax credits allocable to the tax equity investor will be available.

2.The tax equity investor does not have the ability to exercise significant influence over the operating and financial policies of the underlying project.

3.Substantially all of the projected benefits are from income tax credits and other income tax benefits. Projected benefits include income tax credits, other income tax benefits, and other non-income-tax-related benefits. The projected benefits are determined on a discounted basis, using a discount rate that is consistent with the cash flow assumptions used by the tax equity investor in making its decision to invest in the project.

4.The tax equity investor’s projected yield based solely on the cash flows from the income tax credits and other income tax benefits is positive.

5.The tax equity investor is a limited liability investor in the limited liability entity for both legal and tax purposes, and the tax equity investor’s liability is limited to its capital investment.

Under existing accounting standards, the proportional amortization method is allowable only for equity investments in low-income-housing tax credit structures. Under the proportional amortization method, an entity amortizes the initial cost of the investment in proportion to the income tax credits and other income tax benefits received and recognizes the net amortization and income tax credits and other income tax benefits in the income statement as a component of income tax expense (benefit). Updates made by ASU 2023-02 allow a reporting entity to make an accounting policy election to apply the

proportional amortization method on a tax-credit-program-by-tax-credit-program basis. The Company had previously made an accounting policy election to account for its investments in low-income-housing tax credit investments using the proportional amortization method. This election was made upon the Company’s adoption of ASU 2014-01, Investments–Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects, which introduced the option to apply proportional amortization to low-income-housing tax credit investments. The Company adopted this standard on January 1, 2024 and such adoption did not have a material impact on its Consolidated Financial Statements.