Eastern Bankshares (EBC) 10-Q 10 May 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2022	May 04, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-39610
Entity Registrant Name	Eastern Bankshares, Inc.
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	84-4199750
Entity Address, Address Line One	265 Franklin Street
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02110
City Area Code	800
Local Phone Number	327-8376
Title of 12(b) Security	Common Stock
Trading Symbol	EBC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		182,674,973
Amendment Flag	false
Entity Central Index Key	0001810546
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1

Unaudited Consolidated Balance

Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
ASSETS
Cash and due from banks	$ 118,362	$ 144,634
Short-term investments	712,132	1,087,158
Cash and cash equivalents	830,494	1,231,792
Securities:
Available for sale (amortized cost $8,456,620 and $8,587,179, respectively)	7,917,305	8,511,224
Held to maturity (fair value $392,123 and $0, respectively)	395,434	0
Total securities	8,312,739	8,511,224
Loans held for sale	1,166	1,206
Loans:
Total loans	12,182,203	12,281,510
Less: allowance for loan losses	(124,166)	(97,787)
Less: unamortized premiums, net of unearned discounts and deferred fees	(24,434)	(26,442)
Net loans	12,033,603	12,157,281
Federal Home Loan Bank stock, at cost	10,904	10,904
Premises and equipment	73,180	80,984
Bank-owned life insurance	157,954	157,091
Goodwill and other intangibles, net	654,759	649,703
Deferred income taxes, net	183,137	76,535
Prepaid expenses	188,704	179,330
Other assets	389,432	456,078
Total assets	22,836,072	23,512,128
Deposits:
Demand	6,788,742	7,020,864
Interest checking accounts	4,662,134	4,478,566
Savings accounts	2,089,427	2,077,495
Money market investment	5,406,198	5,525,005
Certificates of deposit	446,315	526,381
Total deposits	19,392,816	19,628,311
Borrowed funds:
Federal Home Loan Bank advances	13,689	14,020
Escrow deposits of borrowers	21,233	20,258
Total borrowed funds	34,922	34,278
Other liabilities	399,942	443,187
Total liabilities	19,827,680	20,105,776
Commitments and contingencies (see footnote 12)
Shareholders’ equity
#REF!	1,834	1,863
Additional paid in capital	1,777,670	1,835,241
Unallocated common shares held by the Employee Stock Ownership Plan	(141,455)	(142,709)
Retained earnings	1,782,997	1,768,653
Accumulated other comprehensive loss, net of tax	(412,654)	(56,696)
Total shareholders’ equity	3,008,392	3,406,352
Total liabilities and shareholders’ equity	22,836,072	23,512,128
Commercial Portfolio Segment | Commercial and industrial
Loans:
Total loans	2,886,560	2,960,527
Less: allowance for loan losses	(26,841)	(18,018)
Commercial Portfolio Segment | Commercial real estate
Loans:
Total loans	4,609,824	4,522,513
Less: allowance for loan losses	(44,612)	(52,373)
Commercial Portfolio Segment | Commercial construction
Loans:
Total loans	246,093	222,328
Less: allowance for loan losses	(4,414)	(2,585)
Commercial Portfolio Segment | Business Banking
Loans:
Total loans	1,201,007	1,334,694
Less: allowance for loan losses	(17,269)	(10,983)
Residential Portfolio Segment | Residential real estate
Loans:
Total loans	1,936,182	1,926,810
Less: allowance for loan losses	(22,243)	(6,556)
Consumer Portfolio Segment | Consumer home equity
Loans:
Total loans	1,099,211	1,100,153
Less: allowance for loan losses	(6,018)	(3,722)
Consumer Portfolio Segment | Other consumer
Loans:
Total loans	$ 203,326	$ 214,485

Unaudited Consolidated Balanc_2

Unaudited Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Amortized Cost	$ 8,456,620,000	$ 8,587,179,000
Fair Value	$ 392,123,000	$ 0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock issued (in shares)	183,438,711	186,305,332
Common stock outstanding (in shares)	183,438,711	186,305,332

Unaudited Consolidated Statemen

Unaudited Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Interest and dividend income:
Interest and fees on loans	$ 101,367	$ 88,639
Taxable interest and dividends on securities	27,876	10,206
Non-taxable interest and dividends on securities	1,806	1,856
Interest on federal funds sold and other short-term investments	436	432
Total interest and dividend income	131,485	101,133
Interest expense:
Interest on deposits	3,322	1,002
Interest on borrowings	39	40
Total interest expense	3,361	1,042
Net interest income	128,124	100,091
Release of allowance for loan losses	(485)	(580)
Net interest income after provision for loan losses	128,609	100,671
Noninterest income:
Insurance commissions	28,713	28,147
Service charges on deposit accounts	8,537	5,367
Trust and investment advisory fees	6,141	5,663
Debit card processing fees	2,945	2,749
Interest rate swap income	2,932	5,405
(Losses) income from investments held in rabbi trusts	(4,433)	1,846
Gains on sales of mortgage loans held for sale, net	169	1,479
(Losses) gains on sales of securities available for sale, net	(2,172)	1,164
Other	3,583	3,392
Total noninterest income	46,415	55,212
Noninterest expense:
Salaries and employee benefits	69,526	64,040
Office occupancy and equipment	11,614	8,217
Data processing	15,320	12,129
Professional services	4,701	4,148
Marketing	1,574	1,691
Loan expenses	1,168	1,847
FDIC insurance	1,412	948
Amortization of intangible assets	827	532
Other	2,724	497
Total noninterest expense	108,866	94,049
Income before income tax expense	66,158	61,834
Income tax expense	14,642	14,171
Net income	$ 51,516	$ 47,663
Basic earnings per share (in dollars per share)	$ 0.30	$ 0.28
Diluted earnings per share (in dollars per share)	$ 0.30	$ 0.28

Unaudited Consolidated Statem_2

Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 51,516	$ 47,663
Other comprehensive loss, net of tax:
Net change in fair value of securities available for sale	(352,025)	(74,904)
Net change in fair value of cash flow hedges	(3,809)	(5,948)
Net change in other comprehensive income for defined benefit postretirement plans	(124)	426
Total other comprehensive loss	(355,958)	(80,426)
Total comprehensive loss	$ (304,442)	$ (32,763)

Unaudited Consolidated Statem_3

Unaudited Consolidated Statements of Changes in Shareholders Equity - USD ($) $ in Thousands	Total	Cumulative effect accounting adjustment	[1]	Common Stock	Additional Paid in Capital	Retained Earnings	Retained EarningsCumulative effect accounting adjustment	[1]	Accumulated Other Comprehensive Income (Loss)	Unallocated Common Stock Held by ESOP
Beginning balance (in shares) at Dec. 31, 2020				186,758,154
Beginning Balance at Dec. 31, 2020	$ 3,428,052			$ 1,868	$ 1,854,068	$ 1,665,607			$ 54,234	$ (147,725)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common shareholders	(10,324)					(10,324)
Net income	47,663					47,663
Other comprehensive loss, net of tax	(80,426)								(80,426)
ESOP shares committed to be released	2,080				827					1,253
Ending balance (in shares) at Mar. 31, 2021				186,758,154
Ending balance at Mar. 31, 2021	$ 3,387,045			$ 1,868	1,854,895	1,702,946			(26,192)	(146,472)
Beginning balance (in shares) at Dec. 31, 2021	186,305,332			186,305,332
Beginning Balance at Dec. 31, 2021	$ 3,406,352	$ (20,098)		$ 1,863	1,835,241	1,768,653	$ (20,098)		(56,696)	(142,709)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common shareholders	(17,074)					(17,074)
Repurchased common stock (in shares)				(2,866,621)
Repurchased common stock	(60,595)			$ (29)	(60,566)
Share-based compensation	1,623				1,623
Net income	51,516					51,516
Other comprehensive loss, net of tax	(355,958)								(355,958)
ESOP shares committed to be released	$ 2,626				1,372					1,254
Ending balance (in shares) at Mar. 31, 2022	183,438,711			183,438,711
Ending balance at Mar. 31, 2022	$ 3,008,392			$ 1,834	$ 1,777,670	$ 1,782,997			$ (412,654)	$ (141,455)
[1]	Represents gross transition adjustment amount of $28.0 million, net of taxes of $7.9 million, to reflect the cumulative impact on retained earnings pursuant to the Company’s adoption of Accounting Standards Update 2016-13. Refer to Note 4, “Loans and Allowance for Credit Losses” for additional discussion.

Unaudited Consolidated Statem_4

Unaudited Consolidated Statements of Changes in Shareholders Equity (Parenthetical) $ in Thousands	Dec. 31, 2021USD ($)
Retained earnings	$ 1,768,653
Cumulative effect accounting adjustment
Retained earnings	$ (28,000)

Unaudited Consolidated Statem_5

Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net income	$ 51,516	$ 47,663
Adjustments to reconcile net income to net cash provided by operating activities
Release of provision for loan losses	(485)	(580)
Depreciation and amortization	3,803	3,283
Accretion of deferred loan fees and premiums, net	(2,653)	(6,859)
Deferred income tax expense	14,129	5,118
Amortization of investment security premiums and discounts	4,669	3,277
Right-of-use asset amortization	3,272	2,862
Share-based compensation	1,623	0
Increase in cash surrender value of bank-owned life insurance	(863)	(549)
Loss (gain) on sale of securities available for sale, net	2,172	(1,164)
Amortization of gains from terminated interest rate swaps	(5,298)	(8,274)
Employee Stock Ownership Plan expense	2,626	2,080
Other	1,013	(8)
Change in:
Loans held for sale	40	(863)
Prepaid pension expense	(7,680)	838
Other assets	40,300	43,683
Other liabilities	(39,806)	(25,597)
Net cash provided by operating activities	68,378	64,910
Investing activities
Proceeds from sales of securities available for sale	232,561	23,236
Proceeds from maturities and principal paydowns of securities available for sale	362,680	214,085
Purchases of securities available for sale	(471,543)	(1,137,969)
Proceeds from maturities and principal paydowns of securities held to maturity	421	0
Purchases of securities held to maturity	(395,835)	0
Contributions to low income housing tax credit investments	(5,642)	(2,727)
Distributions from other equity investments	606	7
Net decrease (increase) in outstanding loans	99,847	(171,325)
Proceeds from life insurance policies	19,736	0
Acquisitions, net of cash and cash equivalents acquired	(5,200)	0
Purchased banking premises and equipment, net	(3,280)	(719)
Proceeds from sale of premises held for sale	8,390	736
Net cash used in investing activities	(157,259)	(1,074,676)
Financing activities
Net (decrease) increase in demand, savings, interest checking, and money market investment deposit accounts	(155,429)	840,423
Net decrease in time deposits	(80,066)	(15,332)
Net increase in borrowed funds	644	1,302
Contingent consideration paid	(63)	(41)
Payments for repurchases of common stock	(60,595)	0
Dividends declared and paid to common shareholders	(16,908)	(10,324)
Net cash provided by financing activities	(312,417)	816,028
Net (decrease) increase in cash, cash equivalents, and restricted cash	(401,298)	(193,738)
Cash, cash equivalents, and restricted cash at beginning of period	1,231,792	2,054,070
Cash, cash equivalents, and restricted cash at end of period	830,494	1,860,332
Supplemental disclosure of cash flow information
Interest paid	3,343	1,049
Income taxes	5,505	4,858
Non-cash activities
Net increase in capital commitments relating to low income housing tax credit projects	$ 530	$ 2,943

Corporate Structure and Nature

Corporate Structure and Nature of Operations; Basis of Presentation	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Corporate Structure and Nature of Operations; Basis of Presentation	Corporate Structure and Nature of Operations; Basis of Presentation Corporate Structure and Nature of Operations Eastern Bankshares, Inc., a Massachusetts corporation (the “Company”), is a bank holding company. Through its wholly-owned subsidiaries, Eastern Bank (the “Bank”) and Eastern Insurance Group LLC (“Eastern Insurance Group”), the Company provides a variety of banking, trust and investment, and insurance services, through its full-service bank branches and insurance offices, located primarily in Eastern Massachusetts, southern and coastal New Hampshire and Rhode Island. Eastern Insurance Group LLC is a wholly-owned subsidiary of the Bank. The activities of the Company are subject to the regulatory supervision of the Board of Governors of the Federal Reserve System (“Federal Reserve”). The activities of the Bank are subject to the regulatory supervision of the Massachusetts Commissioner of Banks, the Federal Deposit Insurance Corporation (“FDIC”) and the Consumer Financial Protection Bureau. The Company and the activities of the Bank and Eastern Insurance Group are also subject to various Massachusetts, New Hampshire and Rhode Island business and banking regulations. 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 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. The accompanying consolidated balance sheet as of March 31, 2022, the consolidated statements of income and comprehensive income and of changes in equity for the three months ended March 31, 2022 and 2021 and statement of cash flows for the three months ended March 31, 2022 and 2021 are unaudited. The consolidated balance sheet as of December 31, 2021 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, 2021 (“2021 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, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The following describes the Company’s use of estimates as well as relevant accounting pronouncements that were recently issued but not yet adopted as of March 31, 2022 and those that were adopted during the three months ended March 31, 2022. For a full discussion of significant accounting policies, refer to the notes included within the Company’s 2021 Form 10-K. 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, 2022: In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”). This update modifies how an acquiring entity measures contract assets and contract liabilities of an acquiree in a business combination in accordance with Topic 606. The amendments in this update require the acquiring entity in a business combination to account for revenue contracts as if they had originated the contract and assess how the acquiree accounted for the contract under Topic 606. ASU 2021-08 improves comparability of recognition and measurement of revenue contracts with customers both before and after a business combination. For public business entities, the amendments in this update are effective for fiscal years beginning after December 15, 2022. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023. The amendments in this update should be applied prospectively to business combinations occurring on or after the effective date of the amendments with early adoption permitted. The Company expects the adoption of this standard will not have a material impact on its consolidated financial statements. In March 2022, the FASB issued ASU 2022-02, Financial Instruments–Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures (“ASU 2022-02”). The amendments in this update eliminate the accounting guidance on troubled debt restructurings (“TDRs”) for creditors in ASC 310-40 and amends the guidance on vintage disclosures, referenced in ASC 326-20-50, to require disclosure of current-period gross write-offs by year of origination. This update supersedes the existing account guidance for TDRs in ASC 310-40 in its entirety and requires entities to evaluate all receivable modifications under existing accounting guidance in ASC 310-20 to determine whether a modification made to a borrower results in a new loan or a continuation of an existing loan. In addition to the elimination of TDR accounting guidance, entities that adopt this update no longer consider renewals, modification and extensions that result from reasonably expected TDRs in their calculation of the allowance for credit losses. Further, if an entity employs a discounted cash flow method to calculate the allowance for credit losses, it will be required to use a post-modification-derived effective interest rate as part of its calculation. The update also requires new disclosures for receivables for which there has been a modification in their contractual cash flows resulting from borrowers experiencing financial difficulties. For public business entities, the amendments in this update are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Entities may elect to apply the updated guidance on TDR recognition and measurement by using a modified retrospective transition method. The amendments on TDR disclosures and vintage disclosures should be adopted prospectively. The Company expects the adoption of this standard will not have a material impact on its consolidated financial statements. Relevant standards that were adopted during the three months ended March 31, 2022: In June 2016, the FASB issued ASU 2016-13, Financial Instruments–Credit Losses on Financial Instruments and relevant amendments (Topic 326) (“ASU 2016-13”). This update was created to replace the then-current GAAP method of calculating credit losses. Specifically, the standard replaces the existing incurred loss impairment guidance by requiring immediate recognition of expected credit losses. For financial assets carried at amortized cost that are held at the reporting date (including trade and other receivables, loans and commitments, held-to-maturity debt securities and other financial assets), credit losses are measured based on historical experience, current conditions and reasonable supportable forecasts. The standard also amends existing impairment guidance for available for sale securities, in which credit losses will be recorded as an allowance versus a write-down of the amortized cost basis of the security. It also allows for a reversal of impairment loss when the credit of the issuer improves. The guidance requires a cumulative effect of the initial application to be recognized in retained earnings at the date of initial application. In November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses (“ASU 2018-19”). The amendments in ASU 2018-19 were intended to clarify that receivables arising from operating leases are not within the scope of Subtopic 326-20. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with Topic 842, Leases . In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments – Credit Losses . This update requires entities to include expected recoveries of the amortized cost basis previously written off or expected to be written off in the valuation account for purchased financial assets with credit deterioration. In addition, the amendments in this update clarify and improve various aspects of the guidance for ASU 2016-13. On January 1, 2022, the Company adopted ASUs 2016-13, 2018-19 and 2019-11 (codified in ASC 326, “Financial Instruments-Credit Losses” ), which replaced the incurred loss methodology (codified in ASC 450, “Contingencies,” ASC 310, “Receivables” and ASC 320, “Debt Securities” ) with an expected loss methodology that is referred to as current expected credit losses methodology (“CECL methodology”). The Company adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost and off-balance sheet credit exposures by means of a cumulative-effect adjustment to the opening retained earnings balance on the Company’s consolidated balance sheet as of the Company’s date of adoption of January 1, 2022. Accordingly, results for reporting periods beginning after December 31, 2021 are presented under ASU 2016-13, while prior period amounts continue to be reported in accordance with previously applicable GAAP. The Company recorded a net decrease to retained earnings of $20.1 million, net of deferred taxes of $7.9 million, as of January 1, 2022, for the cumulative effect of adopting ASU 2016-13. The Company adopted ASU 2016-13 using the prospective transition approach for purchased credit-deteriorated (“PCD”) financial assets that were previously classified as purchased credit-impaired (“PCI”) financial assets and accounted for under ASC 310-30. In accordance with ASU 2016-13, the Company did not reassess whether its assets previously classified as PCI assets met the criteria of PCD assets as of the date of adoption. Rather, loans previously determined to be PCI loans are considered to be PCD loans as of January 1, 2022. On January 1, 2022, the amortized cost basis of the PCD assets was adjusted to reflect the addition of the allowance for loan losses on PCD loans. The remaining noncredit discount will be accreted into the Company’s interest income at the then-effective interest rate as of January 1, 2022. The amount of the adjustment for PCD assets was not material to the Company. In March 2020, the FASB issued ASU 2020-4, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). This update addresses optional expedients and exceptions for applying GAAP to certain contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The new guidance applies only to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships existing as of December 31, 2022, that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. For public and nonpublic entities, the guidance is effective as of March 12, 2020 through December 31, 2022 and does not apply to contract modifications made after December 31, 2022. The Company performed a review its contracts and existing processes to assess the risks and potential impact of the transition away from LIBOR and noted no material impact to the Company’s consolidated financial statements as of March 31, 2022. Significant Accounting Policies The adoption of the ASUs 2016-13, 2018-19 and 2019-11 resulted in changes in the Company’s accounting policies and estimates as it relates to available for sale securities, held to maturity securities, loans receivable and off-balance sheet commitments to lend. The following describes the changes to the Company’s significant accounting policies from December 31, 2021, that resulted from the adoption of the ASUs described above: Allowance for Credit Losses - Available for Sale Securities ASU 2016-13 made targeted changes to ASC 320 to eliminate the concept of “other than temporary” from the impairment loss estimation model for available for sale (“AFS”) securities. A summary of the changes made by the Company to the existing impairment model (previously referred to as the “OTTI” impairment model) as a result of adoption of ASU 2016-13 is as follows: • The use of an allowance approach, rather than a permanent write-down of a security’s cost basis upon determination of an impairment loss. • The amount of the allowance is limited to the amount at which the security’s fair value is less than its amortized cost basis. • The Company may not consider the length of time a security’s fair value has been less than amortized cost. • The Company may not consider recoveries in fair value after the balance sheet date when assessing whether a credit loss exists. The Company’s AFS securities are carried at fair value. For AFS securities in an unrealized loss position, management will first evaluate whether there is intent to sell a security, 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 AFS 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 security is determined to be uncollectible, or when either of the aforementioned criteria surrounding intent or requirement to sell have been met. On January 1, 2022, the date on which the Company adopted ASU 2016-13, no allowance for credit losses was recorded for AFS securities. Refer to Note 3, “Securities” for additional information regarding the measurement of impairment losses on AFS securities. Allowance for Credit Losses - Held to Maturity Securities The Company measures expected credit losses on held to maturity (“HTM”) securities on a collective basis by major security type which, as of March 31, 2022, includes government-sponsored residential and commercial mortgage-backed securities. Securities in the Company’s held to maturity portfolio are 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 that these securities have a zero loss expectation and therefore does not estimate an allowance for credit losses on these securities. The Company held no securities classified as held to maturity at December 31, 2021. Refer to Note 3, “Securities” for additional information regarding the measurement of credit losses on HTM securities. Allowance for Loan Losses - Loans Held for Investment Loans Individually Assessed for Impairment ASU 2016-13 indicates that a loan should be measured for impairment individually if that loan shares no similar risk characteristics with other loans. For the Company, loans which have been identified as those to be individually assessed for impairment under CECL include loans that do not share similar risk characteristics with other loans in the corresponding reserve segment. Characteristics of loans meeting this definition may include, but is not limited to: • Loans previously restructured and determined to be TDR loans; • Loans on non-accrual status; and • Loans with a risk rating of 12 under the Company’s risk rating scale, substandard (well-defined weakness) or worse. Collateral-Dependent Loans Management considers a loan to be collateral-dependent when foreclosure of the underlying collateral is probable. In addition, in accordance with ASU 2016-13, the Company elected to apply the collateral-dependent practical expedient whereby the Company measures expected credit losses using the fair value of the collateral, less any estimated costs to sell, when foreclosure is not probable but repayment of the loan is expected to be provided substantially through the operation or sale of the collateral, and the borrower is experiencing financial difficulty. Troubled Debt Restructured Loans In cases where a borrower experiences financial difficulties and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. Modifications may include adjustments to interest rates, extensions of maturity, consumer loans where the borrower’s obligations have been effectively discharged through Chapter 7 bankruptcy and the borrower has not reaffirmed the debt to the Company, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. Prior to the Company’s adoption of ASU 2016-13, all TDR loans were subject to a specific review for impairment loss each period beginning in the period in which the modification was executed. Subsequent to the adoption of ASU 2016-13, management identifies loans as TDR loans when it has a reasonable expectation that it will execute a TDR modification with a borrower. In addition, subsequent to adoption of ASU 2016-13, management estimates expected credit losses on a collective basis if a group of TDR loans share similar risk characteristics. If a TDR loan’s risk characteristics are not similar to those of any of the Company’s other TDR loans, expected credit losses on the TDR loan are measured individually. The impairment analysis discounts the present value of the anticipated cash flows by the loan’s contractual rate of interest in effect prior to the loan’s modification or the fair value of collateral if the loan is collateral dependent. The amount of credit loss, if any, is recorded as a specific loss allocation to each individual loan or as a loss allocation to the pool of loans, for those loans for which credit loss is measured on a collective basis, in the allowance for credit losses. Any commercial (commercial and industrial, commercial real estate, commercial construction, and business banking loans) or residential loan that has been classified as a TDR and which subsequently defaults is reviewed to determine if the loan should be deemed collateral-dependent. In such an instance, any shortfall between the value of the collateral and the book value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. The Company’s policy is to retain any restructured loan, which is on non-accrual status prior to being modified, on non-accrual status for approximately six months subsequent to being modified before the Company considers its return to accrual status. If the restructured loan is on accrual status prior to being modified, the Company reviews it to determine if the modified loan should remain on accrual status. Purchased Credit-Deteriorated Loans As described above, the Company applied the prospective transition approach with respect to PCD assets upon adoption of ASU 2016-13. Under this approach, loans previously determined to be PCI loans are considered to be PCD loans as of January 1, 2022. PCD loans are acquired individual loans (or acquired groups of loans with similar risk characteristics) that, as of the date of acquisition, have experienced a more-than-insignificant deterioration in credit quality since origination, as determined by the Company’s assessment. A PCD loan is recorded at its purchase price plus the allowance for loan losses expected at the time of acquisition, or “gross up” of the amortized cost basis, if any. Changes in the current estimate of the allowance for loan losses subsequent to acquisition from the estimated allowance previously recorded are recognized in the income statement as provision for credit losses or reversal of provision for credit losses in subsequent periods as they arise. A purchased loan that does not qualify as a PCD asset is accounted for similar to the Company’s method of accounting for originated assets, whereby an allowance for loan losses is recognized with a corresponding increase to the income statement provision for loan losses. Evidence that purchased loans, measured at amortized cost, have more-than-insignificant deterioration in credit quality since origination and, therefore meet the PCD definition, may include past-due status, non-accrual status, risk rating and other standard indicators (i.e., TDRs, charge-offs, bankruptcy). Allowance for Credit Losses Through December 31, 2021, the allowance for loan losses represented management’s best estimate of incurred probable losses in the Company’s loan portfolios based upon management’s assessment of various factors, including the risk characteristics of its loan portfolio, current economic conditions, and trends in loan delinquencies and charge-offs. The Company’s methodology for determining the qualitative component through December 31, 2021 included an assessment of factors affecting the determination of incurred losses in the loan portfolio. Such factors included trends in economic conditions, loan growth, credit underwriting policy exceptions, regulatory and audit findings, and peer comparisons, among others. Upon adoption of ASU 2016-13, effective January 1, 2022, the Company changed its reserve methodology to estimate expected credit losses over the contractual life of loans and leases. The allowance for credit losses, or ACL, is established to provide for the Company’s current estimate of expected lifetime credit losses on loans measured at amortized cost and unfunded lending commitments at the balance sheet date and is established through a provision for credit losses charged to net income. Credit losses are charged directly to the ACL. Subsequent recoveries, if any, are credited to the ACL. Commercial and residential loans are charged-off in the period in which they are deemed uncollectible. Delinquent loans in these product types are subject to ongoing review and analysis to determine if a charge-off in the current period is appropriate. For consumer finance loans, policies and procedures exist that require charge-off consideration upon a certain triggering event depending on the product type. Charge-off triggers include: 120 days delinquent for automobile, home equity, and other consumer loans with the exception of cash reserve loans for which the trigger is 150 days delinquent; death of the borrower; or Chapter 7 bankruptcy. In addition to those events, the charge-off determination includes other loan quality indicators, such as collateral position and adequacy or the presence of other repayment sources. The ACL is evaluated on a regular basis by management. Management uses a methodology to systematically estimate the amount of expected lifetime losses in the portfolio. Expected lifetime losses are estimated on a collective basis for loans sharing similar risk characteristics and are determined 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. For commercial and industrial, commercial real estate, commercial construction and business banking portfolios, the quantitative model uses a loan rating system which is comprised of management’s determination of a financial asset’s probability of default (“PD”), loss given default (“LGD”) and exposure at default (“EAD”), which are derived from historical loss experience and other factors. For residential real estate, consumer home equity and other consumer portfolios, the Company’s quantitative model uses historical loss experience. The quantitative 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 loss average. Management has determined that a reasonable and supportable forecast period of eight quarters, and a straight-line reversion period of four quarters, are appropriate forecast periods for purposes of estimating expected credit losses. As described above, quantitative model results are adjusted for risk factors not considered within the model but which are relevant in estimating the expected credit losses within the loan portfolio. The qualitative risk factors impacting the expected risk of loss within the loan portfolio include the following: • Lending policies and procedures, including underwriting standards and collection, charge-off and recovery practices; • Nature and volume of the portfolio; • Volume and severity of past-due, non-accrual and classified loans; • The value of the underlying collateral for loans that are not collateral dependent; • Concentrations of credit risk; • Model and data limitations; and • Other external factors, such as changes in legal, regulatory or competitive environments. 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. For loans that are individually evaluated, the Company uses either a discounted cash flow (“DCF”) approach or, for loans deemed to be collateral dependent or when foreclosure is probable, a fair value of collateral approach. Accrued interest receivable amounts are excluded from balances of loans held at amortized cost and are included within other assets on the consolidated balance sheet. 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 non-accrual loans, accrued interest receivable is typically written off when loans reach 90 days past due and are placed on non-accrual status. In the ordinary course of business, the Company enters into commitments to extend 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 reserving method for loans receivable previously described. The reserve for unfunded lending commitments is included in other liabilities in the balance sheet. Additionally, various regulatory agencies, as an integral part of the Company’s examination process, periodically assess the appropriateness of the allowance for credit losses and may require the Company to increase its allowance for loan losses or recognize further loan charge-offs, in accordance with GAAP. Refer to Note 4, “Loans and Allowance for Credit Losses” for additional information regarding the Company’s measurement of credit losses on loans receivable and off-balance sheet commitments to lend as of March 31, 2022. For comparative allowance for loan loss information for which ASC 450, “Contingencies” and ASC 310, “Receivables” were applied (i.e., prior to the Company’s adoption of the CECL methodology previously described), refer to Note 5, “Loans and Allowance for Loan Losses.”

Securities

Securities	3 Months Ended
	Mar. 31, 2022
Debt Securities [Abstract]
Securities	Securities Available for Sale Securities The amortized cost, gross unrealized gains and losses, allowance for credit losses and fair value of AFS securities as of March 31, 2022 and December 31, 2021 were as follows: As of March 31, 2022 Amortized Unrealized Unrealized Allowance for Credit Losses Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 5,329,748 $ 264 $ (360,666) $ — $ 4,969,346 Government-sponsored commercial mortgage-backed securities 1,707,131 — (91,204) — 1,615,927 U.S. Agency bonds 1,099,916 — (86,017) — 1,013,899 U.S. Treasury securities 59,458 — (3,223) — 56,235 State and municipal bonds and obligations 258,769 2,792 (1,245) — 260,316 Other debt securities 1,598 — (16) — 1,582 $ 8,456,620 $ 3,056 $ (542,371) $ — $ 7,917,305 As of December 31, 2021 Amortized Unrealized Unrealized Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 5,577,292 $ 17,918 $ (70,502) $ 5,524,708 Government-sponsored commercial mortgage-backed securities 1,420,748 760 (12,640) 1,408,868 U.S. Agency bonds 1,202,377 1,067 (28,430) 1,175,014 U.S. Treasury securities 89,434 5 (834) 88,605 State and municipal bonds and obligations 263,910 16,460 (41) 280,329 Small business administration pooled securities 31,821 282 — 32,103 Other debt securities 1,597 — — 1,597 $ 8,587,179 $ 36,492 $ (112,447) $ 8,511,224 The Company did not record a provision for credit losses on any AFS securities for the three months ended March 31, 2022. Accrued interest receivable on AFS securities totaled $13.8 million and $14.3 million as of March 31, 2022 and December 31, 2021, respectively, and is included within other assets on the consolidated balance sheets. The Company did not record any write-offs of accrued interest income on AFS securities during the three months ended March 31, 2022. No securities held by the Company were delinquent on contractual payments as of March 31, 2022, nor were any securities placed on non-accrual status for the period then ended. Gross realized gains from sales of AFS securities during the three months ended March 31, 2022 and 2021 were $1.0 million and $1.2 million, respectively. Gross realized losses from sales of AFS securities during the three months ended March 31, 2022 were $3.2 million. The Company had no significant gross realized losses from sales of AFS securities during the three months ended March 31, 2021. There was no OTTI recorded during the three months ended March 31, 2021. Prior to the Company’s adoption of ASU 2016-13, management prepared an estimate of the Company’s expected cash flows for AFS investment securities that potentially may be deemed to have been an OTTI. This estimate began with the contractual cash flows of the security which was then reduced by an estimate of probable credit losses associated with the security. When estimating the extent of probable losses on the securities, management considered the credit quality and the ability to pay of the underlying issuers. Indicators of diminished credit quality of the issuers included defaults, interest deferrals, or “payments in kind.” Management also considered those factors listed in the “Investments – Debt and Equity Securities” topic of the FASB ASC when estimating the ultimate realizability of the cash flows for each individual security. The resulting estimate of expected cash flows after considering credit was then subject to a present value computation using a discount rate equal to the current yield used to accrete the beneficial interest or the effective interest rate implicit in the security at the date of acquisition. If the present value of the estimated expected cash flows was less than the current amortized cost basis, an OTTI was considered to have occurred and the security was written down to the fair value indicated by the cash flow analysis. As part of the analysis, management considered whether it intended to sell the security or whether it was more than likely that it would be required to sell the security before the expected recovery of its amortized cost basis. Information pertaining to AFS securities with gross unrealized losses as of March 31, 2022, for which the Company did not recognize a provision for credit losses under CECL, and as of December 31, 2021, for which the Company did not deem to be OTTI under its prior methodology, aggregated by investment category and length of time that individual securities had been in a continuous loss position, follows: As of March 31, 2022 Less than 12 Months 12 Months or Longer Total # of Gross Fair Gross Fair Gross Fair (Dollars in thousands) Government-sponsored residential mortgage-backed securities 322 $ 223,347 $ 3,513,073 $ 137,319 $ 1,403,234 $ 360,666 $ 4,916,307 Government-sponsored commercial mortgage-backed securities 205 85,425 1,548,080 5,779 67,847 91,204 1,615,927 U.S. Agency bonds 37 12,573 226,708 73,444 787,191 86,017 1,013,899 U.S. Treasury securities 2 3,223 56,235 — — 3,223 56,235 State and municipal bonds and obligations 103 1,245 82,709 — — 1,245 82,709 Other debt securities 3 16 1,582 — — 16 1,582 672 $ 325,829 $ 5,428,387 $ 216,542 $ 2,258,272 $ 542,371 $ 7,686,659 As of December 31, 2021 Less than 12 Months 12 Months or Longer Total # of Gross Fair Gross Fair Gross Fair (Dollars in thousands) Government-sponsored residential mortgage-backed securities 264 $ 70,502 $ 4,615,457 $ — $ — $ 70,502 $ 4,615,457 Government-sponsored commercial mortgage-backed securities 165 12,218 1,102,444 422 15,682 12,640 1,118,126 U.S. Agency bonds 27 2,169 191,222 26,261 794,353 28,430 985,575 U.S. Treasury securities 3 834 78,588 — — 834 78,588 State and municipal bonds and obligations 11 41 5,436 — — 41 5,436 470 $ 85,764 $ 5,993,147 $ 26,683 $ 810,035 $ 112,447 $ 6,803,182 The Company does not intend to sell these investments and has determined based upon available evidence that it is more likely than not that the Company will not be required to sell each security before the expected recovery of its amortized cost basis. As a result, the Company did not recognize a provision for credit losses on these investments as of March 31, 2022. As it relates to securities with gross unrealized losses as of December 31, 2021, the Company did not consider these investments to be OTTI under its prior methodology. The Company made this determination by reviewing various qualitative and quantitative factors regarding each investment category, such as current market conditions, extent and nature of changes in fair value, issuer rating changes and trends, and volatility of earnings. As a result of the Company’s review of these qualitative and quantitative factors, the causes of the impairments listed in the tables above by category are as follows as of March 31, 2022 and December 31, 2021: • Government-sponsored residential mortgage-backed securities – The securities with unrealized losses in this portfolio have contractual terms that generally do not permit the issuer to settle the security at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Additionally, these securities are implicitly guaranteed by the U.S. government or one of its agencies. • Government-sponsored commercial mortgage-backed securities – The securities with unrealized losses in this portfolio have contractual terms that generally do not permit the issuer to settle the security at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Additionally, these securities are implicitly guaranteed by the U.S. government or one of its agencies. • U.S. Agency bonds – The securities with unrealized losses in this portfolio have contractual terms that generally do not permit the issuer to settle the security at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Additionally, these securities are implicitly guaranteed by the U.S. government or one of its agencies. • U.S. Treasury securities – The securities with unrealized losses in this portfolio have contractual terms that generally do not permit the issuer to settle the security at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Additionally, these securities are implicitly guaranteed by the U.S. government. • State and municipal bonds and obligations – The securities with unrealized losses in this portfolio have contractual terms that generally do not permit the issuer to settle the security at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. • Other debt securities – This securities portfolio consists of three foreign debt securities which are performing in accordance with the terms of the respective contractual agreements. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Held to Maturity Securities The amortized cost, gross unrealized gains and losses, and fair value of HTM securities as of March 31, 2022 were as follows: As of March 31, 2022 Amortized Unrealized Unrealized Allowance for Credit Losses Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 192,231 $ — $ (3,318) $ — $ 188,913 Government-sponsored commercial mortgage-backed securities 203,203 17 (10) — 203,210 $ 395,434 $ 17 $ (3,328) $ — $ 392,123 The Company held no HTM securities as of December 31, 2021. The Company did not record a provision for estimated credit losses on any HTM securities for the three months ended March 31, 2022. Accrued interest receivable on HTM securities totaled $0.8 million as of March 31, 2022 and is included within other assets on the consolidated balance sheets. The Company did not record any write-offs of accrued interest income on HTM securities during the three months ended March 31, 2022. No securities held by the Company were delinquent on contractual payments as of March 31, 2022, nor were any securities placed on non-accrual status for the period then ended. Available for Sale and Held to Maturity Securities Contractual Maturity The amortized cost and estimated fair value of AFS and HTM securities by contractual maturities as of March 31, 2022 and December 31, 2021 are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without prepayment penalties. The scheduled contractual maturities of AFS and HTM securities as of the dates indicated were as follows: As of March 31, 2022 Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (In thousands) Available for sale securities Government-sponsored residential mortgage-backed securities $ 1 $ 1 $ 20,992 $ 21,143 $ 832,510 $ 790,125 $ 4,476,245 $ 4,158,077 $ 5,329,748 $ 4,969,346 Government-sponsored commercial mortgage-backed securities — — 190,509 182,639 700,994 658,732 815,628 774,556 1,707,131 1,615,927 U.S. Agency bonds — — 578,810 537,301 521,106 476,598 — — 1,099,916 1,013,899 U.S. Treasury securities 10,000 9,955 49,458 46,280 — — — — 59,458 56,235 State and municipal bonds and obligations 4,659 4,653 36,766 36,723 68,574 68,850 148,770 150,090 258,769 260,316 Other debt securities 300 299 1,298 1,283 — — — — 1,598 1,582 Total available for sale securities 14,960 14,908 877,833 825,369 2,123,184 1,994,305 5,440,643 5,082,723 8,456,620 7,917,305 Held to maturity securities Government-sponsored residential mortgage-backed securities — — — — — — 192,231 188,913 192,231 188,913 Government-sponsored commercial mortgage-backed securities — — — — 203,203 203,210 — — 203,203 203,210 Total held to maturity securities — — — — 203,203 203,210 192,231 188,913 395,434 392,123 Total $ 14,960 $ 14,908 $ 877,833 $ 825,369 $ 2,326,387 $ 2,197,515 $ 5,632,874 $ 5,271,636 $ 8,852,054 $ 8,309,428 As of December 31, 2021 Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (In thousands) Available for sale securities Government-sponsored residential mortgage-backed securities $ — $ — $ 24,935 $ 25,962 $ 899,169 $ 892,029 $ 4,653,188 $ 4,606,717 $ 5,577,292 $ 5,524,708 Government-sponsored commercial mortgage-backed securities — — 139,095 137,755 387,177 378,414 894,476 892,699 1,420,748 1,408,868 U.S. Agency bonds 5,508 5,515 531,821 520,935 665,048 648,564 — — 1,202,377 1,175,014 U.S. Treasury securities 40,010 40,001 49,424 48,604 — — — — 89,434 88,605 State and municipal bonds and obligations 6,137 6,116 33,692 34,704 72,226 75,416 151,855 164,093 263,910 280,329 Small Business Administration pooled securities — — 4,062 4,092 — — 27,759 28,011 31,821 32,103 Other debt securities 300 300 1,297 1,297 — — — — 1,597 1,597 Total $ 51,955 $ 51,932 $ 784,326 $ 773,349 $ 2,023,620 $ 1,994,423 $ 5,727,278 $ 5,691,520 $ 8,587,179 $ 8,511,224 Securities Pledged as Collateral As of March 31, 2022 and December 31, 2021, securities with a carrying value of $491.2 million and $2.2 billion, respectively, were pledged to secure public deposits and for other purposes required by law. As of March 31, 2022 and December 31, 2021, deposits with associated pledged collateral included Eastern Wealth Management cash accounts and municipal accounts. At March 31, 2022 and December 31, 2021, the carrying value of securities pledged as collateral with respect to municipal accounts acquired from Century Bancorp, Inc. (“Century”) was approximately $461.9 million and $2.1 billion, respectively. During the first quarter of 2022, the Company eliminated certain pledging arrangements acquired from Century which resulted in the decrease in securities pledged at March 31, 2022 compared to December 31, 2021.

Loans and Allowance for Credit

Loans and Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Loans and Allowance for Credit Losses	Loans and Allowance for Credit Losses Loans The following table provides a summary of the Company’s loan portfolio as of the dates indicated: At March 31, At December 31, 2022 2021 (In thousands) Commercial and industrial $ 2,886,560 $ 2,960,527 Commercial real estate 4,609,824 4,522,513 Commercial construction 246,093 222,328 Business banking 1,201,007 1,334,694 Residential real estate 1,936,182 1,926,810 Consumer home equity 1,099,211 1,100,153 Other consumer 203,326 214,485 Gross loans before unamortized premiums, unearned discounts and deferred fees 12,182,203 12,281,510 Allowance for loan losses (1) (124,166) (97,787) Unamortized premiums, net of unearned discounts and deferred fees (24,434) (26,442) Loans after the allowance for loan losses, unamortized premiums, unearned discounts and deferred fees $ 12,033,603 $ 12,157,281 (1) The Company adopted ASU 2016-13 on January 1, 2022 with a modified retrospective approach. Accordingly, at March 31, 2022 the allowance for loan losses at was determined in accordance with ASC 326, “Financial Instruments-Credit Losses” and ASC 310, “Receivables,” as amended. At December 31, 2021 the allowance for loan losses was determined in accordance with ASC 450, “Contingencies” and ASC 310, “Receivables.” There are no other loan categories that exceed 10% of total loans not already reflected in the preceding table. The Company’s lending activities are conducted principally in the New England area with the exception of its Shared National Credit Program (“SNC Program”) portfolio. The Company participates in the SNC Program in an effort to improve its industry and geographical diversification. The SNC Program portfolio is included in the Company’s commercial and industrial portfolio. The SNC Program portfolio is defined as loan syndications with exposure over $100 million and with three or more lenders participating. Most loans originated by the Company are either collateralized by real estate or other assets or guaranteed by federal and local governmental authorities. The ability and willingness of the single-family residential and consumer borrowers to honor their repayment commitments is generally dependent on the level of overall economic activity within the borrowers’ geographic areas and real estate values. The ability and willingness of commercial real estate, commercial and industrial, and construction loan borrowers to honor their repayment commitments is generally dependent on the health of the real estate economy in the borrowers’ geographic areas and the general economy. Loans Pledged as Collateral The carrying value of loans pledged to secure advances from the Federal Home Loan Bank (“FHLB”) of Boston (“FHLBB”) were $3.0 billion and $2.6 billion March 31, 2022 and December 31, 2021, respectively. The balance of funds borrowed from the FHLBB were $13.7 million and $14.0 million at March 31, 2022 and December 31, 2021, respectively. The carrying value of loans pledged to secure advances from the Federal Reserve Bank (“FRB”) were $799.9 million and $784.0 million at March 31, 2022 and December 31, 2021, respectively. There were no funds borrowed from the FRB outstanding at March 31, 2022 and December 31, 2021. Serviced Loans At March 31, 2022 and December 31, 2021, mortgage loans partially or wholly-owned by others and serviced by the Company amounted to approximately $91.2 million and $95.8 million, respectively. Allowance for Loan Losses The allowance for loan losses is established to provide for management’s estimate of expected lifetime credit losses on loans measured at amortized cost at the balance sheet date and is established through a provision for loan losses charged to net income. Charge-offs, net of recoveries, are charged directly to the allowance. Commercial and residential loans are charged-off in the period in which they are deemed uncollectible. Delinquent loans in these product types are subject to ongoing review and analysis to determine if a charge-off in the current period is appropriate. For consumer loans, policies and procedures exist that require charge-off consideration upon a certain triggering event depending on the product type. The following table summarizes the change in the allowance for loan losses by loan category for the three months ended March 31, 2022: Three Months Ended March 31, 2022 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance, prior to adoption of ASU 2016-13 $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Cumulative effect of change in accounting principle (1) 11,533 (6,655) 1,485 6,160 13,489 1,857 (541) (242) 27,086 Charge-offs (1) — — (945) — — (661) — (1,607) Recoveries 250 14 — 928 10 4 179 — 1,385 (Release of) provision (2,959) (1,120) 344 143 2,188 435 484 — (485) Ending balance (2) $ 26,841 $ 44,612 $ 4,414 $ 17,269 $ 22,243 $ 6,018 $ 2,769 $ — $ 124,166 (1) Represents the adjustment needed to reflect the cumulative day one impact pursuant to the Company’s adoption of ASU 2016-13 (i.e., cumulative effect adjustment related the adoption of ASU 2016-13 as of January 1, 2022). The adjustment represents a $27.1 million increase to the allowance attributable to the change in accounting methodology for estimating the allowance for loan losses resulting from the Company’s adoption of the standard. The adjustment also includes the adjustment needed to reflect the day one reclassification of the Company’s PCI loan balances to PCD and the associated gross-up of $0.1 million, pursuant to the Company’s adoption of ASU 2016-13. (2) The balance of accrued interest receivable excluded from amortized cost and the calculation of the allowance for loan losses amounted to $31.4 million at March 31, 2022. Reserve for Unfunded Commitments Management evaluates the need for a reserve on unfunded lending commitments in a manner consistent with loans held for investment. Upon adoption of ASU 2016-13 on January 1, 2022, the Company recorded a transition adjustment related to the reserve for unfunded lending commitments of $1.0 million, resulting in a total reserve for unfunded lending commitments of $11.1 million as of January 1, 2022. As of March 31, 2022, the Company’s reserve for unfunded commitments was $10.4 million which is recorded within other liabilities. Portfolio Segmentation Management uses a methodology to systematically estimate the amount of expected losses in the portfolio. Commercial and industrial business banking, investment commercial real estate, and commercial and industrial loans are evaluated based upon loan-level risk characteristics, historical losses and other factors which form the basis for estimating expected losses. Other portfolios, including owner occupied commercial real estate, which includes commercial and industrial and business banking owner occupied commercial real estate, commercial construction, residential mortgages, home equity and consumer loans, are analyzed as groups taking into account delinquency ratios, and the Company’s and peer banks’ historical loss experience. For the purposes of estimating the allowance for loan losses, management segregates the loan portfolio into loan categories that share similar risk characteristics such as the purpose of the loan, repayment source, and collateral. These characteristics are considered when determining the appropriate level of the allowance for each category. Some examples of these risk characteristics unique to each loan category include: Commercial Lending Commercial and industrial : The primary risk associated with commercial and industrial loans is the ability of borrowers to achieve business results consistent with those projected at origination. Collateral frequently consists of a first lien position on business assets including, but not limited to accounts receivable, inventory, aircraft and equipment. The primary repayment source is operating cash flow and, secondarily, the liquidation of assets. Under its lending guidelines, the Company generally requires a corporate or personal guarantee from individuals that hold material ownership in the borrowing entity when the loan-to-value of a commercial and industrial loan is in excess of a specified threshold. Commercial real estate : Collateral values are established by independent third-party appraisals and evaluations. Primary repayment sources include operating income generated by the real estate, permanent debt refinancing, sale of the real estate and, secondarily, liquidation of the collateral. Under its lending guidelines, the Company generally requires a corporate or personal guarantee from individuals that hold material ownership in the borrowing entity when the loan-to-value of a commercial real estate loan is in excess of a specified threshold. Commercial construction : These loans are generally considered to present a higher degree of risk than other real estate loans and may be affected by a variety of factors, such as adverse changes in interest rates and the borrower’s ability to control costs and adhere to time schedules. Construction loans are underwritten utilizing feasibility studies, independent appraisal reviews, sensitivity analysis of absorption and lease rates and financial analysis of the developers and property owners. Construction loans are generally based upon estimates of costs and value associated with the completed project. Construction loan repayment is substantially dependent on the ability of the borrower to complete the project and obtain permanent financing. Business banking : These loans are typically secured by all business assets or commercial real estate. Business banking originations include traditionally underwritten loans as well as partially automated scored loans. Business banking scored loans are determined by utilizing the Company’s proprietary decision matrix that has a number of quantitative factors including, but not limited to, a guarantor’s credit score, industry risk, and time in business. The Company also engages in Small Business Association (“SBA”) lending, both in the business banking and commercial banking divisions. The SBA guarantees reduce the Company’s loss due to default and are considered a credit enhancement to the loan structure. Residential Lending These loans are made to borrowers who demonstrate the ability to repay principal and interest on a monthly basis. Underwriting considerations include, among others, income sources and their reliability, willingness to repay as evidenced by credit repayment history, financial resources (including cash reserves) and the value of the collateral. The Company maintains policy standards for minimum credit score and cash reserves and maximum loan to value consistent with a “prime” portfolio. Collateral consists of mortgage liens on 1-4 family residential dwellings. The Company does not originate or purchase sub-prime or other high-risk loans. Residential loans are originated either for sale to investors or retained in the Company’s loan portfolio. Decisions about whether to sell or retain residential loans are made based on the interest rate characteristics, pricing for loans in the secondary mortgage market, competitive factors and the Company’s capital needs. Consumer Lending Consumer home equity : Home equity lines of credit are granted for ten years with monthly interest-only repayment requirements. Full principal repayment is required at the end of the ten-year draw period. Home equity loans are term loans that require the monthly payment of principal and interest such that the loan will be fully amortized at maturity. Underwriting considerations are materially consistent with those utilized in residential real estate. Collateral consists of a senior or subordinate lien on owner-occupied residential property. Other consumer : The Company’s policy and underwriting in this category, which is comprised primarily of home improvement, automobile loans and aircraft loans, include the following factors, among others: income sources and reliability, credit histories, term of repayment, and collateral value, as applicable. These are typically granted on an unsecured basis, with the exception of aircraft and automobile loans. Credit Quality Commercial Lending Credit Quality The credit quality of the Company’s commercial loan portfolio is actively monitored and supported by a comprehensive credit approval process and all large dollar transactions are sent for approval to a committee of seasoned business line and credit professionals. The Company maintains an independent credit risk review function that reports directly to the Risk Management Committee of the Board of Directors. Credits that demonstrate significant deterioration in credit quality are transferred to a specialized group of experienced officers for individual attention. The Company monitors credit quality indicators and utilizes portfolio scorecards to assess the risk of its commercial portfolio. Specifically, the Company utilizes a 15-point credit risk-rating system to manage risk and identify potential problem loans. Under this point system, risk-rating assignments are based upon a number of quantitative and qualitative factors that are under continual review. Factors include cash flow, collateral coverage, liquidity, leverage, position within the industry, internal controls and management, financial reporting, and other considerations. Commercial loan risk ratings are (re)evaluated for each loan at least once-per-year. The risk-rating categories under the credit risk-rating system are defined as follows: 0 Risk Rating - Unrated Certain segments of the portfolios are not rated. These segments include aircraft loans, business banking scored loan products, and other commercial loans managed by exception. Loans within this unrated loan segment are monitored by delinquency status; and for lines of credit greater than $100,000 in exposure, an annual review is conducted which includes the review of the business score and loan and deposit account performance. The Company supplements performance data with current business credit scores for the business banking portfolio on a quarterly basis. Unrated commercial and business banking loans are generally restricted to commercial exposure of less than $1 million. Loans included in this category generally are not required to provide regular financial reporting or regular covenant monitoring. For purposes of estimating the allowance for loan losses, unrated loans are considered in the same manner as pass rated loans. 1-10 Risk Rating – Pass Loans with a risk rating of 1-10 are classified as “Pass” and are comprised of loans that range from “substantially risk free” which indicates borrowers of unquestioned credit standing, well-established national companies with a very strong financial condition, and loans fully secured by policy conforming cash levels, through “low pass” which indicates acceptable rated loans that may be experiencing weak cash flow, impending lease rollover or minor liquidity concerns. 11 Risk Rating – Special Mention (Potential Weakness) Loans to borrowers in this category exhibit potential weaknesses or downward trends deserving management’s close attention. While potentially weak, no loss of principal or interest is envisioned. Included in this category are borrowers who are performing as agreed, are weak when compared to industry standards, may be experiencing an interim loss and may be in declining industries. An element of asset quality, financial flexibility or management is below average. The Company does not consider borrowers within this category as new business prospects. Borrowers rated special mention may find it difficult to obtain alternative financing from traditional bank sources. 12 Risk Rating – Substandard (Well-Defined Weakness) Loans with a risk-rating of 12 exhibit well-defined weaknesses that, if not corrected, may jeopardize the orderly liquidation of the debt. A loan is classified as substandard if it is inadequately protected by the repayment capacity of the obligor or by the collateral pledged. Specifically, repayment under market rates and terms, or by the requirements under the existing loan documents, is in jeopardy, but no loss of principal or interest is envisioned. There is a possibility that a partial loss of principal and/or interest will occur in the future if the deficiencies are not corrected. Loss potential, while existing in the aggregate portfolio of substandard assets, does not have to exist in individual assets classified as substandard. Non-accrual is possible, but not mandatory, in this class. 13 Risk Rating – Doubtful (Loss Probable) Loans classified as doubtful have comparable weaknesses as found in the loans classified as substandard, with the added provision that such weaknesses make collection of the debt in full (based on currently existing facts, conditions and values) highly questionable and improbable. Serious problems exist such that a partial loss of principal is likely. The probability of loss exists, but because of reasonably specific pending factors that may work to strengthen the credit, estimated losses are deferred until a more exact status can be determined. Specific reserves will be the amount identified after specific review. Non-accrual is mandatory in this class. 14 Risk Rating – Loss Loans to borrowers in this category are deemed incapable of repayment. Loans to such borrowers are considered uncollectible and of such little value that continuance as active assets of the Company is not warranted. This classification does not mean that the loans have no recovery or salvage value, but rather, it is not practical or desirable to defer writing off these assets even though partial recovery may occur in the future. Loans in this category have a recorded investment of $0 at the time of the downgrade. Residential and Consumer Lending Credit Quality For the Company’s residential and consumer portfolios, the quality of the loan is best indicated by the repayment performance of an individual borrower. Updated appraisals, broker opinions of value and other collateral valuation methods are employed in the residential and consumer portfolios, typically for credits that are deteriorating. Delinquency status is determined using payment performance, while accrual status may be determined using a combination of payment performance, expected borrower viability and collateral value. Delinquent consumer loans are handled by a team of seasoned collection specialists. The following table details the amortized cost balances of the Company’s loan portfolios, presented by credit quality indicator and origination year as of March 31, 2022: 2022 2021 2020 2019 2018 Prior Revolving Loans Revolving Loans Converted to Term Loans (1) Total (In thousands) Commercial and industrial Pass $ 117,534 $ 566,764 $ 498,791 $ 231,968 $ 142,428 $ 689,728 $ 504,127 $ 686 $ 2,752,026 Special Mention — 886 — 514 278 4,459 51,581 — 57,718 Substandard — 11,302 3,756 340 23,031 8,275 790 346 47,840 Doubtful — 4,996 — — — 114 3,384 — 8,494 Loss — — — — — — — — — Total commercial and industrial 117,534 583,948 502,547 232,822 165,737 702,576 559,882 1,032 2,866,078 Commercial real estate Pass 378,744 845,405 641,300 676,903 495,084 1,304,769 43,970 3,478 4,389,653 Special Mention 26,613 — 16,142 3,796 19,562 19,776 — — 85,889 Substandard 29,903 58 4,663 1,654 38,038 49,327 8,000 — 131,643 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial real estate 435,260 845,463 662,105 682,353 552,684 1,373,872 51,970 3,478 4,607,185 Commercial construction Pass 3,623 124,777 59,181 32,857 — — 15,760 — 236,198 Special Mention — — 2,097 — — — — — 2,097 Substandard — — — 6,743 — — — — 6,743 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial construction 3,623 124,777 61,278 39,600 — — 15,760 — 245,038 Business banking Pass 54,881 309,961 200,726 141,974 69,341 285,849 77,782 3,436 1,143,950 Special Mention 2,174 2,176 3,219 9,152 7,181 14,498 1,908 — 40,308 Substandard — 464 1,617 4,993 564 9,542 1,244 680 19,104 Doubtful — — — 203 — 103 — — 306 Loss — — — — — — — — — Total business banking 57,055 312,601 205,562 156,322 77,086 309,992 80,934 4,116 1,203,668 Residential real estate Current and accruing 81,889 740,106 406,401 112,976 78,320 505,432 — — 1,925,124 30-89 days past due and accruing — 2,553 1,387 201 1,513 6,808 — — 12,462 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 129 582 784 6,761 — — 8,256 Total residential real estate 81,889 742,659 407,917 113,759 80,617 519,001 — — 1,945,842 Consumer home equity Current and accruing 15,321 12,792 6,903 6,448 26,582 91,599 929,383 1,788 1,090,816 30-89 days past due and accruing — 33 31 — 170 1,490 2,004 67 3,795 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 74 679 1,293 1,948 3,147 — 7,141 Total consumer home equity 15,321 12,825 7,008 7,127 28,045 95,037 934,534 1,855 1,101,752 Other consumer Current and accruing 15,652 39,868 22,534 25,531 33,967 33,664 15,295 — 186,511 30-89 days past due and accruing 12 107 76 117 449 429 — — 1,190 Accruing loans past 90 days due — — — — — — — — — Non-accrual — 95 27 37 174 172 — — 505 Total other consumer 15,664 40,070 22,637 25,685 34,590 34,265 15,295 — 188,206 Total $ 726,346 $ 2,662,343 $ 1,869,054 $ 1,257,668 $ 938,759 $ 3,034,743 $ 1,658,375 $ 10,481 $ 12,157,769 (1) The amounts presented represent the amortized cost as of March 31, 2022 of revolving loans that were converted to term loans during the three months ended March 31, 2022. Paycheck Protection Program (“PPP”) loans are included within the unrated category of the commercial and industrial and business banking portfolios in the tables above. Commercial and industrial PPP loans and business banking PPP loans amounted to $51.7 million and $89.5 million, respectively, at March 31, 2022 and $112.8 million and $218.6 million, respectively, at December 31, 2021 on a recorded investment basis. The Company does not have an allowance for loan losses for PPP loans as they are 100% guaranteed by the SBA. Asset Quality The Company manages its loan portfolio with careful monitoring. As a general rule, loans more than 90 days past due with respect to principal and interest are classified as non-accrual loans. Exceptions may be made if management believes that collateral held by the Company is clearly sufficient and in full satisfaction of both principal and interest. The Company may also use discretion regarding other loans over 90 days delinquent if the loan is well secured and in the process of collection. Non-accrual loans and loans that are more than 90 days past due but still accruing interest are considered non-performing loans. Non-accrual loans may be returned to an accrual status when principal and interest payments are no longer delinquent, and the risk characteristics of the loan have improved to the extent that there no longer exists a concern as to the collectability of principal and interest. Loans are considered past due based upon the number of days delinquent according to their contractual terms. A loan is expected to remain on non-accrual status until it becomes current with respect to principal and interest, the loan is liquidated, or the loan is determined to be uncollectible and is charged-off against the allowance for loan losses. The following tables show the age analysis of past due loans as of the dates indicated: As of March 31, 2022 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 146 $ — $ 1,994 $ 2,140 $ 2,863,938 $ 2,866,078 Commercial real estate 600 — 501 1,101 4,606,084 4,607,185 Commercial construction 6,743 — — 6,743 238,295 245,038 Business banking 4,599 875 3,294 8,768 1,194,900 1,203,668 Residential real estate 10,384 2,162 6,379 18,925 1,926,917 1,945,842 Consumer home equity 2,517 1,348 6,726 10,591 1,091,161 1,101,752 Other consumer 971 219 505 1,695 186,511 188,206 Total $ 25,960 $ 4,604 $ 19,399 $ 49,963 $ 12,107,806 $ 12,157,769 As of December 31, 2021 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 45 $ 31 $ 1,672 $ 1,748 $ 2,958,779 $ 2,960,527 Commercial real estate 25,931 — 1,196 27,127 4,495,386 4,522,513 Commercial construction — — — — 222,328 222,328 Business banking 5,043 1,793 4,640 11,476 1,323,218 1,334,694 Residential real estate 17,523 3,511 5,543 26,577 1,900,233 1,926,810 Consumer home equity 3,774 1,510 4,571 9,855 1,090,298 1,100,153 Other consumer 1,194 548 889 2,631 211,854 214,485 Total (1) $ 53,510 $ 7,393 $ 18,511 $ 79,414 $ 12,202,096 $ 12,281,510 (1) The amounts presented in the table above represent the recorded investment balance of loans as of December 31, 2021. The following table presents information regarding non-accrual loans as of the dates indicated: As of and for the Three Months Ended March 31, 2022 As of December 31, 2021 Non-Accrual Loans With ACL Non-Accrual Loans Without ACL (4) Total Non-Accrual Loans Amortized Cost of Loans >90 DPD and Still Accruing (2) Total Non-Accrual Loans (1) Recorded Investment >90 DPD and Still Accruing (In thousands) Commercial and industrial $ 3,496 $ 6,990 $ 10,486 $ — $ 12,400 $ — Commercial real estate — 501 501 — — 1,196 Commercial construction — — — — — — Business banking 6,410 522 6,932 — 8,230 — Residential real estate 8,256 — 8,256 — 6,681 769 Consumer home equity 7,141 — 7,141 — 4,732 25 Other consumer 505 — 505 — 950 — Total non-accrual loans $ 25,808 $ 8,013 $ 33,821 $ — $ 32,993 $ 1,990 (1) The amounts presented represent the recorded investment balance of loans as of December 31, 2021. (2) “DPD” indicated in the table above refers to “days past due.” (3) The amount of interest income recognized on non-accrual loans during the three months ended March 31, 2022 was not significant. (4) The loans on non-accrual status and without an ACL as of March 31, 2022, were primarily comprised of collateral dependent loans for which the fair value of the underlying loan collateral exceeded the loan carrying value. It is the Company’s policy to reverse any accrued interest when a loan is put on non-accrual status, and, as such, the Company did not record any interest income on non-accrual loans during the three months ended March 31, 2022. Accrued interest reversed against interest income for the three months ended March 31, 2022 was insignificant. For collateral values for residential mortgage and home equity loans, the Company relies primarily upon third-party valuation information from certified appraisers and values are generally based upon recent appraisals of the underlying collateral, brokers’ opinions based upon recent sales of comparable properties, estimated equipment auction or liquidation values less estimated costs to sell. As of March 31, 2022 and December 31, 2021, the Company had collateral-dependent residential mortgage and home equity loans totaling $0.8 million and $0.6 million, respectively. For collateral-dependent commercial loans, the amount of the allowance for loan losses is individually assessed based upon the fair value of the collateral. Various types of collateral are used, including real estate, inventory, equipment, accounts receivable, securities and cash, among others. For commercial real estate loans, the Company relies primarily upon third-party valuation information from certified appraisers and values are generally based upon recent appraisals of the underlying collateral, brokers’ opinions based upon recent sales of comparable properties, estimated equipment auction or liquidation values, income capitalization, or a combination of income capitalization and comparable sales. As of March 31, 2022 and December 31, 2021, the Company had collateral-dependent commercial loans totaling $11.6 million and $13.1 million, respectively. Appraisals for all loan types are obtained at the time of loan origination as part of the loan approval process and are updated at the time of a loan modification and/or refinance and as considered necessary by management for impairment review purposes. In addition, appraisals are updated as required by regulatory pronouncements. As of both March 31, 2022 and December 31, 2021, the Company had no residential real estate held in other real estate owned (“OREO”). As of both March 31, 2022 and December 31, 2021, there were no mortgage loans collateralized by residential real estate property for which formal foreclosure proceedings were in-process. In the normal course of business, the Company may become aware of possible credit problems in which borrowers exhibit potential for the inability to comply with the contractual terms of their loans, but which currently do not yet meet the criteria for classification as non-performing loans (which consist of non-accrual loans and loans that are more than 90 days past due but still accruing interest). Based upon the Company’s past experiences, some of the loans with potential weaknesses will ultimately be restructured or placed in non-accrual status. As of both March 31, 2022 and December 31, 2021, management is unable to reasonably estimate the amount of these loans that will be restructured or placed on non-accrual status. Troubled Debt Restructurings As described above in Note 2, “Summary of Significant Accounting Policies,” in cases where a borrower experiences financial difficulty and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. The process through which management identifies loans as TDR loans, the methodology employed to record any loan losses, and the calculation of any shortfall on collateral dependent loans, is also described above. In response to the novel coronavirus (“COVID-19”) pandemic, the Company has granted loan modifications to allow deferral of payments for borrowers negatively impacted by the COVID-19 pandemic. Modifications granted to customers allowed for full payment deferrals (principal and interest) or deferral of only principal payments. The balance of loans which underwent a modification and have not yet resumed payment as of March 31, 2022 and December 31, 2021 was $49.0 million and $106.7 million, respectively. The Company defines a modified loan to have resumed payment if it is one month past the modification end date and not more than 30 days past due. These modifications with active deferrals met the criteria of either Section 4013 of the CARES Act or the Interagency Statement on Loan Modifications and Reporting for Financial Institutions Working with Customers Affected by the Coronavirus (Revised) and therefore are not deemed troubled debt restructurings, or TDRs. Additionally, loans that are performing in accordance with the contractual terms of the modification are not reflected as being past due and therefore are not impacting non-accrual or delinquency totals as of March 31, 2022 and December 31, 2021. The Company continued to accrue interest on these COVID-19 modified loans and evaluated the deferred interest for collectability as of March 31, 2022 and December 31, 2021. The Consolidated Appropriations Act, which was enacted on December 27, 2020, extended certain provisions related to the COVID-19 pandemic in the United States (which were due to expire) and provided additional emergency relief to individuals and businesses. Included within the provisions of the Consolidated Appropriations Act is the extension to January 1, 2022 of Section 4013 of the CARES Act, which provides relief from a requirement to evaluate loans that had received a COVID-19 modification to determine if the loans required TDR treatment, provided certain criteria were met. As such, the Company applied the TDR relief granted pursuant to such section to any qualifying loan modification executed during the allowable time period. The Company’s policy is to have any TDR loan which is on non-accrual status prior to being modified remain on non-accrual status for approximately six months subsequent to being modified before management considers its return to accrual status. If the TDR loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. TDR loan information as of December 31, 2021 and the period then ended was prepared in accordance with U.S. GAAP effective for the Company as of December 31, 2021, or prior to our adoption of ASU 2016-13. The following tables show the TDR loans on accrual and non-accrual status as of the dates indicated: As of March 31, 2022 TDRs on Accrual Status TDRs on Non-Accrual Status Total TDRs Number of Loans Balanc

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Loans and Allowance for Loan Losses	Loans and Allowance for Credit Losses Loans The following table provides a summary of the Company’s loan portfolio as of the dates indicated: At March 31, At December 31, 2022 2021 (In thousands) Commercial and industrial $ 2,886,560 $ 2,960,527 Commercial real estate 4,609,824 4,522,513 Commercial construction 246,093 222,328 Business banking 1,201,007 1,334,694 Residential real estate 1,936,182 1,926,810 Consumer home equity 1,099,211 1,100,153 Other consumer 203,326 214,485 Gross loans before unamortized premiums, unearned discounts and deferred fees 12,182,203 12,281,510 Allowance for loan losses (1) (124,166) (97,787) Unamortized premiums, net of unearned discounts and deferred fees (24,434) (26,442) Loans after the allowance for loan losses, unamortized premiums, unearned discounts and deferred fees $ 12,033,603 $ 12,157,281 (1) The Company adopted ASU 2016-13 on January 1, 2022 with a modified retrospective approach. Accordingly, at March 31, 2022 the allowance for loan losses at was determined in accordance with ASC 326, “Financial Instruments-Credit Losses” and ASC 310, “Receivables,” as amended. At December 31, 2021 the allowance for loan losses was determined in accordance with ASC 450, “Contingencies” and ASC 310, “Receivables.” There are no other loan categories that exceed 10% of total loans not already reflected in the preceding table. The Company’s lending activities are conducted principally in the New England area with the exception of its Shared National Credit Program (“SNC Program”) portfolio. The Company participates in the SNC Program in an effort to improve its industry and geographical diversification. The SNC Program portfolio is included in the Company’s commercial and industrial portfolio. The SNC Program portfolio is defined as loan syndications with exposure over $100 million and with three or more lenders participating. Most loans originated by the Company are either collateralized by real estate or other assets or guaranteed by federal and local governmental authorities. The ability and willingness of the single-family residential and consumer borrowers to honor their repayment commitments is generally dependent on the level of overall economic activity within the borrowers’ geographic areas and real estate values. The ability and willingness of commercial real estate, commercial and industrial, and construction loan borrowers to honor their repayment commitments is generally dependent on the health of the real estate economy in the borrowers’ geographic areas and the general economy. Loans Pledged as Collateral The carrying value of loans pledged to secure advances from the Federal Home Loan Bank (“FHLB”) of Boston (“FHLBB”) were $3.0 billion and $2.6 billion March 31, 2022 and December 31, 2021, respectively. The balance of funds borrowed from the FHLBB were $13.7 million and $14.0 million at March 31, 2022 and December 31, 2021, respectively. The carrying value of loans pledged to secure advances from the Federal Reserve Bank (“FRB”) were $799.9 million and $784.0 million at March 31, 2022 and December 31, 2021, respectively. There were no funds borrowed from the FRB outstanding at March 31, 2022 and December 31, 2021. Serviced Loans At March 31, 2022 and December 31, 2021, mortgage loans partially or wholly-owned by others and serviced by the Company amounted to approximately $91.2 million and $95.8 million, respectively. Allowance for Loan Losses The allowance for loan losses is established to provide for management’s estimate of expected lifetime credit losses on loans measured at amortized cost at the balance sheet date and is established through a provision for loan losses charged to net income. Charge-offs, net of recoveries, are charged directly to the allowance. Commercial and residential loans are charged-off in the period in which they are deemed uncollectible. Delinquent loans in these product types are subject to ongoing review and analysis to determine if a charge-off in the current period is appropriate. For consumer loans, policies and procedures exist that require charge-off consideration upon a certain triggering event depending on the product type. The following table summarizes the change in the allowance for loan losses by loan category for the three months ended March 31, 2022: Three Months Ended March 31, 2022 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance, prior to adoption of ASU 2016-13 $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Cumulative effect of change in accounting principle (1) 11,533 (6,655) 1,485 6,160 13,489 1,857 (541) (242) 27,086 Charge-offs (1) — — (945) — — (661) — (1,607) Recoveries 250 14 — 928 10 4 179 — 1,385 (Release of) provision (2,959) (1,120) 344 143 2,188 435 484 — (485) Ending balance (2) $ 26,841 $ 44,612 $ 4,414 $ 17,269 $ 22,243 $ 6,018 $ 2,769 $ — $ 124,166 (1) Represents the adjustment needed to reflect the cumulative day one impact pursuant to the Company’s adoption of ASU 2016-13 (i.e., cumulative effect adjustment related the adoption of ASU 2016-13 as of January 1, 2022). The adjustment represents a $27.1 million increase to the allowance attributable to the change in accounting methodology for estimating the allowance for loan losses resulting from the Company’s adoption of the standard. The adjustment also includes the adjustment needed to reflect the day one reclassification of the Company’s PCI loan balances to PCD and the associated gross-up of $0.1 million, pursuant to the Company’s adoption of ASU 2016-13. (2) The balance of accrued interest receivable excluded from amortized cost and the calculation of the allowance for loan losses amounted to $31.4 million at March 31, 2022. Reserve for Unfunded Commitments Management evaluates the need for a reserve on unfunded lending commitments in a manner consistent with loans held for investment. Upon adoption of ASU 2016-13 on January 1, 2022, the Company recorded a transition adjustment related to the reserve for unfunded lending commitments of $1.0 million, resulting in a total reserve for unfunded lending commitments of $11.1 million as of January 1, 2022. As of March 31, 2022, the Company’s reserve for unfunded commitments was $10.4 million which is recorded within other liabilities. Portfolio Segmentation Management uses a methodology to systematically estimate the amount of expected losses in the portfolio. Commercial and industrial business banking, investment commercial real estate, and commercial and industrial loans are evaluated based upon loan-level risk characteristics, historical losses and other factors which form the basis for estimating expected losses. Other portfolios, including owner occupied commercial real estate, which includes commercial and industrial and business banking owner occupied commercial real estate, commercial construction, residential mortgages, home equity and consumer loans, are analyzed as groups taking into account delinquency ratios, and the Company’s and peer banks’ historical loss experience. For the purposes of estimating the allowance for loan losses, management segregates the loan portfolio into loan categories that share similar risk characteristics such as the purpose of the loan, repayment source, and collateral. These characteristics are considered when determining the appropriate level of the allowance for each category. Some examples of these risk characteristics unique to each loan category include: Commercial Lending Commercial and industrial : The primary risk associated with commercial and industrial loans is the ability of borrowers to achieve business results consistent with those projected at origination. Collateral frequently consists of a first lien position on business assets including, but not limited to accounts receivable, inventory, aircraft and equipment. The primary repayment source is operating cash flow and, secondarily, the liquidation of assets. Under its lending guidelines, the Company generally requires a corporate or personal guarantee from individuals that hold material ownership in the borrowing entity when the loan-to-value of a commercial and industrial loan is in excess of a specified threshold. Commercial real estate : Collateral values are established by independent third-party appraisals and evaluations. Primary repayment sources include operating income generated by the real estate, permanent debt refinancing, sale of the real estate and, secondarily, liquidation of the collateral. Under its lending guidelines, the Company generally requires a corporate or personal guarantee from individuals that hold material ownership in the borrowing entity when the loan-to-value of a commercial real estate loan is in excess of a specified threshold. Commercial construction : These loans are generally considered to present a higher degree of risk than other real estate loans and may be affected by a variety of factors, such as adverse changes in interest rates and the borrower’s ability to control costs and adhere to time schedules. Construction loans are underwritten utilizing feasibility studies, independent appraisal reviews, sensitivity analysis of absorption and lease rates and financial analysis of the developers and property owners. Construction loans are generally based upon estimates of costs and value associated with the completed project. Construction loan repayment is substantially dependent on the ability of the borrower to complete the project and obtain permanent financing. Business banking : These loans are typically secured by all business assets or commercial real estate. Business banking originations include traditionally underwritten loans as well as partially automated scored loans. Business banking scored loans are determined by utilizing the Company’s proprietary decision matrix that has a number of quantitative factors including, but not limited to, a guarantor’s credit score, industry risk, and time in business. The Company also engages in Small Business Association (“SBA”) lending, both in the business banking and commercial banking divisions. The SBA guarantees reduce the Company’s loss due to default and are considered a credit enhancement to the loan structure. Residential Lending These loans are made to borrowers who demonstrate the ability to repay principal and interest on a monthly basis. Underwriting considerations include, among others, income sources and their reliability, willingness to repay as evidenced by credit repayment history, financial resources (including cash reserves) and the value of the collateral. The Company maintains policy standards for minimum credit score and cash reserves and maximum loan to value consistent with a “prime” portfolio. Collateral consists of mortgage liens on 1-4 family residential dwellings. The Company does not originate or purchase sub-prime or other high-risk loans. Residential loans are originated either for sale to investors or retained in the Company’s loan portfolio. Decisions about whether to sell or retain residential loans are made based on the interest rate characteristics, pricing for loans in the secondary mortgage market, competitive factors and the Company’s capital needs. Consumer Lending Consumer home equity : Home equity lines of credit are granted for ten years with monthly interest-only repayment requirements. Full principal repayment is required at the end of the ten-year draw period. Home equity loans are term loans that require the monthly payment of principal and interest such that the loan will be fully amortized at maturity. Underwriting considerations are materially consistent with those utilized in residential real estate. Collateral consists of a senior or subordinate lien on owner-occupied residential property. Other consumer : The Company’s policy and underwriting in this category, which is comprised primarily of home improvement, automobile loans and aircraft loans, include the following factors, among others: income sources and reliability, credit histories, term of repayment, and collateral value, as applicable. These are typically granted on an unsecured basis, with the exception of aircraft and automobile loans. Credit Quality Commercial Lending Credit Quality The credit quality of the Company’s commercial loan portfolio is actively monitored and supported by a comprehensive credit approval process and all large dollar transactions are sent for approval to a committee of seasoned business line and credit professionals. The Company maintains an independent credit risk review function that reports directly to the Risk Management Committee of the Board of Directors. Credits that demonstrate significant deterioration in credit quality are transferred to a specialized group of experienced officers for individual attention. The Company monitors credit quality indicators and utilizes portfolio scorecards to assess the risk of its commercial portfolio. Specifically, the Company utilizes a 15-point credit risk-rating system to manage risk and identify potential problem loans. Under this point system, risk-rating assignments are based upon a number of quantitative and qualitative factors that are under continual review. Factors include cash flow, collateral coverage, liquidity, leverage, position within the industry, internal controls and management, financial reporting, and other considerations. Commercial loan risk ratings are (re)evaluated for each loan at least once-per-year. The risk-rating categories under the credit risk-rating system are defined as follows: 0 Risk Rating - Unrated Certain segments of the portfolios are not rated. These segments include aircraft loans, business banking scored loan products, and other commercial loans managed by exception. Loans within this unrated loan segment are monitored by delinquency status; and for lines of credit greater than $100,000 in exposure, an annual review is conducted which includes the review of the business score and loan and deposit account performance. The Company supplements performance data with current business credit scores for the business banking portfolio on a quarterly basis. Unrated commercial and business banking loans are generally restricted to commercial exposure of less than $1 million. Loans included in this category generally are not required to provide regular financial reporting or regular covenant monitoring. For purposes of estimating the allowance for loan losses, unrated loans are considered in the same manner as pass rated loans. 1-10 Risk Rating – Pass Loans with a risk rating of 1-10 are classified as “Pass” and are comprised of loans that range from “substantially risk free” which indicates borrowers of unquestioned credit standing, well-established national companies with a very strong financial condition, and loans fully secured by policy conforming cash levels, through “low pass” which indicates acceptable rated loans that may be experiencing weak cash flow, impending lease rollover or minor liquidity concerns. 11 Risk Rating – Special Mention (Potential Weakness) Loans to borrowers in this category exhibit potential weaknesses or downward trends deserving management’s close attention. While potentially weak, no loss of principal or interest is envisioned. Included in this category are borrowers who are performing as agreed, are weak when compared to industry standards, may be experiencing an interim loss and may be in declining industries. An element of asset quality, financial flexibility or management is below average. The Company does not consider borrowers within this category as new business prospects. Borrowers rated special mention may find it difficult to obtain alternative financing from traditional bank sources. 12 Risk Rating – Substandard (Well-Defined Weakness) Loans with a risk-rating of 12 exhibit well-defined weaknesses that, if not corrected, may jeopardize the orderly liquidation of the debt. A loan is classified as substandard if it is inadequately protected by the repayment capacity of the obligor or by the collateral pledged. Specifically, repayment under market rates and terms, or by the requirements under the existing loan documents, is in jeopardy, but no loss of principal or interest is envisioned. There is a possibility that a partial loss of principal and/or interest will occur in the future if the deficiencies are not corrected. Loss potential, while existing in the aggregate portfolio of substandard assets, does not have to exist in individual assets classified as substandard. Non-accrual is possible, but not mandatory, in this class. 13 Risk Rating – Doubtful (Loss Probable) Loans classified as doubtful have comparable weaknesses as found in the loans classified as substandard, with the added provision that such weaknesses make collection of the debt in full (based on currently existing facts, conditions and values) highly questionable and improbable. Serious problems exist such that a partial loss of principal is likely. The probability of loss exists, but because of reasonably specific pending factors that may work to strengthen the credit, estimated losses are deferred until a more exact status can be determined. Specific reserves will be the amount identified after specific review. Non-accrual is mandatory in this class. 14 Risk Rating – Loss Loans to borrowers in this category are deemed incapable of repayment. Loans to such borrowers are considered uncollectible and of such little value that continuance as active assets of the Company is not warranted. This classification does not mean that the loans have no recovery or salvage value, but rather, it is not practical or desirable to defer writing off these assets even though partial recovery may occur in the future. Loans in this category have a recorded investment of $0 at the time of the downgrade. Residential and Consumer Lending Credit Quality For the Company’s residential and consumer portfolios, the quality of the loan is best indicated by the repayment performance of an individual borrower. Updated appraisals, broker opinions of value and other collateral valuation methods are employed in the residential and consumer portfolios, typically for credits that are deteriorating. Delinquency status is determined using payment performance, while accrual status may be determined using a combination of payment performance, expected borrower viability and collateral value. Delinquent consumer loans are handled by a team of seasoned collection specialists. The following table details the amortized cost balances of the Company’s loan portfolios, presented by credit quality indicator and origination year as of March 31, 2022: 2022 2021 2020 2019 2018 Prior Revolving Loans Revolving Loans Converted to Term Loans (1) Total (In thousands) Commercial and industrial Pass $ 117,534 $ 566,764 $ 498,791 $ 231,968 $ 142,428 $ 689,728 $ 504,127 $ 686 $ 2,752,026 Special Mention — 886 — 514 278 4,459 51,581 — 57,718 Substandard — 11,302 3,756 340 23,031 8,275 790 346 47,840 Doubtful — 4,996 — — — 114 3,384 — 8,494 Loss — — — — — — — — — Total commercial and industrial 117,534 583,948 502,547 232,822 165,737 702,576 559,882 1,032 2,866,078 Commercial real estate Pass 378,744 845,405 641,300 676,903 495,084 1,304,769 43,970 3,478 4,389,653 Special Mention 26,613 — 16,142 3,796 19,562 19,776 — — 85,889 Substandard 29,903 58 4,663 1,654 38,038 49,327 8,000 — 131,643 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial real estate 435,260 845,463 662,105 682,353 552,684 1,373,872 51,970 3,478 4,607,185 Commercial construction Pass 3,623 124,777 59,181 32,857 — — 15,760 — 236,198 Special Mention — — 2,097 — — — — — 2,097 Substandard — — — 6,743 — — — — 6,743 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial construction 3,623 124,777 61,278 39,600 — — 15,760 — 245,038 Business banking Pass 54,881 309,961 200,726 141,974 69,341 285,849 77,782 3,436 1,143,950 Special Mention 2,174 2,176 3,219 9,152 7,181 14,498 1,908 — 40,308 Substandard — 464 1,617 4,993 564 9,542 1,244 680 19,104 Doubtful — — — 203 — 103 — — 306 Loss — — — — — — — — — Total business banking 57,055 312,601 205,562 156,322 77,086 309,992 80,934 4,116 1,203,668 Residential real estate Current and accruing 81,889 740,106 406,401 112,976 78,320 505,432 — — 1,925,124 30-89 days past due and accruing — 2,553 1,387 201 1,513 6,808 — — 12,462 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 129 582 784 6,761 — — 8,256 Total residential real estate 81,889 742,659 407,917 113,759 80,617 519,001 — — 1,945,842 Consumer home equity Current and accruing 15,321 12,792 6,903 6,448 26,582 91,599 929,383 1,788 1,090,816 30-89 days past due and accruing — 33 31 — 170 1,490 2,004 67 3,795 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 74 679 1,293 1,948 3,147 — 7,141 Total consumer home equity 15,321 12,825 7,008 7,127 28,045 95,037 934,534 1,855 1,101,752 Other consumer Current and accruing 15,652 39,868 22,534 25,531 33,967 33,664 15,295 — 186,511 30-89 days past due and accruing 12 107 76 117 449 429 — — 1,190 Accruing loans past 90 days due — — — — — — — — — Non-accrual — 95 27 37 174 172 — — 505 Total other consumer 15,664 40,070 22,637 25,685 34,590 34,265 15,295 — 188,206 Total $ 726,346 $ 2,662,343 $ 1,869,054 $ 1,257,668 $ 938,759 $ 3,034,743 $ 1,658,375 $ 10,481 $ 12,157,769 (1) The amounts presented represent the amortized cost as of March 31, 2022 of revolving loans that were converted to term loans during the three months ended March 31, 2022. Paycheck Protection Program (“PPP”) loans are included within the unrated category of the commercial and industrial and business banking portfolios in the tables above. Commercial and industrial PPP loans and business banking PPP loans amounted to $51.7 million and $89.5 million, respectively, at March 31, 2022 and $112.8 million and $218.6 million, respectively, at December 31, 2021 on a recorded investment basis. The Company does not have an allowance for loan losses for PPP loans as they are 100% guaranteed by the SBA. Asset Quality The Company manages its loan portfolio with careful monitoring. As a general rule, loans more than 90 days past due with respect to principal and interest are classified as non-accrual loans. Exceptions may be made if management believes that collateral held by the Company is clearly sufficient and in full satisfaction of both principal and interest. The Company may also use discretion regarding other loans over 90 days delinquent if the loan is well secured and in the process of collection. Non-accrual loans and loans that are more than 90 days past due but still accruing interest are considered non-performing loans. Non-accrual loans may be returned to an accrual status when principal and interest payments are no longer delinquent, and the risk characteristics of the loan have improved to the extent that there no longer exists a concern as to the collectability of principal and interest. Loans are considered past due based upon the number of days delinquent according to their contractual terms. A loan is expected to remain on non-accrual status until it becomes current with respect to principal and interest, the loan is liquidated, or the loan is determined to be uncollectible and is charged-off against the allowance for loan losses. The following tables show the age analysis of past due loans as of the dates indicated: As of March 31, 2022 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 146 $ — $ 1,994 $ 2,140 $ 2,863,938 $ 2,866,078 Commercial real estate 600 — 501 1,101 4,606,084 4,607,185 Commercial construction 6,743 — — 6,743 238,295 245,038 Business banking 4,599 875 3,294 8,768 1,194,900 1,203,668 Residential real estate 10,384 2,162 6,379 18,925 1,926,917 1,945,842 Consumer home equity 2,517 1,348 6,726 10,591 1,091,161 1,101,752 Other consumer 971 219 505 1,695 186,511 188,206 Total $ 25,960 $ 4,604 $ 19,399 $ 49,963 $ 12,107,806 $ 12,157,769 As of December 31, 2021 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 45 $ 31 $ 1,672 $ 1,748 $ 2,958,779 $ 2,960,527 Commercial real estate 25,931 — 1,196 27,127 4,495,386 4,522,513 Commercial construction — — — — 222,328 222,328 Business banking 5,043 1,793 4,640 11,476 1,323,218 1,334,694 Residential real estate 17,523 3,511 5,543 26,577 1,900,233 1,926,810 Consumer home equity 3,774 1,510 4,571 9,855 1,090,298 1,100,153 Other consumer 1,194 548 889 2,631 211,854 214,485 Total (1) $ 53,510 $ 7,393 $ 18,511 $ 79,414 $ 12,202,096 $ 12,281,510 (1) The amounts presented in the table above represent the recorded investment balance of loans as of December 31, 2021. The following table presents information regarding non-accrual loans as of the dates indicated: As of and for the Three Months Ended March 31, 2022 As of December 31, 2021 Non-Accrual Loans With ACL Non-Accrual Loans Without ACL (4) Total Non-Accrual Loans Amortized Cost of Loans >90 DPD and Still Accruing (2) Total Non-Accrual Loans (1) Recorded Investment >90 DPD and Still Accruing (In thousands) Commercial and industrial $ 3,496 $ 6,990 $ 10,486 $ — $ 12,400 $ — Commercial real estate — 501 501 — — 1,196 Commercial construction — — — — — — Business banking 6,410 522 6,932 — 8,230 — Residential real estate 8,256 — 8,256 — 6,681 769 Consumer home equity 7,141 — 7,141 — 4,732 25 Other consumer 505 — 505 — 950 — Total non-accrual loans $ 25,808 $ 8,013 $ 33,821 $ — $ 32,993 $ 1,990 (1) The amounts presented represent the recorded investment balance of loans as of December 31, 2021. (2) “DPD” indicated in the table above refers to “days past due.” (3) The amount of interest income recognized on non-accrual loans during the three months ended March 31, 2022 was not significant. (4) The loans on non-accrual status and without an ACL as of March 31, 2022, were primarily comprised of collateral dependent loans for which the fair value of the underlying loan collateral exceeded the loan carrying value. It is the Company’s policy to reverse any accrued interest when a loan is put on non-accrual status, and, as such, the Company did not record any interest income on non-accrual loans during the three months ended March 31, 2022. Accrued interest reversed against interest income for the three months ended March 31, 2022 was insignificant. For collateral values for residential mortgage and home equity loans, the Company relies primarily upon third-party valuation information from certified appraisers and values are generally based upon recent appraisals of the underlying collateral, brokers’ opinions based upon recent sales of comparable properties, estimated equipment auction or liquidation values less estimated costs to sell. As of March 31, 2022 and December 31, 2021, the Company had collateral-dependent residential mortgage and home equity loans totaling $0.8 million and $0.6 million, respectively. For collateral-dependent commercial loans, the amount of the allowance for loan losses is individually assessed based upon the fair value of the collateral. Various types of collateral are used, including real estate, inventory, equipment, accounts receivable, securities and cash, among others. For commercial real estate loans, the Company relies primarily upon third-party valuation information from certified appraisers and values are generally based upon recent appraisals of the underlying collateral, brokers’ opinions based upon recent sales of comparable properties, estimated equipment auction or liquidation values, income capitalization, or a combination of income capitalization and comparable sales. As of March 31, 2022 and December 31, 2021, the Company had collateral-dependent commercial loans totaling $11.6 million and $13.1 million, respectively. Appraisals for all loan types are obtained at the time of loan origination as part of the loan approval process and are updated at the time of a loan modification and/or refinance and as considered necessary by management for impairment review purposes. In addition, appraisals are updated as required by regulatory pronouncements. As of both March 31, 2022 and December 31, 2021, the Company had no residential real estate held in other real estate owned (“OREO”). As of both March 31, 2022 and December 31, 2021, there were no mortgage loans collateralized by residential real estate property for which formal foreclosure proceedings were in-process. In the normal course of business, the Company may become aware of possible credit problems in which borrowers exhibit potential for the inability to comply with the contractual terms of their loans, but which currently do not yet meet the criteria for classification as non-performing loans (which consist of non-accrual loans and loans that are more than 90 days past due but still accruing interest). Based upon the Company’s past experiences, some of the loans with potential weaknesses will ultimately be restructured or placed in non-accrual status. As of both March 31, 2022 and December 31, 2021, management is unable to reasonably estimate the amount of these loans that will be restructured or placed on non-accrual status. Troubled Debt Restructurings As described above in Note 2, “Summary of Significant Accounting Policies,” in cases where a borrower experiences financial difficulty and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. The process through which management identifies loans as TDR loans, the methodology employed to record any loan losses, and the calculation of any shortfall on collateral dependent loans, is also described above. In response to the novel coronavirus (“COVID-19”) pandemic, the Company has granted loan modifications to allow deferral of payments for borrowers negatively impacted by the COVID-19 pandemic. Modifications granted to customers allowed for full payment deferrals (principal and interest) or deferral of only principal payments. The balance of loans which underwent a modification and have not yet resumed payment as of March 31, 2022 and December 31, 2021 was $49.0 million and $106.7 million, respectively. The Company defines a modified loan to have resumed payment if it is one month past the modification end date and not more than 30 days past due. These modifications with active deferrals met the criteria of either Section 4013 of the CARES Act or the Interagency Statement on Loan Modifications and Reporting for Financial Institutions Working with Customers Affected by the Coronavirus (Revised) and therefore are not deemed troubled debt restructurings, or TDRs. Additionally, loans that are performing in accordance with the contractual terms of the modification are not reflected as being past due and therefore are not impacting non-accrual or delinquency totals as of March 31, 2022 and December 31, 2021. The Company continued to accrue interest on these COVID-19 modified loans and evaluated the deferred interest for collectability as of March 31, 2022 and December 31, 2021. The Consolidated Appropriations Act, which was enacted on December 27, 2020, extended certain provisions related to the COVID-19 pandemic in the United States (which were due to expire) and provided additional emergency relief to individuals and businesses. Included within the provisions of the Consolidated Appropriations Act is the extension to January 1, 2022 of Section 4013 of the CARES Act, which provides relief from a requirement to evaluate loans that had received a COVID-19 modification to determine if the loans required TDR treatment, provided certain criteria were met. As such, the Company applied the TDR relief granted pursuant to such section to any qualifying loan modification executed during the allowable time period. The Company’s policy is to have any TDR loan which is on non-accrual status prior to being modified remain on non-accrual status for approximately six months subsequent to being modified before management considers its return to accrual status. If the TDR loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. TDR loan information as of December 31, 2021 and the period then ended was prepared in accordance with U.S. GAAP effective for the Company as of December 31, 2021, or prior to our adoption of ASU 2016-13. The following tables show the TDR loans on accrual and non-accrual status as of the dates indicated: As of March 31, 2022 TDRs on Accrual Status TDRs on Non-Accrual Status Total TDRs Number of Loans Balanc

Leases

Leases	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Leases	Leases The Company leases certain office space and equipment under various non-cancelable operating leases. These leases have original terms ranging from 1 year to 25 years. Operating lease liabilities and right-of-use (“ROU”) assets are recognized at the lease commencement date based upon the present value of the future minimum lease payments over the lease term. Operating lease liabilities are recorded within other liabilities and ROU assets are recorded within other assets in the Company’s consolidated balance sheets. As of the dates indicated, the Company had the following related to operating leases: As of March 31, 2022 As of December 31, 2021 (In thousands) Right-of-use assets $ 80,408 $ 83,821 Lease liabilities 85,573 89,296 Finance leases are not material. Finance lease liabilities are recorded within other liabilities and finance ROU assets are recorded within other assets in the Company’s consolidated balance sheets. The following tables are a summary of the Company’s components of net lease cost for the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Operating lease cost $ 3,694 $ 3,561 Finance lease cost 88 31 Variable lease cost 829 490 Total lease cost $ 4,611 $ 4,082 During the three months ended March 31, 2022 and 2021 the Company made $4.7 million and $3.6 million, respectively, in cash payments for operating and finance lease payments. Supplemental balance sheet information related to operating leases are as follows: As of March 31, 2022 As of December 31, 2021 Weighted-average remaining lease term (in years) 7.65 7.83 Weighted-average discount rate 2.54 % 2.52 %
Leases	Leases The Company leases certain office space and equipment under various non-cancelable operating leases. These leases have original terms ranging from 1 year to 25 years. Operating lease liabilities and right-of-use (“ROU”) assets are recognized at the lease commencement date based upon the present value of the future minimum lease payments over the lease term. Operating lease liabilities are recorded within other liabilities and ROU assets are recorded within other assets in the Company’s consolidated balance sheets. As of the dates indicated, the Company had the following related to operating leases: As of March 31, 2022 As of December 31, 2021 (In thousands) Right-of-use assets $ 80,408 $ 83,821 Lease liabilities 85,573 89,296 Finance leases are not material. Finance lease liabilities are recorded within other liabilities and finance ROU assets are recorded within other assets in the Company’s consolidated balance sheets. The following tables are a summary of the Company’s components of net lease cost for the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Operating lease cost $ 3,694 $ 3,561 Finance lease cost 88 31 Variable lease cost 829 490 Total lease cost $ 4,611 $ 4,082 During the three months ended March 31, 2022 and 2021 the Company made $4.7 million and $3.6 million, respectively, in cash payments for operating and finance lease payments. Supplemental balance sheet information related to operating leases are as follows: As of March 31, 2022 As of December 31, 2021 Weighted-average remaining lease term (in years) 7.65 7.83 Weighted-average discount rate 2.54 % 2.52 %

Goodwill and Other Intangibles

Goodwill and Other Intangibles	3 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangibles	Goodwill and Other Intangibles The following tables set forth the carrying amount of goodwill and other intangible assets, net of accumulated amortization, by reporting unit at the dates indicated below: As of March 31, 2022 Banking Insurance Net (In thousands) Balances not subject to amortization Goodwill $ 557,635 $ 77,144 $ 634,779 Balances subject to amortization Insurance agency (1) — 8,708 8,708 Core deposit intangible 11,272 — 11,272 Total other intangible assets 11,272 8,708 19,980 Total goodwill and other intangible assets $ 568,907 $ 85,852 $ 654,759 (1) Insurance agency intangible assets include customer list, non-compete agreement and supplier relationship intangible assets. As of December 31, 2021 Banking Insurance Net (In thousands) Balances not subject to amortization Goodwill $ 557,635 $ 73,861 $ 631,496 Balances subject to amortization Insurance agency (1) — 6,635 6,635 Core deposit intangible 11,572 — 11,572 Total other intangible assets 11,572 6,635 18,207 Total goodwill and other intangible assets $ 569,207 $ 80,496 $ 649,703 (1) Insurance agency intangible assets include customer list, non-compete agreement and supplier relationship intangible assets. The Company acquired one insurance agency during the three months ended March 31, 2022. The purchase price and goodwill recorded as a result of the acquisition were not material. The Company quantitatively assesses goodwill for impairment at the reporting unit level on an annual basis or sooner if an event occurs or circumstances change which might indicate that the fair value of a reporting unit is below its carrying amount. The Company has identified and assigned goodwill to two reporting units - the banking business and insurance agency business. The quantitative assessments for both the banking business and insurance agency business were most recently performed as of September 30, 2021. The assessment for the banking business included a market capitalization analysis, as well as a comparison of the banking business’ book value to the implied fair value using a pricing multiple of the Company’s tangible book value. The assessment for insurance agency business included a price-to-earnings analysis, as well as an earnings before interest, taxes, depreciation, and amortization ("EBITDA") multiplier valuation based upon recent and observed agency mergers and acquisitions. The Company considered the economic conditions for the period, including the potential impact of the COVID-19 pandemic, as it pertains to the goodwill above and determined that there was no indication of impairment related to goodwill as of March 31, 2022 or December 31, 2021.

Earnings Per Share ("EPS")

Earnings Per Share ("EPS")	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share ("EPS")	Earnings Per Share (“EPS”) Basic EPS represents income available to common shareholders divided by the weighted-average number of common shares outstanding during the year. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common shares (such as stock options) were exercised or converted into additional common shares that would then share in the earnings of the Company. Diluted EPS is computed by dividing net income attributable to common shareholders by the weighted-average number of common shares outstanding for the year, plus the effect of potential dilutive common share equivalents computed using the treasury stock method. There were no securities that had a dilutive effect during the three months ended March 31, 2021. Shares held by the Employee Stock Ownership Plan (“ESOP”) that have not been allocated to employees in accordance with the terms of the ESOP, referred to as “unallocated ESOP shares,” are not deemed outstanding for earnings per share calculations. For the Three Months Ended March 31, 2022 2021 (Dollars in thousands, except per share data) Net income applicable to common shares $ 51,516 $ 47,663 Average number of common shares outstanding 184,066,326 186,758,154 Less: Average unallocated ESOP shares (14,208,376) (14,709,110) Average number of common shares outstanding used to calculate basic earnings per common share 169,857,950 172,049,044 Common stock equivalents - share-based compensation 110,206 — Average number of common shares outstanding used to calculate diluted earnings per common share 169,968,156 172,049,044 Earnings per common share Basic $ 0.30 $ 0.28 Diluted $ 0.30 $ 0.28

Low Income Housing Tax Credits

Low Income Housing Tax Credits and Other Tax Credit Investments	3 Months Ended
	Mar. 31, 2022
Investments in Affordable Housing Projects [Abstract]
Low Income Housing Tax Credits and Other Tax Credit Investments	Low Income Housing Tax Credits and Other Tax Credit Investments The Community Reinvestment Act (“CRA”) encourages banks to meet the credit needs of their communities for housing and other purposes, particularly in neighborhoods with low or moderate income. The Company has primarily invested in separate Low Income Housing Tax Credits (“LIHTC”) projects, also referred to as qualified affordable housing projects, which provide the Company with tax credits and operating loss tax benefits over a period of approximately 15 years. The return on these investments is generally generated through tax credits and tax losses. In addition to LIHTC projects, the Company invests in new markets tax credit projects that qualify for CRA credits and eligible projects that qualify for renewable energy and historic tax credits. As of March 31, 2022 and December 31, 2021, the Company had $82.5 million and $83.8 million, respectively, in tax credit investments that were included in other assets in the consolidated balance sheets. When permissible, the Company accounts for its investments in LIHTC projects using the proportional amortization method, under which it amortizes the initial cost of the investment in proportion to the amount of the tax credits and other tax benefits received and recognizes that amortization as a component of income tax expense. The net investment in the housing projects is included in other assets. The Company will continue to use the proportional amortization method on any new qualifying LIHTC investments. The following table presents the Company’s investments in LIHTC projects accounted for using the proportional amortization method for the periods indicated: As of March 31, 2022 As of December 31, 2021 (In thousands) Current recorded investment included in other assets $ 79,722 $ 81,035 Commitments to fund qualified affordable housing projects included in recorded investment noted above 43,287 48,399 The following table presents additional information related to the Company's investments in LIHTC projects for the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Tax credits and benefits recognized $ 2,321 $ 1,464 Amortization expense included in income tax expense 1,843 1,264 The Company accounts for certain other investments in renewable energy projects using the equity method of accounting. These investments in renewable energy projects are included in other assets on the consolidated balance sheet and totaled $2.8 million as of both March 31, 2022 and December 31, 2021. There were no outstanding commitments related to these investments as of both March 31, 2022 and December 31, 2021.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Share Repurchases On November 12, 2021, the Company announced receipt of a notice of non-objection from the Board of Governors of the Federal Reserve System to its previously announced share repurchase program which was approved by the Company’s Board of Directors on October 1, 2021. The program authorizes the purchase of up to 9,337,900 shares, or 5% of the Company’s then-outstanding shares of common stock over a 12-month period. Repurchases are made at management’s discretion from time to time at prices management considers to be attractive and in the best interests of both the Company and its shareholders, subject to the availability of shares, general market conditions, the trading price of the shares, alternative uses for capital, and the Company’s financial performance. Repurchases may be suspended, terminated or modified by the Company at any time for any reason. The program is limited to $225.0 million through November 30, 2022. Information regarding the shares repurchased under the plan is presented in the following table: Period Total Number of Shares Repurchased Average Price Paid per Share Total Number of Shares Repurchased as Part of the Share Repurchase Program at the end of Each Respective Period Maximum Number of Shares That May Yet Be Purchased Under the Share Repurchase Program at the end of Each Respective Period January 1, 2022 –  January 31, 2022 987,526 $ 21.02 2,123,404 7,214,496 February 1, 2022 –  February 28, 2022 1,109,697 $ 21.08 3,233,101 6,104,799 March 1, 2022 –  March 31, 2022 769,398 $ 21.31 4,002,499 5,335,401 The Company repurchased no shares of its common stock during the three months ended March 31, 2021. Dividends During the three months ended March 31, 2022, the Company declared and paid aggregate dividends of $16.9 million at a dividend per share of $0.10. During the three months ended March 31, 2021, the Company declared and paid aggregate dividends of $10.3 million at a dividend per share of $0.06.

Employee Benefits

Employee Benefits	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Employee Benefits	Employee BenefitsPension Plans The Company provides pension benefits for its employees through membership in the Savings Banks Employees’ Retirement Association. The plan through which benefits are provided is a noncontributory, qualified defined benefit plan and is referred to as the Defined Benefit Plan. The Company’s annual contribution to the Defined Benefit Plan is based upon standards established by the Pension Protection Act. The contribution is based on an actuarial method intended to provide not only for benefits attributable to service to date, but also for those expected to be earned in the future. The Defined Benefit Plan has a plan year end of October 31. The Company has an unfunded Defined Benefit Supplemental Executive Retirement Plan (“DB SERP”) that provides certain retired officers with defined pension benefits in excess of qualified plan limits imposed by U.S. federal tax law. The DB SERP has a plan year end of December 31. In addition, the Company has an unfunded Benefit Equalization Plan (“BEP”), to provide retirement benefits to certain employees whose retirement benefits under the qualified pension plan are limited per the Internal Revenue Code. The BEP has a plan year end of October 31. The Company also has an unfunded Outside Directors’ Retainer Continuance Plan (“ODRCP”) that provides pension benefits to outside directors who retire from service. The ODRCP has a plan year end of December 31. Effective December 31, 2020, the Company closed the ODRCP to new participants and froze benefit accruals for active participants. Components of Net Periodic Benefit Cost The components of net pension expense for the plans for the periods indicated are as follows: Three Months Ended March 31, 2022 2021 (In thousands) Components of net periodic benefit cost: Service cost $ 8,092 $ 7,896 Interest cost 2,430 1,269 Expected return on plan assets (9,281) (8,141) Past service credit (2,970) (2,946) Recognized net actuarial loss 2,798 3,538 Net periodic benefit cost $ 1,069 $ 1,616 Service costs for the Defined Benefit Plan, the BEP, and the DB SERP are recognized within salaries and employee benefits in the consolidated statement of income. Service costs for the ODRCP are recognized within professional services in the consolidated statements of income. The remaining components of net periodic benefit cost are recognized in other noninterest expense in the consolidated statements of income. In accordance with the Pension Protection Act, the Company was not required to make any contributions to the Defined Benefit Plan for the plan year beginning November 1, 2021. The Company chose to make contributions to the Defined Benefit Plan of $7.2 million during the three months ended March 31, 2022. In accordance with the Pension Protection Act, the Company was not required to make any contributions to the Defined Benefit Plan for the plan year beginning November 1, 2020. Accordingly, during the three months ended March 31, 2021, there were no contributions made to the Defined Benefit Plan. Rabbi Trust Variable Interest Entity The Company established a rabbi trust to meet its obligations under certain executive non-qualified retirement benefits and deferred compensation plans and to mitigate the expense volatility of the aforementioned retirement plans. The rabbi trust is considered a variable interest entity (“VIE”) as the equity investment at risk is insufficient to permit the trust to finance its activities without additional subordinated financial support from the Company. The Company is considered the primary beneficiary of the rabbi trust as it has the power to direct the activities of the rabbi trust that significantly affect the rabbi trust’s economic performance and it has the obligation to absorb losses of the rabbi trust that could potentially be significant to the rabbi trust by virtue of its contingent call options on the rabbi trust’s assets in the event of the Company’s bankruptcy. As the primary beneficiary of this VIE, the Company consolidates the rabbi trust investments. In general, the rabbi trust investments and any earnings received thereon are accumulated, reinvested and used exclusively for trust purposes. These rabbi trust investments consist primarily of cash and cash equivalents, U.S. government agency obligations, equity securities, mutual funds and other exchange-traded funds, and are recorded at fair value in other assets in the Company's consolidated balance sheet. Changes in fair value are recorded in noninterest income. At March 31, 2022 and December 31, 2021 the amount of rabbi trust investments at fair value were $87.3 million and $104.4 million, respectively. Investments in rabbi trust accounts are recorded at fair value within the Company's consolidated balance sheets with changes in fair value recorded through noninterest income. The following table presents the book value, mark-to-market, and fair value of assets held in rabbi trust accounts by asset type: As of March 31, 2022 As of December 31, 2021 Book Value Mark-to-Market Fair Value Book Value Mark-to-Market Fair Value Asset Type (In thousands) Cash and cash equivalents $ 5,445 $ — $ 5,445 $ 4,494 $ — $ 4,494 Equities (1) 59,487 14,257 73,744 67,401 24,295 91,696 Fixed income 8,466 (363) 8,103 8,126 56 8,182 Total assets $ 73,398 $ 13,894 $ 87,292 $ 80,021 $ 24,351 $ 104,372 (1) Equities include mutual funds and other exchange-traded funds. Share-Based Compensation Plan On November 29, 2021, the shareholders of the Company approved the Eastern Bankshares, Inc. 2021 Equity Incentive Plan (the “2021 Plan”). The 2021 Plan provides for the issuance of up to 26,146,141 shares of common stock pursuant to grants of restricted stock, restricted stock units (“RSUs”), non-qualified stock options and incentive stock options, any or all of which can be granted with performance-based vesting conditions. Under the 2021 Plan, 7,470,326 shares may be issued as restricted stock or RSUs and 18,675,815 shares may be issued upon the exercise of stock options. These shares may be awarded from the Company’s authorized but unissued shares. However, the 2021 Plan permits the grant of additional awards of restricted stock or RSUs above the aforementioned limit, provided that, for each additional share of restricted stock or RSU awarded in excess of such limit, the pool of shares available to be issued upon the exercise of stock options will be reduced by three shares. Pursuant to the terms of the 2021 Plan, each of the Company’s non-employee directors were automatically granted awards of restricted stock on November 30, 2021. Such restricted stock awards vest pro-rata on an annual basis over a five-year period. The maximum term for stock options is ten years. On March 1, 2022, the Company granted to all of the Company’s executive officers and certain other employees a total of 978,364 RSUs, which vest pro-rata on an annual basis over a period of three The following table summarizes the Company’s restricted stock award activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested restricted stock as of December 31, 2021 683,056 $ 20.13 Granted — — Non-vested restricted stock as of March 31, 2022 683,056 $ 20.13 The following table summarizes the Company’s restricted stock unit activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested restricted stock units as of December 31, 2021 — $ — Granted 978,364 21.08 Non-vested restricted stock units as of March 31, 2022 978,364 $ 21.08 The following table summarizes the Company’s performance stock unit activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested performance stock units as of December 31, 2021 — $ — Granted 533,676 21.12 Non-vested performance stock units as of March 31, 2022 533,676 $ 21.12 As of both March 31, 2022 and December 31, 2021, no awards had vested. For the three months ended March 31, 2022, share-based compensation expense under the 2021 Plan and the related tax benefit totaled $1.6 million and $0.4 million, respectively. No share-based compensation expense was incurred for the three months ended March 31, 2021 as the Company began issuing awards in November 2021. As of March 31, 2022 and December 31, 2021, there was $44.0 million and $13.5 million, respectively, of total unrecognized compensation expense related to non-vested restricted stock awards, restricted stock units and performance stock units granted and issued under the 2021 Plan. This cost is expected to be recognized over a weighted average remaining period of approximately 4.1 years.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Financial Instruments with Off-Balance Sheet Risk In order to meet the financing needs of its customers and to reduce its own exposure to fluctuations in interest rates, the Company is party to financial instruments with off-balance sheet risk in the normal course of business. These financial instruments include commitments to extend credit, standby letters of credit, and forward commitments to sell loans, all of which involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The contract or notional amounts of those instruments reflect the extent of involvement the Company has in each particular class of financial instruments. Substantially all of the Company’s commitments to extend credit, which normally have fixed expiration dates or termination clauses, are contingent upon customers maintaining specific credit standards at the time of loan funding. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. In the event the customer does not perform in accordance with the terms of agreement with the third party, the Company would be required to fund the commitment. The maximum potential amount of future payments the Company could be required to make is represented by the contractual amount of the commitment. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. For forward loan sale commitments, the contract or notional amount does not represent exposure to credit loss. The Company does not sell loans with recourse. The following table summarizes the above financial instruments as of the dates indicated: As of March 31, 2022 As of December 31, 2021 (In thousands) Commitments to extend credit $ 5,306,596 $ 5,175,521 Standby letters of credit 65,687 65,602 Forward commitments to sell loans 12,917 24,440 Other Contingencies The Company has been named a defendant in various legal proceedings arising in the normal course of business. Set out below are descriptions of significant legal matters involving the Company and its subsidiaries. In the opinion of management, based on the advice of legal counsel, the ultimate resolution of these proceedings will not have a material effect on the Company’s consolidated financial statements. In the second quarter of 2021, the Company entered into a preliminary settlement of two purported class action matters concerning overdraft and nonsufficient funds fees. The matters were filed in the Massachusetts Superior Court in November 2019 and April 2021, respectively, and were consolidated into one matter for final settlement purposes. The matters were settled during the quarter ended March 31, 2022 and the total settlement expense, including related costs, was $3.3 million. The Company incurred no costs in 2022 related to these matters as the total settlement expense had been accrued in 2021 when management determined the loss contingency to be both probable and estimable. The Company’s regulators conducted inquiries and reviewed data related to one of these class action matters and, in February 2022, made an additional request for data and notified management that they may require additional restitution for certain matters associated with the nonsufficient funds fees matter. Based on this discussion, management believed that a loss contingency for this restitution was probable but was not able to determine a reasonable estimate for the loss. However, later during the quarter ended March 31, 2022, the Company was informed by its regulators that no additional remediation on this issue would be required. As a result, as of March 31, 2022, management no longer believes that a loss contingency for restitution associated with this issue is probable. As a member of the Federal Reserve System, the Bank is required to maintain certain reserves of vault cash and/or deposits with the Federal Reserve Bank of Boston (the “FRBB”). However, in response to the COVID-19 pandemic, the Federal Reserve temporarily eliminated reserve requirements and therefore there was no minimum reserve requirement as of either March 31, 2022 or December 31, 2021.

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2022
Summary of Derivative Instruments [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company uses derivative financial instruments to manage its interest rate risk resulting from the differences in the amount, timing, and duration of known or expected cash receipts and known or expected cash payments. Additionally, the Company enters into interest rate derivatives and foreign exchange contracts to accommodate the business requirements of its customers (“customer-related positions”) and risk participation agreements entered into as financial guarantees of performance on customer-related interest rate swap derivatives. The Company also enters into residential mortgage loan commitments to fund mortgage loans at specified rates and times in the future and enters into forward sale commitments to sell such residential mortgage loans at specified prices and times in the future, both of which are considered derivative instruments. 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 dependent upon whether or not the instrument qualifies as a hedge for accounting purposes, and further, by the type of hedging relationship. By using derivatives, the Company is exposed to credit risk to the extent that counterparties to the derivative contracts do not perform as required. Should a counterparty fail to perform under the terms of a derivative contract, the Company’s credit exposure on interest rate swaps is limited to the net positive fair value and accrued interest of all swaps with each counterparty plus any initial margin collateral posted. The Company seeks to minimize counterparty credit risk through credit approvals, limits, monitoring procedures, and obtaining collateral, where appropriate. As such, management believes the risk of incurring credit losses on derivative contracts with those counterparties is remote. Interest Rate Positions An interest rate swap is an agreement whereby one party agrees to pay a floating rate of interest on a notional principal amount in exchange for receiving a fixed rate of interest on the same notional amount, for a predetermined period of time, from a second party. The amounts relating to the notional principal amount are not actually exchanged. The Company may enter into interest rate swaps in which it pays floating and receives fixed interest in order to manage its interest rate risk exposure to the variability in interest cash flows on certain floating-rate commercial loans. For interest rate swaps that are accounted for as cash flow hedges, changes in fair value are included in other comprehensive income and reclassified into net income in the same period or periods during which the hedged forecasted transaction affects net income. As of March 31, 2022 and December 31, 2021, the Company did not have any active interest rate swaps which qualify as cash flow hedges for accounting purposes. Due to the phase-out, and eventual discontinuation, of LIBOR, central clearinghouses have begun to transition to alternative rates for valuation purposes. As of October 16, 2020, the Company changed its valuation methodology to reflect changes made by the Chicago Mercantile Exchange (“CME”), through which the Company clears derivative financial instruments that are eligible for clearing. The changes from the CME changed the discounting methodology and interest calculation of cash margin from Overnight Index Swap to the Secured Overnight Financing Rate, or SOFR, for U.S. dollar cleared interest rate swaps. The Company believes that the improvements to its valuation methodology will result in valuations for cleared interest rate swaps that better reflect prices obtainable in the markets in which the Company transacts. The changes in valuation methodology are applied prospectively as a change in accounting estimate and are immaterial to the Company’s financial statements. The following table presents the pre-tax impact of terminated cash flow hedges on accumulated other comprehensive income (“AOCI”) for the three months ended March 31, 2022 and March 31, 2021: For the Three Months Ended March 31, 2022 2021 (In thousands) Unrealized gains on terminated hedges included in AOCI – beginning of respective period $ 10,239 $ 41,473 Unrealized gains on terminated hedges arising during the period — — Reclassification adjustments for amortization of unrealized (gains) into net income (5,298) (8,274) Unrealized gains on terminated hedges included in AOCI – end of respective period $ 4,941 $ 33,199 The balance of terminated cash flow hedges in AOCI will be amortized into earnings through January 2023. The Company expects the remaining $4.9 million to be reclassified into interest income from other comprehensive income related to the Company’s terminated cash flow hedges in the next 12 months as of March 31, 2022. Customer-Related Positions Interest rate swaps offered to commercial customers do not qualify as hedges for accounting purposes. These swaps allow the Company to retain variable rate commercial loans while allowing the commercial customer to synthetically fix the loan rate by entering into a variable-to-fixed rate interest rate swap. The Company believes that its exposure to commercial customer derivatives is limited to non-performance by either the customer or the dealer because these contracts are simultaneously matched at inception with an offsetting dealer transaction. Risk participation agreements are entered into as financial guarantees of performance on interest rate swap derivatives. The purchased (asset) or sold (liability) guarantee allow the Company to participate-out (fee paid) or participate-in (fee received) the risk associated with certain derivative positions executed with the borrower by the lead bank in a customer-related interest rate swap derivative. Foreign exchange contracts consist of those offered to commercial customers and those entered into to hedge the Company’s foreign currency risk associated with a foreign-currency loan. Neither qualifies as a hedge for accounting purposes. These commercial customer derivatives are offset with matching derivatives with correspondent-bank counterparties in order to minimize foreign exchange rate risk to the Company. Exposure with respect to these derivatives is largely limited to non-performance by either the customer or the other counterparty. Neither the Company nor the correspondent-bank counterparty are required to post collateral but each has established foreign-currency transaction limits to manage the exposure risk. The Company requires its customers to post collateral to minimize risk exposure. The following tables present the Company’s customer-related derivative positions as of the dates indicated below for those derivatives not designated as hedging. March 31, 2022 Number of Positions Total Notional (Dollars in thousands) Interest rate swaps 468 $ 2,867,637 Risk participation agreements 63 263,496 Foreign exchange contracts: Matched commercial customer book 70 10,343 Foreign currency loan 5 11,586 December 31, 2021 Number of Positions Total Notional (Dollars in thousands) Interest rate swaps 494 $ 3,009,150 Risk participation agreements 64 238,772 Foreign exchange contracts: Matched commercial customer book 72 7,922 Foreign currency loan 6 10,830 The level of interest rate swaps, risk participation agreements and foreign currency exchange contracts at the end of each period noted above was commensurate with the activity throughout those periods. The table below presents the fair value of the Company’s derivative financial instruments, as well as their classification on the consolidated balance sheet for the periods indicated. There were no derivatives designated as hedging instruments at March 31, 2022 or December 31, 2021. Asset Derivatives Liability Derivatives Balance Fair Value at March 31, Fair Value at December 31, Balance Sheet Fair Value at March 31, Fair Value at December 31, (In thousands) Derivatives not designated as hedging instruments Customer-related positions: Interest rate swaps Other assets $ 23,725 $ 64,338 Other liabilities $ 24,988 $ 17,880 Risk participation agreements Other assets 196 315 Other liabilities 401 580 Foreign currency exchange contracts - matched customer book Other assets 91 61 Other liabilities 78 46 Foreign currency exchange contracts - foreign currency loan Other assets 7 — Other liabilities 16 87 Total $ 24,019 $ 64,714 $ 25,483 $ 18,593 The table below presents the net effect of the Company’s derivative financial instruments on the consolidated income statements as well as the effect of the Company’s derivative financial instruments included in other comprehensive income (“OCI”) as follows: Three Months Ended March 31, 2022 2021 (In thousands) Derivatives designated as hedges: (Loss) gain in OCI on derivatives $ — $ — Gain reclassified from OCI into interest income (effective portion) $ 5,298 $ 8,274 Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test) Interest income — — Other income — — Total $ — $ — Derivatives not designated as hedges: Customer-related positions: Gain recognized in interest rate swap income $ 2,298 $ 4,851 Gain recognized in interest rate swap income for risk participation agreements 60 369 (Loss) gain recognized in other income for foreign currency exchange contracts: Matched commercial customer book (2) 6 Foreign currency loan 78 73 Total gain for derivatives not designated as hedges $ 2,434 $ 5,299 The Company has agreements with its customer-related interest rate swap derivative counterparties that contain a provision whereby if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. The Company also has agreements with certain of its customer-related interest rate swap derivative correspondent-bank counterparties that contain a provision whereby if the Company fails to maintain its status as a well-capitalized institution, then the counterparty could terminate the derivative positions and the Company would be required to settle its obligations under the agreements. The Company’s exposure related to its customer-related interest rate swap derivatives consists of exposure on cleared derivative transactions and exposure on non-cleared derivative transactions. Cleared derivative transactions are with the Chicago Mercantile Exchange, or CME, and exposure is settled to market daily, with additional credit exposure related to initial-margin collateral pledged to CME at trade execution. At March 31, 2022 and December 31, 2021, the Company’s exposure to CME for settled variation margin in excess of the customer-related interest rate swap termination values was $1.4 million and $0.4 million, respectively. In addition, at March 31, 2022 and December 31, 2021, the Company had posted initial-margin collateral in the form of U.S. Treasury notes amounting to $37.0 million and $48.9 million, respectively, to CME for these derivatives. The U.S. Treasury notes were considered restricted assets and were included in AFS securities. At March 31, 2022 and December 31, 2021 the fair value of all customer-related interest rate swap derivatives with credit-risk related contingent features that were in a net liability position, which includes accrued interest but excludes any adjustment for non-performance risk, was $0.2 million and $13.7 million, respectively. The Company has minimum collateral posting thresholds with its customer-related interest rate swap derivative correspondent-bank counterparties to the extent that the Company has a liability position with the correspondent-bank counterparties. At March 31, 2022 and December 31, 2021, the Company had posted collateral in the form of cash amounting to $5.5 million and $21.3 million, respectively, which was considered to be a restricted asset and was included in other short-term investments. If the Company had breached any of these provisions at March 31, 2022 or December 31, 2021, it would have been required to settle its obligations under the agreements at the termination value. In addition, the Company had cross-default provisions with its commercial customer loan agreements which provide cross-collateralization with the customer loan collateral. Mortgage Banking Derivatives The Company enters into residential mortgage loan commitments in connection with its consumer mortgage banking activities to fund mortgage loans at specified rates and times in the future. In addition, the Company enters into forward sale commitments to sell such residential mortgage loans at specified prices and times in the future. These commitments are short-term in nature and generally expire in 30 to 60 days. The residential mortgage loan commitments that relate to the origination of mortgage loans that will be held for sale and the related forward sale commitments are considered derivative instruments under ASC Topic 815, “Derivatives and Hedging” and are reported at fair value. Changes in fair value are reported in earnings and included in other non-interest income on the consolidated statements of income. As of March 31, 2022 and December 31, 2021, the Company had an outstanding notional balance of residential mortgage loan origination commitments of $22.8 million and $31.9 million, respectively and forward sale commitments of $12.9 million and $24.4 million, respectively. During both the three months ended March 31, 2022 and 2021, the Company recorded $0.2 million of net losses related to the change in fair value of commitments to originate and sell mortgage loans. The aggregate fair value of the Company’s mortgage banking derivative asset and liability as of March 31, 2022 was $0.2 million and $0.2 million, respectively. The aggregate fair value of the Company’s mortgage banking derivative asset and liability as of December 31, 2021 was $0.3 million and $0.1 million, respectively. Mortgage banking derivative assets and liabilities are included in other assets and other liabilities, respectively, on the consolidated balance sheet. Residential mortgages sold are generally sold with servicing rights released. Mortgage banking derivatives do not qualify as hedges for accounting purposes.

Balance Sheet Offsetting

Balance Sheet Offsetting	3 Months Ended
	Mar. 31, 2022
Offsetting [Abstract]
Balance Sheet Offsetting	Balance Sheet OffsettingCertain financial instruments, including derivatives, may be eligible for offset in the consolidated balance sheets and/or subject to master netting arrangements or similar agreements. The Company’s derivative transactions with upstream financial institution counterparties are generally executed under International Swaps and Derivative Association master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts. However, the Company does not offset fair value amounts recognized for derivative instruments. The Company nets the amount recognized for the right to reclaim cash collateral against the obligation to return cash collateral arising from derivative instruments executed with the same counterparty under a master netting arrangement. Collateral legally required to be maintained at dealer banks by the Company is monitored and adjusted as necessary. As of March 31, 2022 and December 31, 2021, it was determined that no additional collateral would have to be posted to immediately settle these instruments. The following tables present the Company’s asset and liability positions that were eligible for offset and the potential effect of netting arrangements on its consolidated balance sheet, as of the dates indicated: As of March 31, 2022 Gross Gross Net Gross Amounts Not Offset Net Description Financial Collateral (In thousands) Derivative Assets Customer-related positions: Interest rate swaps $ 23,725 $ — $ 23,725 $ 3,470 $ — $ 20,255 Risk participation agreements 196 — 196 — — 196 Foreign currency exchange contracts – matched customer book 91 — 91 — — 91 Foreign currency exchange contracts – foreign currency loan 7 — 7 — — 7 $ 24,019 $ — $ 24,019 $ 3,470 $ — $ 20,549 Derivative Liabilities Customer-related positions: Interest rate swaps $ 24,988 $ — $ 24,988 $ 3,470 $ 21,518 $ — Risk participation agreements 401 — 401 — — 401 Foreign currency exchange contracts – matched customer book 78 — 78 — — 78 Foreign currency exchange contracts – foreign currency loan 16 — 16 — — 16 $ 25,483 $ — $ 25,483 $ 3,470 $ 21,518 $ 495 As of December 31, 2021 Gross Gross Net Gross Amounts Not Offset Net Description Financial Collateral (In thousands) Derivative Assets Customer-related positions: Interest rate swaps $ 64,338 $ — $ 64,338 $ 1,440 $ — $ 62,898 Risk participation agreements 315 — 315 — — 315 Foreign currency exchange contracts – matched customer book 61 — 61 — — 61 Foreign currency exchange contracts – foreign currency loan — — — — — — $ 64,714 $ — $ 64,714 $ 1,440 $ — $ 63,274 Derivative Liabilities Customer-related positions: Interest rate swaps $ 17,880 $ — $ 17,880 $ 1,440 $ 16,440 $ — Risk participation agreements 580 — 580 — — 580 Foreign currency exchange contracts – matched customer book 46 — 46 — — 46 Foreign currency exchange contracts – foreign currency loan 87 — 87 — — 87 $ 18,593 $ — $ 18,593 $ 1,440 $ 16,440 $ 713

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities The Company uses fair value measurements to record adjustments to certain assets and liabilities and to determine fair value disclosures. The fair value of a financial instrument is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined based upon quoted market prices. However, in many instances, there are no quoted market prices for the Company’s various financial instruments. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. Accordingly, the fair value estimates may not be realized in an immediate settlement of the instrument. Fair value is a market-based measure considered from the perspective of a market participant rather than an entity-specific measure. Therefore, even when market assumptions are not readily available, the Company’s own assumptions are set to reflect those that the Company believes market participants would use in pricing the asset or liability at the measurement date. The Company uses prices and inputs that are current as of the measurement date, including during periods of market dislocation. In periods of market dislocation, the observability of prices and inputs may be reduced for many instruments. This condition could cause an instrument to be reclassified from Level 1 to Level 2 or from Level 2 to Level 3. Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no active market exists for a portion of the Company’s financial instruments, fair value estimates are based on judgements regarding future expected loss experience, current economic conditions, risk characteristics of various financial instruments, and other factors. These estimates are subjective in nature and involve uncertainties and matters of significant judgement, and therefore cannot be determined with precision. Changes in assumptions could significantly affect these estimates. The following methods and assumptions were used by the Company in estimating fair value disclosures: Cash and Cash Equivalents For these financial instruments, which have original maturities of 90 days or less, their carrying amounts reported in the consolidated balance sheets approximate fair value. Securities Securities consisted of U.S. Treasury securities, U.S. government-sponsored residential and commercial mortgage-backed securities, U.S. Agency bonds and state and municipal bonds. AFS securities are recorded at fair value. The Company’s U.S. Treasury securities are traded on active markets and therefore these securities were classified as Level 1. The fair value of U.S. Agency bonds, including SBA pooled securities, are evaluated using relevant trade data, benchmark quotes and spreads obtained from publicly available trade data, and generated on a price, yield or spread basis as determined by the observed market data. Therefore, these securities were categorized as Level 2 given the use of observable inputs. The fair value of U.S. government-sponsored residential and commercial mortgage-backed securities were estimated using either a matrix or benchmarks. The inputs used include benchmark yields, reported trades, broker/dealer quotes, and issuer spreads. Therefore, these securities were categorized as Level 2 given the use of observable inputs. The fair value of state and municipal bonds were estimated using a valuation matrix with inputs including observable bond interest rate tables, recent transactions, and yield relationships. Therefore, these securities were categorized as Level 2 given the use of observable inputs. The fair value of other debt securities were estimated using a valuation matrix with inputs including observable bond interest rate tables, recent transactions, and yield relationships. Therefore, these securities were categorized as Level 2 given the use of observable inputs. Fair value was based on the value of one unit without regard to any premium or discount that may result from concentrations of ownership of a financial instrument, possible tax ramifications, or estimated transaction costs. The estimated fair value of the Company’s securities, by type, is disclosed in Note 3, “Securities.” Loans Held for Sale The fair value of loans held for sale, whose carrying amounts approximate fair value, was estimated using the anticipated market price based upon pricing indications provided by investor banks. These assets were classified as Level 2 given the use of observable inputs. Loans The fair value of commercial construction, commercial and industrial lines of credit, and certain other consumer loans was estimated by discounting the contractual cash flows using interest rates currently being offered for loans with similar terms to borrowers of similar credit quality. For commercial, commercial real estate, residential real estate, automobile, and consumer home equity loans, fair value was estimated by discounting contractual cash flows adjusted for prepayment estimates using interest rates currently being offered for loans with similar terms to borrowers of similar credit quality. The fair value of PPP loans, which are fully guaranteed by the SBA, approximates the carrying amount. Loans are classified as Level 3 since the valuation methodology utilizes significant unobservable inputs. Loans that are deemed to be collateral-dependent, as described in Note 2, “Summary of Significant Accounting Policies” were recorded at the fair value of the underlying collateral. FHLB Stock The fair value of FHLB stock approximates the carrying amount based on the redemption provisions of the FHLB. These assets were classified as Level 2. Rabbi Trust Investments Rabbi trust investments consisted primarily of cash and cash equivalents, U.S. government agency obligations, equity securities, mutual funds and other exchange-traded funds, and were recorded at fair value and included in other assets. The purpose of these rabbi trust investments is to fund certain executive non-qualified retirement benefits and deferred compensation. The fair value of other U.S. government agency obligations was estimated using either a matrix or benchmarks. The inputs used include benchmark yields, reported trades, broker/dealer quotes, and issuer spreads. These securities were categorized as Level 2 given the use of observable inputs. The equity securities, mutual funds and other exchange-traded funds were valued based on quoted prices from the market. The equities, mutual funds and exchange-traded funds traded in an active market were categorized as Level 1 as they were valued based upon quoted prices from the market. Mutual funds at net asset value amounted to $45.8 million at March 31, 2022 and $58.1 million at December 31, 2021. There were no redemption restrictions on these mutual funds at the end of any period presented. Bank-Owned Life Insurance The fair value of bank-owned life insurance was based upon quotations received from bank-owned life insurance dealers. These assets were classified as Level 2 given the use of observable inputs. Deposits The fair value of deposits with no stated maturity, such as noninterest-bearing demand deposits, savings and interest checking accounts, and money market accounts, was equal to their carrying amount. The fair value of time deposits was based on the discounted value of contractual cash flows using current market interest rates. Deposits were classified as Level 2 given the use of observable market inputs. The fair value estimates of deposits do not include the benefit that results from the low-cost funding provided by the deposit liabilities compared to the cost of borrowing funds in the wholesale market (core deposit intangibles). FHLB Advances The fair value of FHLB advances was based on the discounted value of contractual cash flows. The discount rates used are representative of approximate rates currently offered on instruments with similar remaining maturities. FHLB advances were classified as Level 2. Escrow Deposits of Borrowers The fair value of escrow deposits of borrowers, which have no stated maturity, approximates the carrying amount. Escrow deposits of borrowers were classified as Level 2. Interest Rate Swaps The fair value of interest rate swaps was determined using discounted cash flow analysis on the expected cash flows of the interest rate swaps. This analysis reflects the contractual terms of the interest rate swaps, including the period of maturity, and uses observable market-based inputs, including interest rate curves and implied volatility. In addition, for customer-related interest rate swaps, the analysis reflects a credit valuation adjustment to reflect the Company’s own non-performance risk and the respective counterparty’s non-performance risk in the fair value measurements. The majority of inputs used to value the Company's interest rate swaps fall within Level 2 of the fair value hierarchy, but the credit valuation adjustments associated with the interest rate swaps utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, at March 31, 2022 and December 31, 2021, the impact of the Level 3 inputs on the overall valuation of the interest rate swaps was deemed insignificant to the overall valuation. As a result, the interest rate swaps were categorized as Level 2 within the fair value hierarchy. Risk Participations The fair value of risk participations was determined based upon the total expected exposure of the derivative which considers the present value of cash flows discounted using market-based inputs and were therefore categorized as Level 2 within the fair value hierarchy. The fair value also included a credit valuation adjustment which evaluates the credit risk of its counterparties by considering factors such as the likelihood of default by the counterparties, its net exposures, the remaining contractual life, as well as the amount of collateral securing the position. The change in value of derivative assets and liabilities attributable to credit risk was not significant during the reported periods. Foreign Currency Forward Contracts The fair values of foreign currency forward contracts were based upon the remaining expiration period of the contracts and bid quotations received from foreign exchange contract dealers and were categorized as Level 2 within the fair value hierarchy. Mortgage Derivatives The fair value of mortgage derivatives is determined based upon current market prices for similar assets in the secondary market and, therefore are classified as Level 2 within the fair value hierarchy. Fair Value of Assets and Liabilities Measured on a Recurring Basis The following tables present the balances of assets and liabilities measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021: Fair Value Measurements at Reporting Date Using Balance as of March 31, 2022 Quoted Prices in Significant Significant Description (In thousands) Assets Securities available for sale Government-sponsored residential mortgage-backed securities $ 4,969,346 $ — $ 4,969,346 $ — Government-sponsored commercial mortgage-backed securities 1,615,927 — 1,615,927 — U.S. Agency bonds 1,013,899 — 1,013,899 — U.S. Treasury securities 56,235 56,235 — — State and municipal bonds and obligations 260,316 — 260,316 — Other debt securities 1,582 — 1,582 — Rabbi trust investments 87,292 79,189 8,103 — Loans held for sale 1,166 — 1,166 — Interest rate swap contracts Customer-related positions 23,725 — 23,725 — Risk participation agreements 196 — 196 — Foreign currency forward contracts Matched customer book 91 — 91 — Foreign currency loan 7 — 7 — Mortgage derivatives 239 — 239 — Total $ 8,030,021 $ 135,424 $ 7,894,597 $ — Liabilities Interest rate swap contracts Customer-related positions $ 24,988 $ — $ 24,988 $ — Risk participation agreements 401 — 401 — Foreign currency forward contracts Matched customer book 78 — 78 — Foreign currency loan 16 — 16 — Mortgage derivatives 168 — 168 — Total $ 25,651 $ — $ 25,651 $ — Fair Value Measurements at Reporting Date Using Description Balance as of December 31, 2021 Quoted Prices in Significant Significant (In thousands) Assets Securities available for sale Government-sponsored residential mortgage-backed securities $ 5,524,708 $ — $ 5,524,708 $ — Government-sponsored commercial mortgage-backed securities 1,408,868 — 1,408,868 — U.S. Agency bonds 1,175,014 — 1,175,014 — U.S. Treasury securities 88,605 88,605 — — State and municipal bonds and obligations 280,329 — 280,329 — Small Business Administration pooled securities 32,103 — 32,103 — Other debt securities 1,597 — 1,597 — Rabbi trust investments 104,372 96,190 8,182 — Loans held for sale 1,206 — 1,206 — Interest rate swap contracts Customer-related positions 64,338 — 64,338 — Risk participation agreements 315 — 315 — Foreign currency forward contracts Matched customer book 61 — 61 — Mortgage derivatives 256 — 256 — Total $ 8,681,772 $ 184,795 $ 8,496,977 $ — Liabilities Interest rate swap contracts Customer-related positions $ 17,880 $ — $ 17,880 $ — Risk participation agreements 580 — 580 — Foreign currency forward contracts Matched customer book 46 — 46 — Foreign currency loan 87 — 87 — Mortgage derivatives 16 — 16 — Total $ 18,609 $ — $ 18,609 $ — There were no transfers to or from Level 1, 2 and 3 during the three months ended March 31, 2022 and twelve months ended December 31, 2021. The Company held no assets or liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) as of March 31, 2022 or December 31, 2021. Fair Value of Assets and Liabilities Measured on a Nonrecurring Basis The Company may also be required, from time to time, to measure certain other assets on a nonrecurring basis in accordance with generally accepted accounting principles. The following tables summarize the fair value of assets and liabilities measured at fair value on a nonrecurring basis, as of March 31, 2022 and December 31, 2021. Fair Value Measurements at Reporting Date Using Description Balance as of March 31, 2022 Quoted Prices Significant Significant (In thousands) Assets Individually assessed collateral-dependent loans whose fair value is based upon appraisals $ 11,879 $ — $ — $ 11,879 Fair Value Measurements at Reporting Date Using Description Balance as of December 31, 2021 Quoted Prices Significant Significant (In thousands) Assets Collateral-dependent impaired loans whose fair value is based upon appraisals $ 12,068 $ — $ — $ 12,068 For the valuation of the collateral-dependent loans, the Company relies primarily on third-party valuation information from certified appraisers and values are generally based upon recent appraisals of the underlying collateral, brokers’ opinions based upon recent sales of comparable properties, estimated equipment auction or liquidation values, income capitalization, or a combination of income capitalization and comparable sales. Depending on the type of underlying collateral, valuations may be adjusted by management for qualitative factors such as economic factors and estimated liquidation expenses. The range of these possible adjustments may vary. Refer to Note 2, “Summary of Significant Accounting Policies” and Note 4, “Loans and Allowance for Credit Losses” for further discussion regarding the Company’s adoption of ASU 2016-13 and the effect of that adoption on the management’s process for estimating the allowance for loan losses. Loans for which a reserve was established based upon expected cash flows discounted at the loan’s effective interest rate are not deemed to be measured at fair value. Disclosures about Fair Value of Financial Instruments The estimated fair values and related carrying amounts for assets and liabilities for which fair value is only disclosed are shown below as of the dates indicated: Fair Value Measurements at Reporting Date Using Description Carrying Value as of March 31, 2022 Fair Value as of March 31, 2022 Quoted Prices Significant Significant (In thousands) Assets Held to maturity securities: Government-sponsored residential mortgage-backed securities $ 192,231 $ 188,913 $ — $ 188,913 $ — Government-sponsored commercial mortgage-backed securities 203,203 203,210 — 203,210 — Loans, net of allowance for loan losses 12,033,603 11,817,706 — — 11,817,706 FHLB stock 10,904 10,904 — 10,904 — Bank-owned life insurance 157,954 157,954 — 157,954 — Liabilities Deposits $ 19,392,816 $ 19,387,023 $ — $ 19,387,023 $ — FHLB advances 13,689 12,767 — 12,767 — Escrow deposits from borrowers 21,233 21,233 — 21,233 — Fair Value Measurements at Reporting Date Using Description Carrying Value as of December 31, 2021 Fair Value as of December 31, 2021 Quoted Prices Significant Significant (In thousands) Assets Loans, net of allowance for loan losses $ 12,157,281 $ 12,282,323 $ — $ — $ 12,282,323 FHLB stock 10,904 10,904 — 10,904 — Bank-owned life insurance 157,091 157,091 — 157,091 — Liabilities Deposits $ 19,628,311 $ 19,626,376 $ — $ 19,626,376 $ — FHLB advances 14,020 13,558 — 13,558 — Escrow deposits from borrowers 20,258 20,258 — 20,258 — This summary excludes certain financial assets and liabilities for which the carrying value approximates fair value. For financial assets, these may include cash and due from banks, federal funds sold and short-term investments. For financial liabilities, these may include federal funds purchased. These instruments would all be considered to be classified as Level 1 within the fair value hierarchy. Also excluded from the summary are financial instruments measured at fair value on a recurring and nonrecurring basis, as previously described.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Revenue from contracts with customers within the scope of ASC 606, Revenue from Contracts with Customers (Topic 606) (“ASC 606”) is recognized when control of goods or services is transferred to the customer, in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. The Company considers the terms of the contract and all relevant facts and circumstances when applying this guidance. The Company measures revenue and timing of recognition by applying the following five steps: 1. Identify the contract(s) with the customers. 2. Identify the performance obligations. 3. Determine the transaction price. 4. Allocate the transaction price to the performance obligations. 5. Recognize revenue when (or as) the entity satisfies a performance obligation. The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. Performance obligations The Company’s performance obligations are generally satisfied either at a point in time or over time, as services are rendered. Unsatisfied performance obligations at the report date are not material to the Company’s consolidated financial statements. A portion of the Company's noninterest income is derived from contracts with customers within the scope of ASC 606. The Company has disaggregated such revenues by type of service, as presented in the table below. These categories reflect how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors. Three Months Ended March 31, 2022 2021 (In thousands) Insurance commissions $ 28,713 $ 28,147 Service charges on deposit accounts 8,537 5,367 Trust and investment advisory fees 6,141 5,663 Debit card processing fees 2,945 2,749 Other noninterest income 2,361 1,792 Total noninterest income in-scope of ASC 606 48,697 43,718 Total noninterest (loss) income out-of-scope of ASC 606 (2,282) 11,494 Total noninterest income $ 46,415 $ 55,212 Additional information related to each of the revenue streams is further noted below. Insurance Commissions The Company acts as an agent in offering property, casualty, and life and health insurance to both commercial and consumer customers though Eastern Insurance Group. The Company earns a fixed commission on the sales of these products and services. The Company may also earn bonus commissions based upon meeting certain volume thresholds. In general, the Company recognizes commission revenues when earned based upon the effective date of the policy. For certain insurance products, the Company may also earn and recognize annual residual commissions commensurate with annual premiums being paid. The Company also earns profit-sharing, or contingency revenues from the insurers with whom the Company places business. These profit-sharing revenues are performance bonuses from the insurers based upon certain performance metrics such as floors on written premiums, loss rates, and growth rates. Because the Company’s expectation of the ultimate profit-sharing revenue amounts to be earned can vary from period to period, the Company does not recognize this revenue until it has concluded that, based on all the facts and information available, it is probable that a significant revenue reversal will not occur in future periods. Insurance commissions earned but not yet received amounted to $11.9 million as of March 31, 2022, and $15.6 million as of December 31, 2021 and were included in other assets. Deposit Service Charges The Company offers various deposit account products to its customers governed by specific deposit agreements applicable to either personal customers or business customers. These agreements identify the general conditions and obligations of both parties and include standard information regarding deposit account-related fees. Deposit account services include providing access to deposit accounts as well as access to the various deposit transactional services of the Company. These transactional services are primarily those that are identified in the standard fee schedule, and include, but are not limited to, services such as overdraft protection, wire transfer, and check collection. The Company charges monthly fixed service fees associated with the customer having access to the deposit account as well as separate fixed fees associated with and at the time specific transactions are entered into by the customer. As such, the Company considers that its performance obligations are fulfilled when customers are provided deposit account access or when the requested deposit transaction is completed. Cash management services are a subset of the deposit service charges revenue stream. These services include automated clearing house, or ACH, transaction processing, positive pay, lockbox, and remote deposit services. These services are also governed by separate agreements entered into by the customer. The fee arrangement for these services is structured as a fixed fee per transaction which may be offset by earnings credits. An earnings credit is a discount that a customer receives based upon the investable balance in the applicable covered deposit account(s) for a given month. Earnings credits are only good for the given month. That is, if cash management fees for a given month are less than the month’s earnings credit, the remainder of the credit does not carry over to the following month. Cash management fees are recognized as revenue in the month that the services are provided. Cash management fees earned but not yet received amounted to $2.3 million and $1.8 million as of March 31, 2022 and December 31, 2021 and were included in other assets. Trust and Investment Advisory Fees The Company offers investment management and trust services to individuals, institutions, small businesses and charitable institutions. Each investment management product is governed by its own contract along with a separate identifiable fee schedule unique to that product. The Company also offers additional services, such as estate settlement, financial planning, tax services, and other special services quoted at the customer’s request. The asset management and/or custody fees are primarily based upon a percentage of the monthly valuation of the principal assets in the customer’s account. Customers are also charged a base fee which is prorated over a twelve-month period. Fees for additional or special services are generally fixed in nature and are charged as services are rendered. All revenue is recognized in correlation to the monthly management fee determinations or as transactional services are provided. Debit Card Processing Fees The Company provides debit cards to its customers which are authorized and settled through various card payment networks, and in exchange, the Company earns revenue as determined by each payment network’s interchange program. Regardless of the network that is utilized to authorize and settle the payment, the merchant that provides the product or service to the debit card holder is ultimately responsible for the interchange payment to the Company. Debit card processing fees are recognized as card transactions are settled within each network. Debit card processing fees earned but not yet received amounted to $0.3 million as of both March 31, 2022 and December 31, 2021 and were included in other assets. Other Noninterest Income

Other Comprehensive Income

Other Comprehensive Income	3 Months Ended
	Mar. 31, 2022
Statement of Other Comprehensive Income [Abstract]
Other Comprehensive Income	Other Comprehensive Income The following tables present a reconciliation of the changes in the components of other comprehensive (loss) income for the dates indicated including the amount of income tax (expense) benefit allocated to each component of other comprehensive (loss) income: Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Pre Tax Tax After Tax Pre Tax Tax After Tax (In thousands) Unrealized losses on securities available for sale: Change in fair value of securities available for sale $ (465,532) $ 112,008 $ (353,524) $ (94,979) $ 20,982 $ (73,997) Less: reclassification adjustment for gains included in net income (2,172) 673 (1,499) 1,164 (257) 907 Net change in fair value of securities available for sale (463,360) 111,335 (352,025) (96,143) 21,239 (74,904) Unrealized gains (losses) on cash flow hedges: Change in fair value of cash flow hedges — — — — — — Less: net cash flow hedge gains reclassified into interest income (1) 5,298 (1,489) 3,809 8,274 (2,326) 5,948 Net change in fair value of cash flow hedges (5,298) 1,489 (3,809) (8,274) 2,326 (5,948) Defined benefit pension plans: Change in actuarial net loss — — — — — — Less: amortization of actuarial net loss (2,798) 787 (2,011) (3,537) 994 (2,543) Less: accretion of prior service credit 2,970 (835) 2,135 2,945 (828) 2,117 Net change in other comprehensive income for defined benefit postretirement plans (172) 48 (124) 592 (166) 426 Total other comprehensive loss $ (468,830) $ 112,872 $ (355,958) $ (103,825) $ 23,399 $ (80,426) (1) Represents amortization of realized gains on terminated cash flow hedges for the three months ended March 31, 2022 and 2021. The total realized gain of $41.2 million, net of tax, will be recognized in earnings through January 2023. The balance of this gain had amortized to $3.6 million and $7.4 million, net of tax, at March 31, 2022 and December 31, 2021, respectively. The following table illustrates the changes in the balances of each component of accumulated other comprehensive income (loss), net of tax: Unrealized Unrealized Defined Benefit Total (In thousands) Beginning Balance: January 1, 2022 $ (58,586) $ 7,361 $ (5,471) $ (56,696) Other comprehensive loss before reclassifications (353,524) — — (353,524) Less: Amounts reclassified from accumulated other comprehensive (loss) income (1,499) 3,809 124 2,434 Net current-period other comprehensive loss (352,025) (3,809) (124) (355,958) Ending Balance: March 31, 2022 $ (410,611) $ 3,552 $ (5,595) $ (412,654) Beginning Balance: January 1, 2021 $ 45,672 $ 29,815 $ (21,253) $ 54,234 Other comprehensive loss before reclassifications (73,997) — — (73,997) Less: Amounts reclassified from accumulated other comprehensive income (loss) 907 5,948 (426) 6,429 Net current-period other comprehensive (loss) income (74,904) (5,948) 426 (80,426) Ending Balance: March 31, 2021 $ (29,232) $ 23,867 $ (20,827) $ (26,192)

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company’s primary reportable segment is its banking business, which offers a range of commercial, retail, wealth management and banking services and consists primarily of attracting deposits from the general public and investing those deposits, together with borrowings and funds generated from operations, to originate loans in a variety of sectors and to invest in securities. Revenue from the banking business reportable segment consists primarily of interest earned on loans and investment securities. In addition to its banking business reportable segment, the Company has an insurance agency business reportable segment, which consists of insurance-related activities, acting as an independent agent in offering commercial, personal and employee benefits insurance products to individual and commercial clients. Revenue from the insurance agency business consists primarily of commissions on sales of insurance products and services. Results of operations and selected financial information by segment and reconciliation to the consolidated financial statements as of and for the three months ended March 31, 2022 and 2021 was as follows: As of and for the three months ended March 31, 2022 2021 Banking Insurance Other / Total Banking Insurance Other / Total (In thousands) Net interest income $ 128,124 $ — $ — $ 128,124 $ 100,091 $ — $ — $ 100,091 (Release of) provision for loan losses (485) — — (485) (580) — — (580) Net interest income after provision for loan losses 128,609 — — 128,609 100,671 — — 100,671 Noninterest income 18,137 28,449 (171) 46,415 26,960 28,284 (32) 55,212 Noninterest expense 90,446 19,473 (1,053) 108,866 75,274 19,811 (1,036) 94,049 Income before provision for income taxes 56,300 8,976 882 66,158 52,357 8,473 1,004 61,834 Income tax provision 12,108 2,534 — 14,642 11,793 2,378 — 14,171 Net income $ 44,192 $ 6,442 $ 882 $ 51,516 $ 40,564 $ 6,095 $ 1,004 $ 47,663 Total assets $ 22,695,895 $ 211,401 $ (71,224) $ 22,836,072 $ 16,595,311 $ 194,664 $ (63,180) $ 16,726,795 Total liabilities $ 19,848,995 $ 49,909 $ (71,224) $ 19,827,680 $ 13,359,075 $ 43,855 $ (63,180) $ 13,339,750

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn January 14, 2022, the Company announced it had entered into an asset purchase agreement for the transfer of the Company’s cannabis-related and money service business deposits relationships, which it had acquired from Century, to Needham Bank. On April 1, 2022, the Company completed the transfer of such deposits which amounted to $297.7 million. The Company did not recognize a material gain or loss in connection with this transaction. The terms of the transfer included a post-transfer settlement period of 60 days from the date of the initial transfer of April 1, 2022.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
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 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. The accompanying consolidated balance sheet as of March 31, 2022, the consolidated statements of income and comprehensive income and of changes in equity for the three months ended March 31, 2022 and 2021 and statement of cash flows for the three months ended March 31, 2022 and 2021 are unaudited. The consolidated balance sheet as of December 31, 2021 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, 2021 (“2021 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, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period.
Use of Estimates	Use of EstimatesIn 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, 2022: In October 2021, the FASB issued ASU 2021-08, Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers (“ASU 2021-08”). This update modifies how an acquiring entity measures contract assets and contract liabilities of an acquiree in a business combination in accordance with Topic 606. The amendments in this update require the acquiring entity in a business combination to account for revenue contracts as if they had originated the contract and assess how the acquiree accounted for the contract under Topic 606. ASU 2021-08 improves comparability of recognition and measurement of revenue contracts with customers both before and after a business combination. For public business entities, the amendments in this update are effective for fiscal years beginning after December 15, 2022. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2023. The amendments in this update should be applied prospectively to business combinations occurring on or after the effective date of the amendments with early adoption permitted. The Company expects the adoption of this standard will not have a material impact on its consolidated financial statements. In March 2022, the FASB issued ASU 2022-02, Financial Instruments–Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures (“ASU 2022-02”). The amendments in this update eliminate the accounting guidance on troubled debt restructurings (“TDRs”) for creditors in ASC 310-40 and amends the guidance on vintage disclosures, referenced in ASC 326-20-50, to require disclosure of current-period gross write-offs by year of origination. This update supersedes the existing account guidance for TDRs in ASC 310-40 in its entirety and requires entities to evaluate all receivable modifications under existing accounting guidance in ASC 310-20 to determine whether a modification made to a borrower results in a new loan or a continuation of an existing loan. In addition to the elimination of TDR accounting guidance, entities that adopt this update no longer consider renewals, modification and extensions that result from reasonably expected TDRs in their calculation of the allowance for credit losses. Further, if an entity employs a discounted cash flow method to calculate the allowance for credit losses, it will be required to use a post-modification-derived effective interest rate as part of its calculation. The update also requires new disclosures for receivables for which there has been a modification in their contractual cash flows resulting from borrowers experiencing financial difficulties. For public business entities, the amendments in this update are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Entities may elect to apply the updated guidance on TDR recognition and measurement by using a modified retrospective transition method. The amendments on TDR disclosures and vintage disclosures should be adopted prospectively. The Company expects the adoption of this standard will not have a material impact on its consolidated financial statements. Relevant standards that were adopted during the three months ended March 31, 2022: In June 2016, the FASB issued ASU 2016-13, Financial Instruments–Credit Losses on Financial Instruments and relevant amendments (Topic 326) (“ASU 2016-13”). This update was created to replace the then-current GAAP method of calculating credit losses. Specifically, the standard replaces the existing incurred loss impairment guidance by requiring immediate recognition of expected credit losses. For financial assets carried at amortized cost that are held at the reporting date (including trade and other receivables, loans and commitments, held-to-maturity debt securities and other financial assets), credit losses are measured based on historical experience, current conditions and reasonable supportable forecasts. The standard also amends existing impairment guidance for available for sale securities, in which credit losses will be recorded as an allowance versus a write-down of the amortized cost basis of the security. It also allows for a reversal of impairment loss when the credit of the issuer improves. The guidance requires a cumulative effect of the initial application to be recognized in retained earnings at the date of initial application. In November 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments – Credit Losses (“ASU 2018-19”). The amendments in ASU 2018-19 were intended to clarify that receivables arising from operating leases are not within the scope of Subtopic 326-20. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with Topic 842, Leases . In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments – Credit Losses . This update requires entities to include expected recoveries of the amortized cost basis previously written off or expected to be written off in the valuation account for purchased financial assets with credit deterioration. In addition, the amendments in this update clarify and improve various aspects of the guidance for ASU 2016-13. On January 1, 2022, the Company adopted ASUs 2016-13, 2018-19 and 2019-11 (codified in ASC 326, “Financial Instruments-Credit Losses” ), which replaced the incurred loss methodology (codified in ASC 450, “Contingencies,” ASC 310, “Receivables” and ASC 320, “Debt Securities” ) with an expected loss methodology that is referred to as current expected credit losses methodology (“CECL methodology”). The Company adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost and off-balance sheet credit exposures by means of a cumulative-effect adjustment to the opening retained earnings balance on the Company’s consolidated balance sheet as of the Company’s date of adoption of January 1, 2022. Accordingly, results for reporting periods beginning after December 31, 2021 are presented under ASU 2016-13, while prior period amounts continue to be reported in accordance with previously applicable GAAP. The Company recorded a net decrease to retained earnings of $20.1 million, net of deferred taxes of $7.9 million, as of January 1, 2022, for the cumulative effect of adopting ASU 2016-13. The Company adopted ASU 2016-13 using the prospective transition approach for purchased credit-deteriorated (“PCD”) financial assets that were previously classified as purchased credit-impaired (“PCI”) financial assets and accounted for under ASC 310-30. In accordance with ASU 2016-13, the Company did not reassess whether its assets previously classified as PCI assets met the criteria of PCD assets as of the date of adoption. Rather, loans previously determined to be PCI loans are considered to be PCD loans as of January 1, 2022. On January 1, 2022, the amortized cost basis of the PCD assets was adjusted to reflect the addition of the allowance for loan losses on PCD loans. The remaining noncredit discount will be accreted into the Company’s interest income at the then-effective interest rate as of January 1, 2022. The amount of the adjustment for PCD assets was not material to the Company. In March 2020, the FASB issued ASU 2020-4, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). This update addresses optional expedients and exceptions for applying GAAP to certain contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The new guidance applies only to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued because of reference rate reform. The expedients and exceptions provided by the amendments do not apply to contract modifications made and hedging relationships existing as of December 31, 2022, that an entity has elected certain optional expedients for and that are retained through the end of the hedging relationship. For public and nonpublic entities, the guidance is effective as of March 12, 2020 through December 31, 2022 and does not apply to contract modifications made after December 31, 2022. The Company performed a review its contracts and existing processes to assess the risks and potential impact of the transition away from LIBOR and noted no material impact to the Company’s consolidated financial statements as of March 31, 2022.
Allowance for Credit Losses	Allowance for Credit Losses - Available for Sale Securities ASU 2016-13 made targeted changes to ASC 320 to eliminate the concept of “other than temporary” from the impairment loss estimation model for available for sale (“AFS”) securities. A summary of the changes made by the Company to the existing impairment model (previously referred to as the “OTTI” impairment model) as a result of adoption of ASU 2016-13 is as follows: • The use of an allowance approach, rather than a permanent write-down of a security’s cost basis upon determination of an impairment loss. • The amount of the allowance is limited to the amount at which the security’s fair value is less than its amortized cost basis. • The Company may not consider the length of time a security’s fair value has been less than amortized cost. • The Company may not consider recoveries in fair value after the balance sheet date when assessing whether a credit loss exists. The Company’s AFS securities are carried at fair value. For AFS securities in an unrealized loss position, management will first evaluate whether there is intent to sell a security, 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 AFS 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 security is determined to be uncollectible, or when either of the aforementioned criteria surrounding intent or requirement to sell have been met. On January 1, 2022, the date on which the Company adopted ASU 2016-13, no allowance for credit losses was recorded for AFS securities. Refer to Note 3, “Securities” for additional information regarding the measurement of impairment losses on AFS securities. Allowance for Credit Losses - Held to Maturity Securities The Company measures expected credit losses on held to maturity (“HTM”) securities on a collective basis by major security type which, as of March 31, 2022, includes government-sponsored residential and commercial mortgage-backed securities. Securities in the Company’s held to maturity portfolio are 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 that these securities have a zero loss expectation and therefore does not estimate an allowance for credit losses on these securities. The Company held no securities classified as held to maturity at December 31, 2021. Refer to Note 3, “Securities” for additional information regarding the measurement of credit losses on HTM securities. Allowance for Loan Losses - Loans Held for Investment Loans Individually Assessed for Impairment ASU 2016-13 indicates that a loan should be measured for impairment individually if that loan shares no similar risk characteristics with other loans. For the Company, loans which have been identified as those to be individually assessed for impairment under CECL include loans that do not share similar risk characteristics with other loans in the corresponding reserve segment. Characteristics of loans meeting this definition may include, but is not limited to: • Loans previously restructured and determined to be TDR loans; • Loans on non-accrual status; and • Loans with a risk rating of 12 under the Company’s risk rating scale, substandard (well-defined weakness) or worse. Collateral-Dependent Loans Management considers a loan to be collateral-dependent when foreclosure of the underlying collateral is probable. In addition, in accordance with ASU 2016-13, the Company elected to apply the collateral-dependent practical expedient whereby the Company measures expected credit losses using the fair value of the collateral, less any estimated costs to sell, when foreclosure is not probable but repayment of the loan is expected to be provided substantially through the operation or sale of the collateral, and the borrower is experiencing financial difficulty. Troubled Debt Restructured Loans In cases where a borrower experiences financial difficulties and the Company makes certain concessionary modifications to contractual terms, the loan is classified as a TDR. Modifications may include adjustments to interest rates, extensions of maturity, consumer loans where the borrower’s obligations have been effectively discharged through Chapter 7 bankruptcy and the borrower has not reaffirmed the debt to the Company, and other actions intended to minimize economic loss and avoid foreclosure or repossession of collateral. Prior to the Company’s adoption of ASU 2016-13, all TDR loans were subject to a specific review for impairment loss each period beginning in the period in which the modification was executed. Subsequent to the adoption of ASU 2016-13, management identifies loans as TDR loans when it has a reasonable expectation that it will execute a TDR modification with a borrower. In addition, subsequent to adoption of ASU 2016-13, management estimates expected credit losses on a collective basis if a group of TDR loans share similar risk characteristics. If a TDR loan’s risk characteristics are not similar to those of any of the Company’s other TDR loans, expected credit losses on the TDR loan are measured individually. The impairment analysis discounts the present value of the anticipated cash flows by the loan’s contractual rate of interest in effect prior to the loan’s modification or the fair value of collateral if the loan is collateral dependent. The amount of credit loss, if any, is recorded as a specific loss allocation to each individual loan or as a loss allocation to the pool of loans, for those loans for which credit loss is measured on a collective basis, in the allowance for credit losses. Any commercial (commercial and industrial, commercial real estate, commercial construction, and business banking loans) or residential loan that has been classified as a TDR and which subsequently defaults is reviewed to determine if the loan should be deemed collateral-dependent. In such an instance, any shortfall between the value of the collateral and the book value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. The Company’s policy is to retain any restructured loan, which is on non-accrual status prior to being modified, on non-accrual status for approximately six months subsequent to being modified before the Company considers its return to accrual status. If the restructured loan is on accrual status prior to being modified, the Company reviews it to determine if the modified loan should remain on accrual status. Purchased Credit-Deteriorated Loans As described above, the Company applied the prospective transition approach with respect to PCD assets upon adoption of ASU 2016-13. Under this approach, loans previously determined to be PCI loans are considered to be PCD loans as of January 1, 2022. PCD loans are acquired individual loans (or acquired groups of loans with similar risk characteristics) that, as of the date of acquisition, have experienced a more-than-insignificant deterioration in credit quality since origination, as determined by the Company’s assessment. A PCD loan is recorded at its purchase price plus the allowance for loan losses expected at the time of acquisition, or “gross up” of the amortized cost basis, if any. Changes in the current estimate of the allowance for loan losses subsequent to acquisition from the estimated allowance previously recorded are recognized in the income statement as provision for credit losses or reversal of provision for credit losses in subsequent periods as they arise. A purchased loan that does not qualify as a PCD asset is accounted for similar to the Company’s method of accounting for originated assets, whereby an allowance for loan losses is recognized with a corresponding increase to the income statement provision for loan losses. Evidence that purchased loans, measured at amortized cost, have more-than-insignificant deterioration in credit quality since origination and, therefore meet the PCD definition, may include past-due status, non-accrual status, risk rating and other standard indicators (i.e., TDRs, charge-offs, bankruptcy). Allowance for Credit Losses Through December 31, 2021, the allowance for loan losses represented management’s best estimate of incurred probable losses in the Company’s loan portfolios based upon management’s assessment of various factors, including the risk characteristics of its loan portfolio, current economic conditions, and trends in loan delinquencies and charge-offs. The Company’s methodology for determining the qualitative component through December 31, 2021 included an assessment of factors affecting the determination of incurred losses in the loan portfolio. Such factors included trends in economic conditions, loan growth, credit underwriting policy exceptions, regulatory and audit findings, and peer comparisons, among others. Upon adoption of ASU 2016-13, effective January 1, 2022, the Company changed its reserve methodology to estimate expected credit losses over the contractual life of loans and leases. The allowance for credit losses, or ACL, is established to provide for the Company’s current estimate of expected lifetime credit losses on loans measured at amortized cost and unfunded lending commitments at the balance sheet date and is established through a provision for credit losses charged to net income. Credit losses are charged directly to the ACL. Subsequent recoveries, if any, are credited to the ACL. Commercial and residential loans are charged-off in the period in which they are deemed uncollectible. Delinquent loans in these product types are subject to ongoing review and analysis to determine if a charge-off in the current period is appropriate. For consumer finance loans, policies and procedures exist that require charge-off consideration upon a certain triggering event depending on the product type. Charge-off triggers include: 120 days delinquent for automobile, home equity, and other consumer loans with the exception of cash reserve loans for which the trigger is 150 days delinquent; death of the borrower; or Chapter 7 bankruptcy. In addition to those events, the charge-off determination includes other loan quality indicators, such as collateral position and adequacy or the presence of other repayment sources. The ACL is evaluated on a regular basis by management. Management uses a methodology to systematically estimate the amount of expected lifetime losses in the portfolio. Expected lifetime losses are estimated on a collective basis for loans sharing similar risk characteristics and are determined 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. For commercial and industrial, commercial real estate, commercial construction and business banking portfolios, the quantitative model uses a loan rating system which is comprised of management’s determination of a financial asset’s probability of default (“PD”), loss given default (“LGD”) and exposure at default (“EAD”), which are derived from historical loss experience and other factors. For residential real estate, consumer home equity and other consumer portfolios, the Company’s quantitative model uses historical loss experience. The quantitative 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 loss average. Management has determined that a reasonable and supportable forecast period of eight quarters, and a straight-line reversion period of four quarters, are appropriate forecast periods for purposes of estimating expected credit losses. As described above, quantitative model results are adjusted for risk factors not considered within the model but which are relevant in estimating the expected credit losses within the loan portfolio. The qualitative risk factors impacting the expected risk of loss within the loan portfolio include the following: • Lending policies and procedures, including underwriting standards and collection, charge-off and recovery practices; • Nature and volume of the portfolio; • Volume and severity of past-due, non-accrual and classified loans; • The value of the underlying collateral for loans that are not collateral dependent; • Concentrations of credit risk; • Model and data limitations; and • Other external factors, such as changes in legal, regulatory or competitive environments. 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. For loans that are individually evaluated, the Company uses either a discounted cash flow (“DCF”) approach or, for loans deemed to be collateral dependent or when foreclosure is probable, a fair value of collateral approach. Accrued interest receivable amounts are excluded from balances of loans held at amortized cost and are included within other assets on the consolidated balance sheet. 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 non-accrual loans, accrued interest receivable is typically written off when loans reach 90 days past due and are placed on non-accrual status. In the ordinary course of business, the Company enters into commitments to extend 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 reserving method for loans receivable previously described. The reserve for unfunded lending commitments is included in other liabilities in the balance sheet. Additionally, various regulatory agencies, as an integral part of the Company’s examination process, periodically assess the appropriateness of the allowance for credit losses and may require the Company to increase its allowance for loan losses or recognize further loan charge-offs, in accordance with GAAP.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Securities [Abstract]
Debt Securities, Available-for-sale	The amortized cost, gross unrealized gains and losses, allowance for credit losses and fair value of AFS securities as of March 31, 2022 and December 31, 2021 were as follows: As of March 31, 2022 Amortized Unrealized Unrealized Allowance for Credit Losses Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 5,329,748 $ 264 $ (360,666) $ — $ 4,969,346 Government-sponsored commercial mortgage-backed securities 1,707,131 — (91,204) — 1,615,927 U.S. Agency bonds 1,099,916 — (86,017) — 1,013,899 U.S. Treasury securities 59,458 — (3,223) — 56,235 State and municipal bonds and obligations 258,769 2,792 (1,245) — 260,316 Other debt securities 1,598 — (16) — 1,582 $ 8,456,620 $ 3,056 $ (542,371) $ — $ 7,917,305 As of December 31, 2021 Amortized Unrealized Unrealized Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 5,577,292 $ 17,918 $ (70,502) $ 5,524,708 Government-sponsored commercial mortgage-backed securities 1,420,748 760 (12,640) 1,408,868 U.S. Agency bonds 1,202,377 1,067 (28,430) 1,175,014 U.S. Treasury securities 89,434 5 (834) 88,605 State and municipal bonds and obligations 263,910 16,460 (41) 280,329 Small business administration pooled securities 31,821 282 — 32,103 Other debt securities 1,597 — — 1,597 $ 8,587,179 $ 36,492 $ (112,447) $ 8,511,224
Summary Of Government-Sponsored Residential Mortgage-Backed Securities With Gross Unrealized Losses	Information pertaining to AFS securities with gross unrealized losses as of March 31, 2022, for which the Company did not recognize a provision for credit losses under CECL, and as of December 31, 2021, for which the Company did not deem to be OTTI under its prior methodology, aggregated by investment category and length of time that individual securities had been in a continuous loss position, follows: As of March 31, 2022 Less than 12 Months 12 Months or Longer Total # of Gross Fair Gross Fair Gross Fair (Dollars in thousands) Government-sponsored residential mortgage-backed securities 322 $ 223,347 $ 3,513,073 $ 137,319 $ 1,403,234 $ 360,666 $ 4,916,307 Government-sponsored commercial mortgage-backed securities 205 85,425 1,548,080 5,779 67,847 91,204 1,615,927 U.S. Agency bonds 37 12,573 226,708 73,444 787,191 86,017 1,013,899 U.S. Treasury securities 2 3,223 56,235 — — 3,223 56,235 State and municipal bonds and obligations 103 1,245 82,709 — — 1,245 82,709 Other debt securities 3 16 1,582 — — 16 1,582 672 $ 325,829 $ 5,428,387 $ 216,542 $ 2,258,272 $ 542,371 $ 7,686,659 As of December 31, 2021 Less than 12 Months 12 Months or Longer Total # of Gross Fair Gross Fair Gross Fair (Dollars in thousands) Government-sponsored residential mortgage-backed securities 264 $ 70,502 $ 4,615,457 $ — $ — $ 70,502 $ 4,615,457 Government-sponsored commercial mortgage-backed securities 165 12,218 1,102,444 422 15,682 12,640 1,118,126 U.S. Agency bonds 27 2,169 191,222 26,261 794,353 28,430 985,575 U.S. Treasury securities 3 834 78,588 — — 834 78,588 State and municipal bonds and obligations 11 41 5,436 — — 41 5,436 470 $ 85,764 $ 5,993,147 $ 26,683 $ 810,035 $ 112,447 $ 6,803,182
Debt Securities, Held-to-maturity	The amortized cost, gross unrealized gains and losses, and fair value of HTM securities as of March 31, 2022 were as follows: As of March 31, 2022 Amortized Unrealized Unrealized Allowance for Credit Losses Fair (In thousands) Debt securities: Government-sponsored residential mortgage-backed securities $ 192,231 $ — $ (3,318) $ — $ 188,913 Government-sponsored commercial mortgage-backed securities 203,203 17 (10) — 203,210 $ 395,434 $ 17 $ (3,328) $ — $ 392,123
Summary Of Fair Value Of Securities By Contractual Maturities	The scheduled contractual maturities of AFS and HTM securities as of the dates indicated were as follows: As of March 31, 2022 Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (In thousands) Available for sale securities Government-sponsored residential mortgage-backed securities $ 1 $ 1 $ 20,992 $ 21,143 $ 832,510 $ 790,125 $ 4,476,245 $ 4,158,077 $ 5,329,748 $ 4,969,346 Government-sponsored commercial mortgage-backed securities — — 190,509 182,639 700,994 658,732 815,628 774,556 1,707,131 1,615,927 U.S. Agency bonds — — 578,810 537,301 521,106 476,598 — — 1,099,916 1,013,899 U.S. Treasury securities 10,000 9,955 49,458 46,280 — — — — 59,458 56,235 State and municipal bonds and obligations 4,659 4,653 36,766 36,723 68,574 68,850 148,770 150,090 258,769 260,316 Other debt securities 300 299 1,298 1,283 — — — — 1,598 1,582 Total available for sale securities 14,960 14,908 877,833 825,369 2,123,184 1,994,305 5,440,643 5,082,723 8,456,620 7,917,305 Held to maturity securities Government-sponsored residential mortgage-backed securities — — — — — — 192,231 188,913 192,231 188,913 Government-sponsored commercial mortgage-backed securities — — — — 203,203 203,210 — — 203,203 203,210 Total held to maturity securities — — — — 203,203 203,210 192,231 188,913 395,434 392,123 Total $ 14,960 $ 14,908 $ 877,833 $ 825,369 $ 2,326,387 $ 2,197,515 $ 5,632,874 $ 5,271,636 $ 8,852,054 $ 8,309,428 As of December 31, 2021 Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (In thousands) Available for sale securities Government-sponsored residential mortgage-backed securities $ — $ — $ 24,935 $ 25,962 $ 899,169 $ 892,029 $ 4,653,188 $ 4,606,717 $ 5,577,292 $ 5,524,708 Government-sponsored commercial mortgage-backed securities — — 139,095 137,755 387,177 378,414 894,476 892,699 1,420,748 1,408,868 U.S. Agency bonds 5,508 5,515 531,821 520,935 665,048 648,564 — — 1,202,377 1,175,014 U.S. Treasury securities 40,010 40,001 49,424 48,604 — — — — 89,434 88,605 State and municipal bonds and obligations 6,137 6,116 33,692 34,704 72,226 75,416 151,855 164,093 263,910 280,329 Small Business Administration pooled securities — — 4,062 4,092 — — 27,759 28,011 31,821 32,103 Other debt securities 300 300 1,297 1,297 — — — — 1,597 1,597 Total $ 51,955 $ 51,932 $ 784,326 $ 773,349 $ 2,023,620 $ 1,994,423 $ 5,727,278 $ 5,691,520 $ 8,587,179 $ 8,511,224

Loans and Allowance for Credi_2

Loans and Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	The following table provides a summary of the Company’s loan portfolio as of the dates indicated: At March 31, At December 31, 2022 2021 (In thousands) Commercial and industrial $ 2,886,560 $ 2,960,527 Commercial real estate 4,609,824 4,522,513 Commercial construction 246,093 222,328 Business banking 1,201,007 1,334,694 Residential real estate 1,936,182 1,926,810 Consumer home equity 1,099,211 1,100,153 Other consumer 203,326 214,485 Gross loans before unamortized premiums, unearned discounts and deferred fees 12,182,203 12,281,510 Allowance for loan losses (1) (124,166) (97,787) Unamortized premiums, net of unearned discounts and deferred fees (24,434) (26,442) Loans after the allowance for loan losses, unamortized premiums, unearned discounts and deferred fees $ 12,033,603 $ 12,157,281 (1) The Company adopted ASU 2016-13 on January 1, 2022 with a modified retrospective approach. Accordingly, at March 31, 2022 the allowance for loan losses at was determined in accordance with ASC 326, “Financial Instruments-Credit Losses” and ASC 310, “Receivables,” as amended. At December 31, 2021 the allowance for loan losses was determined in accordance with ASC 450, “Contingencies” and ASC 310, “Receivables.”
Financing Receivable, Allowance for Credit Loss	The following table summarizes the change in the allowance for loan losses by loan category for the three months ended March 31, 2022: Three Months Ended March 31, 2022 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance, prior to adoption of ASU 2016-13 $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Cumulative effect of change in accounting principle (1) 11,533 (6,655) 1,485 6,160 13,489 1,857 (541) (242) 27,086 Charge-offs (1) — — (945) — — (661) — (1,607) Recoveries 250 14 — 928 10 4 179 — 1,385 (Release of) provision (2,959) (1,120) 344 143 2,188 435 484 — (485) Ending balance (2) $ 26,841 $ 44,612 $ 4,414 $ 17,269 $ 22,243 $ 6,018 $ 2,769 $ — $ 124,166 (1) Represents the adjustment needed to reflect the cumulative day one impact pursuant to the Company’s adoption of ASU 2016-13 (i.e., cumulative effect adjustment related the adoption of ASU 2016-13 as of January 1, 2022). The adjustment represents a $27.1 million increase to the allowance attributable to the change in accounting methodology for estimating the allowance for loan losses resulting from the Company’s adoption of the standard. The adjustment also includes the adjustment needed to reflect the day one reclassification of the Company’s PCI loan balances to PCD and the associated gross-up of $0.1 million, pursuant to the Company’s adoption of ASU 2016-13. (2) The balance of accrued interest receivable excluded from amortized cost and the calculation of the allowance for loan losses amounted to $31.4 million at March 31, 2022. For the Three Months Ended March 31, 2021 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance $ 26,617 $ 54,569 $ 4,553 $ 13,152 $ 6,435 $ 3,744 $ 3,467 $ 494 $ 113,031 Charge-offs — (234) — (1,384) — — (364) — (1,982) Recoveries 9 — — 365 10 71 156 — 611 (Release of) Provision (1,220) 803 (1,203) 1,371 (210) (239) 239 (121) (580) Ending balance $ 25,406 $ 55,138 $ 3,350 $ 13,504 $ 6,235 $ 3,576 $ 3,498 $ 373 $ 111,080 The following tables bifurcate the amount of loans and the allowance for loan losses allocated to each loan category based on the type of impairment analysis as of December 31, 2021: As of December 31, 2021 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses ending balance: Individually evaluated for impairment $ 1,540 $ — $ — $ 450 $ 1,549 $ 270 $ 161 $ — $ 3,970 Acquired with deteriorated credit quality 5 298 — — 243 — — — 546 Collectively evaluated for impairment 16,473 52,075 2,585 10,533 4,764 3,452 3,147 242 93,271 Total allowance for loan losses by group $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Loans ending balance: Individually evaluated for impairment $ 16,145 $ 3,520 $ — $ 12,060 $ 22,378 $ 3,922 $ 179 $ — $ 58,204 Acquired with deteriorated credit quality 19,028 47,553 — — 3,058 — — — 69,639 Collectively evaluated for impairment 2,925,354 4,471,440 222,328 1,322,634 1,901,374 1,096,231 214,306 — 12,153,667 Total loans by group $ 2,960,527 $ 4,522,513 $ 222,328 $ 1,334,694 $ 1,926,810 $ 1,100,153 $ 214,485 $ — $ 12,281,510
Financing Receivable Credit Quality Indicators	The following table details the amortized cost balances of the Company’s loan portfolios, presented by credit quality indicator and origination year as of March 31, 2022: 2022 2021 2020 2019 2018 Prior Revolving Loans Revolving Loans Converted to Term Loans (1) Total (In thousands) Commercial and industrial Pass $ 117,534 $ 566,764 $ 498,791 $ 231,968 $ 142,428 $ 689,728 $ 504,127 $ 686 $ 2,752,026 Special Mention — 886 — 514 278 4,459 51,581 — 57,718 Substandard — 11,302 3,756 340 23,031 8,275 790 346 47,840 Doubtful — 4,996 — — — 114 3,384 — 8,494 Loss — — — — — — — — — Total commercial and industrial 117,534 583,948 502,547 232,822 165,737 702,576 559,882 1,032 2,866,078 Commercial real estate Pass 378,744 845,405 641,300 676,903 495,084 1,304,769 43,970 3,478 4,389,653 Special Mention 26,613 — 16,142 3,796 19,562 19,776 — — 85,889 Substandard 29,903 58 4,663 1,654 38,038 49,327 8,000 — 131,643 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial real estate 435,260 845,463 662,105 682,353 552,684 1,373,872 51,970 3,478 4,607,185 Commercial construction Pass 3,623 124,777 59,181 32,857 — — 15,760 — 236,198 Special Mention — — 2,097 — — — — — 2,097 Substandard — — — 6,743 — — — — 6,743 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial construction 3,623 124,777 61,278 39,600 — — 15,760 — 245,038 Business banking Pass 54,881 309,961 200,726 141,974 69,341 285,849 77,782 3,436 1,143,950 Special Mention 2,174 2,176 3,219 9,152 7,181 14,498 1,908 — 40,308 Substandard — 464 1,617 4,993 564 9,542 1,244 680 19,104 Doubtful — — — 203 — 103 — — 306 Loss — — — — — — — — — Total business banking 57,055 312,601 205,562 156,322 77,086 309,992 80,934 4,116 1,203,668 Residential real estate Current and accruing 81,889 740,106 406,401 112,976 78,320 505,432 — — 1,925,124 30-89 days past due and accruing — 2,553 1,387 201 1,513 6,808 — — 12,462 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 129 582 784 6,761 — — 8,256 Total residential real estate 81,889 742,659 407,917 113,759 80,617 519,001 — — 1,945,842 Consumer home equity Current and accruing 15,321 12,792 6,903 6,448 26,582 91,599 929,383 1,788 1,090,816 30-89 days past due and accruing — 33 31 — 170 1,490 2,004 67 3,795 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 74 679 1,293 1,948 3,147 — 7,141 Total consumer home equity 15,321 12,825 7,008 7,127 28,045 95,037 934,534 1,855 1,101,752 Other consumer Current and accruing 15,652 39,868 22,534 25,531 33,967 33,664 15,295 — 186,511 30-89 days past due and accruing 12 107 76 117 449 429 — — 1,190 Accruing loans past 90 days due — — — — — — — — — Non-accrual — 95 27 37 174 172 — — 505 Total other consumer 15,664 40,070 22,637 25,685 34,590 34,265 15,295 — 188,206 Total $ 726,346 $ 2,662,343 $ 1,869,054 $ 1,257,668 $ 938,759 $ 3,034,743 $ 1,658,375 $ 10,481 $ 12,157,769 (1) The amounts presented represent the amortized cost as of March 31, 2022 of revolving loans that were converted to term loans during the three months ended March 31, 2022. As of December 31, 2021 Category Commercial and Commercial Commercial Business Total (In thousands) Unrated $ 171,537 $ 4,378 $ — $ 696,629 $ 872,544 Pass 2,656,873 4,199,803 213,744 569,956 7,640,376 Special mention 70,141 104,517 1,889 50,085 226,632 Substandard 50,339 213,815 6,695 17,814 288,663 Doubtful 11,637 — — 210 11,847 Loss — — — — — Total $ 2,960,527 $ 4,522,513 $ 222,328 $ 1,334,694 $ 9,040,062
Financing Receivable, Past Due	The following tables show the age analysis of past due loans as of the dates indicated: As of March 31, 2022 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 146 $ — $ 1,994 $ 2,140 $ 2,863,938 $ 2,866,078 Commercial real estate 600 — 501 1,101 4,606,084 4,607,185 Commercial construction 6,743 — — 6,743 238,295 245,038 Business banking 4,599 875 3,294 8,768 1,194,900 1,203,668 Residential real estate 10,384 2,162 6,379 18,925 1,926,917 1,945,842 Consumer home equity 2,517 1,348 6,726 10,591 1,091,161 1,101,752 Other consumer 971 219 505 1,695 186,511 188,206 Total $ 25,960 $ 4,604 $ 19,399 $ 49,963 $ 12,107,806 $ 12,157,769 As of December 31, 2021 30-59 60-89 90 or More Total Past Current Total (In thousands) Commercial and industrial $ 45 $ 31 $ 1,672 $ 1,748 $ 2,958,779 $ 2,960,527 Commercial real estate 25,931 — 1,196 27,127 4,495,386 4,522,513 Commercial construction — — — — 222,328 222,328 Business banking 5,043 1,793 4,640 11,476 1,323,218 1,334,694 Residential real estate 17,523 3,511 5,543 26,577 1,900,233 1,926,810 Consumer home equity 3,774 1,510 4,571 9,855 1,090,298 1,100,153 Other consumer 1,194 548 889 2,631 211,854 214,485 Total (1) $ 53,510 $ 7,393 $ 18,511 $ 79,414 $ 12,202,096 $ 12,281,510 (1) The amounts presented in the table above represent the recorded investment balance of loans as of December 31, 2021.
Financing Receivable, Nonaccrual	The following table presents information regarding non-accrual loans as of the dates indicated: As of and for the Three Months Ended March 31, 2022 As of December 31, 2021 Non-Accrual Loans With ACL Non-Accrual Loans Without ACL (4) Total Non-Accrual Loans Amortized Cost of Loans >90 DPD and Still Accruing (2) Total Non-Accrual Loans (1) Recorded Investment >90 DPD and Still Accruing (In thousands) Commercial and industrial $ 3,496 $ 6,990 $ 10,486 $ — $ 12,400 $ — Commercial real estate — 501 501 — — 1,196 Commercial construction — — — — — — Business banking 6,410 522 6,932 — 8,230 — Residential real estate 8,256 — 8,256 — 6,681 769 Consumer home equity 7,141 — 7,141 — 4,732 25 Other consumer 505 — 505 — 950 — Total non-accrual loans $ 25,808 $ 8,013 $ 33,821 $ — $ 32,993 $ 1,990 (1) The amounts presented represent the recorded investment balance of loans as of December 31, 2021. (2) “DPD” indicated in the table above refers to “days past due.” (3) The amount of interest income recognized on non-accrual loans during the three months ended March 31, 2022 was not significant. (4) The loans on non-accrual status and without an ACL as of March 31, 2022, were primarily comprised of collateral dependent loans for which the fair value of the underlying loan collateral exceeded the loan carrying value.
Financing Receivable, Troubled Debt Restructuring	The following tables show the TDR loans on accrual and non-accrual status as of the dates indicated: As of March 31, 2022 TDRs on Accrual Status TDRs on Non-Accrual Status Total TDRs Number of Loans Balance of Number of Balance of Number of Balance of (Dollars in thousands) Commercial and industrial 1 $ 3,894 7 $ 8,381 8 $ 12,275 Commercial real estate 1 3,520 — — 1 3,520 Business banking 5 3,771 8 814 13 4,585 Residential real estate 116 17,786 29 3,583 145 21,369 Consumer home equity 66 3,028 15 859 81 3,887 Other consumer 2 17 — — 2 17 Total 191 $ 32,016 59 $ 13,637 250 $ 45,653 As of December 31, 2021 TDRs on Accrual Status TDRs on Non-Accrual Status Total TDRs Number of Loans Balance of Number of Loans Balance of Number of Loans Balance of (Dollars in thousands) Commercial and industrial 1 $ 3,745 6 $ 9,983 7 $ 13,728 Commercial real estate 1 3,520 — — 1 3,520 Business banking 5 3,830 3 383 8 4,213 Residential real estate 121 19,119 27 3,015 148 22,134 Consumer home equity 67 3,104 16 818 83 3,922 Other consumer 2 18 — — 2 18 Total (1) 197 $ 33,336 52 $ 14,199 249 $ 47,535 (1) The amounts presented in the table above represent the recorded investment balance of loans as of December 31, 2021. The following tables show the modifications which occurred during the periods and the change in the recorded investment subsequent to the modifications occurring: For the Three Months Ended March 31, 2022 For the Three Months Ended March 31, 2021 Number Pre- Post- Number Pre-Modification Post- (Dollars in thousands) Business banking 5 $ 440 $ 448 — $ — $ — Residential real estate 1 134 134 1 295 295 Consumer home equity 1 210 210 — — — Total 7 $ 784 $ 792 1 $ 295 $ 295 (1) The post-modification balances represent the balance of the loan on the date of modification. These amounts may show an increase when modification includes capitalization of interest. The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Extended maturity $ 402 $ — Adjusted interest rate and extended maturity 390 — Court-ordered concession — 295 Total $ 792 $ 295 The following table shows the number of loans and the recorded investment amount of those loans, as of the respective date, that have been modified during the prior 12 months which have subsequently defaulted during the periods indicated. The Company considers a loan to have defaulted when it reaches 90 days past due or is transferred to non-accrual: For the Three Months Ended March 31, 2022 2021 Number of Recorded Number of Recorded (Dollars in thousands) Troubled debt restructurings that subsequently defaulted (1): Business banking — $ — 1 $ 419 Consumer home equity — — 1 59 Total — $ — 2 $ 478
Schedule of Participating Mortgage Loans	The following table summarizes the Company’s loan participations: As of and for the Three Months Ended March 31, 2022 As of and for the Year Ended December 31, 2021 Balance (1) Non-performing Gross Balance (1) Non-performing Gross (Dollars in thousands) Commercial and industrial $ 744,231 1.13 % $ — $ 732,425 1.36 % $ — Commercial real estate 390,540 0.00 % — 362,898 0.00 % — Commercial construction 42,661 0.00 % — 37,081 0.00 % — Business banking 143 0.00 % — 98 0.00 % — Total loan participations $ 1,177,575 0.71 % $ — $ 1,132,502 0.88 % $ — (1) The balance of loan participations as of March 31, 2022 represents the amortized cost basis and the balance as of December 31, 2021 represents the recorded investment balance. The difference between amortized cost basis and recorded investment basis as of March 31, 2022 is not material.

Loans and Allowance for Loan _2

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Financing Receivable, Allowance for Credit Loss	The following table summarizes the change in the allowance for loan losses by loan category for the three months ended March 31, 2022: Three Months Ended March 31, 2022 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance, prior to adoption of ASU 2016-13 $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Cumulative effect of change in accounting principle (1) 11,533 (6,655) 1,485 6,160 13,489 1,857 (541) (242) 27,086 Charge-offs (1) — — (945) — — (661) — (1,607) Recoveries 250 14 — 928 10 4 179 — 1,385 (Release of) provision (2,959) (1,120) 344 143 2,188 435 484 — (485) Ending balance (2) $ 26,841 $ 44,612 $ 4,414 $ 17,269 $ 22,243 $ 6,018 $ 2,769 $ — $ 124,166 (1) Represents the adjustment needed to reflect the cumulative day one impact pursuant to the Company’s adoption of ASU 2016-13 (i.e., cumulative effect adjustment related the adoption of ASU 2016-13 as of January 1, 2022). The adjustment represents a $27.1 million increase to the allowance attributable to the change in accounting methodology for estimating the allowance for loan losses resulting from the Company’s adoption of the standard. The adjustment also includes the adjustment needed to reflect the day one reclassification of the Company’s PCI loan balances to PCD and the associated gross-up of $0.1 million, pursuant to the Company’s adoption of ASU 2016-13. (2) The balance of accrued interest receivable excluded from amortized cost and the calculation of the allowance for loan losses amounted to $31.4 million at March 31, 2022. For the Three Months Ended March 31, 2021 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses: Beginning balance $ 26,617 $ 54,569 $ 4,553 $ 13,152 $ 6,435 $ 3,744 $ 3,467 $ 494 $ 113,031 Charge-offs — (234) — (1,384) — — (364) — (1,982) Recoveries 9 — — 365 10 71 156 — 611 (Release of) Provision (1,220) 803 (1,203) 1,371 (210) (239) 239 (121) (580) Ending balance $ 25,406 $ 55,138 $ 3,350 $ 13,504 $ 6,235 $ 3,576 $ 3,498 $ 373 $ 111,080 The following tables bifurcate the amount of loans and the allowance for loan losses allocated to each loan category based on the type of impairment analysis as of December 31, 2021: As of December 31, 2021 Commercial Commercial Commercial Business Residential Consumer Other Other Total (In thousands) Allowance for loan losses ending balance: Individually evaluated for impairment $ 1,540 $ — $ — $ 450 $ 1,549 $ 270 $ 161 $ — $ 3,970 Acquired with deteriorated credit quality 5 298 — — 243 — — — 546 Collectively evaluated for impairment 16,473 52,075 2,585 10,533 4,764 3,452 3,147 242 93,271 Total allowance for loan losses by group $ 18,018 $ 52,373 $ 2,585 $ 10,983 $ 6,556 $ 3,722 $ 3,308 $ 242 $ 97,787 Loans ending balance: Individually evaluated for impairment $ 16,145 $ 3,520 $ — $ 12,060 $ 22,378 $ 3,922 $ 179 $ — $ 58,204 Acquired with deteriorated credit quality 19,028 47,553 — — 3,058 — — — 69,639 Collectively evaluated for impairment 2,925,354 4,471,440 222,328 1,322,634 1,901,374 1,096,231 214,306 — 12,153,667 Total loans by group $ 2,960,527 $ 4,522,513 $ 222,328 $ 1,334,694 $ 1,926,810 $ 1,100,153 $ 214,485 $ — $ 12,281,510
Financing Receivable Credit Quality Indicators	The following table details the amortized cost balances of the Company’s loan portfolios, presented by credit quality indicator and origination year as of March 31, 2022: 2022 2021 2020 2019 2018 Prior Revolving Loans Revolving Loans Converted to Term Loans (1) Total (In thousands) Commercial and industrial Pass $ 117,534 $ 566,764 $ 498,791 $ 231,968 $ 142,428 $ 689,728 $ 504,127 $ 686 $ 2,752,026 Special Mention — 886 — 514 278 4,459 51,581 — 57,718 Substandard — 11,302 3,756 340 23,031 8,275 790 346 47,840 Doubtful — 4,996 — — — 114 3,384 — 8,494 Loss — — — — — — — — — Total commercial and industrial 117,534 583,948 502,547 232,822 165,737 702,576 559,882 1,032 2,866,078 Commercial real estate Pass 378,744 845,405 641,300 676,903 495,084 1,304,769 43,970 3,478 4,389,653 Special Mention 26,613 — 16,142 3,796 19,562 19,776 — — 85,889 Substandard 29,903 58 4,663 1,654 38,038 49,327 8,000 — 131,643 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial real estate 435,260 845,463 662,105 682,353 552,684 1,373,872 51,970 3,478 4,607,185 Commercial construction Pass 3,623 124,777 59,181 32,857 — — 15,760 — 236,198 Special Mention — — 2,097 — — — — — 2,097 Substandard — — — 6,743 — — — — 6,743 Doubtful — — — — — — — — — Loss — — — — — — — — — Total commercial construction 3,623 124,777 61,278 39,600 — — 15,760 — 245,038 Business banking Pass 54,881 309,961 200,726 141,974 69,341 285,849 77,782 3,436 1,143,950 Special Mention 2,174 2,176 3,219 9,152 7,181 14,498 1,908 — 40,308 Substandard — 464 1,617 4,993 564 9,542 1,244 680 19,104 Doubtful — — — 203 — 103 — — 306 Loss — — — — — — — — — Total business banking 57,055 312,601 205,562 156,322 77,086 309,992 80,934 4,116 1,203,668 Residential real estate Current and accruing 81,889 740,106 406,401 112,976 78,320 505,432 — — 1,925,124 30-89 days past due and accruing — 2,553 1,387 201 1,513 6,808 — — 12,462 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 129 582 784 6,761 — — 8,256 Total residential real estate 81,889 742,659 407,917 113,759 80,617 519,001 — — 1,945,842 Consumer home equity Current and accruing 15,321 12,792 6,903 6,448 26,582 91,599 929,383 1,788 1,090,816 30-89 days past due and accruing — 33 31 — 170 1,490 2,004 67 3,795 Accruing loans past 90 days due — — — — — — — — — Non-accrual — — 74 679 1,293 1,948 3,147 — 7,141 Total consumer home equity 15,321 12,825 7,008 7,127 28,045 95,037 934,534 1,855 1,101,752 Other consumer Current and accruing 15,652 39,868 22,534 25,531 33,967 33,664 15,295 — 186,511 30-89 days past due and accruing 12 107 76 117 449 429 — — 1,190 Accruing loans past 90 days due — — — — — — — — — Non-accrual — 95 27 37 174 172 — — 505 Total other consumer 15,664 40,070 22,637 25,685 34,590 34,265 15,295 — 188,206 Total $ 726,346 $ 2,662,343 $ 1,869,054 $ 1,257,668 $ 938,759 $ 3,034,743 $ 1,658,375 $ 10,481 $ 12,157,769 (1) The amounts presented represent the amortized cost as of March 31, 2022 of revolving loans that were converted to term loans during the three months ended March 31, 2022. As of December 31, 2021 Category Commercial and Commercial Commercial Business Total (In thousands) Unrated $ 171,537 $ 4,378 $ — $ 696,629 $ 872,544 Pass 2,656,873 4,199,803 213,744 569,956 7,640,376 Special mention 70,141 104,517 1,889 50,085 226,632 Substandard 50,339 213,815 6,695 17,814 288,663 Doubtful 11,637 — — 210 11,847 Loss — — — — — Total $ 2,960,527 $ 4,522,513 $ 222,328 $ 1,334,694 $ 9,040,062
Impaired Financing Receivables	The following table summarizes the Company’s impaired loans by loan portfolio as of December 31, 2021: As of December 31, 2021 Recorded Unpaid Related (In thousands) With no related allowance recorded: Commercial and industrial $ 12,309 $ 13,212 $ — Commercial real estate 3,520 3,520 — Business banking 4,199 5,069 — Residential real estate 11,217 12,587 — Consumer home equity 1,924 1,924 — Other consumer 18 18 — Sub-total 33,187 36,330 — With an allowance recorded: Commercial and industrial 3,836 4,226 1,540 Commercial real estate — — — Business banking 7,861 11,240 450 Residential real estate 11,161 11,161 1,549 Consumer home equity 1,998 1,998 270 Other consumer 161 161 161 Sub-total 25,017 28,786 3,970 Total $ 58,204 $ 65,116 $ 3,970 The following table displays information regarding interest income recognized on impaired loans, by portfolio, for the three months ended March 31, 2021: For the Three Months Ended March 31, 2021 Average Total (In thousands) With no related allowance recorded: Commercial and industrial $ 9,899 $ 46 Commercial real estate 4,176 44 Business banking 5,024 26 Residential real estate 14,648 144 Consumer home equity 2,438 20 Other consumer 27 — Sub-total 36,212 280 With an allowance recorded: Commercial and industrial 7,965 — Commercial real estate 657 — Business banking 16,325 14 Residential real estate 12,248 127 Consumer home equity 2,150 18 Sub-total 39,345 159 Total $ 75,557 $ 439
Schedule Financing Receivable, Purchased with Credit Deterioration	The following table displays the outstanding and carrying amounts of PCI loans as of December 31, 2021: As of December 31, 2021 (In thousands) Outstanding balance $ 78,074 Carrying amount 69,639
Schedule Of Certain Loans And Debt Securities Acquired In Transfer	The following table summarizes activity in the accretable yield for the PCI loan portfolio: For the Three Months Ended March 31, 2021 (In thousands) Balance at beginning of period $ 2,495 Accretion (216) Other change in expected cash flows (248) Balance at end of period $ 2,031

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Summary of Lease Cost	As of the dates indicated, the Company had the following related to operating leases: As of March 31, 2022 As of December 31, 2021 (In thousands) Right-of-use assets $ 80,408 $ 83,821 Lease liabilities 85,573 89,296 The following tables are a summary of the Company’s components of net lease cost for the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Operating lease cost $ 3,694 $ 3,561 Finance lease cost 88 31 Variable lease cost 829 490 Total lease cost $ 4,611 $ 4,082
Summary of Other Information Related to Leases	Supplemental balance sheet information related to operating leases are as follows: As of March 31, 2022 As of December 31, 2021 Weighted-average remaining lease term (in years) 7.65 7.83 Weighted-average discount rate 2.54 % 2.52 %

Goodwill and Other Intangibles

Goodwill and Other Intangibles (Tables)	3 Months Ended
	Mar. 31, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill and Other Intangible Assets	The following tables set forth the carrying amount of goodwill and other intangible assets, net of accumulated amortization, by reporting unit at the dates indicated below: As of March 31, 2022 Banking Insurance Net (In thousands) Balances not subject to amortization Goodwill $ 557,635 $ 77,144 $ 634,779 Balances subject to amortization Insurance agency (1) — 8,708 8,708 Core deposit intangible 11,272 — 11,272 Total other intangible assets 11,272 8,708 19,980 Total goodwill and other intangible assets $ 568,907 $ 85,852 $ 654,759 (1) Insurance agency intangible assets include customer list, non-compete agreement and supplier relationship intangible assets. As of December 31, 2021 Banking Insurance Net (In thousands) Balances not subject to amortization Goodwill $ 557,635 $ 73,861 $ 631,496 Balances subject to amortization Insurance agency (1) — 6,635 6,635 Core deposit intangible 11,572 — 11,572 Total other intangible assets 11,572 6,635 18,207 Total goodwill and other intangible assets $ 569,207 $ 80,496 $ 649,703 (1) Insurance agency intangible assets include customer list, non-compete agreement and supplier relationship intangible assets.

Earnings Per Share ("EPS") (Tab

Earnings Per Share ("EPS") (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share, Basic and Diluted	For the Three Months Ended March 31, 2022 2021 (Dollars in thousands, except per share data) Net income applicable to common shares $ 51,516 $ 47,663 Average number of common shares outstanding 184,066,326 186,758,154 Less: Average unallocated ESOP shares (14,208,376) (14,709,110) Average number of common shares outstanding used to calculate basic earnings per common share 169,857,950 172,049,044 Common stock equivalents - share-based compensation 110,206 — Average number of common shares outstanding used to calculate diluted earnings per common share 169,968,156 172,049,044 Earnings per common share Basic $ 0.30 $ 0.28 Diluted $ 0.30 $ 0.28

Low Income Housing Tax Credit_2

Low Income Housing Tax Credits and Other Tax Credit Investments (Tables)	3 Months Ended
	Mar. 31, 2022
Investments in Affordable Housing Projects [Abstract]
Summary of the Company's Investments in Low Income Housing Projects Accounted for Using the Proportional Amortization Method	The following table presents the Company’s investments in LIHTC projects accounted for using the proportional amortization method for the periods indicated: As of March 31, 2022 As of December 31, 2021 (In thousands) Current recorded investment included in other assets $ 79,722 $ 81,035 Commitments to fund qualified affordable housing projects included in recorded investment noted above 43,287 48,399 The following table presents additional information related to the Company's investments in LIHTC projects for the periods indicated: For the Three Months Ended March 31, 2022 2021 (In thousands) Tax credits and benefits recognized $ 2,321 $ 1,464 Amortization expense included in income tax expense 1,843 1,264

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Schedule of Shares Repurchased	Information regarding the shares repurchased under the plan is presented in the following table: Period Total Number of Shares Repurchased Average Price Paid per Share Total Number of Shares Repurchased as Part of the Share Repurchase Program at the end of Each Respective Period Maximum Number of Shares That May Yet Be Purchased Under the Share Repurchase Program at the end of Each Respective Period January 1, 2022 –  January 31, 2022 987,526 $ 21.02 2,123,404 7,214,496 February 1, 2022 –  February 28, 2022 1,109,697 $ 21.08 3,233,101 6,104,799 March 1, 2022 –  March 31, 2022 769,398 $ 21.31 4,002,499 5,335,401

Employee Benefits (Tables)

Employee Benefits (Tables)	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Summary of Components of Net Pension Expense	The components of net pension expense for the plans for the periods indicated are as follows: Three Months Ended March 31, 2022 2021 (In thousands) Components of net periodic benefit cost: Service cost $ 8,092 $ 7,896 Interest cost 2,430 1,269 Expected return on plan assets (9,281) (8,141) Past service credit (2,970) (2,946) Recognized net actuarial loss 2,798 3,538 Net periodic benefit cost $ 1,069 $ 1,616
Schedule of Assets Held in Rabbi Trust	Investments in rabbi trust accounts are recorded at fair value within the Company's consolidated balance sheets with changes in fair value recorded through noninterest income. The following table presents the book value, mark-to-market, and fair value of assets held in rabbi trust accounts by asset type: As of March 31, 2022 As of December 31, 2021 Book Value Mark-to-Market Fair Value Book Value Mark-to-Market Fair Value Asset Type (In thousands) Cash and cash equivalents $ 5,445 $ — $ 5,445 $ 4,494 $ — $ 4,494 Equities (1) 59,487 14,257 73,744 67,401 24,295 91,696 Fixed income 8,466 (363) 8,103 8,126 56 8,182 Total assets $ 73,398 $ 13,894 $ 87,292 $ 80,021 $ 24,351 $ 104,372 (1) Equities include mutual funds and other exchange-traded funds.
Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity	The following table summarizes the Company’s restricted stock award activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested restricted stock as of December 31, 2021 683,056 $ 20.13 Granted — — Non-vested restricted stock as of March 31, 2022 683,056 $ 20.13 The following table summarizes the Company’s restricted stock unit activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested restricted stock units as of December 31, 2021 — $ — Granted 978,364 21.08 Non-vested restricted stock units as of March 31, 2022 978,364 $ 21.08
Share-based Payment Arrangement, Performance Shares, Activity	The following table summarizes the Company’s performance stock unit activity for the three months ended March 31, 2022: Number of Shares Weighted-Average Grant Price Per Share Non-vested performance stock units as of December 31, 2021 — $ — Granted 533,676 21.12 Non-vested performance stock units as of March 31, 2022 533,676 $ 21.12

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Summary of Financial Instruments as of the Dates Indicated	The following table summarizes the above financial instruments as of the dates indicated: As of March 31, 2022 As of December 31, 2021 (In thousands) Commitments to extend credit $ 5,306,596 $ 5,175,521 Standby letters of credit 65,687 65,602 Forward commitments to sell loans 12,917 24,440

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2022
Summary of Derivative Instruments [Abstract]
Schedule of Pre-tax Impact of Terminated Cash Flow Hedges on AOCI	The following table presents the pre-tax impact of terminated cash flow hedges on accumulated other comprehensive income (“AOCI”) for the three months ended March 31, 2022 and March 31, 2021: For the Three Months Ended March 31, 2022 2021 (In thousands) Unrealized gains on terminated hedges included in AOCI – beginning of respective period $ 10,239 $ 41,473 Unrealized gains on terminated hedges arising during the period — — Reclassification adjustments for amortization of unrealized (gains) into net income (5,298) (8,274) Unrealized gains on terminated hedges included in AOCI – end of respective period $ 4,941 $ 33,199
Derivatives Not Designated as Hedging Instruments	The following tables present the Company’s customer-related derivative positions as of the dates indicated below for those derivatives not designated as hedging. March 31, 2022 Number of Positions Total Notional (Dollars in thousands) Interest rate swaps 468 $ 2,867,637 Risk participation agreements 63 263,496 Foreign exchange contracts: Matched commercial customer book 70 10,343 Foreign currency loan 5 11,586 December 31, 2021 Number of Positions Total Notional (Dollars in thousands) Interest rate swaps 494 $ 3,009,150 Risk participation agreements 64 238,772 Foreign exchange contracts: Matched commercial customer book 72 7,922 Foreign currency loan 6 10,830
Schedule of Derivative Financial Instruments	The table below presents the fair value of the Company’s derivative financial instruments, as well as their classification on the consolidated balance sheet for the periods indicated. There were no derivatives designated as hedging instruments at March 31, 2022 or December 31, 2021. Asset Derivatives Liability Derivatives Balance Fair Value at March 31, Fair Value at December 31, Balance Sheet Fair Value at March 31, Fair Value at December 31, (In thousands) Derivatives not designated as hedging instruments Customer-related positions: Interest rate swaps Other assets $ 23,725 $ 64,338 Other liabilities $ 24,988 $ 17,880 Risk participation agreements Other assets 196 315 Other liabilities 401 580 Foreign currency exchange contracts - matched customer book Other assets 91 61 Other liabilities 78 46 Foreign currency exchange contracts - foreign currency loan Other assets 7 — Other liabilities 16 87 Total $ 24,019 $ 64,714 $ 25,483 $ 18,593
Schedule of Derivative Financial Instruments On The Consolidated Income Statements	The table below presents the net effect of the Company’s derivative financial instruments on the consolidated income statements as well as the effect of the Company’s derivative financial instruments included in other comprehensive income (“OCI”) as follows: Three Months Ended March 31, 2022 2021 (In thousands) Derivatives designated as hedges: (Loss) gain in OCI on derivatives $ — $ — Gain reclassified from OCI into interest income (effective portion) $ 5,298 $ 8,274 Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test) Interest income — — Other income — — Total $ — $ — Derivatives not designated as hedges: Customer-related positions: Gain recognized in interest rate swap income $ 2,298 $ 4,851 Gain recognized in interest rate swap income for risk participation agreements 60 369 (Loss) gain recognized in other income for foreign currency exchange contracts: Matched commercial customer book (2) 6 Foreign currency loan 78 73 Total gain for derivatives not designated as hedges $ 2,434 $ 5,299

Balance Sheet Offsetting (Table

Balance Sheet Offsetting (Tables)	3 Months Ended
	Mar. 31, 2022
Offsetting [Abstract]
Disclosure Detail Of Balance Sheet Offsetting Of Financial Assets And Liabilities	The following tables present the Company’s asset and liability positions that were eligible for offset and the potential effect of netting arrangements on its consolidated balance sheet, as of the dates indicated: As of March 31, 2022 Gross Gross Net Gross Amounts Not Offset Net Description Financial Collateral (In thousands) Derivative Assets Customer-related positions: Interest rate swaps $ 23,725 $ — $ 23,725 $ 3,470 $ — $ 20,255 Risk participation agreements 196 — 196 — — 196 Foreign currency exchange contracts – matched customer book 91 — 91 — — 91 Foreign currency exchange contracts – foreign currency loan 7 — 7 — — 7 $ 24,019 $ — $ 24,019 $ 3,470 $ — $ 20,549 Derivative Liabilities Customer-related positions: Interest rate swaps $ 24,988 $ — $ 24,988 $ 3,470 $ 21,518 $ — Risk participation agreements 401 — 401 — — 401 Foreign currency exchange contracts – matched customer book 78 — 78 — — 78 Foreign currency exchange contracts – foreign currency loan 16 — 16 — — 16 $ 25,483 $ — $ 25,483 $ 3,470 $ 21,518 $ 495 As of December 31, 2021 Gross Gross Net Gross Amounts Not Offset Net Description Financial Collateral (In thousands) Derivative Assets Customer-related positions: Interest rate swaps $ 64,338 $ — $ 64,338 $ 1,440 $ — $ 62,898 Risk participation agreements 315 — 315 — — 315 Foreign currency exchange contracts – matched customer book 61 — 61 — — 61 Foreign currency exchange contracts – foreign currency loan — — — — — — $ 64,714 $ — $ 64,714 $ 1,440 $ — $ 63,274 Derivative Liabilities Customer-related positions: Interest rate swaps $ 17,880 $ — $ 17,880 $ 1,440 $ 16,440 $ — Risk participation agreements 580 — 580 — — 580 Foreign currency exchange contracts – matched customer book 46 — 46 — — 46 Foreign currency exchange contracts – foreign currency loan 87 — 87 — — 87 $ 18,593 $ — $ 18,593 $ 1,440 $ 16,440 $ 713

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary Of The Balances Of Assets And Liabilities Measured At Fair Value On A Recurring Basis	The following tables present the balances of assets and liabilities measured at fair value on a recurring basis as of March 31, 2022 and December 31, 2021: Fair Value Measurements at Reporting Date Using Balance as of March 31, 2022 Quoted Prices in Significant Significant Description (In thousands) Assets Securities available for sale Government-sponsored residential mortgage-backed securities $ 4,969,346 $ — $ 4,969,346 $ — Government-sponsored commercial mortgage-backed securities 1,615,927 — 1,615,927 — U.S. Agency bonds 1,013,899 — 1,013,899 — U.S. Treasury securities 56,235 56,235 — — State and municipal bonds and obligations 260,316 — 260,316 — Other debt securities 1,582 — 1,582 — Rabbi trust investments 87,292 79,189 8,103 — Loans held for sale 1,166 — 1,166 — Interest rate swap contracts Customer-related positions 23,725 — 23,725 — Risk participation agreements 196 — 196 — Foreign currency forward contracts Matched customer book 91 — 91 — Foreign currency loan 7 — 7 — Mortgage derivatives 239 — 239 — Total $ 8,030,021 $ 135,424 $ 7,894,597 $ — Liabilities Interest rate swap contracts Customer-related positions $ 24,988 $ — $ 24,988 $ — Risk participation agreements 401 — 401 — Foreign currency forward contracts Matched customer book 78 — 78 — Foreign currency loan 16 — 16 — Mortgage derivatives 168 — 168 — Total $ 25,651 $ — $ 25,651 $ — Fair Value Measurements at Reporting Date Using Description Balance as of December 31, 2021 Quoted Prices in Significant Significant (In thousands) Assets Securities available for sale Government-sponsored residential mortgage-backed securities $ 5,524,708 $ — $ 5,524,708 $ — Government-sponsored commercial mortgage-backed securities 1,408,868 — 1,408,868 — U.S. Agency bonds 1,175,014 — 1,175,014 — U.S. Treasury securities 88,605 88,605 — — State and municipal bonds and obligations 280,329 — 280,329 — Small Business Administration pooled securities 32,103 — 32,103 — Other debt securities 1,597 — 1,597 — Rabbi trust investments 104,372 96,190 8,182 — Loans held for sale 1,206 — 1,206 — Interest rate swap contracts Customer-related positions 64,338 — 64,338 — Risk participation agreements 315 — 315 — Foreign currency forward contracts Matched customer book 61 — 61 — Mortgage derivatives 256 — 256 — Total $ 8,681,772 $ 184,795 $ 8,496,977 $ — Liabilities Interest rate swap contracts Customer-related positions $ 17,880 $ — $ 17,880 $ — Risk participation agreements 580 — 580 — Foreign currency forward contracts Matched customer book 46 — 46 — Foreign currency loan 87 — 87 — Mortgage derivatives 16 — 16 — Total $ 18,609 $ — $ 18,609 $ —
Summary Of The Fair Value Of Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis	The following tables summarize the fair value of assets and liabilities measured at fair value on a nonrecurring basis, as of March 31, 2022 and December 31, 2021. Fair Value Measurements at Reporting Date Using Description Balance as of March 31, 2022 Quoted Prices Significant Significant (In thousands) Assets Individually assessed collateral-dependent loans whose fair value is based upon appraisals $ 11,879 $ — $ — $ 11,879 Fair Value Measurements at Reporting Date Using Description Balance as of December 31, 2021 Quoted Prices Significant Significant (In thousands) Assets Collateral-dependent impaired loans whose fair value is based upon appraisals $ 12,068 $ — $ — $ 12,068
Fair Value, by Balance Sheet Grouping	The estimated fair values and related carrying amounts for assets and liabilities for which fair value is only disclosed are shown below as of the dates indicated: Fair Value Measurements at Reporting Date Using Description Carrying Value as of March 31, 2022 Fair Value as of March 31, 2022 Quoted Prices Significant Significant (In thousands) Assets Held to maturity securities: Government-sponsored residential mortgage-backed securities $ 192,231 $ 188,913 $ — $ 188,913 $ — Government-sponsored commercial mortgage-backed securities 203,203 203,210 — 203,210 — Loans, net of allowance for loan losses 12,033,603 11,817,706 — — 11,817,706 FHLB stock 10,904 10,904 — 10,904 — Bank-owned life insurance 157,954 157,954 — 157,954 — Liabilities Deposits $ 19,392,816 $ 19,387,023 $ — $ 19,387,023 $ — FHLB advances 13,689 12,767 — 12,767 — Escrow deposits from borrowers 21,233 21,233 — 21,233 — Fair Value Measurements at Reporting Date Using Description Carrying Value as of December 31, 2021 Fair Value as of December 31, 2021 Quoted Prices Significant Significant (In thousands) Assets Loans, net of allowance for loan losses $ 12,157,281 $ 12,282,323 $ — $ — $ 12,282,323 FHLB stock 10,904 10,904 — 10,904 — Bank-owned life insurance 157,091 157,091 — 157,091 — Liabilities Deposits $ 19,628,311 $ 19,626,376 $ — $ 19,626,376 $ — FHLB advances 14,020 13,558 — 13,558 — Escrow deposits from borrowers 20,258 20,258 — 20,258 —

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Products and Services	Three Months Ended March 31, 2022 2021 (In thousands) Insurance commissions $ 28,713 $ 28,147 Service charges on deposit accounts 8,537 5,367 Trust and investment advisory fees 6,141 5,663 Debit card processing fees 2,945 2,749 Other noninterest income 2,361 1,792 Total noninterest income in-scope of ASC 606 48,697 43,718 Total noninterest (loss) income out-of-scope of ASC 606 (2,282) 11,494 Total noninterest income $ 46,415 $ 55,212

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2022
Statement of Other Comprehensive Income [Abstract]
Comprehensive Income (Loss)	The following tables present a reconciliation of the changes in the components of other comprehensive (loss) income for the dates indicated including the amount of income tax (expense) benefit allocated to each component of other comprehensive (loss) income: Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Pre Tax Tax After Tax Pre Tax Tax After Tax (In thousands) Unrealized losses on securities available for sale: Change in fair value of securities available for sale $ (465,532) $ 112,008 $ (353,524) $ (94,979) $ 20,982 $ (73,997) Less: reclassification adjustment for gains included in net income (2,172) 673 (1,499) 1,164 (257) 907 Net change in fair value of securities available for sale (463,360) 111,335 (352,025) (96,143) 21,239 (74,904) Unrealized gains (losses) on cash flow hedges: Change in fair value of cash flow hedges — — — — — — Less: net cash flow hedge gains reclassified into interest income (1) 5,298 (1,489) 3,809 8,274 (2,326) 5,948 Net change in fair value of cash flow hedges (5,298) 1,489 (3,809) (8,274) 2,326 (5,948) Defined benefit pension plans: Change in actuarial net loss — — — — — — Less: amortization of actuarial net loss (2,798) 787 (2,011) (3,537) 994 (2,543) Less: accretion of prior service credit 2,970 (835) 2,135 2,945 (828) 2,117 Net change in other comprehensive income for defined benefit postretirement plans (172) 48 (124) 592 (166) 426 Total other comprehensive loss $ (468,830) $ 112,872 $ (355,958) $ (103,825) $ 23,399 $ (80,426) (1) Represents amortization of realized gains on terminated cash flow hedges for the three months ended March 31, 2022 and 2021. The total realized gain of $41.2 million, net of tax, will be recognized in earnings through January 2023. The balance of this gain had amortized to $3.6 million and $7.4 million, net of tax, at March 31, 2022 and December 31, 2021, respectively.
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table illustrates the changes in the balances of each component of accumulated other comprehensive income (loss), net of tax: Unrealized Unrealized Defined Benefit Total (In thousands) Beginning Balance: January 1, 2022 $ (58,586) $ 7,361 $ (5,471) $ (56,696) Other comprehensive loss before reclassifications (353,524) — — (353,524) Less: Amounts reclassified from accumulated other comprehensive (loss) income (1,499) 3,809 124 2,434 Net current-period other comprehensive loss (352,025) (3,809) (124) (355,958) Ending Balance: March 31, 2022 $ (410,611) $ 3,552 $ (5,595) $ (412,654) Beginning Balance: January 1, 2021 $ 45,672 $ 29,815 $ (21,253) $ 54,234 Other comprehensive loss before reclassifications (73,997) — — (73,997) Less: Amounts reclassified from accumulated other comprehensive income (loss) 907 5,948 (426) 6,429 Net current-period other comprehensive (loss) income (74,904) (5,948) 426 (80,426) Ending Balance: March 31, 2021 $ (29,232) $ 23,867 $ (20,827) $ (26,192)

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Schedule Of Segment Reporting Information, By Segment	Results of operations and selected financial information by segment and reconciliation to the consolidated financial statements as of and for the three months ended March 31, 2022 and 2021 was as follows: As of and for the three months ended March 31, 2022 2021 Banking Insurance Other / Total Banking Insurance Other / Total (In thousands) Net interest income $ 128,124 $ — $ — $ 128,124 $ 100,091 $ — $ — $ 100,091 (Release of) provision for loan losses (485) — — (485) (580) — — (580) Net interest income after provision for loan losses 128,609 — — 128,609 100,671 — — 100,671 Noninterest income 18,137 28,449 (171) 46,415 26,960 28,284 (32) 55,212 Noninterest expense 90,446 19,473 (1,053) 108,866 75,274 19,811 (1,036) 94,049 Income before provision for income taxes 56,300 8,976 882 66,158 52,357 8,473 1,004 61,834 Income tax provision 12,108 2,534 — 14,642 11,793 2,378 — 14,171 Net income $ 44,192 $ 6,442 $ 882 $ 51,516 $ 40,564 $ 6,095 $ 1,004 $ 47,663 Total assets $ 22,695,895 $ 211,401 $ (71,224) $ 22,836,072 $ 16,595,311 $ 194,664 $ (63,180) $ 16,726,795 Total liabilities $ 19,848,995 $ 49,909 $ (71,224) $ 19,827,680 $ 13,359,075 $ 43,855 $ (63,180) $ 13,339,750

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands		Jan. 01, 2022	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Stockholders' equity attributable to parent			$ (3,008,392)	$ (3,387,045)	$ (3,406,352)	$ (3,428,052)
Deferred income tax expense			14,129	5,118
Retained Earnings
Financing Receivable, Impaired [Line Items]
Stockholders' equity attributable to parent			$ (1,782,997)	$ (1,702,946)	(1,768,653)	$ (1,665,607)
Cumulative effect accounting adjustment
Financing Receivable, Impaired [Line Items]
Stockholders' equity attributable to parent	[1]				20,098
Deferred income tax expense		$ 7,900
Cumulative effect accounting adjustment | Accounting Standards Update 2016-13
Financing Receivable, Impaired [Line Items]
Deferred income tax expense		$ 7,900
Cumulative effect accounting adjustment | Retained Earnings
Financing Receivable, Impaired [Line Items]
Stockholders' equity attributable to parent	[1]				20,098
Cumulative effect accounting adjustment | Retained Earnings | Accounting Standards Update 2016-13
Financing Receivable, Impaired [Line Items]
Stockholders' equity attributable to parent					$ 20,100
[1]	Represents gross transition adjustment amount of $28.0 million, net of taxes of $7.9 million, to reflect the cumulative impact on retained earnings pursuant to the Company’s adoption of Accounting Standards Update 2016-13. Refer to Note 4, “Loans and Allowance for Credit Losses” for additional discussion.

Securities - Debt Securities, A

Securities - Debt Securities, Available-for-sale (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 8,456,620	$ 8,587,179
Unrealized Gains	3,056	36,492
Unrealized Losses	(542,371)	(112,447)
Allowance for Credit Losses	0
Fair Value	7,917,305	8,511,224
Government-sponsored residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	5,329,748	5,577,292
Unrealized Gains	264	17,918
Unrealized Losses	(360,666)	(70,502)
Allowance for Credit Losses	0
Fair Value	4,969,346	5,524,708
Government-sponsored commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,707,131	1,420,748
Unrealized Gains	0	760
Unrealized Losses	(91,204)	(12,640)
Allowance for Credit Losses	0
Fair Value	1,615,927	1,408,868
U.S. Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,099,916	1,202,377
Unrealized Gains	0	1,067
Unrealized Losses	(86,017)	(28,430)
Allowance for Credit Losses	0
Fair Value	1,013,899	1,175,014
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	59,458	89,434
Unrealized Gains	0	5
Unrealized Losses	(3,223)	(834)
Allowance for Credit Losses	0
Fair Value	56,235	88,605
State and municipal bonds and obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	258,769	263,910
Unrealized Gains	2,792	16,460
Unrealized Losses	(1,245)	(41)
Allowance for Credit Losses	0
Fair Value	260,316	280,329
Small Business Administration pooled securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		31,821
Unrealized Gains		282
Unrealized Losses		0
Fair Value		32,103
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,598	1,597
Unrealized Gains	0	0
Unrealized Losses	(16)	0
Allowance for Credit Losses	0
Fair Value	$ 1,582	$ 1,597

Securities - Additional Informa

Securities - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, allowance for credit loss	$ 0
Gross realized gains from sales of available for sale securities	1,000,000	$ 1,200,000
Gross realized losses from sales of available for sale securities	3,200,000	0
Other-than-temporary impairment		$ 0
Debt securities, held-to-maturity, allowance for credit loss	0
Deposit liabilities, collateral issued, financial instruments	491,200,000		$ 2,200,000,000
Century Bancorp, Inc.
Debt Securities, Available-for-sale [Line Items]
Deposit liabilities, collateral issued, financial instruments	461,900,000		2,100,000,000
Available-for-sale Securities
Debt Securities, Available-for-sale [Line Items]
Accrued interest receivable	13,800,000		$ 14,300,000
Held-to-maturity Securities
Debt Securities, Available-for-sale [Line Items]
Accrued interest receivable	$ 800,000

Securities - Summary Of Governm

Securities - Summary Of Government-Sponsored Residential Mortgage-Backed Securities With Gross Unrealized Losses (Detail) $ in Thousands	Mar. 31, 2022USD ($)holding	Dec. 31, 2021USD ($)holding
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	672	470
Gross Unrealized Losses
Less than 12 Months	$ 325,829	$ 85,764
12 Months or Longer	216,542	26,683
Total	542,371	112,447
Fair Value
Less than 12 Months	5,428,387	5,993,147
12 Months or Longer	2,258,272	810,035
Total	$ 7,686,659	$ 6,803,182
Government-sponsored residential mortgage-backed securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	322	264
Gross Unrealized Losses
Less than 12 Months	$ 223,347	$ 70,502
12 Months or Longer	137,319	0
Total	360,666	70,502
Fair Value
Less than 12 Months	3,513,073	4,615,457
12 Months or Longer	1,403,234	0
Total	$ 4,916,307	$ 4,615,457
Government-sponsored commercial mortgage-backed securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	205	165
Gross Unrealized Losses
Less than 12 Months	$ 85,425	$ 12,218
12 Months or Longer	5,779	422
Total	91,204	12,640
Fair Value
Less than 12 Months	1,548,080	1,102,444
12 Months or Longer	67,847	15,682
Total	$ 1,615,927	$ 1,118,126
U.S. Agency bonds
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	37	27
Gross Unrealized Losses
Less than 12 Months	$ 12,573	$ 2,169
12 Months or Longer	73,444	26,261
Total	86,017	28,430
Fair Value
Less than 12 Months	226,708	191,222
12 Months or Longer	787,191	794,353
Total	$ 1,013,899	$ 985,575
U.S. Treasury securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	2	3
Gross Unrealized Losses
Less than 12 Months	$ 3,223	$ 834
12 Months or Longer	0	0
Total	3,223	834
Fair Value
Less than 12 Months	56,235	78,588
12 Months or Longer	0	0
Total	$ 56,235	$ 78,588
State and municipal bonds and obligations
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	103	11
Gross Unrealized Losses
Less than 12 Months	$ 1,245	$ 41
12 Months or Longer	0	0
Total	1,245	41
Fair Value
Less than 12 Months	82,709	5,436
12 Months or Longer	0	0
Total	$ 82,709	$ 5,436
Other debt securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Line Items]
Number of holdings | holding	3
Gross Unrealized Losses
Less than 12 Months	$ 16
12 Months or Longer	0
Total	16
Fair Value
Less than 12 Months	1,582
12 Months or Longer	0
Total	$ 1,582

Securities - Debt Securities, H

Securities - Debt Securities, Held-to-maturity (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 395,434,000	$ 0
Unrealized Gains	17,000
Unrealized Losses	(3,328,000)
Allowance for Credit Losses	0
Fair Value	392,123,000	$ 0
Government-sponsored residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	192,231,000
Unrealized Gains	0
Unrealized Losses	(3,318,000)
Allowance for Credit Losses	0
Fair Value	188,913,000
Government-sponsored commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	203,203,000
Unrealized Gains	17,000
Unrealized Losses	(10,000)
Allowance for Credit Losses	0
Fair Value	$ 203,210,000

Securities - Summary Of Fair Va

Securities - Summary Of Fair Value Of Securities By Contractual Maturities (Detail) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Available for sale securities
Due in one year or less, Amortized Cost	$ 14,960,000	$ 51,955,000
Due in one year or less, Fair value	14,908,000	51,932,000
Due after one year to five years, Amortized Cost	877,833,000	784,326,000
Due after one year to five years, Fair value	825,369,000	773,349,000
Due after five to ten years, Amortized Cost	2,123,184,000	2,023,620,000
Due after five to ten years, Fair value	1,994,305,000	1,994,423,000
Due after ten years, Amortized Cost	5,440,643,000	5,727,278,000
Due after ten years, Fair value	5,082,723,000	5,691,520,000
Amortized Cost	8,456,620,000	8,587,179,000
Fair Value	7,917,305,000	8,511,224,000
Held to maturity securities
Due in one year or less, Amortized Cost	0
Due in one year or less, Fair value	0
Due after one year to five years, Amortized Cost	0
Due after one year to five years, Fair value	0
Due after five to ten years, Amortized Cost	203,203,000
Due after five to ten years, Fair value	203,210,000
Due after ten years, Amortized Cost	192,231,000
Due after ten years, Fair value	188,913,000
Amortized Cost	395,434,000
Fair Value	392,123,000	0
Total
Due in one year or less, Amortized Cost	14,960,000
Due in one year or less, Fair value	14,908,000
Due after one year to five years, Amortized Cost	877,833,000
Due after one year to five years, Fair value	825,369,000
Due after five to ten years, Amortized Cost	2,326,387,000
Due after five to ten years, Fair value	2,197,515,000
Due after ten years, Amortized Cost	5,632,874,000
Due after ten years, Fair value	5,271,636,000
Amortized Cost	8,852,054,000
Fair Value	8,309,428,000
Government-sponsored residential mortgage-backed securities
Available for sale securities
Due in one year or less, Amortized Cost	1,000	0
Due in one year or less, Fair value	1,000	0
Due after one year to five years, Amortized Cost	20,992,000	24,935,000
Due after one year to five years, Fair value	21,143,000	25,962,000
Due after five to ten years, Amortized Cost	832,510,000	899,169,000
Due after five to ten years, Fair value	790,125,000	892,029,000
Due after ten years, Amortized Cost	4,476,245,000	4,653,188,000
Due after ten years, Fair value	4,158,077,000	4,606,717,000
Amortized Cost	5,329,748,000	5,577,292,000
Fair Value	4,969,346,000	5,524,708,000
Held to maturity securities
Due in one year or less, Amortized Cost	0
Due in one year or less, Fair value	0
Due after one year to five years, Amortized Cost	0
Due after one year to five years, Fair value	0
Due after five to ten years, Amortized Cost	0
Due after five to ten years, Fair value	0
Due after ten years, Amortized Cost	192,231,000
Due after ten years, Fair value	188,913,000
Amortized Cost	192,231,000
Fair Value	188,913,000
Government-sponsored commercial mortgage-backed securities
Available for sale securities
Due in one year or less, Amortized Cost	0	0
Due in one year or less, Fair value	0	0
Due after one year to five years, Amortized Cost	190,509,000	139,095,000
Due after one year to five years, Fair value	182,639,000	137,755,000
Due after five to ten years, Amortized Cost	700,994,000	387,177,000
Due after five to ten years, Fair value	658,732,000	378,414,000
Due after ten years, Amortized Cost	815,628,000	894,476,000
Due after ten years, Fair value	774,556,000	892,699,000
Amortized Cost	1,707,131,000	1,420,748,000
Fair Value	1,615,927,000	1,408,868,000
Held to maturity securities
Due in one year or less, Amortized Cost	0
Due in one year or less, Fair value	0
Due after one year to five years, Amortized Cost	0
Due after one year to five years, Fair value	0
Due after five to ten years, Amortized Cost	203,203,000
Due after five to ten years, Fair value	203,210,000
Due after ten years, Amortized Cost	0
Due after ten years, Fair value	0
Amortized Cost	203,203,000
Fair Value	203,210,000
U.S. Agency bonds
Available for sale securities
Due in one year or less, Amortized Cost	0	5,508,000
Due in one year or less, Fair value	0	5,515,000
Due after one year to five years, Amortized Cost	578,810,000	531,821,000
Due after one year to five years, Fair value	537,301,000	520,935,000
Due after five to ten years, Amortized Cost	521,106,000	665,048,000
Due after five to ten years, Fair value	476,598,000	648,564,000
Due after ten years, Amortized Cost	0	0
Due after ten years, Fair value	0	0
Amortized Cost	1,099,916,000	1,202,377,000
Fair Value	1,013,899,000	1,175,014,000
U.S. Treasury securities
Available for sale securities
Due in one year or less, Amortized Cost	10,000,000	40,010,000
Due in one year or less, Fair value	9,955,000	40,001,000
Due after one year to five years, Amortized Cost	49,458,000	49,424,000
Due after one year to five years, Fair value	46,280,000	48,604,000
Due after five to ten years, Amortized Cost	0	0
Due after five to ten years, Fair value	0	0
Due after ten years, Amortized Cost	0	0
Due after ten years, Fair value	0	0
Amortized Cost	59,458,000	89,434,000
Fair Value	56,235,000	88,605,000
State and municipal bonds and obligations
Available for sale securities
Due in one year or less, Amortized Cost	4,659,000	6,137,000
Due in one year or less, Fair value	4,653,000	6,116,000
Due after one year to five years, Amortized Cost	36,766,000	33,692,000
Due after one year to five years, Fair value	36,723,000	34,704,000
Due after five to ten years, Amortized Cost	68,574,000	72,226,000
Due after five to ten years, Fair value	68,850,000	75,416,000
Due after ten years, Amortized Cost	148,770,000	151,855,000
Due after ten years, Fair value	150,090,000	164,093,000
Amortized Cost	258,769,000	263,910,000
Fair Value	260,316,000	280,329,000
Small Business Administration pooled securities
Available for sale securities
Due in one year or less, Amortized Cost		0
Due in one year or less, Fair value		0
Due after one year to five years, Amortized Cost		4,062,000
Due after one year to five years, Fair value		4,092,000
Due after five to ten years, Amortized Cost		0
Due after five to ten years, Fair value		0
Due after ten years, Amortized Cost		27,759,000
Due after ten years, Fair value		28,011,000
Amortized Cost		31,821,000
Fair Value		32,103,000
Other debt securities
Available for sale securities
Due in one year or less, Amortized Cost	300,000	300,000
Due in one year or less, Fair value	299,000	300,000
Due after one year to five years, Amortized Cost	1,298,000	1,297,000
Due after one year to five years, Fair value	1,283,000	1,297,000
Due after five to ten years, Amortized Cost	0	0
Due after five to ten years, Fair value	0	0
Due after ten years, Amortized Cost	0	0
Due after ten years, Fair value	0	0
Amortized Cost	1,598,000	1,597,000
Fair Value	$ 1,582,000	$ 1,597,000

Loans and Allowance for Loan _3

Loans and Allowance for Loan Losses - Summary of Company's Loan Portfolio as of the Dates Indicated (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 12,182,203	$ 12,281,510
Less: allowance for loan losses	(124,166)	(97,787)	$ (111,080)	$ (113,031)
Unamortized premiums, net of unearned discounts and deferred fees	(24,434)	(26,442)
Loans after the allowance for loan losses, unamortized premiums, unearned discounts and deferred fees	12,033,603	12,157,281
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,886,560	2,960,527
Less: allowance for loan losses	(26,841)	(18,018)	(25,406)	(26,617)
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,609,824	4,522,513
Less: allowance for loan losses	(44,612)	(52,373)	(55,138)	(54,569)
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	246,093	222,328
Less: allowance for loan losses	(4,414)	(2,585)	(3,350)	(4,553)
Business Banking | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,201,007	1,334,694
Less: allowance for loan losses	(17,269)	(10,983)	(13,504)	(13,152)
Residential real estate | Residential Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,936,182	1,926,810
Less: allowance for loan losses	(22,243)	(6,556)	(6,235)	(6,435)
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,099,211	1,100,153
Less: allowance for loan losses	(6,018)	(3,722)	(3,576)	(3,744)
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	203,326	214,485
Less: allowance for loan losses	$ (2,769)	$ (3,308)	$ (3,498)	$ (3,467)

Loans and Allowance for Loan _4

Loans and Allowance for Loan Losses - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Jan. 01, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in lines of credit,resrticted to commercial exposure
Loan syndications, amount	$ 100,000,000
Mortgage loans partially or wholly-owned by others and serviced by the Company	91,200,000			$ 95,800,000
Financing receivable, allowance for credit loss, excluding accrued interest	124,166,000	$ 111,080,000		97,787,000	$ 113,031,000
Total loans	$ 12,182,203,000			12,281,510,000
Maximum number of days required for special mention	90 days
Amount of specific reserve associated with the TDR	$ 2,500,000			3,400,000
Amount of additional commitments to lend to borrowers who have been a party to a TDR	0			0
Outstanding recorded investment of loans that were new to troubled debt restructuring	800,000			800,000
Amounts charged-off on TDRs	0	$ 0
Residential Portfolio Segment
Changes in lines of credit,resrticted to commercial exposure
Financing receivable, collateral dependent loans	800,000			600,000
Commercial Portfolio Segment
Changes in lines of credit,resrticted to commercial exposure
Financing receivable, collateral dependent loans	11,600,000			13,100,000
Cumulative effect accounting adjustment
Changes in lines of credit,resrticted to commercial exposure
Financing receivable, allowance for credit loss, excluding accrued interest				27,086,000
CARES Act | Payment Deferral
Changes in lines of credit,resrticted to commercial exposure
Loans which underwent a modification, CARES Act	49,000,000			106,700,000
Unfunded Loan Commitment
Changes in lines of credit,resrticted to commercial exposure
Financing receivable, allowance for credit loss, excluding accrued interest	10,400,000		$ 11,100,000
Unfunded Loan Commitment | Cumulative effect accounting adjustment
Changes in lines of credit,resrticted to commercial exposure
Financing receivable, allowance for credit loss, excluding accrued interest			$ 1,000,000
Federal Home Loan Bank Advances
Changes in lines of credit,resrticted to commercial exposure
Carrying value of loans pledged to secure advances from federal banks	3,000,000,000			2,600,000,000
Funds borrowed from federal banks	13,700,000			14,000,000
Federal Reserve Bank Advances
Changes in lines of credit,resrticted to commercial exposure
Carrying value of loans pledged to secure advances from federal banks	799,900,000			784,000,000
Funds borrowed from federal banks	0			0
Nonperforming Loans
Changes in lines of credit,resrticted to commercial exposure
Total loans				9,040,062,000
Unrated
Changes in lines of credit,resrticted to commercial exposure
Lines of credit, exposure	100,000
Unrated | Nonperforming Loans
Changes in lines of credit,resrticted to commercial exposure
Total loans				872,544,000
Unrated | Nonperforming Loans | Paycheck Protection Program | Commercial Portfolio Segment
Changes in lines of credit,resrticted to commercial exposure
Total loans	51,700,000			112,800,000
Unrated | Nonperforming Loans | Paycheck Protection Program | Business Banking
Changes in lines of credit,resrticted to commercial exposure
Total loans	89,500,000			218,600,000
Unrated | Line of Credit | Commercial Portfolio Segment
Changes in lines of credit,resrticted to commercial exposure
Lines of credit, exposure	1,000,000
Unrated | Line of Credit | Business Banking
Changes in lines of credit,resrticted to commercial exposure
Lines of credit, exposure	1,000,000
Loss
Changes in lines of credit,resrticted to commercial exposure
Loans, net of allowance for loan losses	$ 0
Loss | Nonperforming Loans
Changes in lines of credit,resrticted to commercial exposure
Total loans				$ 0

Loans and Allowance for Loan _5

Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Loan Category (Detail) - USD ($) $ in Thousands	Jan. 01, 2022	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,787	$ 97,787	$ 113,031
Charge-offs		(1,607)	(1,982)
Recoveries		1,385	611
Release of allowance for loan losses		(485)	(580)
Ending balance		124,166	111,080
Financing receivable, accrued interest, before allowance for credit loss		31,400
Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	27,086	27,086
Financing receivable, allowance for credit loss, purchased with credit deterioration, increase	100
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	18,018	18,018	26,617
Charge-offs		(1)	0
Recoveries		250	9
Release of allowance for loan losses		(2,959)	(1,220)
Ending balance		26,841	25,406
Commercial and industrial | Commercial Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	11,533	11,533
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	52,373	52,373	54,569
Charge-offs		0	(234)
Recoveries		14	0
Release of allowance for loan losses		(1,120)	803
Ending balance		44,612	55,138
Commercial real estate | Commercial Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(6,655)	(6,655)
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,585	2,585	4,553
Charge-offs		0	0
Recoveries		0	0
Release of allowance for loan losses		344	(1,203)
Ending balance		4,414	3,350
Commercial construction | Commercial Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,485	1,485
Business Banking | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	10,983	10,983	13,152
Charge-offs		(945)	(1,384)
Recoveries		928	365
Release of allowance for loan losses		143	1,371
Ending balance		17,269	13,504
Business Banking | Commercial Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,160	6,160
Residential real estate | Residential Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,556	6,556	6,435
Charge-offs		0	0
Recoveries		10	10
Release of allowance for loan losses		2,188	(210)
Ending balance		22,243	6,235
Residential real estate | Residential Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	13,489	13,489
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,722	3,722	3,744
Charge-offs		0	0
Recoveries		4	71
Release of allowance for loan losses		435	(239)
Ending balance		6,018	3,576
Consumer home equity | Consumer Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,857	1,857
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,308	3,308	3,467
Charge-offs		(661)	(364)
Recoveries		179	156
Release of allowance for loan losses		484	239
Ending balance		2,769	3,498
Other Consumer | Consumer Portfolio Segment | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	(541)	(541)
Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	242	242	494
Charge-offs		0	0
Recoveries		0	0
Release of allowance for loan losses		0	(121)
Ending balance		0	$ 373
Other | Cumulative effect accounting adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ (242)	$ (242)

Loans and Allowance for Loan _6

Loans and Allowance for Loan Losses - Summary of Internal Risk-rating Categories (Detail) $ in Thousands	Mar. 31, 2022USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2022	$ 726,346
2021	2,662,343
2020	1,869,054
2019	1,257,668
2018	938,759
Prior	3,034,743
Revolving Loans	1,658,375
Revolving Loans Converted to Term Loans	10,481
Total	12,157,769
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	117,534
2021	583,948
2020	502,547
2019	232,822
2018	165,737
Prior	702,576
Revolving Loans	559,882
Revolving Loans Converted to Term Loans	1,032
Total	2,866,078
Commercial and industrial | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	117,534
2021	566,764
2020	498,791
2019	231,968
2018	142,428
Prior	689,728
Revolving Loans	504,127
Revolving Loans Converted to Term Loans	686
Total	2,752,026
Commercial and industrial | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	886
2020	0
2019	514
2018	278
Prior	4,459
Revolving Loans	51,581
Revolving Loans Converted to Term Loans	0
Total	57,718
Commercial and industrial | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	11,302
2020	3,756
2019	340
2018	23,031
Prior	8,275
Revolving Loans	790
Revolving Loans Converted to Term Loans	346
Total	47,840
Commercial and industrial | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	4,996
2020	0
2019	0
2018	0
Prior	114
Revolving Loans	3,384
Revolving Loans Converted to Term Loans	0
Total	8,494
Commercial and industrial | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	435,260
2021	845,463
2020	662,105
2019	682,353
2018	552,684
Prior	1,373,872
Revolving Loans	51,970
Revolving Loans Converted to Term Loans	3,478
Total	4,607,185
Commercial real estate | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	378,744
2021	845,405
2020	641,300
2019	676,903
2018	495,084
Prior	1,304,769
Revolving Loans	43,970
Revolving Loans Converted to Term Loans	3,478
Total	4,389,653
Commercial real estate | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	26,613
2021	0
2020	16,142
2019	3,796
2018	19,562
Prior	19,776
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	85,889
Commercial real estate | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	29,903
2021	58
2020	4,663
2019	1,654
2018	38,038
Prior	49,327
Revolving Loans	8,000
Revolving Loans Converted to Term Loans	0
Total	131,643
Commercial real estate | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial real estate | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	3,623
2021	124,777
2020	61,278
2019	39,600
2018	0
Prior	0
Revolving Loans	15,760
Revolving Loans Converted to Term Loans	0
Total	245,038
Commercial construction | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	3,623
2021	124,777
2020	59,181
2019	32,857
2018	0
Prior	0
Revolving Loans	15,760
Revolving Loans Converted to Term Loans	0
Total	236,198
Commercial construction | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	2,097
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	2,097
Commercial construction | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	6,743
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	6,743
Commercial construction | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Commercial construction | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Business Banking | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	57,055
2021	312,601
2020	205,562
2019	156,322
2018	77,086
Prior	309,992
Revolving Loans	80,934
Revolving Loans Converted to Term Loans	4,116
Total	1,203,668
Business Banking | Pass | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	54,881
2021	309,961
2020	200,726
2019	141,974
2018	69,341
Prior	285,849
Revolving Loans	77,782
Revolving Loans Converted to Term Loans	3,436
Total	1,143,950
Business Banking | Special Mention | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	2,174
2021	2,176
2020	3,219
2019	9,152
2018	7,181
Prior	14,498
Revolving Loans	1,908
Revolving Loans Converted to Term Loans	0
Total	40,308
Business Banking | Substandard | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	464
2020	1,617
2019	4,993
2018	564
Prior	9,542
Revolving Loans	1,244
Revolving Loans Converted to Term Loans	680
Total	19,104
Business Banking | Doubtful | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	203
2018	0
Prior	103
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	306
Business Banking | Loss | Commercial Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Residential real estate | Residential Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	81,889
2021	742,659
2020	407,917
2019	113,759
2018	80,617
Prior	519,001
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	1,945,842
Residential real estate | Residential Portfolio Segment | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	81,889
2021	740,106
2020	406,401
2019	112,976
2018	78,320
Prior	505,432
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	1,925,124
Residential real estate | Residential Portfolio Segment | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	2,553
2020	1,387
2019	201
2018	1,513
Prior	6,808
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	12,462
Residential real estate | Residential Portfolio Segment | Accruing loans past 90 days due
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Residential real estate | Residential Portfolio Segment | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	129
2019	582
2018	784
Prior	6,761
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	8,256
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	15,321
2021	12,825
2020	7,008
2019	7,127
2018	28,045
Prior	95,037
Revolving Loans	934,534
Revolving Loans Converted to Term Loans	1,855
Total	1,101,752
Consumer home equity | Consumer Portfolio Segment | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	15,321
2021	12,792
2020	6,903
2019	6,448
2018	26,582
Prior	91,599
Revolving Loans	929,383
Revolving Loans Converted to Term Loans	1,788
Total	1,090,816
Consumer home equity | Consumer Portfolio Segment | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	33
2020	31
2019	0
2018	170
Prior	1,490
Revolving Loans	2,004
Revolving Loans Converted to Term Loans	67
Total	3,795
Consumer home equity | Consumer Portfolio Segment | Accruing loans past 90 days due
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Consumer home equity | Consumer Portfolio Segment | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	74
2019	679
2018	1,293
Prior	1,948
Revolving Loans	3,147
Revolving Loans Converted to Term Loans	0
Total	7,141
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Credit Quality Indicator [Line Items]
2022	15,664
2021	40,070
2020	22,637
2019	25,685
2018	34,590
Prior	34,265
Revolving Loans	15,295
Revolving Loans Converted to Term Loans	0
Total	188,206
Other Consumer | Consumer Portfolio Segment | Current and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	15,652
2021	39,868
2020	22,534
2019	25,531
2018	33,967
Prior	33,664
Revolving Loans	15,295
Revolving Loans Converted to Term Loans	0
Total	186,511
Other Consumer | Consumer Portfolio Segment | 30-89 days past due and accruing
Financing Receivable, Credit Quality Indicator [Line Items]
2022	12
2021	107
2020	76
2019	117
2018	449
Prior	429
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	1,190
Other Consumer | Consumer Portfolio Segment | Accruing loans past 90 days due
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	0
2020	0
2019	0
2018	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	0
Other Consumer | Consumer Portfolio Segment | Non-accrual
Financing Receivable, Credit Quality Indicator [Line Items]
2022	0
2021	95
2020	27
2019	37
2018	174
Prior	172
Revolving Loans	0
Revolving Loans Converted to Term Loans	0
Total	$ 505

Loans and Allowance for Loan _7

Loans and Allowance for Loan Losses - Summary of Shows the Age Analysis of Past Due Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total Loans	$ 12,157,769
Total loans	12,182,203	$ 12,281,510
Total Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	49,963
Total loans		79,414
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	25,960
Total loans		53,510
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	4,604
Total loans		7,393
90 or More Days Past Due
Financing Receivable, Past Due [Line Items]
Total Loans	19,399
Total loans		18,511
Current
Financing Receivable, Past Due [Line Items]
Total Loans	12,107,806
Total loans		12,202,096
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	2,866,078
Total loans	2,886,560	2,960,527
Commercial and industrial | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	2,140
Total loans		1,748
Commercial and industrial | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	146
Total loans		45
Commercial and industrial | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	0
Total loans		31
Commercial and industrial | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,994
Total loans		1,672
Commercial and industrial | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	2,863,938
Total loans		2,958,779
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	4,607,185
Total loans	4,609,824	4,522,513
Commercial real estate | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,101
Total loans		27,127
Commercial real estate | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	600
Total loans		25,931
Commercial real estate | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	0
Total loans		0
Commercial real estate | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	501
Total loans		1,196
Commercial real estate | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	4,606,084
Total loans		4,495,386
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	245,038
Total loans	246,093	222,328
Commercial construction | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	6,743
Total loans		0
Commercial construction | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	6,743
Total loans		0
Commercial construction | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	0
Total loans		0
Commercial construction | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	0
Total loans		0
Commercial construction | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	238,295
Total loans		222,328
Business Banking | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,203,668
Total loans	1,201,007	1,334,694
Business Banking | Total Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	8,768
Total loans		11,476
Business Banking | 30-59 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	4,599
Total loans		5,043
Business Banking | 60-89 Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	875
Total loans		1,793
Business Banking | 90 or More Days Past Due | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	3,294
Total loans		4,640
Business Banking | Current | Commercial Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,194,900
Total loans		1,323,218
Residential real estate | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,945,842
Total loans	1,936,182	1,926,810
Residential real estate | Total Past Due | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	18,925
Total loans		26,577
Residential real estate | 30-59 Days Past Due | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	10,384
Total loans		17,523
Residential real estate | 60-89 Days Past Due | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	2,162
Total loans		3,511
Residential real estate | 90 or More Days Past Due | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	6,379
Total loans		5,543
Residential real estate | Current | Residential Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,926,917
Total loans		1,900,233
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,101,752
Total loans	1,099,211	1,100,153
Consumer home equity | Total Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	10,591
Total loans		9,855
Consumer home equity | 30-59 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	2,517
Total loans		3,774
Consumer home equity | 60-89 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,348
Total loans		1,510
Consumer home equity | 90 or More Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	6,726
Total loans		4,571
Consumer home equity | Current | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,091,161
Total loans		1,090,298
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	188,206
Total loans	203,326	214,485
Other Consumer | Total Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	1,695
Total loans		2,631
Other Consumer | 30-59 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	971
Total loans		1,194
Other Consumer | 60-89 Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	219
Total loans		548
Other Consumer | 90 or More Days Past Due | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	505
Total loans		889
Other Consumer | Current | Consumer Portfolio Segment
Financing Receivable, Past Due [Line Items]
Total Loans	$ 186,511
Total loans		$ 211,854

Loans and Allowance for Credi_3

Loans and Allowance for Credit Losses - Schedule of Non-Accrual Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	$ 25,808
Non-Accrual Loans Without ACL	8,013
Total Non-Accrual Loans	33,821	$ 32,993
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	1,990
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	3,496
Non-Accrual Loans Without ACL	6,990
Total Non-Accrual Loans	10,486	12,400
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	0
Non-Accrual Loans Without ACL	501
Total Non-Accrual Loans	501	0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	1,196
Commercial Portfolio Segment | Commercial construction
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	0
Non-Accrual Loans Without ACL	0
Total Non-Accrual Loans	0	0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Commercial Portfolio Segment | Business Banking
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	6,410
Non-Accrual Loans Without ACL	522
Total Non-Accrual Loans	6,932	8,230
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Residential Portfolio Segment | Residential real estate
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	8,256
Non-Accrual Loans Without ACL	0
Total Non-Accrual Loans	8,256	6,681
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	769
Consumer Portfolio Segment | Consumer home equity
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	7,141
Non-Accrual Loans Without ACL	0
Total Non-Accrual Loans	7,141	4,732
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	25
Consumer Portfolio Segment | Other Consumer
Financing Receivable, Past Due [Line Items]
Non-Accrual Loans With ACL	505
Non-Accrual Loans Without ACL	0
Total Non-Accrual Loans	505	950
Financing Receivable, 90 Days or More Past Due, Still Accruing	$ 0	$ 0

Loans and Allowance for Loan _8

Loans and Allowance for Loan Losses - Summary of TDR Loans on Accrual and Nonaccrual (Detail) $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2022USD ($)loan	Mar. 31, 2022USD ($)contract	Mar. 31, 2021contract	Dec. 31, 2021USD ($)loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans	250	7	1	249
Balance of Loans	$ 45,653	$ 45,653		$ 47,535
TDRs on Accrual Status | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	191			197
Balance of Loans	$ 32,016	32,016		$ 33,336
TDRs on Non-Accrual Status | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	59			52
Balance of Loans	$ 13,637	13,637		$ 14,199
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	8			7
Balance of Loans	$ 12,275	12,275		$ 13,728
Commercial and industrial | TDRs on Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	1			1
Balance of Loans	$ 3,894	3,894		$ 3,745
Commercial and industrial | TDRs on Non-Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	7			6
Balance of Loans	$ 8,381	8,381		$ 9,983
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	1			1
Balance of Loans	$ 3,520	3,520		$ 3,520
Commercial real estate | TDRs on Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	1			1
Balance of Loans	$ 3,520	3,520		$ 3,520
Commercial real estate | TDRs on Non-Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	0			0
Balance of Loans	$ 0	$ 0		$ 0
Business Banking | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans	13	5	0	8
Balance of Loans	$ 4,585	$ 4,585		$ 4,213
Business Banking | TDRs on Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	5			5
Balance of Loans	$ 3,771	3,771		$ 3,830
Business Banking | TDRs on Non-Accrual Status | Commercial Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	8			3
Balance of Loans	$ 814	$ 814		$ 383
Residential real estate | Residential Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans	145	1	1	148
Balance of Loans	$ 21,369	$ 21,369		$ 22,134
Residential real estate | TDRs on Accrual Status | Residential Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	116			121
Balance of Loans	$ 17,786	17,786		$ 19,119
Residential real estate | TDRs on Non-Accrual Status | Residential Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	29			27
Balance of Loans	$ 3,583	$ 3,583		$ 3,015
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans	81	1	0	83
Balance of Loans	$ 3,887	$ 3,887		$ 3,922
Consumer home equity | TDRs on Accrual Status | Consumer Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	66			67
Balance of Loans	$ 3,028	3,028		$ 3,104
Consumer home equity | TDRs on Non-Accrual Status | Consumer Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	15			16
Balance of Loans	$ 859	859		$ 818
Other Consumer | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	2			2
Balance of Loans	$ 17	17		$ 18
Other Consumer | TDRs on Accrual Status | Consumer Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	2			2
Balance of Loans	$ 17	17		$ 18
Other Consumer | TDRs on Non-Accrual Status | Consumer Portfolio Segment | Special mention | Contractual Obligation Modification
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans | loan	0			0
Balance of Loans	$ 0	$ 0		$ 0

Loans and Allowance for Loan _9

Loans and Allowance for Loan Losses - Summary of the Modifications Which Occurred During the Periods and the Change in the Recorded Investment Subsequent to the Modifications Occurring (Detail) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2022loan	Mar. 31, 2022contract	Mar. 31, 2022USD ($)	Mar. 31, 2021USD ($)contract	Dec. 31, 2021loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	250	7		1	249
Pre- Modification Outstanding Recorded Investment			$ 784	$ 295
Post-Modification Modification Outstanding Recorded Investment			792	$ 295
Business Banking | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	13	5		0	8
Pre- Modification Outstanding Recorded Investment			440	$ 0
Post-Modification Modification Outstanding Recorded Investment			448	$ 0
Residential real estate | Residential Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	145	1		1	148
Pre- Modification Outstanding Recorded Investment			134	$ 295
Post-Modification Modification Outstanding Recorded Investment			134	$ 295
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	81	1		0	83
Pre- Modification Outstanding Recorded Investment			210	$ 0
Post-Modification Modification Outstanding Recorded Investment			$ 210	$ 0

Loans and Allowance for Loan_10

Loans and Allowance for Loan Losses - Summary of Post-modification Balance of TDRs listed by Type of Modification (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post modification balance of TDRs	$ 792	$ 295
Extended maturity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post modification balance of TDRs	402	0
Adjusted interest rate and extended maturity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post modification balance of TDRs	390	0
Court-ordered concession
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post modification balance of TDRs	$ 0	$ 295

Loans and Allowance for Loan_11

Loans and Allowance for Loan Losses - Summary of Subsequent Default (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)loan	Mar. 31, 2021USD ($)loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	2
Recorded Investment | $	$ 0	$ 478
Business Banking | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	1
Recorded Investment | $	$ 0	$ 419
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts | loan	0	1
Recorded Investment | $	$ 0	$ 59

Loans and Allowance for Loan_12

Loans and Allowance for Loan Losses - Summary of the Company's Loan participations (Detail) - Loan Participations and Assignments - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2022	Jun. 30, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 1,177,575		$ 1,132,502
Non-performing Loan Rate (%)	0.71%		0.88%
Gross Charge-offs	$ 0	$ 0
Business Banking | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 143		$ 98
Non-performing Loan Rate (%)	0.00%		0.00%
Gross Charge-offs	$ 0	0
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 744,231		$ 732,425
Non-performing Loan Rate (%)	1.13%		1.36%
Gross Charge-offs	$ 0	0
Commercial real estate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 390,540		$ 362,898
Non-performing Loan Rate (%)	0.00%		0.00%
Gross Charge-offs	$ 0	0
Commercial construction | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Loss [Line Items]
Balance	$ 42,661		$ 37,081
Non-performing Loan Rate (%)	0.00%		0.00%
Gross Charge-offs	$ 0	$ 0

Loans and Allowance for Loan_13

Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Loan Category (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 97,787	$ 113,031	$ 113,031
Charge-offs	(1,607)	(1,982)
Recoveries	1,385	611
Release of allowance for loan losses	(485)	(580)
Ending balance	124,166	111,080	97,787
Individually evaluated for impairment			3,970
Acquired with deteriorated credit quality			546
Collectively evaluated for impairment			93,271
Total allowance for loan losses by group	124,166	111,080	97,787
Loans ending balance:
Individually evaluated for impairment			58,204
Acquired with deteriorated credit quality			69,639
Collectively evaluated for impairment			12,153,667
Gross loans before unamortized premiums, unearned discounts and deferred fees	12,182,203		12,281,510
Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	242	494	494
Charge-offs	0	0
Recoveries	0	0
Release of allowance for loan losses	0	(121)
Ending balance	0	373	242
Individually evaluated for impairment			0
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			242
Total allowance for loan losses by group	0	373	242
Loans ending balance:
Individually evaluated for impairment			0
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			0
Gross loans before unamortized premiums, unearned discounts and deferred fees			0
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	18,018	26,617	26,617
Charge-offs	(1)	0
Recoveries	250	9
Release of allowance for loan losses	(2,959)	(1,220)
Ending balance	26,841	25,406	18,018
Individually evaluated for impairment			1,540
Acquired with deteriorated credit quality			5
Collectively evaluated for impairment			16,473
Total allowance for loan losses by group	26,841	25,406	18,018
Loans ending balance:
Individually evaluated for impairment			16,145
Acquired with deteriorated credit quality			19,028
Collectively evaluated for impairment			2,925,354
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,886,560		2,960,527
Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	52,373	54,569	54,569
Charge-offs	0	(234)
Recoveries	14	0
Release of allowance for loan losses	(1,120)	803
Ending balance	44,612	55,138	52,373
Individually evaluated for impairment			0
Acquired with deteriorated credit quality			298
Collectively evaluated for impairment			52,075
Total allowance for loan losses by group	44,612	55,138	52,373
Loans ending balance:
Individually evaluated for impairment			3,520
Acquired with deteriorated credit quality			47,553
Collectively evaluated for impairment			4,471,440
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,609,824		4,522,513
Commercial Portfolio Segment | Commercial construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,585	4,553	4,553
Charge-offs	0	0
Recoveries	0	0
Release of allowance for loan losses	344	(1,203)
Ending balance	4,414	3,350	2,585
Individually evaluated for impairment			0
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			2,585
Total allowance for loan losses by group	4,414	3,350	2,585
Loans ending balance:
Individually evaluated for impairment			0
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			222,328
Gross loans before unamortized premiums, unearned discounts and deferred fees	246,093		222,328
Commercial Portfolio Segment | Business Banking
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	10,983	13,152	13,152
Charge-offs	(945)	(1,384)
Recoveries	928	365
Release of allowance for loan losses	143	1,371
Ending balance	17,269	13,504	10,983
Individually evaluated for impairment			450
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			10,533
Total allowance for loan losses by group	17,269	13,504	10,983
Loans ending balance:
Individually evaluated for impairment			12,060
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			1,322,634
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,201,007		1,334,694
Residential Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,556	6,435	6,435
Charge-offs	0	0
Recoveries	10	10
Release of allowance for loan losses	2,188	(210)
Ending balance	22,243	6,235	6,556
Individually evaluated for impairment			1,549
Acquired with deteriorated credit quality			243
Collectively evaluated for impairment			4,764
Total allowance for loan losses by group	22,243	6,235	6,556
Loans ending balance:
Individually evaluated for impairment			22,378
Acquired with deteriorated credit quality			3,058
Collectively evaluated for impairment			1,901,374
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,936,182		1,926,810
Consumer Portfolio Segment | Consumer home equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,722	3,744	3,744
Charge-offs	0	0
Recoveries	4	71
Release of allowance for loan losses	435	(239)
Ending balance	6,018	3,576	3,722
Individually evaluated for impairment			270
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			3,452
Total allowance for loan losses by group	6,018	3,576	3,722
Loans ending balance:
Individually evaluated for impairment			3,922
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			1,096,231
Gross loans before unamortized premiums, unearned discounts and deferred fees	1,099,211		1,100,153
Consumer Portfolio Segment | Other Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,308	3,467	3,467
Charge-offs	(661)	(364)
Recoveries	179	156
Release of allowance for loan losses	484	239
Ending balance	2,769	3,498	3,308
Individually evaluated for impairment			161
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			3,147
Total allowance for loan losses by group	2,769	$ 3,498	3,308
Loans ending balance:
Individually evaluated for impairment			179
Acquired with deteriorated credit quality			0
Collectively evaluated for impairment			214,306
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 203,326		$ 214,485

Loans and Allowance for Loan_14

Loans and Allowance for Loan Losses - Summary of Internal Risk-Rating Categories (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 12,182,203	$ 12,281,510
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	2,886,560	2,960,527
Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	4,609,824	4,522,513
Commercial Portfolio Segment | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	246,093	222,328
Commercial Portfolio Segment | Business Banking
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees	$ 1,201,007	1,334,694
Nonperforming Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		9,040,062
Nonperforming Loans | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		872,544
Nonperforming Loans | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		7,640,376
Nonperforming Loans | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		226,632
Nonperforming Loans | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		288,663
Nonperforming Loans | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		11,847
Nonperforming Loans | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		2,960,527
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		171,537
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		2,656,873
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		70,141
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		50,339
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		11,637
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,522,513
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,378
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		4,199,803
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		104,517
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		213,815
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial real estate | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		222,328
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		213,744
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		1,889
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		6,695
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Commercial construction | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		0
Nonperforming Loans | Commercial Portfolio Segment | Business Banking
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		1,334,694
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Unrated
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		696,629
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		569,956
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		50,085
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		17,814
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		210
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Loss
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans before unamortized premiums, unearned discounts and deferred fees		$ 0

Loans and Allowance for Loan_15

Loans and Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total loans	$ 12,182,203	$ 12,281,510
Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans	2,886,560	2,960,527
Commercial Portfolio Segment | Business Banking
Financing Receivable, Past Due [Line Items]
Total loans	$ 1,201,007	1,334,694
Nonperforming Loans
Financing Receivable, Past Due [Line Items]
Total loans		9,040,062
Nonperforming Loans | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		872,544
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans		2,960,527
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		171,537
Nonperforming Loans | Commercial Portfolio Segment | Commercial and industrial | Unrated | Paycheck Protection Program
Financing Receivable, Past Due [Line Items]
Total loans		112,800
Nonperforming Loans | Commercial Portfolio Segment | Business Banking
Financing Receivable, Past Due [Line Items]
Total loans		1,334,694
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Unrated
Financing Receivable, Past Due [Line Items]
Total loans		696,629
Nonperforming Loans | Commercial Portfolio Segment | Business Banking | Unrated | Paycheck Protection Program
Financing Receivable, Past Due [Line Items]
Total loans		$ 218,600

Loans and Allowance for Loan_16

Loans and Allowance for Loan Losses - Summary of Company's Impaired Loans by Loan Portfolio (Detail) $ in Thousands	Dec. 31, 2021USD ($)
Recorded Investment
With no related allowance recorded:	$ 33,187
With an allowance recorded:	25,017
Total	58,204
Unpaid Principal Balance
With no related allowance recorded:	36,330
With an allowance recorded:	28,786
Total	65,116
Related Allowance	3,970
Commercial Portfolio Segment | Commercial and industrial
Recorded Investment
With no related allowance recorded:	12,309
With an allowance recorded:	3,836
Unpaid Principal Balance
With no related allowance recorded:	13,212
With an allowance recorded:	4,226
Related Allowance	1,540
Commercial Portfolio Segment | Commercial real estate
Recorded Investment
With no related allowance recorded:	3,520
With an allowance recorded:	0
Unpaid Principal Balance
With no related allowance recorded:	3,520
With an allowance recorded:	0
Related Allowance	0
Commercial Portfolio Segment | Business Banking
Recorded Investment
With no related allowance recorded:	4,199
With an allowance recorded:	7,861
Unpaid Principal Balance
With no related allowance recorded:	5,069
With an allowance recorded:	11,240
Related Allowance	450
Residential Portfolio Segment | Residential real estate
Recorded Investment
With no related allowance recorded:	11,217
With an allowance recorded:	11,161
Unpaid Principal Balance
With no related allowance recorded:	12,587
With an allowance recorded:	11,161
Related Allowance	1,549
Consumer Portfolio Segment | Consumer home equity
Recorded Investment
With no related allowance recorded:	1,924
With an allowance recorded:	1,998
Unpaid Principal Balance
With no related allowance recorded:	1,924
With an allowance recorded:	1,998
Related Allowance	270
Consumer Portfolio Segment | Other Consumer
Recorded Investment
With no related allowance recorded:	18
With an allowance recorded:	161
Unpaid Principal Balance
With no related allowance recorded:	18
With an allowance recorded:	161
Related Allowance	$ 161

Loans and Allowance for Loan_17

Loans and Allowance for Loan Losses - Summary of Information Regarding Interest Income Recognized on Impaired Loans,by Portfolio (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Average Recorded Investment
With no related allowance recorded:	$ 36,212
With an allowance recorded:	39,345
Total	75,557
Total Interest Recognized
With no related allowance recorded:	280
With an allowance recorded:	159
Total	439
Commercial Portfolio Segment | Commercial and industrial
Average Recorded Investment
With no related allowance recorded:	9,899
With an allowance recorded:	7,965
Total Interest Recognized
With no related allowance recorded:	46
With an allowance recorded:	0
Commercial Portfolio Segment | Commercial real estate
Average Recorded Investment
With no related allowance recorded:	4,176
With an allowance recorded:	657
Total Interest Recognized
With no related allowance recorded:	44
With an allowance recorded:	0
Commercial Portfolio Segment | Business Banking
Average Recorded Investment
With no related allowance recorded:	5,024
With an allowance recorded:	16,325
Total Interest Recognized
With no related allowance recorded:	26
With an allowance recorded:	14
Residential Portfolio Segment | Residential real estate
Average Recorded Investment
With no related allowance recorded:	14,648
With an allowance recorded:	12,248
Total Interest Recognized
With no related allowance recorded:	144
With an allowance recorded:	127
Consumer Portfolio Segment | Consumer home equity
Average Recorded Investment
With no related allowance recorded:	2,438
With an allowance recorded:	2,150
Total Interest Recognized
With no related allowance recorded:	20
With an allowance recorded:	18
Consumer Portfolio Segment | Other Consumer
Average Recorded Investment
With no related allowance recorded:	27
Total Interest Recognized
With no related allowance recorded:	$ 0

Loans and Allowance for Loan_18

Loans and Allowance for Loan Losses - Summary of Outstanding and Carrying Amounts of PCI Loans (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Financing Receivable, Impaired [Line Items]
Financing receivable, purchased with credit deterioration, amount at purchase price	$ 58,204
Outstanding balance
Financing Receivable, Impaired [Line Items]
Financing receivable, purchased with credit deterioration, amount at purchase price	78,074
Carrying amount
Financing Receivable, Impaired [Line Items]
Financing receivable, purchased with credit deterioration, amount at purchase price	$ 69,639

Loans and Allowance for Loan_19

Loans and Allowance for Loan Losses - Summary of Activity in the Accretable Yield for the PCI Loan Portfolio (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 2,495
Accretion	(216)
Other change in expected cash flows	(248)
Balance at end of period	$ 2,031

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disclosure of Leases [Line Items]
Payment of lease payments	$ 4.7	$ 3.6
Minimum
Disclosure of Leases [Line Items]
Operating lease remaining lease term	1 year
Maximum
Disclosure of Leases [Line Items]
Operating lease remaining lease term	25 years

Leases - Summary of Information

Leases - Summary of Information Relating to Operating Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Right-of-use assets	$ 80,408	$ 83,821
Lease liabilities	$ 85,573	$ 89,296

Leases - Summary of Net Lease C

Leases - Summary of Net Lease Cost (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Leases [Abstract]
Operating lease cost	$ 3,694	$ 3,561
Finance lease cost	88	31
Variable lease cost	829	490
Total lease cost	$ 4,611	$ 4,082

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information Related to Operating Leases (Detail)	Mar. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Weighted-average remaining lease term (in years)	7 years 7 months 24 days	7 years 9 months 29 days
Weighted-average discount rate	2.54%	2.52%

Goodwill and Other Intangible_2

Goodwill and Other Intangibles - Summary of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Balances not subject to amortization
Goodwill	$ 634,779	$ 631,496
Balances subject to amortization
Total other intangible assets	19,980	18,207
Total goodwill and other intangible assets	654,759	649,703
Insurance agency
Balances subject to amortization
Net Carrying Amount	8,708	6,635
Core deposit intangible
Balances subject to amortization
Net Carrying Amount	11,272	11,572
Banking Business
Balances not subject to amortization
Goodwill	557,635	557,635
Balances subject to amortization
Total other intangible assets	11,272	11,572
Total goodwill and other intangible assets	568,907	569,207
Banking Business | Insurance agency
Balances subject to amortization
Net Carrying Amount	0	0
Banking Business | Core deposit intangible
Balances subject to amortization
Net Carrying Amount	11,272	11,572
Insurance Agency Business
Balances not subject to amortization
Goodwill	77,144	73,861
Balances subject to amortization
Total other intangible assets	8,708	6,635
Total goodwill and other intangible assets	85,852	80,496
Insurance Agency Business | Insurance agency
Balances subject to amortization
Net Carrying Amount	8,708	6,635
Insurance Agency Business | Core deposit intangible
Balances subject to amortization
Net Carrying Amount	$ 0	$ 0

Goodwill and Other Intangible_3

Goodwill and Other Intangibles - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022agencyreporting_unit
Business Acquisition [Line Items]
Number of reporting units | reporting_unit	2
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Number of insurance agencies acquired | agency	1

Earnings Per Share ("EPS") (Det

Earnings Per Share ("EPS") (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income applicable to common shares	$ 51,516	$ 47,663
Average number of common shares outstanding (in shares)	184,066,326	186,758,154
Less: Average unallocated ESOP shares (in shares)	(14,208,376)	(14,709,110)
Average number of common shares outstanding used to calculate basic earnings per common share (in shares)	169,857,950	172,049,044
Common stock equivalents (in shares)	110,206	0
Average number of common shares outstanding used to calculate diluted earnings per common share (in shares)	169,968,156	172,049,044
Earnings per common share
Basic earnings per share (in dollars per share)	$ 0.30	$ 0.28
Diluted earnings per share (in dollars per share)	$ 0.30	$ 0.28

Low Income Housing Tax Credit_3

Low Income Housing Tax Credits and Other Tax Credit Investments - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Investments In Affordable Housing Projects [Line Items]
Tax credit investment	$ 82,500,000	$ 83,800,000
Renewable Energy Program
Investments In Affordable Housing Projects [Line Items]
Equity investments	2,800,000	2,800,000
Outstanding investment commitments	$ 0	$ 0
Low income housing tax credit and other tax credit investments
Investments In Affordable Housing Projects [Line Items]
Tax credit period of benefits	15 years
Operating loss tax benefits period	15 years

Low Income Housing Tax Credit_4

Low Income Housing Tax Credits and Other Tax Credit Investments - Summary of the Company's Investments in Low Income Housing Projects Accounted for Using the Proportional Amortization Method (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Investments in Affordable Housing Projects [Abstract]
Current recorded investment included in other assets	$ 79,722		$ 81,035
Commitments to fund qualified affordable housing projects included in recorded investment noted above	43,287		$ 48,399
Tax credits and benefits recognized	2,321	$ 1,464
Amortization expense included in income tax expense	$ 1,843	$ 1,264

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 12, 2021	Mar. 31, 2022	Feb. 28, 2022	Jan. 31, 2022	Mar. 31, 2022	Mar. 31, 2021
Equity [Abstract]
Number of shares authorized to be repurchased (in shares)	9,337,900
Percentage of shares authorized (in percent)	5.00%
Share repurchase program, authorized amount	$ 225,000
Number of shares repurchased (in shares)		769,398	1,109,697	987,526		0
Aggregate dividends					$ 16,908	$ 10,324
Dividends declared (in dollars per share)					$ 0.10	$ 0.06
Dividends paid (in dollars per share)					$ 0.10	$ 0.06

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Shares Repurchased (Details) - $ / shares	1 Months Ended			3 Months Ended
	Mar. 31, 2022	Feb. 28, 2022	Jan. 31, 2022	Mar. 31, 2021
Equity [Abstract]
Total Number of Shares Repurchased (in shares)	769,398	1,109,697	987,526	0
Average Price Paid per Share (in dollars per share)	$ 21.31	$ 21.08	$ 21.02
Total Number of Shares Repurchased as Part of the Share Repurchase Program at the end of Each Respective Period (in shares)	4,002,499	3,233,101	2,123,404
Maximum Number of Shares That May Yet Be Purchased Under the Share Repurchase Program at the end of Each Respective Period (in shares)	5,335,401	6,104,799	7,214,496

Employee Benefits - Summary of

Employee Benefits - Summary of Components of Net Pension Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Components of net periodic benefit cost:
Service cost	$ 8,092	$ 7,896
Interest cost	2,430	1,269
Expected return on plan assets	(9,281)	(8,141)
Past service credit	(2,970)	(2,946)
Recognized net actuarial loss	2,798	3,538
Net periodic benefit cost	$ 1,069	$ 1,616

Employee Benefits - Narrative (

Employee Benefits - Narrative (Details) - USD ($)	Mar. 01, 2022	Nov. 29, 2021	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, reduction of shares available to be issued upon exercise of stock options with each additional restricted stock grant		3
Share-based payment arrangement, noncash expense			$ 1,623,000	$ 0
Restricted Stock Units (RSUs)
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period (in shares)	978,364		978,364
Restricted Stock
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period (in shares)			0
Performance Stock Units (PSUs)
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	3 years
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period (in shares)	533,676		533,676
Eastern Bankshares, Inc. 2021 Equity Incentive Plan
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)		26,146,141
Share-based payment arrangement, noncash expense			$ 1,600,000	0
Share-based payment arrangement, expense, tax benefit			400,000
Share-based payment arrangement, nonvested award, excluding option, cost not yet recognized, amount			$ 44,000,000		$ 44,000,000	$ 13,500,000
Share-based payment arrangement, nonvested award, cost not yet recognized, period for recognition			4 years 1 month 6 days
Eastern Bankshares, Inc. 2021 Equity Incentive Plan | Restricted Stock Units (RSUs)
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)		7,470,326
Share-based compensation arrangement by share-based payment award, number of shares available for grant (in shares)			5,275,230		5,275,230	6,787,270
Share-based compensation arrangement by share-based payment award, equity instruments other than options, vested in period (in shares)					0
Eastern Bankshares, Inc. 2021 Equity Incentive Plan | Share-based Payment Arrangement, Option
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized (in shares)		18,675,815
Share-based compensation arrangement by share-based payment award, expiration period		10 years
Share-based compensation arrangement by share-based payment award, number of shares available for grant (in shares)			18,675,815		18,675,815	18,675,815
Share-based compensation arrangement by share-based payment award, options, grants in period, gross (in shares)					0
Eastern Bankshares, Inc. 2021 Equity Incentive Plan | Restricted Stock
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period		5 years
Minimum | Eastern Bankshares, Inc. 2021 Equity Incentive Plan | Restricted Stock Units (RSUs)
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	3 years
Maximum | Eastern Bankshares, Inc. 2021 Equity Incentive Plan | Restricted Stock Units (RSUs)
Defined Benefit Plan, Plan Assets, Category [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	5 years
Primary Beneficiary
Defined Benefit Plan, Plan Assets, Category [Line Items]
Rabbi trust investments			$ 87,292,000		$ 87,292,000	$ 104,372,000
Pension Plan
Defined Benefit Plan, Plan Assets, Category [Line Items]
Discretionary employer contributions to defined benefit plans			$ 7,200,000	$ 0

Employee Benefits - Asset Held

Employee Benefits - Asset Held in Rabbi Trust by Plan Type (Details) - Primary Beneficiary - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Book Value	$ 73,398	$ 80,021
Mark-to-Market	13,894	24,351
Fair Value	87,292	104,372
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Book Value	5,445	4,494
Fair Value	5,445	4,494
Equities
Defined Benefit Plan Disclosure [Line Items]
Book Value	59,487	67,401
Mark-to-Market	14,257	24,295
Fair Value	73,744	91,696
Fixed income
Defined Benefit Plan Disclosure [Line Items]
Book Value	8,466	8,126
Mark-to-Market	(363)	56
Fair Value	$ 8,103	$ 8,182

Employee Benefits - Share-based

Employee Benefits - Share-based Payment Arrangement, Restricted Stock, Restricted Stock Unit, and Performance Stock Unit, Activity (Details) - $ / shares	Mar. 01, 2022	Mar. 31, 2022
Restricted Stock
Number of Shares
Non-vested stock at beginning of year (in shares)		683,056
Granted (in shares)		0
Non-vested stock at end of year (in shares)		683,056
Weighted-Average Grant Price Per Share
Non-vested stock at beginning of year (in dollars per share)		$ 20.13
Granted (in dollars per share)		0
Non-vested stock at end of year (in dollars per share)		$ 20.13
Restricted Stock Units (RSUs)
Number of Shares
Non-vested stock at beginning of year (in shares)		0
Granted (in shares)	978,364	978,364
Non-vested stock at end of year (in shares)		978,364
Weighted-Average Grant Price Per Share
Non-vested stock at beginning of year (in dollars per share)		$ 0
Granted (in dollars per share)		21.08
Non-vested stock at end of year (in dollars per share)		$ 21.08
Performance Stock Units (PSUs)
Number of Shares
Non-vested stock at beginning of year (in shares)		0
Granted (in shares)	533,676	533,676
Non-vested stock at end of year (in shares)		533,676
Weighted-Average Grant Price Per Share
Non-vested stock at beginning of year (in dollars per share)		$ 0
Granted (in dollars per share)		21.12
Non-vested stock at end of year (in dollars per share)		$ 21.12

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments as of the Dates Indicated (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments to extend credit
Disclosure Of Financial Instruments Indicated [Line Items]
Contractual obligation	$ 5,306,596	$ 5,175,521
Standby letters of credit
Disclosure Of Financial Instruments Indicated [Line Items]
Contractual obligation	65,687	65,602
Forward commitments to sell loans
Disclosure Of Financial Instruments Indicated [Line Items]
Contractual obligation	$ 12,917	$ 24,440

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2022USD ($)	Jun. 30, 2021settlement	Dec. 31, 2021USD ($)
Disclosure of Commitments and Contingencies [Line Items]
Number of legal settlements | settlement		2
Loss contingency, loss in period	$ 3,300,000
Cash and Cash Equivalents
Disclosure of Commitments and Contingencies [Line Items]
Other contingencies	$ 0		$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments - Pre-tax Impact of Terminated Cash Flow Hedges on AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Before Tax [Roll Forward]
Beginning Balance	$ 3,406,352	$ 3,428,052
Unrealized gains on terminated hedges arising during the period	0	0
Reclassification adjustments for amortization of unrealized (gains) into net income	(5,298)	(8,274)
Ending balance	3,008,392	3,387,045
Accumulated Gain (Loss), Net, Terminated Cash Flow Hedge, Parent
AOCI Attributable to Parent, Before Tax [Roll Forward]
Beginning Balance	10,239	41,473
Ending balance	$ 4,941	$ 33,199

Derivative Financial Instrume_4

Derivative Financial Instruments - Additional information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Derivative [Line Items]
Credit exposure to settled variation margin in excess of customer related interest rate swap (less than)	$ 1.4		$ 0.4
Derivative, gain (loss) on derivative, net	(0.2)	$ (0.2)
Loan Origination Commitments
Derivative [Line Items]
Derivative, notional amount	22.8		31.9
Derivative asset	0.2		0.3
Derivative liability	0.2		0.1
Forward Contracts
Derivative [Line Items]
Derivative, notional amount	12.9		24.4
Non Cleared Derivative Transactions | Customer Related Interest Rate Swap Derivatives
Derivative [Line Items]
Fair value of interest rate swap liabilities that are net in a net liability position	0.2		13.7
Cash and Cash Equivalents | Non Cleared Derivative Transactions | Customer Related Interest Rate Swap Derivatives
Derivative [Line Items]
Additional collateral posted	5.5
Available-for-sale Securities | Non Cleared Derivative Transactions | Customer Related Interest Rate Swap Derivatives
Derivative [Line Items]
Additional collateral posted			21.3
Restricted Assets | Cash and Cash Equivalents | Cleared Derivative Transaction
Derivative [Line Items]
Additional collateral posted	37
Restricted Assets | Available-for-sale Securities | Cleared Derivative Transaction
Derivative [Line Items]
Additional collateral posted			$ 48.9
Interest Income | Termination Of Cash Flow Hedges
Derivative [Line Items]
Interest rate swap cash flow hedges amount expected to reclassified from other comprehensive income to income statement in the next twelve months	$ 4.9

Derivative Financial Instrume_5

Derivative Financial Instruments - Customer-related derivative positions (Detail) - Not Designated as Hedging Instrument $ in Thousands	Mar. 31, 2022USD ($)position	Dec. 31, 2021USD ($)position
Interest rate swaps
Disclosure Of Customer Related Derivatives Not Designated As Hedging [Line Items]
Number of Positions | position	468	494
Total Notional | $	$ 2,867,637	$ 3,009,150
Risk participation agreements
Disclosure Of Customer Related Derivatives Not Designated As Hedging [Line Items]
Number of Positions | position	63	64
Total Notional | $	$ 263,496	$ 238,772
Matched commercial customer book
Disclosure Of Customer Related Derivatives Not Designated As Hedging [Line Items]
Number of Positions | position	70	72
Total Notional | $	$ 10,343	$ 7,922
Foreign currency loan
Disclosure Of Customer Related Derivatives Not Designated As Hedging [Line Items]
Number of Positions | position	5	6
Total Notional | $	$ 11,586	$ 10,830

Derivative Financial Instrume_6

Derivative Financial Instruments - Classification on the balance sheet for the periods indicated (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Asset Derivatives
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Interest rate swaps, Other assets	$ 23,725	$ 64,338
Derivatives not designated as hedging instruments, Other assets	24,019	64,714
Asset Derivatives | Risk participation agreements
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other assets	196	315
Asset Derivatives | Foreign currency exchange contracts – matched customer book
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other assets	91	61
Asset Derivatives | Foreign currency exchange contracts – foreign currency loan
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other assets	7	0
Liability Derivatives
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivative not designated as hedging instruments, Interest rate swaps, Other liabilities	24,988	17,880
Derivatives not designated as hedging instruments, Other liabilities	25,483	18,593
Liability Derivatives | Risk participation agreements
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other liabilities	401	580
Liability Derivatives | Foreign currency exchange contracts – matched customer book
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other liabilities	78	46
Liability Derivatives | Foreign currency exchange contracts – foreign currency loan
Disclosure Of Fair Value Of Derivative Instruments And Their Balance Sheet Classification [Line Items]
Derivatives not designated as hedging instruments, Other liabilities	$ 16	$ 87

Derivative Financial Instrume_7

Derivative Financial Instruments - Company's derivative financial instruments included in OCI as follows (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain in OCI on derivatives	$ 0	$ 0
Gain reclassified from OCI into interest income (effective portion)	5,298	8,274
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0
(Loss) gain recognized in other income for foreign currency exchange contracts:	2,434	5,299
Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain reclassified from OCI into interest income (effective portion)	5,298	8,274
Interest Income | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0
Interest Income | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Customer-related positions:	2,298	4,851
Interest Income | Risk participation agreements
Derivative Instruments, Gain (Loss) [Line Items]
Customer-related positions:	60	369
Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness test)	0	0
Other Income | Foreign currency exchange contracts – matched customer book
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain recognized in other income for foreign currency exchange contracts:	(2)	6
Other Income | Foreign currency exchange contracts – foreign currency loan
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain recognized in other income for foreign currency exchange contracts:	$ 78	$ 73

Balance Sheet Offsetting - Disc

Balance Sheet Offsetting - Disclosure Detail Of Balance Sheet Offsetting Of Financial Assets And Liabilities (Detail) - Customer-related positions - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivative Assets
Gross Amounts Recognized	$ 24,019	$ 64,714
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	24,019	64,714
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	3,470	1,440
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	20,549	63,274
Derivative Liabilities
Gross Amounts Recognized	25,483	18,593
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	25,483	18,593
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	3,470	1,440
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	21,518	16,440
Net Amount	495	713
Interest rate swaps
Derivative Assets
Gross Amounts Recognized	23,725	64,338
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	23,725	64,338
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	3,470	1,440
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	20,255	62,898
Derivative Liabilities
Gross Amounts Recognized	24,988	17,880
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	24,988	17,880
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	3,470	1,440
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	21,518	16,440
Net Amount	0	0
Risk participation agreements
Derivative Assets
Gross Amounts Recognized	196	315
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	196	315
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	196	315
Derivative Liabilities
Gross Amounts Recognized	401	580
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	401	580
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	401	580
Foreign currency exchange contracts – matched customer book
Derivative Assets
Gross Amounts Recognized	91	61
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	91	61
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	91	61
Derivative Liabilities
Gross Amounts Recognized	78	46
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	78	46
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	78	46
Foreign currency exchange contracts – foreign currency loan
Derivative Assets
Gross Amounts Recognized	7	0
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	7	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	7	0
Derivative Liabilities
Gross Amounts Recognized	16	87
Gross Amounts Offset in the Consolidated Balance Sheet	0	0
Net Amounts Presented in the Consolidated Balance Sheet	16	87
Gross Amounts Not Offset in the Consolidated Balance Sheet, Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheet, Collateral Pledged (Received)	0	0
Net Amount	$ 16	$ 87

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Additional information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfer from level one to level two fair value assets	$ 0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment in mutual funds	$ 45,800,000	$ 58,100,000
Carrying amount | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial instruments original maturity	90 days

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Summary Of The Balances Of Assets And Liabilities Measured At Fair Value On A Recurring Basis (Detail) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets
Rabbi trust investments	$ 87,292	$ 104,372
Loans held for sale	1,166	1,206
Customer-related positions	23,725	64,338
Risk participation agreements	196	315
Matched customer book	91	61
Foreign currency loan	7
Mortgage derivatives	239	256
Total	8,030,021	8,681,772
Liabilities
Customer-related positions	24,988	17,880
Risk participation agreements	401	580
Matched customer book	78	46
Foreign currency loan	16	87
Mortgage derivatives	168	16
Total	25,651	18,609
Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	4,969,346	5,524,708
Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	1,615,927	1,408,868
U.S. Agency bonds
Assets
Securities available for sale	1,013,899	1,175,014
U.S. Treasury securities
Assets
Securities available for sale	56,235	88,605
State and municipal bonds and obligations
Assets
Securities available for sale	260,316	280,329
Small Business Administration pooled securities
Assets
Securities available for sale		32,103
Other debt securities
Assets
Securities available for sale	1,582	1,597
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Rabbi trust investments	79,189	96,190
Loans held for sale	0	0
Customer-related positions	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0
Mortgage derivatives	0	0
Total	135,424	184,795
Liabilities
Customer-related positions	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0	0
Mortgage derivatives	0	0
Total	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Agency bonds
Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities
Assets
Securities available for sale	56,235	88,605
Quoted Prices in Active Markets for Identical Assets (Level 1) | State and municipal bonds and obligations
Assets
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Small Business Administration pooled securities
Assets
Securities available for sale		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other debt securities
Assets
Securities available for sale	0	0
Significant Other Observable Inputs (Level 2)
Assets
Rabbi trust investments	8,103	8,182
Loans held for sale	1,166	1,206
Customer-related positions	23,725	64,338
Risk participation agreements	196	315
Matched customer book	91	61
Foreign currency loan	7
Mortgage derivatives	239	256
Total	7,894,597	8,496,977
Liabilities
Customer-related positions	24,988	17,880
Risk participation agreements	401	580
Matched customer book	78	46
Foreign currency loan	16	87
Mortgage derivatives	168	16
Total	25,651	18,609
Significant Other Observable Inputs (Level 2) | Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	4,969,346	5,524,708
Significant Other Observable Inputs (Level 2) | Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	1,615,927	1,408,868
Significant Other Observable Inputs (Level 2) | U.S. Agency bonds
Assets
Securities available for sale	1,013,899	1,175,014
Significant Other Observable Inputs (Level 2) | U.S. Treasury securities
Assets
Securities available for sale	0	0
Significant Other Observable Inputs (Level 2) | State and municipal bonds and obligations
Assets
Securities available for sale	260,316	280,329
Significant Other Observable Inputs (Level 2) | Small Business Administration pooled securities
Assets
Securities available for sale		32,103
Significant Other Observable Inputs (Level 2) | Other debt securities
Assets
Securities available for sale	1,582	1,597
Significant Unobservable Inputs (Level 3)
Assets
Rabbi trust investments	0	0
Loans held for sale	0	0
Customer-related positions	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0
Mortgage derivatives	0	0
Total	0	0
Liabilities
Customer-related positions	0	0
Risk participation agreements	0	0
Matched customer book	0	0
Foreign currency loan	0	0
Mortgage derivatives	0	0
Total	0	0
Significant Unobservable Inputs (Level 3) | Government-sponsored residential mortgage-backed securities
Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Government-sponsored commercial mortgage-backed securities
Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | U.S. Agency bonds
Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | U.S. Treasury securities
Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | State and municipal bonds and obligations
Assets
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Small Business Administration pooled securities
Assets
Securities available for sale		0
Significant Unobservable Inputs (Level 3) | Other debt securities
Assets
Securities available for sale	$ 0	$ 0

Fair Value of Assets and Liab_5

Fair Value of Assets and Liabilities - Summary Of The Fair Value Of Assets And Liabilities Measured At Fair Value On A Nonrecurring Basis (Detail) - Fair Value, Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Individually assessed collateral-dependent loans whose fair value is based upon appraisals	$ 11,879	$ 12,068
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Individually assessed collateral-dependent loans whose fair value is based upon appraisals	0	0
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Individually assessed collateral-dependent loans whose fair value is based upon appraisals	0	0
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Individually assessed collateral-dependent loans whose fair value is based upon appraisals	$ 11,879	$ 12,068

Fair Value of Assets and Liab_6

Fair Value of Assets and Liabilities - Schedule of Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	$ 395,434	$ 0
FHLB stock	10,904	10,904
Bank-owned life insurance	157,954	157,091
Deposits	19,392,816	19,628,311
Federal Home Loan Bank advances	13,689	14,020
Escrow deposits of borrowers	21,233	20,258
Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	192,231
Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	203,203
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Loans, net of allowance for loan losses	0	0
FHLB stock	0	0
Bank-owned life insurance	0	0
Deposits	0	0
Federal Home Loan Bank advances	0	0
Escrow deposits of borrowers	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	0
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Loans, net of allowance for loan losses	0	0
FHLB stock	10,904	10,904
Bank-owned life insurance	157,954	157,091
Deposits	19,387,023	19,626,376
Federal Home Loan Bank advances	12,767	13,558
Escrow deposits of borrowers	21,233	20,258
Significant Other Observable Inputs (Level 2) | Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	188,913
Significant Other Observable Inputs (Level 2) | Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	203,210
Significant Unobservable Inputs (Level 3)
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Loans, net of allowance for loan losses	11,817,706	12,282,323
FHLB stock	0	0
Bank-owned life insurance	0	0
Deposits	0	0
Federal Home Loan Bank advances	0	0
Escrow deposits of borrowers	0	0
Significant Unobservable Inputs (Level 3) | Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	0
Significant Unobservable Inputs (Level 3) | Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	0
Carrying Value
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Loans, net of allowance for loan losses	12,033,603	12,157,281
FHLB stock	10,904	10,904
Bank-owned life insurance	157,954	157,091
Deposits	19,392,816	19,628,311
Federal Home Loan Bank advances	13,689	14,020
Escrow deposits of borrowers	21,233	20,258
Carrying Value | Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	192,231
Carrying Value | Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	203,203
Outstanding balance
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Loans, net of allowance for loan losses	11,817,706	12,282,323
FHLB stock	10,904	10,904
Bank-owned life insurance	157,954	157,091
Deposits	19,387,023	19,626,376
Federal Home Loan Bank advances	12,767	13,558
Escrow deposits of borrowers	21,233	$ 20,258
Outstanding balance | Government-sponsored residential mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	188,913
Outstanding balance | Government-sponsored commercial mortgage-backed securities
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Held to maturity securities:	$ 203,210

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Revenue from External Customers by Products and Services (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	$ 48,697	$ 43,718
Total noninterest (loss) income out-of-scope of ASC 606	(2,282)	11,494
Total noninterest income	46,415	55,212
Insurance commissions
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	28,713	28,147
Service charges on deposit accounts
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	8,537	5,367
Trust and investment advisory fees
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	6,141	5,663
Debit card processing fees
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	2,945	2,749
Other noninterest income
Revenue from External Customer [Line Items]
Total noninterest income in-scope of ASC 606	$ 2,361	$ 1,792

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Additional information (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Insurance commission earned but not yet received	$ 11.9	$ 15.6
Cash Management Fees
Disaggregation of Revenue [Line Items]
Fess earned but not yet received	2.3	1.8
Debit Card
Disaggregation of Revenue [Line Items]
Fess earned but not yet received	$ 0.3	$ 0.3

Other Comprehensive Income - Co

Other Comprehensive Income - Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Unrealized losses on securities available for sale:
Change in fair value of securities available for sale, Pre Tax Amount	$ (465,532)	$ (94,979)
Less: reclassification adjustments for gains included in net income, Pre-Tax Amount	(2,172)	1,164
Net change in fair value of securities available for sale, Pre Tax Amount	(463,360)	(96,143)
Unrealized gains (losses) on cash flow hedges:
Change in fair value of cash flow hedges, Pre Tax Amount	0	0
Less: net cash flow hedge losses reclassified into interest income, Pre Tax Amount	5,298	8,274
Net change in fair value of cash flow hedges, Pre Tax Amount	(5,298)	(8,274)
Defined benefit pension plans:
Change in actuarial loss, Pre Tax Amount	0	0
Less: amortization of actuarial net loss, Pre Tax Amount	(2,798)	(3,537)
Less: amortization of prior service cost, pre tax amount	2,970	2,945
Net change in other comprehensive income for defined benefit postretirement plans, Pre Tax Amount	(172)	592
Total other comprehensive income, Pre Tax Amount	(468,830)	(103,825)
Unrealized losses on securities available for sale:
Change in fair value of securities available for sale, Tax (Expense) Benefit	112,008	20,982
Less: reclassification adjustments for gains included in net income, Tax (Expense) Benefit	673	(257)
Net change in fair value of securities available for sale, Tax (Expense) Benefit	111,335	21,239
Unrealized gains (losses) on cash flow hedges:
Change in fair value of cash flow hedges, Tax (Expense) Benefit	0	0
Less: net cash flow hedge losses reclassified into interest income, Tax (Expense) Benefit	(1,489)	(2,326)
Net change in fair value of cash flow hedges, Tax (Expense) Benefit	1,489	2,326
Defined benefit pension plans:
Change in actuarial net loss, Tax (Expense) Benefit	0	0
Less: amortization of actuarial net loss, Tax (Expense) Benefit	787	994
Less: net accretion of prior service credit, Tax (Expense) Benefit	(835)	(828)
Net change in other comprehensive income for defined benefit postretirement plans, Tax (Expense) Benefit	48	(166)
Total other comprehensive income, Tax (Expense) Benefit	112,872	23,399
Unrealized losses on securities available for sale:
Change in fair value of securities available for sale, After Tax Amount	(353,524)	(73,997)
Less: reclassification adjustment for gains included in net income, After Tax Amount	(1,499)	907
Net change in fair value of securities available for sale, After Tax Amount	(352,025)	(74,904)
Unrealized gains (losses) on cash flow hedges:
Change in fair value of cash flow hedges, After Tax Amount	0	0
Less: net cash flow hedge losses reclassified into interest income, Amount After Tax	3,809	5,948
Net change in fair value of cash flow hedges, Amount After Tax	(3,809)	(5,948)
Defined benefit pension plans:
Change in actuarial net loss, After Tax Amount	0	0
Less: amortization of actuarial net loss, After Tax Amount	(2,011)	(2,543)
Less: amortization of prior service cost, After Tax Amount	2,135	2,117
Net change in other comprehensive income for defined benefit postretirement plans, Amount After Tax	(124)	426
Total other comprehensive income, After Tax Amount	(355,958)	$ (80,426)
Total realized gain, net of tax	41,200
Balance of gain after amortization, net of tax	$ 3,600		$ 7,400

Other Comprehensive Income - Sc

Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 3,406,352	$ 3,428,052
Other comprehensive loss before reclassifications	(353,524)	(73,997)
Less: Amounts reclassified from accumulated other comprehensive (loss) income	2,434	6,429
Net current-period other comprehensive loss	(355,958)	(80,426)
Ending balance	3,008,392	3,387,045
Defined Benefit Pension Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(5,471)	(21,253)
Other comprehensive loss before reclassifications	0	0
Less: Amounts reclassified from accumulated other comprehensive (loss) income	124	(426)
Net current-period other comprehensive loss	(124)	426
Ending balance	(5,595)	(20,827)
AOCI Including Portion Attributable to Noncontrolling Interest
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(56,696)	54,234
Ending balance	(412,654)	(26,192)
Unrealized Gains and (Losses) on Cash Flow Hedges | Unrealized Gains and (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	7,361	29,815
Other comprehensive loss before reclassifications	0	0
Less: Amounts reclassified from accumulated other comprehensive (loss) income	3,809	5,948
Net current-period other comprehensive loss	(3,809)	(5,948)
Ending balance	3,552	23,867
Unrealized Gains and (Losses) on Available for Sale Securities | Unrealized Gains and (Losses) on Available for Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(58,586)	45,672
Other comprehensive loss before reclassifications	(353,524)	(73,997)
Less: Amounts reclassified from accumulated other comprehensive (loss) income	(1,499)	907
Net current-period other comprehensive loss	(352,025)	(74,904)
Ending balance	$ (410,611)	$ (29,232)

Segment Reporting - Schedule Of

Segment Reporting - Schedule Of Segment Reporting Information, By Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net interest income	$ 128,124	$ 100,091
(Release of) provision for loan losses	(485)	(580)
Net interest income after provision for loan losses	128,609	100,671
Noninterest income	46,415	55,212
Noninterest expense	108,866	94,049
Income before provision for income taxes	66,158	61,834
Income tax provision	14,642	14,171
Net income	51,516	47,663
Total assets	22,836,072	16,726,795	$ 23,512,128
Total liabilities	19,827,680	13,339,750	$ 20,105,776
Eliminations And Reconciling Items
Segment Reporting Information [Line Items]
Net interest income	0	0
(Release of) provision for loan losses	0	0
Net interest income after provision for loan losses	0	0
Noninterest income	(171)	(32)
Noninterest expense	(1,053)	(1,036)
Income before provision for income taxes	882	1,004
Income tax provision	0	0
Net income	882	1,004
Total assets	(71,224)	(63,180)
Total liabilities	(71,224)	(63,180)
Business Banking | Operating Segments
Segment Reporting Information [Line Items]
Net interest income	128,124	100,091
(Release of) provision for loan losses	(485)	(580)
Net interest income after provision for loan losses	128,609	100,671
Noninterest income	18,137	26,960
Noninterest expense	90,446	75,274
Income before provision for income taxes	56,300	52,357
Income tax provision	12,108	11,793
Net income	44,192	40,564
Total assets	22,695,895	16,595,311
Total liabilities	19,848,995	13,359,075
Insurance Agency Business | Operating Segments
Segment Reporting Information [Line Items]
Net interest income	0	0
(Release of) provision for loan losses	0	0
Net interest income after provision for loan losses	0	0
Noninterest income	28,449	28,284
Noninterest expense	19,473	19,811
Income before provision for income taxes	8,976	8,473
Income tax provision	2,534	2,378
Net income	6,442	6,095
Total assets	211,401	194,664
Total liabilities	$ 49,909	$ 43,855

Subsequent Events (Detail)

Subsequent Events (Detail) $ in Millions	Apr. 01, 2022USD ($)
Subsequent Event
Subsequent Event [Line Items]
Deposit assets	$ 297.7

Uncategorized Items - ebc-20220

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-13 [Member]	[1]
[1]	Represents gross transition adjustment amount of $28.0 million, net of taxes of $7.9 million, to reflect the cumulative impact on retained earnings pursuant to the Company’s adoption of Accounting Standards Update 2016-13. Refer to Note 4, “Loans and Allowance for Credit Losses” for additional discussion.