Cambridge Bancorp (CATC) 10-Q 5 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	Apr. 29, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Trading Symbol	CATC
Entity Registrant Name	CAMBRIDGE BANCORP
Entity Central Index Key	0000711772
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		7,000,892
Document Quarterly Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Tax Identification Number	04-2777442
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Incorporation, State or Country Code	MA
Entity Address, Address Line One	1336 Massachusetts Avenue
Entity Address, State or Province	MA
Entity Address, City or Town	Cambridge
Entity Address, Postal Zip Code	02138
City Area Code	617
Local Phone Number	876-5500
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity File Number	001-38184

UNAUDITED CONSOLIDATED BALANCE

UNAUDITED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets
Cash and cash equivalents	$ 81,748	$ 180,153
Investment securities
Available for sale, at fair value (amortized cost $202,688 and $201,270, respectively)	188,205	197,803
Held to maturity, at amortized cost (fair value $1,043,391 and $971,092, respectively)	1,115,824	977,061
Total investment securities	1,304,029	1,174,864
Loans held for sale, at lower of cost or fair value	918	1,490
Loans
Total loans	3,417,213	3,319,106
Less: allowance for credit losses on loans	(34,110)	(34,496)
Net loans	3,383,103	3,284,610
Federal Home Loan Bank of Boston Stock, at cost	4,816	4,816
Bank owned life insurance	47,157	46,970
Banking premises and equipment, net	17,136	17,326
Right-of-use asset operating leases	29,757	31,273
Deferred income taxes, net	10,460	9,985
Accrued interest receivable	9,718	9,162
Goodwill	51,912	51,912
Merger-related intangibles, net	2,526	2,617
Other assets	75,099	76,366
Total assets	5,018,379	4,891,544
Deposits
Demand	1,426,310	1,393,935
Interest-bearing checking	785,003	763,188
Money market	1,209,765	1,104,238
Savings	918,895	907,722
Certificates of deposit	133,762	162,069
Total deposits	4,473,735	4,331,152
Borrowings	16,140	16,510
Operating lease liabilities	32,271	33,871
Other liabilities	60,068	72,174
Total liabilities	4,582,214	4,453,707
Shareholders’ Equity
Common stock, par value $1.00; Authorized: 10,000,000 shares; Outstanding: 7,000,995 shares and 6,968,192 shares, respectively	7,001	6,968
Additional paid-in capital	228,538	229,205
Retained earnings	211,730	202,874
Accumulated other comprehensive income (loss)	(11,104)	(1,210)
Total shareholders’ equity	436,165	437,837
Total liabilities and shareholders’ equity	5,018,379	4,891,544
Residential Mortgage
Loans
Total loans	1,447,141	1,415,079
Commercial Mortgage
Loans
Total loans	1,579,494	1,511,002
Home Equity
Loans
Total loans	86,559	87,960
Commercial and Industrial
Loans
Total loans	262,772	269,446
Consumer
Loans
Total loans	$ 41,247	$ 35,619

UNAUDITED CONSOLIDATED BALANC_2

UNAUDITED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 202,688	$ 201,270
Held-to-maturity securities, fair value	$ 1,043,391	$ 971,092
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares, outstanding	7,000,995	6,968,192

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 on taxable loans	$ 28,404	$ 30,325
Interest on tax-exempt loans	350	222
Interest on taxable investment securities	4,411	1,585
Interest on tax-exempt investment securities	654	658
Dividends on FHLB of Boston stock	25
Interest on overnight investments	54	31
Total interest and dividend income	33,898	32,821
Interest expense
Interest on deposits	1,896	1,275
Interest on borrowed funds	133	140
Total interest expense	2,029	1,415
Net interest and dividend income	31,869	31,406
Release of credit losses	(412)	(206)
Net interest and dividend income after release of credit losses	32,281	31,612
Noninterest income
Bank owned life insurance income	187	196
Gain on loans sold, net	94	569
Loan related derivative income	296	671
Other income	1,318	455
Total noninterest income	11,354	10,849
Noninterest expense
Salaries and employee benefits	17,391	16,045
Occupancy and equipment	3,542	3,576
Data processing	2,645	2,034
Professional services	1,064	1,272
Marketing	224	463
FDIC insurance	455	336
Other expenses	554	493
Total noninterest expense	25,875	24,219
Income before income taxes	17,760	18,242
Income tax expense	4,444	4,743
Net income	$ 13,316	$ 13,499
Share data:
Weighted average shares outstanding, basic	6,948,040	6,907,861
Weighted average shares outstanding, diluted	7,010,983	6,987,216
Basic earnings per share	$ 1.91	$ 1.95
Diluted earnings per share	$ 1.89	$ 1.92
Wealth Management Revenue
Noninterest income
Noninterest income	$ 8,574	$ 8,151
Deposit Account Fees
Noninterest income
Noninterest income	506	474
ATM/Debit Card Income
Noninterest income
Noninterest income	$ 379	$ 333

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	$ 13,316	$ 13,499
Available for sale securities
Unrealized holding losses	(8,227)	(2,887)
Interest rate swaps designated as cash flow hedges
Unrealized holding losses	(1,226)	(322)
Less: reclassification adjustment for losses realized in net income	(441)	(454)
Total unrealized losses on interest rate swaps	(1,667)	(776)
Defined benefit retirement plans
Change in retirement liabilities		8
Other comprehensive loss	(9,894)	(3,655)
Comprehensive income	$ 3,422	$ 9,844

UNAUDITED CONSOLIDATED STATEM_3

UNAUDITED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 401,732	$ 6,927	$ 226,967	$ 165,404	$ 2,434
Net income	13,499			13,499
Other comprehensive loss	(3,655)				(3,655)
Share based compensation and other share-based activity	(93)	33	(126)
Dividends declared	(3,810)			(3,810)
Ending balance at Mar. 31, 2021	407,673	6,960	226,841	175,093	(1,221)
Beginning balance at Dec. 31, 2021	437,837	6,968	229,205	202,874	(1,210)
Net income	13,316			13,316
Other comprehensive loss	(9,894)				(9,894)
Share based compensation and other share-based activity	(634)	33	(667)
Dividends declared	(4,460)			(4,460)
Ending balance at Mar. 31, 2022	$ 436,165	$ 7,001	$ 228,538	$ 211,730	$ (11,104)

UNAUDITED CONSOLIDATED STATEM_4

UNAUDITED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Retained Earnings
Dividends declared, per share	$ 0.64	$ 0.55

UNAUDITED CONSOLIDATED STATEM_5

UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 13,316	$ 13,499
Adjustments to reconcile net income to net cash provided by operating activities:
Release of credit losses	(412)	(206)
Amortization (accretion) of deferred charges and fees, net	733	(382)
(Accretion), depreciation, and amortization, net	52	(763)
Bank owned life insurance income	(187)	(196)
Share-based compensation and other share-based activity	(634)	(93)
Change in accrued interest receivable	(556)	643
Deferred income tax expense	2,960	1,730
Change in loans held for sale	572	3,556
Change in other assets, net	(2,180)	5,777
Change in other liabilities, net	(11,055)	(12,037)
Net cash provided by operating activities	2,609	11,528
CASH FLOWS FROM INVESTING ACTIVITIES
Origination of loans	(274,217)	(353,256)
Proceeds from principal payments of loans	199,307	328,758
Purchase of loans	(22,497)
Proceeds from calls/maturities of securities available for sale	8,624	10,444
Purchase of securities available for sale	(10,169)	(167,019)
Proceeds from calls/maturities of securities held to maturity	37,173	12,099
Purchase of securities held to maturity	(176,574)
Redemption of FHLB of Boston stock		670
Purchase of banking premises and equipment	(460)	(310)
Net cash used in investing activities	(238,813)	(168,614)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in demand, interest bearing, money market and savings accounts	170,890	352,936
Change in certificates of deposit	(28,278)	(25,846)
Change in borrowings	(353)	(15,346)
Cash dividends paid on common stock	(4,460)	(3,810)
Net cash provided by financing activities	137,799	307,934
Net change in cash and cash equivalents	(98,405)	150,848
Cash and cash equivalents at beginning of period	180,153	75,785
Cash and cash equivalents at end of period	81,748	226,633
Cash paid during the period for:
Interest	2,033	1,527
Income taxes	$ 7,790	$ 1,590

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. BASIS OF PRESENTATION The unaudited consolidated financial statements include the accounts of Cambridge Bancorp (the “Company”) and its wholly owned subsidiary, Cambridge Trust Company (the “Bank”), and the Bank’s wholly owned subsidiaries, Cambridge Trust Company of New Hampshire Inc., CTC Security Corporation, and CTC Security Corporation III. References to the Company herein relate to the consolidated group of companies. All significant intercompany accounts and transactions have been eliminated in preparation of the consolidated financial statements. The Company is a state-chartered, federally registered bank holding company headquartered in Cambridge, Massachusetts and was incorporated in 1983. The Company is the sole shareholder of the Bank, a Massachusetts trust company chartered in 1890, which is a commercial bank. The Company operates as a private bank offering a full range of private banking and wealth management services to its clients. The private banking business, the Company’s only reportable operating segment, is managed as a single strategic unit. The unaudited consolidated financial statements reflect all adjustments (consisting of normal recurring adjustments) and disclosures necessary to present fairly the Company’s financial position, as of March 31, 2022 and December 31, 2021, and the results of operations and cash flows for the interim periods presented in accordance with generally accepted accounting principles in the United States (“GAAP”). Interim results are not necessarily reflective of the results of the entire year. For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 , filed with the Securities and Exchange Commission (the “SEC”) on March 14, 2022.

Use of Estimates

Use of Estimates	3 Months Ended
	Mar. 31, 2022
Use Of Estimates [Abstract]
Use of Estimates	2. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements. Actual results could differ from those estimates. The allowance for credit losses is particularly subject to change.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	3. Subsequent Events Management has reviewed events occurring through May 5, 2022, the date the unaudited consolidated financial statements were available to be issued and determined that no subsequent events occurred requiring adjustment to or disclosure in these unaudited consolidated financial statements.

Recently Issued Accounting Guid

Recently Issued Accounting Guidance	3 Months Ended
	Mar. 31, 2022
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recently Issued Accounting Guidance	4. Recently Issued Accounting Guidance Accounting Pronouncements Yet to be Adopted In March 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ( “ASU” ) 2022-02, Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures. The amendments in this ASU eliminate the accounting guidance for troubled debt restructurings (“TDRs”) by creditors in Subtopic 310-40, Receivables – Troubled Debt Restructurings by Creditors , while enhancing disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. For public business entities, the amendments in this ASU require an entity disclose current-period gross write-offs by year of origination for financing receivables and net investments in leases. The ASU is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact the adoption of this guidance will have on the disclosures within its consolidated financial statements. In March 2022, the FASB issued ASU 2022-01, Derivatives and Hedging (Topic 815): Fair Value Hedging - Portfolio Layer Method . The amendments in this ASU allow multiple hedged layers to be designated for a single closed portfolio of financial assets or one or more beneficial interests secured by a portfolio of financial instruments. The amendments in the ASU also clarify the accounting for and promote consistency in the reporting of hedge basis adjustments applicable to both a single hedged layer and multiple hedged layers. These amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. The Company is currently assessing the impact the adoption of this guidance will have on its consolidated financial statements.

Cash and Cash Equivalents

Cash and Cash Equivalents	3 Months Ended
	Mar. 31, 2022
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	5. Cash and cash equivalents At March 31, 2022 and December 31, 2021, cash and cash equivalents totaled $ 81.7 million and $ 180.2 million , respectively. There were no amounts required to be maintained at the Federal Reserve Bank of Boston at March 31, 2022 and December 31, 2021. At March 31, 2022 and December 31, 2021 , the Company pledged $ 500,000 to the New Hampshire Banking Department relating to Cambridge Trust Company of New Hampshire, Inc.’s operations in that state. The Company did no t have any cash pledged as collateral to derivative counterparties at March 31, 2022 , as compared to the $ 13.3 million pledged at December 31, 2021. See Note 16- Derivatives and Hedging Activities for a discussion of the Company’s derivative and hedging activities .

Investment Securities

Investment Securities	3 Months Ended
	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investment Securities	6. Investment Securities Investment securities have been classified in the unaudited consolidated balance sheets according to management’s intent. The carrying amounts of securities and their approximate fair values were as follows: March 31, 2022 December 31, 2021 Amortized Gross Gross Fair Amortized Gross Gross Fair (dollars in thousands) Available for sale securities U.S. Government Sponsored $ 22,997 $ — $ ( 1,329 ) $ 21,668 $ 22,996 $ 246 $ ( 231 ) $ 23,011 Mortgage-backed securities 177,948 32 ( 13,201 ) 164,779 176,531 959 ( 4,462 ) 173,028 Corporate debt securities 1,743 21 ( 6 ) 1,758 1,743 24 ( 3 ) 1,764 Total available for sale securities $ 202,688 $ 53 $ ( 14,536 ) $ 188,205 $ 201,270 $ 1,229 $ ( 4,696 ) $ 197,803 Held to maturity securities Mortgage-backed securities $ 1,009,206 $ 594 $ ( 68,718 ) $ 941,082 $ 864,983 $ 3,981 $ ( 13,258 ) $ 855,706 Corporate debt securities 2,498 7 — 2,505 6,997 26 — 7,023 Municipal securities 104,120 812 ( 5,128 ) 99,804 105,081 3,798 ( 516 ) 108,363 Total held to maturity securities $ 1,115,824 $ 1,413 $ ( 73,846 ) $ 1,043,391 $ 977,061 $ 7,805 $ ( 13,774 ) $ 971,092 Total $ 1,318,512 $ 1,466 $ ( 88,382 ) $ 1,231,596 $ 1,178,331 $ 9,034 $ ( 18,470 ) $ 1,168,895 All of the Company’s mortgage-backed securities have been issued by, or are collateralized by securities issued by, either the Government National Mortgage Association (“Ginnie Mae” or “GNMA”), the Federal National Mortgage Association (“Fannie Mae” or “FNMA”), or the Federal Home Loan Mortgage Corporation (“Freddie Mac” or “FHLMC”). The following tables show the Company’s securities with gross unrealized losses for which an allowance for credit losses has not been recorded at March 31, 2022 or at December 31, 2021, aggregated by investment category and length of time that individual securities have been in a continuous loss position: March 31, 2022 Less than 12 months 12 months or longer Total Fair Unrealized Fair Unrealized Fair Unrealized (dollars in thousands) Available for sale securities U.S. Government Sponsored Enterprise $ 12,318 $ ( 682 ) $ 9,350 $ ( 647 ) $ 21,668 $ ( 1,329 ) Mortgage-backed securities 86,726 ( 4,001 ) 75,489 ( 9,200 ) 162,215 ( 13,201 ) Corporate debt securities — — 753 ( 6 ) 753 ( 6 ) Total available for sale securities $ 99,044 $ ( 4,683 ) $ 85,592 $ ( 9,853 ) $ 184,636 $ ( 14,536 ) Held to maturity securities Mortgage-backed securities $ 837,728 $ ( 60,920 ) $ 61,687 $ ( 7,798 ) $ 899,415 $ ( 68,718 ) Municipal securities 37,654 ( 3,691 ) 6,682 ( 1,437 ) 44,336 ( 5,128 ) Total held to maturity securities $ 875,382 $ ( 64,611 ) $ 68,369 $ ( 9,235 ) $ 943,751 $ ( 73,846 ) Total $ 974,426 $ ( 69,294 ) $ 153,961 $ ( 19,088 ) $ 1,128,387 $ ( 88,382 ) December 31, 2021 Less than 12 months 12 months or longer Total Fair Unrealized Fair Unrealized Fair Unrealized (dollars in thousands) Available for sale securities U.S. Government Sponsored Enterprise $ 4,881 $ ( 115 ) $ 4,884 $ ( 116 ) $ 9,765 $ ( 231 ) Mortgage-backed securities 74,724 ( 2,253 ) 47,871 ( 2,209 ) 122,595 ( 4,462 ) Corporate debt securities 760 ( 3 ) — — 760 ( 3 ) Total available for sale securities $ 80,365 $ ( 2,371 ) $ 52,755 $ ( 2,325 ) $ 133,120 $ ( 4,696 ) Held to maturity securities Mortgage-backed securities $ 740,966 $ ( 12,509 ) $ 15,345 $ ( 749 ) $ 756,311 $ ( 13,258 ) Municipal securities 12,607 ( 194 ) 5,716 ( 322 ) 18,323 ( 516 ) Total held to maturity securities $ 753,573 $ ( 12,703 ) $ 21,061 $ ( 1,071 ) $ 774,634 $ ( 13,774 ) Total $ 833,938 $ ( 15,074 ) $ 73,816 $ ( 3,396 ) $ 907,754 $ ( 18,470 ) As of March 31, 2022 , 338 debt securities had gross unrealized losses, with an aggregate depreciation of 7.3 % from the Company’s amortized cost basis. The largest unrealized dollar loss of any single security was $ 937,000 , or 9.7 % of its amortized cost. The largest unrealized loss percentage of any single security was 22.2 % of its amortized cost, or $ 521,000 . The Company believes that the nature and duration of unrealized losses on its debt security positions are primarily a function of interest rate movements and changes in investment spreads and does not consider full repayment of principal on the reported debt obligations to be at risk. Since nearly all of these securities are rated “investment grade” and (a) the Company does not intend to sell these securities before recovery and (b) it is more likely than not that the Company will not be required to sell these securities before recovery, the Company does not expect to suffer a credit loss as of March 31, 2022. The amortized cost and fair value of debt securities, aggregated by the earlier of call date or contractual maturity, are shown below. Maturities of mortgage-backed securities do not take into consideration scheduled amortization or prepayments. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Within One Year After One, But After Five, But After Ten Years Total Amortized Fair Amortized Fair Amortized Fair Amortized Fair Amortized Fair At March 31, 2022 (dollars in thousands) Available for sale securities U.S. Government $ — $ — $ 9,997 $ 9,350 $ 5,000 $ 4,811 $ 8,000 $ 7,507 $ 22,997 $ 21,668 Mortgage-backed — — 9,378 9,154 47,145 43,409 121,425 112,216 177,948 164,779 Corporate debt securities 759 753 984 1,005 — — — — 1,743 1,758 Total available for $ 759 $ 753 $ 20,359 $ 19,509 $ 52,145 $ 48,220 $ 129,425 $ 119,723 $ 202,688 $ 188,205 Held to maturity securities Mortgage-backed $ — $ — $ 15,139 $ 15,049 $ 56,143 $ 54,324 $ 937,924 $ 871,709 $ 1,009,206 $ 941,082 Corporate debt securities 2,498 2,505 — — — — — — 2,498 2,505 Municipal securities 5,302 5,333 17,858 18,077 35,973 36,310 44,987 40,084 104,120 99,804 Total held to maturity $ 7,800 $ 7,838 $ 32,997 $ 33,126 $ 92,116 $ 90,634 $ 982,911 $ 911,793 $ 1,115,824 $ 1,043,391 Total $ 8,559 $ 8,591 $ 53,356 $ 52,635 $ 144,261 $ 138,854 $ 1,112,336 $ 1,031,516 $ 1,318,512 $ 1,231,596 There were no sales of investment securities during the three months ended March 31, 2022 and March 31, 2021. The Company monitors the credit quality of certain debt securities through the use of credit ratings among other factors on a quarterly basis. The following tables summarize the credit rating of the Company’s debt securities portfolio at March 31, 2022 and December 31, 2021. March 31, 2022 Mortgage-backed Securities (1) Corporate Debt Securities Municipal Securities U.S. GSE Obligations Total (dollars in thousands) Available for sale securities, at fair value AAA/AA/A $ 164,779 $ 753 $ — $ 21,668 $ 187,200 BBB/BB/B — 1,005 — — 1,005 Total available for sale securities $ 164,779 $ 1,758 $ — $ 21,668 $ 188,205 Held to maturity securities, at amortized cost AAA/AA/A $ 1,009,206 $ 2,498 $ 104,120 $ — $ 1,115,824 Total held to maturity securities $ 1,009,206 $ 2,498 $ 104,120 $ — $ 1,115,824 December 31, 2021 Mortgage-backed Securities (1) Corporate Debt Securities Municipal Securities U.S. GSE Obligations Total (dollars in thousands) Available for sale securities, at fair value AAA/AA/A $ 173,028 $ 759 $ — $ 23,011 $ 196,798 BBB/BB/B — 1,005 — — 1,005 Total available for sale securities $ 173,028 $ 1,764 $ — $ 23,011 $ 197,803 Held to maturity securities, at amortized cost AAA/AA/A $ 864,983 $ 6,997 $ 105,081 $ — $ 977,061 Total held to maturity securities $ 864,983 $ 6,997 $ 105,081 $ — $ 977,061 (1) Includes agency mortgage-backed pass-through securities and collateralized mortgage obligations issued by U.S. Government Sponsored Enterprises ("GSEs") and U.S. government agencies, such as FNMA, FHLMC, and GNMA that are not rated by Moody’s or Standard & Poor's. Each security contains a guarantee by the issuing GSE or agency and therefore carries an implicit guarantee of the U.S. government. These have been categorized as AAA/AA/A.

Loans and the Allowance for Cre

Loans and the Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Loans and the Allowance for Credit Losses	7. LOANS AND THE ALLOWANCE FOR CREDIT LOSSES Loans outstanding are detailed by category as follows: March 31, 2022 December 31, 2021 (dollars in thousands) Residential mortgage Mortgages - fixed rate $ 747,716 $ 716,456 Mortgages - adjustable rate 669,495 679,675 Construction 21,722 13,012 Deferred costs, net of unearned fees 8,208 5,936 Total residential mortgages 1,447,141 1,415,079 Commercial mortgage Mortgages - non-owner occupied 1,336,997 1,272,135 Mortgages - owner occupied 151,173 150,632 Construction 89,200 86,246 Deferred costs, net of unearned fees 2,124 1,989 Total commercial mortgages 1,579,494 1,511,002 Home equity Home equity - lines of credit 84,465 85,639 Home equity - term loans 1,781 2,017 Deferred costs, net of unearned fees 313 304 Total home equity 86,559 87,960 Commercial and industrial Commercial and industrial 248,960 247,024 PPP loans 13,963 22,856 Unearned fees, net of deferred costs ( 151 ) ( 434 ) Total commercial and industrial 262,772 269,446 Consumer Secured 40,374 34,308 Unsecured 861 1,303 Deferred costs, net of unearned fees 12 8 Total consumer 41,247 35,619 Total loans $ 3,417,213 $ 3,319,106 The Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was signed into law on March 27, 2020, and provided emergency economic relief to individuals and businesses impacted by the COVID-19 pandemic. Among other things, the CARES Act authorized the Small Business Administration (“SBA”) to temporarily guarantee loans under a new 7(a) loan program called the Paycheck Protection Program (“PPP”). As a qualified SBA lender, the Company was authorized to originate PPP loans. PPP loans have: (a) an interest rate of 1.0%, (b) a two year or five-year loan term to maturity; and (c) principal and interest payments deferred until the SBA remits the forgiven amount to the Company or 10 months from the end of the covered period, as defined. The SBA guarantees 100% of the PPP loans made to eligible borrowers. The entire principal amount of the borrower’s PPP loan, including any accrued interest, is eligible to be reduced by the loan forgiveness amount under the PPP so long as employee and compensation levels of the business are maintained and 60% of the loan proceeds are used for payroll expense, with the remaining 40% of the loan proceeds used for other qualifying expenses. The Company did not record an allowance for credit losses for PPP loans at March 31, 2022 or December 31, 2021. Directors and officers of the Company and their associates are customers of, and have other transactions with, the Company in the normal course of business. All loans and commitments included in such transactions were made on substantially the same terms, including interest rates and collateral, as those prevailing at the time for comparable transactions with other persons and do not involve more than normal risk of collection or present other unfavorable features. Asset Quality The Company’s philosophy toward managing its loan portfolios is predicated upon careful monitoring, which stresses early detection and response to delinquent and default situations. The Company seeks to make arrangements to resolve any delinquent or default situation over the shortest possible time frame. As a general rule, loans more than 90 days past due with respect to principal or interest are classified as nonaccrual loans. The Company may use discretion regarding other loans over 90 days past due if the loan is well secured and/or in process of collection. The following tables set forth information regarding non-performing loans disaggregated by loan category: March 31, 2022 Residential Commercial Home Commercial and Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 4,113 $ 463 $ 523 $ 107 $ 5,206 Troubled debt restructurings 636 — — 101 737 Total $ 4,749 $ 463 $ 523 $ 208 $ 5,943 December 31, 2021 Residential Commercial Home Commercial and Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 3,777 $ 517 $ 223 $ 111 $ 4,628 Troubled debt restructurings 652 — — 106 758 Total $ 4,429 $ 517 $ 223 $ 217 $ 5,386 Pursuant to Section 4013 of the CARES Act, financial institutions could suspend the requirements under U.S. GAAP related to TDRs for modifications made before December 31, 2020 to loans that were current as of December 31, 2019. On January 3, 2021, the President of the United States of America signed into law the Consolidated Appropriations Act, 2021 (the “CAA”). As a result of the CAA, the suspension of TDR accounting was extended, however expired on January 1, 2022. The requirement that a loan be not more than 30 days past due as of December 31, 2019 was still applicable. In response to the COVID-19 pandemic and its economic impact to customers, a short-term modification program that complied with the CARES Act was implemented to provide temporary payment relief to those borrowers directly impacted by COVID-19. The deferred payments along with interest accrued during the deferral period are due and payable on the maturity date. Under issued guidance, provided these loans were current as of either year end or the date of the modification, these loans were not considered TDR loans at March 31, 2022 and will not be reported as past due during the deferral period. As of March 31, 2022 , the Company had $ 4.4 million of loans remaining in deferral. Loans by Credit Quality Indicator. The following tables contain period-end balances of loans receivable disaggregated by credit quality indicator: Credit Quality Indicator - by Origination Year as of March 31, 2022 2022 2021 2020 2019 2018 Prior Revolving loans amortized cost basis Total (dollars in thousands) Residential Mortgage: Current $ 86,983 $ 536,375 $ 315,864 $ 129,036 $ 94,174 $ 279,960 $ — $ 1,442,392 Non-performing — — 148 — 492 4,109 — 4,749 Total $ 86,983 $ 536,375 $ 316,012 $ 129,036 $ 94,666 $ 284,069 $ — $ 1,447,141 Home equity: Current $ — $ — $ 397 $ 2,522 $ 3,791 $ 9,850 $ 69,476 $ 86,036 Non-performing — — — 523 — — — 523 Total $ — $ — $ 397 $ 3,045 $ 3,791 $ 9,850 $ 69,476 $ 86,559 Consumer: Current $ 9,746 $ 12,043 $ 7,746 $ 1,427 $ 2,640 $ 7,144 $ 501 $ 41,247 Non-performing — — — — — — — — Total $ 9,746 $ 12,043 $ 7,746 $ 1,427 $ 2,640 $ 7,144 $ 501 $ 41,247 Credit Quality Indicator - by Origination Year as of March 31, 2022 2022 2021 2020 2019 2018 Prior Revolving loans amortized cost basis Total (dollars in thousands) Commercial Mortgage: Credit risk profile by internally 1-6 (Pass) $ 106,176 $ 323,625 $ 238,962 $ 301,506 $ 153,681 $ 378,667 $ — $ 1,502,617 7 (Special Mention) — — 1,088 45,916 22,333 6,921 — 76,258 8 (Substandard) — — — — — 619 — 619 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 106,176 $ 323,625 $ 240,050 $ 347,422 $ 176,014 $ 386,207 $ — $ 1,579,494 Commercial and Industrial: Credit risk profile by internally 1-6 (Pass) $ 6,723 $ 77,584 $ 75,550 $ 37,872 $ 33,322 $ 20,795 $ 371 $ 252,217 7 (Special Mention) — 291 347 5,624 407 581 10 7,260 8 (Substandard) — — 729 2,324 101 138 3 3,295 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 6,723 $ 77,875 $ 76,626 $ 45,820 $ 33,830 $ 21,514 $ 384 $ 262,772 Credit Quality Indicator - by Origination Year as of December 31, 2021 2021 2020 2019 2018 2017 Prior Revolving loans amortized cost basis Total (dollars in thousands) Residential Mortgage: Current $ 535,071 $ 329,501 $ 135,139 $ 101,108 $ 77,702 $ 232,129 $ — $ 1,410,650 Non-performing — 151 — 330 54 3,894 — 4,429 Total $ 535,071 $ 329,652 $ 135,139 $ 101,438 $ 77,756 $ 236,023 $ — $ 1,415,079 Home equity: Current $ — $ 719 $ 3,088 $ 4,469 $ 5,060 $ 5,475 $ 68,926 $ 87,737 Non-performing — — 223 — — — — 223 Total $ — $ 719 $ 3,311 $ 4,469 $ 5,060 $ 5,475 $ 68,926 $ 87,960 Consumer: Current $ 14,427 $ 8,758 $ 1,544 $ 3,168 $ 1,838 $ 5,357 $ 527 $ 35,619 Non-performing — — — — — — — — Total $ 14,427 $ 8,758 $ 1,544 $ 3,168 $ 1,838 $ 5,357 $ 527 $ 35,619 Credit Quality Indicator - by Origination Year as of December 31, 2021 2021 2020 2019 2018 2017 Prior Revolving loans amortized cost basis Total (dollars in thousands) Commercial Mortgage: Credit risk profile by internally 1-6 (Pass) $ 319,633 $ 248,691 $ 320,189 $ 158,462 $ 93,016 $ 298,791 $ — $ 1,438,782 7 (Special Mention) — 1,096 40,879 22,471 2,913 4,131 — 71,490 8 (Substandard) — — — — — 730 — 730 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 319,633 $ 249,787 $ 361,068 $ 180,933 $ 95,929 $ 303,652 $ — $ 1,511,002 Commercial and Industrial: Credit risk profile by internally 1-6 (Pass) $ 83,614 $ 77,073 $ 38,299 $ 34,360 $ 19,727 $ 4,622 $ 353 $ 258,048 7 (Special Mention) 318 350 5,523 406 161 859 10 7,627 8 (Substandard) — 792 2,331 504 — 144 — 3,771 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 83,932 $ 78,215 $ 46,153 $ 35,270 $ 19,888 $ 5,625 $ 363 $ 269,446 With respect to residential mortgages, home equity, and consumer loans, the Company utilizes the following categories as indicators of credit quality: • Performing – These loans are accruing and are considered having low to moderate risk. • Non-performing – These loans are on nonaccrual, are more than 90 days past due but are still accruing, or are restructured. These loans may contain greater than average risk. With respect to CRE mortgages and commercial and industrial loans, the Company utilizes a 10-grade internal loan rating system as an indicator of credit quality. The grades are as follows: • Loans rated 1-6 (Pass) – These loans are considered “pass” rated with low to moderate risk. • Loans rated 7 (Special Mention) – These loans have potential weaknesses warranting close attention, which, if left uncorrected, may result in deterioration of the credit at some future date. • Loans rated 8 (Substandard) – These loans have well-defined weaknesses that jeopardize the orderly liquidation of the debt under the original loan terms. Loss potential exists but is not identifiable in any one customer. • Loans rated 9 (Doubtful) – These loans have pronounced weaknesses that make full collection highly questionable and improbable. • Loans rated 10 (Loss) – These loans are considered uncollectible and continuance as a bankable asset is not warranted. Delinquencies The past due status of a loan is determined in accordance with its contractual repayment terms. All loan types are reported past due when one scheduled payment is due and unpaid for 30 days or more. Loan delinquencies can be attributed to many factors, such as but not limited to, a continuing weakness in, or deteriorating, economic conditions in the region in which the collateral is located, the loss of a tenant or lower lease rates for commercial borrowers, or the loss of income for consumers and the resulting liquidity impacts on the borrowers. The following tables contain period-end balances of loans receivable disaggregated by past due status: March 31, 2022 30-59 Days 60-89 Days 90 Days or greater Total Past Due Current Loans Total Amortized Cost 90+ Days Past Due and Accruing (dollars in thousands) Residential mortgage $ 7,521 $ — $ 1,083 $ 8,604 $ 1,438,537 $ 1,447,141 $ — Commercial mortgage — 5,148 — 5,148 1,574,346 1,579,494 — Home equity 628 — — 628 85,931 86,559 — Commercial and industrial 456 41 — 497 262,275 262,772 — Consumer 107 — — 107 41,140 41,247 — Total $ 8,712 $ 5,189 $ 1,083 $ 14,984 $ 3,402,229 $ 3,417,213 $ — December 31, 2021 30-59 Days 60-89 Days 90 Days Total Current Total Amortized Cost 90+ Days Past Due and Accruing (dollars in thousands) Residential mortgage $ 8,470 $ 415 $ 1,488 $ 10,373 $ 1,404,706 $ 1,415,079 $ — Commercial mortgage 476 — — 476 1,510,526 1,511,002 — Home equity 314 643 — 957 87,003 87,960 — Commercial and industrial 5 437 — 442 269,004 269,446 — Consumer — — — — 35,619 35,619 — Total $ 9,265 $ 1,495 $ 1,488 $ 12,248 $ 3,306,858 $ 3,319,106 $ — There were no significant commitments to lend additional funds to borrowers whose loans were on nonaccrual status at March 31, 2022 and December 31, 2021. Allowance for Credit Losses The following table presents changes in the allowance for credit losses disaggregated by loan category: For the Three Months Ended March 31, 2022 Residential Commercial Home Commercial & Consumer Unfunded Commitments Total (dollars in thousands) Allowance for credit loss: Allowance for credit losses - loan Balance at December 31, 2021 $ 13,383 $ 17,133 $ 406 $ 2,989 $ 585 $ — $ 34,496 Charge-offs — — — — ( 25 ) — ( 25 ) Recoveries — — — 36 2 — 38 Provision for (release of) credit ( 190 ) 5 ( 29 ) ( 128 ) ( 57 ) — ( 399 ) Allowance for credit losses - $ 13,193 $ 17,138 $ 377 $ 2,897 $ 505 $ — $ 34,110 Allowance for credit losses - Balance at December 31, 2021 $ — $ — $ — $ — $ — $ 1,384 $ 1,384 Release of credit — — — — — ( 13 ) ( 13 ) Allowance for credit losses- $ — $ — $ — $ — $ — $ 1,371 $ 1,371 Total allowance for credit loss $ 13,193 $ 17,138 $ 377 $ 2,897 $ 505 $ 1,371 $ 35,481 For the Three Months Ended March 31, 2021 Residential Commercial Home Commercial & Consumer Unfunded Commitments Total (dollars in thousands) Allowance for credit loss: Allowance for credit losses - loan Balance at December 31, 2020 $ 13,067 $ 18,564 $ 552 $ 3,309 $ 524 $ — $ 36,016 Charge-offs — — — — ( 3 ) — ( 3 ) Recoveries — — — 19 4 — 23 Provision for (release of) credit 77 129 ( 189 ) ( 350 ) ( 57 ) — ( 390 ) Allowance for credit losses - $ 13,144 $ 18,693 $ 363 $ 2,978 $ 468 $ — $ 35,646 Allowance for credit losses - Balance at December 31, 2020 $ — $ — $ — $ — $ — $ 1,004 $ 1,004 Provision for credit — — — — — 184 184 Allowance for credit losses- — — — — — 1,188 1,188 Total allowance for credit loss $ 13,144 $ 18,693 $ 363 $ 2,978 $ 468 $ 1,188 $ 36,834

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The Company’s effective tax rate was 25.0 % for the three months ended March 31, 2022 , as compared to 26.0 % for the three months ended March 31, 2021. Net deferred tax assets totaled $ 10.5 million and $ 10.0 million at March 31, 2022 and December 31, 2021 , respectively. The Company did no t record a valuation allowance for deferred tax assets at March 31, 2022 or December 31, 2021. The components of income tax expense were as follows: Three Months Ended March 31, 2022 2021 (dollars in thousands) Current income tax expense Federal $ 1,095 $ 2,091 State 389 922 Total current income tax expense 1,484 3,013 Deferred income tax expense Federal $ 2,025 $ 1,182 State 935 548 Total deferred income tax expense 2,960 1,730 Total income tax expense $ 4,444 $ 4,743

Pension and Retirement Plans

Pension and Retirement Plans	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Pension and Retirement Plans	9 . Pension and Retirement Plans The components of net periodic benefit cost (credit) were as follows: Three Months Ended March 31, Pension Plan Supplemental Retirement Healthcare Plan 2022 2021 2022 2021 2022 2021 (dollars in thousands) Net periodic benefit cost (credit) Service cost $ — $ — $ 101 $ 106 $ 8 $ 9 Interest cost 310 303 59 57 5 4 Expected return on assets ( 936 ) ( 892 ) — — — — Amortization of prior service credit — ( 1 ) — — — — Amortization of net actuarial loss — — — 11 — — Net periodic benefit cost (credit) $ ( 626 ) $ ( 590 ) $ 160 $ 174 $ 13 $ 13 The Company froze the accrual of benefits on the qualified defined benefit pension plan in 2017. The Company did no t make any contributions to the qualified defined benefit pension plan during the three months ended March 31, 2022 , no r does it expect to make any contributions to the qualified defined benefit plan during the remainder of 2022. Employee Profit-Sharing and 401(k) Plan The Company maintains a Profit-Sharing Plan (“PSP”) that provides for deferral of federal and state income taxes on employee contributions allowed under Section 401(k) of federal law. The Company matches employee contributions up to 100 % of the first 4 % of each participant’s salary, eligible bonus, and eligible incentive. Employees are eligible to participate in the PSP on the first day of their initial date of service. Each year, the Company may also make a discretionary contribution to the PSP and employees are eligible to participate in the discretionary contribution portion of the PSP on the first day of their initial date of service. Additionally, employees must be employed on the last day of the calendar year or retire at the normal retirement age of 65 during the calendar year to receive the discretionary contribution. Employee Stock Ownership Plan The Company has an Employee Stock Ownership Plan (“ESOP”) for its eligible employees. Employees are eligible to participate upon the attainment of age 21 and the completion of 12 months of service consisting of at least 1,000 hours . Purchases of the Company’s common stock by the ESOP will be funded by employer contributions or reinvestment of cash dividends. Total expenses related to the PSP and ESOP for the three months ended March 31, 2022 and March 31, 2021 amounted to $ 1.3 million and $ 1.1 million , respectively. Defined Contribution Supplemental Executive Retirement Plan For executives participating in the Defined Contribution Supplemental Executive Retirement Plan (“DC SERP”), the Company will make a discretionary contribution of up to 10 % of each executive’s base salary and bonus to his or her account under the Company’s DC SERP, the Executive Deferred Compensation Plan. Total expenses related to the DC SERP for the three months ended March 31, 2022 and March 31, 2021 amounted to $ 68,000 and $ 50,000 , respectively.

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2022
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock Based Compensation	10. STOCK BASED COMPENSATION Time Vested Restricted Stock Awards (“RSAs”) and Time Vested Restricted Stock Units (“RSUs”) During the three months ended March 31, 2022 , the Company issued the following RSAs and RSUs pursuant to the Cambridge Bancorp 2017 Equity and Cash Incentive Plan (the “2017 Plan”). RSAs time-vest either over a three-year or five-year period. RSUs vest over a three-year -period. T he fair value of RSAs and RSUs are based upon the closing price of the Company's common stock on the date of the applicable grant. The holders of RSAs participate fully in the rewards of stock ownership of the Company, including voting and dividend rights. The holders of restricted stock units do not participate in the rewards of stock ownership of the Company until vested. For the Three Months Ended March 31, 2022 Weighted-Average Shares Granted Fair Value at Grant Date Type of Award 11,924 $ 87.00 RSAs 8,796 $ 88.18 RSUs Performance-Based Restricted Stock Units (“PRSUs”) On February 15, 2022, the Company granted 30,895 PRSUs. These PRSUs were issued pursuant to the 2017 Cash Plan and had a grant date fair value per share of $ 88.18 . PRSUs are subject to a three-year performance period and are earned based on two factors: (i) operating return on assets and (ii) operating diluted earnings per share growth as compared to the Company’s established peer indices as defined in the Company’s 2022 Proxy Statement filed with the Securities and Exchange Commission on March 16, 2022. The following table presents the pre-tax expense associated with all outstanding non-vested RSAs, RSUs, and PRSUs, and the related tax benefits recognized: Three Months Ended March 31, 2022 2021 (dollars in thousands) Share based compensation expense $ 648 $ 1,375 Related tax benefits $ 181 $ 384 Share-based activity in the statement of changes in stockholders’ equity includes RSA, RSU, and PRSU expense, as well as expense related to the Company’s share-based compensation for directors and shares repurchased by the Company for shares tendered by employees to cover income tax liability as grants vest.

Financial Instruments with Off-

Financial Instruments with Off-Balance-Sheet Risk	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Financial Instruments with Off-Balance-Sheet Risk	11. Financial Instruments with Off-Balance-Sheet Risk To meet the financing needs of its customers, the Company is a party to financial instruments with off-balance-sheet risk in the normal course of business. These financial instruments are primarily comprised of commitments to extend credit, commitments to sell residential mortgage loans, and standby letters of credit. Those instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. The Company’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for loan commitments and standby letters of credit is represented by the contractual amount of those instruments assuming that the amounts are fully advanced, and that collateral or other security is of no value. The Company generally uses the same credit policies in making commitments and conditional obligations as it does for on-balance-sheet instruments. Off-balance-sheet financial instruments with contractual amounts that present credit risk include the following: March 31, 2022 December 31, 2021 (dollars in thousands) Financial instruments whose contractual amount represents credit risk: Commitments to extend credit: Unused portion of existing lines of credit $ 823,005 $ 809,383 Origination of new loans 75,785 70,633 Standby letters of credit 19,346 18,880 Financial instruments whose notional amount exceeds the amount of credit risk: Commitments to sell residential mortgage loans 720 3,920

Leases

Leases	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Leases	12. LEASES Lease Commitments . The Company is obligated under various lease agreements covering its main office, branch offices, and other locations. These agreements are accounted for as operating leases and their terms expire between 2023 and 2032 and, in some instances, contain options to renew for periods up to 30 years. The components of operating lease cost and other related information are as follows: Three Months Ended March 31, 2022 2021 (dollars in thousands) Operating lease cost $ 1,744 $ 1,768 Variable lease cost (Cost excluded from lease payments) 1 — Sublease income ( 16 ) ( 16 ) Total Operating Lease Cost $ 1,729 $ 1,752 Other Information Cash paid for amounts included in the measurement of lease liabilities - $ 1,833 $ 1,854 Operating Lease - Operating cash flows (Liability reduction) $ 1,606 $ 1,597 Weighted average lease term - operating leases 5.96 Years 6.74 Years Weighted average discount rate - operating leases 2.95 % 3.00 % The total minimum lease payments due in future periods for lease agreements in effect at March 31, 2022 were as follows: Future Minimum March 31, 2022 Lease Payments (dollars in thousands) Remainder of 2022 $ 7,144 2023 6,735 2024 5,739 2025 4,982 2026 3,254 Thereafter 7,399 Total minimum lease payments $ 35,253 Less: interest ( 2,982 ) Total lease liability $ 32,271 Several of the Company’s lease agreements contain clauses calling for escalation of minimum lease payments contingent on increases in real estate taxes, gross income adjustments, percentage increases in the consumer price index, and certain ancillary maintenance costs. Total rental expense was $ 1.8 million and $ 1.9 million for the three months ended March 31, 2022 and March 31, 2021 , respectively.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Shareholders' Equity	13. Shareholders’ Equity As of March 31, 2022 and December 31, 2021, the Company and the Bank met all applicable minimum capital requirements and were considered “well-capitalized” by both the Federal Reserve Bank (“FRB”) and the Federal Deposit Insurance Corporation (“FDIC”). Actual Minimum Capital Minimum To Be Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At March 31, 2022 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 428,313 13.5 % $ 332,832 10.5 % N/A N/A Tier 1 capital (to risk-weighted assets) 392,831 12.4 % 269,435 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 392,831 12.4 % 221,888 7.0 % N/A N/A Tier 1 capital (to average assets) 392,831 8.0 % 196,394 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 412,721 13.0 % $ 332,802 10.5 % $ 316,954 10.0 % Tier 1 capital (to risk-weighted assets) 377,239 11.9 % 269,411 8.5 % 253,563 8.0 % Common equity tier I capital (to risk-weighted assets) 377,239 11.9 % 221,868 7.0 % 206,020 6.5 % Tier 1 capital (to average assets) 377,239 7.7 % 196,383 4.0 % 245,479 5.0 % Actual Minimum Capital Minimum To Be Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At December 31, 2021 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 420,398 13.6 % $ 325,617 10.5 % N/A N/A Tier 1 capital (to risk-weighted assets) 384,518 12.4 % 263,595 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 384,518 12.4 % 217,078 7.0 % N/A N/A Tier 1 capital (to average assets) 384,518 8.3 % 185,015 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 409,806 13.2 % $ 325,587 10.5 % $ 310,082 10.0 % Tier 1 capital (to risk-weighted assets) 373,926 12.1 % 263,570 8.5 % 248,066 8.0 % Common equity tier I capital (to risk-weighted assets) 373,926 12.1 % 217,058 7.0 % 201,554 6.5 % Tier 1 capital (to average assets) 373,926 8.1 % 185,003 4.0 % 231,254 5.0 %

Other Comprehensive Loss

Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Other Comprehensive Loss	14. Other Comprehensive LOSS The following table presents the changes in accumulated other comprehensive loss (“AOCL”) during the period, by component, net of tax: Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Before Tax Tax (Expense) Net-of-tax Before Tax Tax (Expense) Net-of-tax (dollars in thousands) Available for sale securities Unrealized holding losses $ ( 11,016 ) $ 2,789 $ ( 8,227 ) $ ( 3,923 ) $ 1,036 $ ( 2,887 ) Interest rate swaps designated as cash flow Unrealized holding losses ( 1,700 ) 474 ( 1,226 ) ( 447 ) 125 ( 322 ) Reclassification adjustment for losses recognized in net income ( 614 ) 173 ( 441 ) ( 630 ) 176 ( 454 ) Defined benefit retirement plans Net change in retirement liability — — — 11 ( 3 ) 8 Total other comprehensive loss $ ( 13,330 ) $ 3,436 $ ( 9,894 ) $ ( 4,989 ) $ 1,334 $ ( 3,655 ) Reclassifications out of AOCL that have an impact on net income are presented below: Three Months Ended Details about Accumulated Other Comprehensive Loss Components March 31, 2022 March 31, 2021 Affected Line Item in the (dollars in thousands) Unrealized gains on derivatives $ 614 $ 630 Interest on taxable loans Tax expense ( 173 ) ( 176 ) Income tax expense Net of tax $ 441 $ 454 Net income

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share	15. Earnings per Share The following represents a reconciliation between basic and diluted earnings per share: Three Months Ended March 31, 2022 2021 (dollars in thousands, except per share data) Earnings per common share - basic: Numerator: Net income $ 13,316 $ 13,499 Less dividends and undistributed earnings allocated ( 59 ) ( 57 ) Net income applicable to common shareholders $ 13,257 $ 13,442 Denominator: Weighted average common shares outstanding 6,948 6,908 Earnings per common share - basic $ 1.91 $ 1.95 Earnings per common share - diluted: Numerator: Net income $ 13,316 $ 13,499 Less dividends and undistributed earnings allocated ( 59 ) ( 57 ) Net income applicable to common shareholders $ 13,257 $ 13,442 Denominator: Weighted average common shares outstanding 6,948 6,908 Dilutive effect of common stock equivalents 63 79 Weighted average diluted common shares outstanding 7,011 6,987 Earnings per common share - diluted $ 1.89 $ 1.92

Derivative And Hedging Activiti

Derivative And Hedging Activities	3 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative And Hedging Activities	16. Derivative AND HEDGING ACTIVITIES The Company utilizes interest rate swaps and floors to mitigate exposure to interest rate risk and to facilitate the needs of its customers. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts principally related to the Company’s assets. Cash Flow Hedges of Interest Rate Risk The Company uses interest rate floors to manage its exposure to interest rate movements. Interest rate floors designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty if interest rates fall below the strike rate on the contract in exchange for an up-front premium. For derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in AOCL and subsequently reclassified into interest income in the same period(s) during which the hedged transaction affects earnings. Gains and losses on the derivative representing hedge components excluded from the assessment of effectiveness are recognized over the life of the hedge on a systematic and rational basis. The earnings recognition of excluded components is presented in interest income. Amounts reported in AOCL related to derivatives will be reclassified to interest income as interest payments are received on the Company’s variable-rate assets. During the next twelve months, the Company estimates that an additional $ 371,000 will be reclassified out of AOCL into earnings, as an increase to interest income. Non-designated Hedges Derivatives not designated as hedges are not speculative and result from a service the Company provides to certain customers. For the Company’s customers, these are interest rate swaps and risk participation agreements. Interest Rate Swaps. The Company enters into interest rate swap contracts to help commercial loan borrowers manage their interest rate risk. The interest rate swap contracts with commercial loan borrowers allow them to convert floating-rate loan payments to fixed rate loan payments. When the Company enters into an interest rate swap contract with a commercial loan borrower, it simultaneously enters into a “mirror” swap contract with a third party. The third party exchanges the borrower’s fixed-rate loan payments for floating-rate loan payments. These derivatives are not designated as hedges and therefore, changes in fair value are recognized in earnings. Because these derivatives have mirror-image contractual terms, the changes in fair value substantially offset each other through earnings. Fees earned in connection with the execution of derivatives related to this program are recognized in earnings through loan-related derivative income. The credit risk associated with swap transactions is the risk of default by the counterparty. To minimize this risk, the Company enters into interest rate agreements only with highly rated counterparties that management believes to be creditworthy and maintains collateral pledging agreements with its counterparties. The notional amounts of these agreements do not represent amounts exchanged by the parties and, thus, are not a measure of the potential loss exposure. Risk Participation Agreements. The Company enters into risk participation agreements (“RPAs”) with other banks participating in commercial loan arrangements. Participating banks guarantee the performance on borrower-related interest rate swap contracts. RPAs are derivative financial instruments and are recorded at fair value. These derivatives are not designated as hedges and, therefore, changes in fair value are recognized in earnings. Under a risk participation-out agreement, a derivative asset, the Company participates out a portion of the credit risk associated with the interest rate swap position executed with the commercial borrower for a fee paid to the participating bank. Under a risk participation-in agreement, a derivative liability, the Company assumes, or participates in, a portion of the credit risk associated with the interest rate swap position with the commercial borrower for a fee received from the other bank. The following tables present the notional amount, the location, and fair values of derivative instruments in the Company’s consolidated balance sheets: March 31, 2022 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Fair Value Notional Amount Balance Sheet Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 1,133 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 1,133 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 193,561 Other Assets $ 4,949 $ 330,101 Other Liabilities $ 18,161 Mirror swaps with counterparties 330,101 Other Assets 18,161 193,561 Other Liabilities 4,949 Risk participation agreements-out to counterparties 47,696 Other Assets 76 — Other Liabilities — Risk participation agreements-in with counterparties — Other Assets — 109,082 Other Liabilities 186 Total derivatives not designated as hedging instruments $ 23,186 $ 23,296 December 31, 2021 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Fair Value Notional Amount Balance Sheet Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 3,513 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 3,513 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 522,581 Other Assets $ 23,431 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 522,581 Other Liabilities 23,431 Risk participation agreements-out to counterparties 47,988 Other Assets 107 — Other Liabilities — Risk participation agreements-in with counterparties — Other Assets — 109,510 Other Liabilities 293 Total derivatives not designated as hedging instruments $ 23,538 $ 23,724 The following tables present the changes to AOCL as a result of cash flow hedge accounting as of the periods presented: For the Three Months Ended March 31, 2022 Amount of Gain Amount of Gain Amount of Gain Location of Gain Amount of Gain Amount of Gain or (Loss) Reclassified from AOCL into Income Included Component Amount of Gain or (Loss) Reclassified from AOCL into Income Excluded Component (dollars in thousands) (dollars in thousands) Interest rate contracts $ ( 2,314 ) $ ( 2,528 ) $ 214 Interest Income $ 614 $ 662 $ ( 48 ) For the Three Months Ended March 31, 2021 Amount of Gain Amount of Gain Amount of Gain Location of Gain Amount of Gain Amount of Gain Amount of Gain (dollars in thousands) (dollars in thousands) Interest rate contracts $ ( 1,077 ) $ ( 1,156 ) $ 79 Interest Income $ 630 $ 678 $ ( 48 ) The following table presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the consolidated statements of income as of the periods presented: Amount of Gain or (Loss) Recognized in Income on Derivatives Three Months Ended March 31, 2022 March 31, 2021 Location of Gain or (Loss) (dollars in thousands) Other contracts Loan related derivative income $ ( 77 ) $ 206 Credit-risk-related Contingent Features By entering into derivative transactions, 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. The Company seeks to minimize counterparty credit risk through credit approvals, limits, monitoring procedures, and obtaining collateral, where appropriate. Institutional counterparties must have an investment grade credit rating and be approved by the Company’s board of directors. As such, management believes the risk of incurring credit losses on derivative contracts with institutional counterparties is remote. The Company has agreements with its derivative counterparties that contain a provision where 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. In addition, the Company also has agreements with certain of its derivative counterparties that contain a provision where if the Company fails to maintain its status as a well-capitalized institution, then the counterparty could terminate the derivative position(s) and the Company would be required to settle its obligations under the agreements. Balance Sheet Offsetting Certain financial instruments may be eligible for offset in the consolidated balance sheet and/or subject to master netting arrangements or similar agreements. The Company’s derivative transactions with institutional counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts and there may be an intention to settle such amounts on a net basis. Generally, the Company does not offset such financial instruments for financial reporting purposes. The following tables present the information about financial instruments that are eligible for offset in the consolidated balance sheets at March 31, 2022 and December 31, 2021: Gross Amounts Not Offset Gross Amounts Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount March 31, 2022 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 24,319 $ — $ 24,319 $ 4,950 $ ( 14,048 ) $ 5,321 Offsetting of Derivative Liabilities Derivative Liabilities $ 23,296 $ — $ 23,296 $ 4,950 $ — $ 18,346 Gross Amounts Not Offset Gross Amounts Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount December 31, 2021 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 27,051 $ — $ 27,051 $ 6,365 $ — $ 20,686 Offsetting of Derivative Liabilities Derivative Liabilities $ 23,724 $ — $ 23,724 $ 6,365 $ 14,011 $ 3,348 As of March 31, 2022 there were no derivatives in a net liability position related to these agreements. At December 31, 2021, the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk, related to these agreements was $ 14.0 million. At December 31, 2021, the Company had minimum collateral posting thresholds with certain of its derivative counterparties and posted cash collateral of $ 13.3 million. If the Company had breached any of these provisions at December 31, 2021, it could have been required to settle its obligations under the agreements at their termination value of $ 14.0 million.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	17. Fair Value Measurements The following is a summary of the carrying values and estimated fair values of the Company’s significant financial instruments as of the dates indicated: March 31, 2022 December 31, 2021 Carrying Estimated Carrying Estimated (dollars in thousands) Financial assets Cash and cash equivalents $ 81,748 $ 81,748 $ 180,153 $ 180,153 Securities available for sale 188,205 188,205 197,803 197,803 Securities held to maturity 1,115,824 1,043,391 977,061 971,092 Loans, net 3,383,103 3,317,481 3,284,610 3,230,339 Loans held for sale 918 918 1,490 1,528 FHLB of Boston stock 4,816 4,816 4,816 4,816 Accrued interest receivable 9,718 9,718 9,162 9,162 Mortgage servicing rights 1,063 1,602 1,083 1,518 Interest rate contracts 1,133 1,133 3,513 3,513 Loan level interest rate swaps 23,110 23,110 23,431 23,431 Risk participation agreements out to counterparties 76 76 107 107 Financial liabilities Deposits 4,473,735 4,472,404 4,331,152 4,330,991 Borrowings 16,140 16,144 16,510 16,523 Loan level interest rate swaps 23,110 23,110 23,431 23,431 Risk participation agreements in with counterparties 186 186 293 293 The Company follows ASC 820, Fair Value Measurements and Disclosures (“ASC 820”) for financial assets and liabilities. ASC 820 defines fair value, establishes a framework for measuring fair value, and expands disclosure requirements about fair value measurements. ASC 820, among other things, emphasizes that fair value is a market-based measurement, not an entity-specific measurement, and states that a fair value measurement should be determined based on the assumptions the market participants would use in pricing the asset or liability. In addition, ASC 820 specifies a hierarchy of valuation techniques based on whether the types of valuation information (“inputs”) are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect the Company’s market assumptions. These two types of inputs have created the following fair value hierarchy: • Level 1 – Quoted prices for identical assets or liabilities in active markets. • Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in inactive markets, and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. • Level 3 – Valuations derived from techniques in which one or more significant inputs or significant value drivers are unobservable in the markets and which reflect the Company’s market assumptions. Under ASC 820, fair values are based on 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. When available, the Company uses quoted market prices to determine fair value. If quoted prices are not available, fair value is based upon valuation techniques, such as matrix pricing or other models that use, where possible, current market-based or independently sourced market parameters, such as interest rates. If observable market-based inputs are not available, the Company uses unobservable inputs to determine appropriate valuation adjustments using methodologies applied consistently over time. Valuation techniques based on unobservable inputs are highly subjective and require judgments regarding significant matters, such as the amount and timing of future cash flows and the selection of discount rates that may appropriately reflect market and credit risks. Changes in these judgments often have a material impact on the fair value estimates. In addition, since these estimates are as of a specific point in time, they are susceptible to material near-term changes. The fair values disclosed do not reflect any premium or discount that could result from offering significant holdings of financial instruments at bulk sale, nor do they reflect the possible tax ramifications or estimated transaction costs. Changes in economic conditions may also dramatically affect the estimated fair values. The Company uses fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Securities available for sale, derivative instruments, and hedges are recorded at fair value on a recurring basis. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as individually evaluated collateral dependent loans. The Company uses an exit price notion for its fair value disclosures. The following tables summarize certain assets and liabilities reported at fair value on a recurring basis: Fair Value as of March 31, 2022 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 21,668 $ — $ 21,668 Mortgage-backed securities — 164,779 — 164,779 Corporate debt securities — 1,758 — 1,758 Other assets Interest rate swaps with customers — 4,949 — 4,949 Mirror swaps with counterparties — 18,161 — 18,161 Risk participation agreements-out to counterparties — 76 — 76 Interest rate contracts — 1,133 — 1,133 Other liabilities Interest rate swaps with customers — 18,161 — 18,161 Mirror swaps with counterparties — 4,949 — 4,949 Risk participation agreements-in with counterparties — 186 — 186 Fair Value as of December 31, 2021 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 23,011 $ — $ 23,011 Mortgage-backed securities — 173,028 — 173,028 Corporate debt securities — 1,764 — 1,764 Other assets Interest rate swaps with customers — 23,431 — 23,431 Risk participation agreements-out to counterparties — 107 — 107 Interest rate contracts — 3,513 — 3,513 Other liabilities Mirror swaps with counterparties — 23,431 — 23,431 Risk participation agreements-in with counterparties — 293 — 293 The following tables present the carrying value of assets held at March 31, 2022 and December 31, 2021, which were measured at fair value on a non-recurring basis: March 31, 2022 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a non-recurring basis Assets Individually evaluated collateral dependent loans $ — $ — $ 101 $ 101 Total $ — $ — $ 101 $ 101 December 31, 2021 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a non-recurring basis Assets Loans held for sale $ 1,490 $ — $ — $ 1,490 Individually evaluated collateral dependent loans — — 130 130 Total $ 1,490 $ — $ 130 $ 1,620 Individually evaluated collateral dependent loans . Collateral dependent loans are carried at the lower of cost or fair value of the collateral less estimated costs to sell which approximates fair value. The Company uses the appraisal value of the collateral and applies certain adjustments depending on the nature, quality, and type of collateral securing the loan. Loans held for sale . Loans held for sale are carried at the lower of fair value or carrying value (unpaid principal and unamortized loans fees). There were no transfers between levels for the three months ended March 31, 2022 or March 31,2021. The following is a description of the principal valuation methodologies used by the Company to estimate the fair values of its financial instruments: Investment Securities For investment securities, fair values are primarily based upon valuations obtained from a national pricing service which uses matrix pricing with inputs that are observable in the market or can be derived from, or corroborated by, observable market data. When available, quoted prices in active markets for identical securities are utilized. Loans Held for Sale For loans held for sale, fair values are estimated using projected future cash flows, discounted at rates based upon either trades of similar loans or mortgage-backed securities, or at current rates at which similar loans would be made to borrowers with similar credit ratings and for similar remaining maturities. Loans For most categories of loans, fair values are estimated using projected future cash flows, discounted at rates based upon current rates at which similar loans would be made to borrowers with similar credit ratings, and for similar remaining maturities. Projected estimated cash flows are adjusted for prepayment assumptions, liquidity premium assumptions, and credit loss assumptions. Loans that are deemed to be impaired in accordance with ASC 310, Receivables, are valued based upon the lower of cost or fair value of the underlying collateral. Federal Home Loan Bank of Boston (“FHLB of Boston”) Stock The fair value of FHLB of Boston stock equals its carrying value since such stock is only redeemable at its par value. Deposits The fair value of non-maturity deposit accounts is the amount payable on demand at the reporting date. This amount does not take into account the value of the Bank’s long-term relationships with core depositors. The fair value of fixed-maturity certificates of deposit is estimated using a replacement cost of funds approach and is based upon rates currently offered for deposits of similar remaining maturities. Borrowings For long-term borrowings, fair values are estimated using future cash flows, discounted at rates based upon current costs for debt securities with similar terms and remaining maturities. Other Financial Assets and Liabilities Cash and cash equivalents, accrued interest receivable, and short-term borrowings have fair values which approximate their respective carrying values because these instruments are payable on demand or have short-term maturities and present relatively low credit risk and interest rate risk. Derivative Instruments and Hedges The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The Company incorporates credit valuation adjustments to appropriately reflect nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings. Off-Balance-Sheet Financial Instruments In the course of originating loans and extending credit, the Company will charge fees in exchange for its commitment. While these commitment fees have value, the Company has not estimated their value due to the short-term nature of the underlying commitments and their immateriality. Values Not Determined In accordance with ASC 820, the Company has not estimated fair values for non-financial assets, such as banking premises and equipment, goodwill, the intangible value of the Company’s portfolio of loans serviced for itself, and the intangible value inherent in the Company’s deposit relationships (i.e., core deposits), among others. Accordingly, the aggregate fair value amounts presented do not represent the underlying value of the Company.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements. Actual results could differ from those estimates. The allowance for credit losses is particularly subject to change.
Recently Issued Accounting Guidance	Accounting Pronouncements Yet to be Adopted In March 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ( “ASU” ) 2022-02, Financial Instruments – Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures. The amendments in this ASU eliminate the accounting guidance for troubled debt restructurings (“TDRs”) by creditors in Subtopic 310-40, Receivables – Troubled Debt Restructurings by Creditors , while enhancing disclosure requirements for certain loan refinancings and restructurings by creditors when a borrower is experiencing financial difficulty. For public business entities, the amendments in this ASU require an entity disclose current-period gross write-offs by year of origination for financing receivables and net investments in leases. The ASU is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact the adoption of this guidance will have on the disclosures within its consolidated financial statements. In March 2022, the FASB issued ASU 2022-01, Derivatives and Hedging (Topic 815): Fair Value Hedging - Portfolio Layer Method . The amendments in this ASU allow multiple hedged layers to be designated for a single closed portfolio of financial assets or one or more beneficial interests secured by a portfolio of financial instruments. The amendments in the ASU also clarify the accounting for and promote consistency in the reporting of hedge basis adjustments applicable to both a single hedged layer and multiple hedged layers. These amendments are effective for fiscal years beginning after December 15, 2022, and interim periods within those fiscal years. The Company is currently assessing the impact the adoption of this guidance will have on its consolidated financial statements.

Investment Securities (Tables)

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Carrying Amounts of Securities and Their Approximate Fair Values	Investment securities have been classified in the unaudited consolidated balance sheets according to management’s intent. The carrying amounts of securities and their approximate fair values were as follows: March 31, 2022 December 31, 2021 Amortized Gross Gross Fair Amortized Gross Gross Fair (dollars in thousands) Available for sale securities U.S. Government Sponsored $ 22,997 $ — $ ( 1,329 ) $ 21,668 $ 22,996 $ 246 $ ( 231 ) $ 23,011 Mortgage-backed securities 177,948 32 ( 13,201 ) 164,779 176,531 959 ( 4,462 ) 173,028 Corporate debt securities 1,743 21 ( 6 ) 1,758 1,743 24 ( 3 ) 1,764 Total available for sale securities $ 202,688 $ 53 $ ( 14,536 ) $ 188,205 $ 201,270 $ 1,229 $ ( 4,696 ) $ 197,803 Held to maturity securities Mortgage-backed securities $ 1,009,206 $ 594 $ ( 68,718 ) $ 941,082 $ 864,983 $ 3,981 $ ( 13,258 ) $ 855,706 Corporate debt securities 2,498 7 — 2,505 6,997 26 — 7,023 Municipal securities 104,120 812 ( 5,128 ) 99,804 105,081 3,798 ( 516 ) 108,363 Total held to maturity securities $ 1,115,824 $ 1,413 $ ( 73,846 ) $ 1,043,391 $ 977,061 $ 7,805 $ ( 13,774 ) $ 971,092 Total $ 1,318,512 $ 1,466 $ ( 88,382 ) $ 1,231,596 $ 1,178,331 $ 9,034 $ ( 18,470 ) $ 1,168,895
Gross Unrealized Losses of Aggregated by Investment Category and Length of Time that Individual Securities have been in Continuous Loss Position	The following tables show the Company’s securities with gross unrealized losses for which an allowance for credit losses has not been recorded at March 31, 2022 or at December 31, 2021, aggregated by investment category and length of time that individual securities have been in a continuous loss position: March 31, 2022 Less than 12 months 12 months or longer Total Fair Unrealized Fair Unrealized Fair Unrealized (dollars in thousands) Available for sale securities U.S. Government Sponsored Enterprise $ 12,318 $ ( 682 ) $ 9,350 $ ( 647 ) $ 21,668 $ ( 1,329 ) Mortgage-backed securities 86,726 ( 4,001 ) 75,489 ( 9,200 ) 162,215 ( 13,201 ) Corporate debt securities — — 753 ( 6 ) 753 ( 6 ) Total available for sale securities $ 99,044 $ ( 4,683 ) $ 85,592 $ ( 9,853 ) $ 184,636 $ ( 14,536 ) Held to maturity securities Mortgage-backed securities $ 837,728 $ ( 60,920 ) $ 61,687 $ ( 7,798 ) $ 899,415 $ ( 68,718 ) Municipal securities 37,654 ( 3,691 ) 6,682 ( 1,437 ) 44,336 ( 5,128 ) Total held to maturity securities $ 875,382 $ ( 64,611 ) $ 68,369 $ ( 9,235 ) $ 943,751 $ ( 73,846 ) Total $ 974,426 $ ( 69,294 ) $ 153,961 $ ( 19,088 ) $ 1,128,387 $ ( 88,382 ) December 31, 2021 Less than 12 months 12 months or longer Total Fair Unrealized Fair Unrealized Fair Unrealized (dollars in thousands) Available for sale securities U.S. Government Sponsored Enterprise $ 4,881 $ ( 115 ) $ 4,884 $ ( 116 ) $ 9,765 $ ( 231 ) Mortgage-backed securities 74,724 ( 2,253 ) 47,871 ( 2,209 ) 122,595 ( 4,462 ) Corporate debt securities 760 ( 3 ) — — 760 ( 3 ) Total available for sale securities $ 80,365 $ ( 2,371 ) $ 52,755 $ ( 2,325 ) $ 133,120 $ ( 4,696 ) Held to maturity securities Mortgage-backed securities $ 740,966 $ ( 12,509 ) $ 15,345 $ ( 749 ) $ 756,311 $ ( 13,258 ) Municipal securities 12,607 ( 194 ) 5,716 ( 322 ) 18,323 ( 516 ) Total held to maturity securities $ 753,573 $ ( 12,703 ) $ 21,061 $ ( 1,071 ) $ 774,634 $ ( 13,774 ) Total $ 833,938 $ ( 15,074 ) $ 73,816 $ ( 3,396 ) $ 907,754 $ ( 18,470 )
Schedule of Amortized Cost and Fair Value of Debt Securities, Aggregated By Earlier of Guaranteed Call Date or Contractual Maturity	The amortized cost and fair value of debt securities, aggregated by the earlier of call date or contractual maturity, are shown below. Maturities of mortgage-backed securities do not take into consideration scheduled amortization or prepayments. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Within One Year After One, But After Five, But After Ten Years Total Amortized Fair Amortized Fair Amortized Fair Amortized Fair Amortized Fair At March 31, 2022 (dollars in thousands) Available for sale securities U.S. Government $ — $ — $ 9,997 $ 9,350 $ 5,000 $ 4,811 $ 8,000 $ 7,507 $ 22,997 $ 21,668 Mortgage-backed — — 9,378 9,154 47,145 43,409 121,425 112,216 177,948 164,779 Corporate debt securities 759 753 984 1,005 — — — — 1,743 1,758 Total available for $ 759 $ 753 $ 20,359 $ 19,509 $ 52,145 $ 48,220 $ 129,425 $ 119,723 $ 202,688 $ 188,205 Held to maturity securities Mortgage-backed $ — $ — $ 15,139 $ 15,049 $ 56,143 $ 54,324 $ 937,924 $ 871,709 $ 1,009,206 $ 941,082 Corporate debt securities 2,498 2,505 — — — — — — 2,498 2,505 Municipal securities 5,302 5,333 17,858 18,077 35,973 36,310 44,987 40,084 104,120 99,804 Total held to maturity $ 7,800 $ 7,838 $ 32,997 $ 33,126 $ 92,116 $ 90,634 $ 982,911 $ 911,793 $ 1,115,824 $ 1,043,391 Total $ 8,559 $ 8,591 $ 53,356 $ 52,635 $ 144,261 $ 138,854 $ 1,112,336 $ 1,031,516 $ 1,318,512 $ 1,231,596
Summary of Credit Rating of Debt Securities Portfolio	The Company monitors the credit quality of certain debt securities through the use of credit ratings among other factors on a quarterly basis. The following tables summarize the credit rating of the Company’s debt securities portfolio at March 31, 2022 and December 31, 2021. March 31, 2022 Mortgage-backed Securities (1) Corporate Debt Securities Municipal Securities U.S. GSE Obligations Total (dollars in thousands) Available for sale securities, at fair value AAA/AA/A $ 164,779 $ 753 $ — $ 21,668 $ 187,200 BBB/BB/B — 1,005 — — 1,005 Total available for sale securities $ 164,779 $ 1,758 $ — $ 21,668 $ 188,205 Held to maturity securities, at amortized cost AAA/AA/A $ 1,009,206 $ 2,498 $ 104,120 $ — $ 1,115,824 Total held to maturity securities $ 1,009,206 $ 2,498 $ 104,120 $ — $ 1,115,824 December 31, 2021 Mortgage-backed Securities (1) Corporate Debt Securities Municipal Securities U.S. GSE Obligations Total (dollars in thousands) Available for sale securities, at fair value AAA/AA/A $ 173,028 $ 759 $ — $ 23,011 $ 196,798 BBB/BB/B — 1,005 — — 1,005 Total available for sale securities $ 173,028 $ 1,764 $ — $ 23,011 $ 197,803 Held to maturity securities, at amortized cost AAA/AA/A $ 864,983 $ 6,997 $ 105,081 $ — $ 977,061 Total held to maturity securities $ 864,983 $ 6,997 $ 105,081 $ — $ 977,061 (1) Includes agency mortgage-backed pass-through securities and collateralized mortgage obligations issued by U.S. Government Sponsored Enterprises ("GSEs") and U.S. government agencies, such as FNMA, FHLMC, and GNMA that are not rated by Moody’s or Standard & Poor's. Each security contains a guarantee by the issuing GSE or agency and therefore carries an implicit guarantee of the U.S. government. These have been categorized as AAA/AA/A.

Loans and the Allowance for C_2

Loans and the Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2022
Receivables [Abstract]
Loans Outstanding by Category	Loans outstanding are detailed by category as follows: March 31, 2022 December 31, 2021 (dollars in thousands) Residential mortgage Mortgages - fixed rate $ 747,716 $ 716,456 Mortgages - adjustable rate 669,495 679,675 Construction 21,722 13,012 Deferred costs, net of unearned fees 8,208 5,936 Total residential mortgages 1,447,141 1,415,079 Commercial mortgage Mortgages - non-owner occupied 1,336,997 1,272,135 Mortgages - owner occupied 151,173 150,632 Construction 89,200 86,246 Deferred costs, net of unearned fees 2,124 1,989 Total commercial mortgages 1,579,494 1,511,002 Home equity Home equity - lines of credit 84,465 85,639 Home equity - term loans 1,781 2,017 Deferred costs, net of unearned fees 313 304 Total home equity 86,559 87,960 Commercial and industrial Commercial and industrial 248,960 247,024 PPP loans 13,963 22,856 Unearned fees, net of deferred costs ( 151 ) ( 434 ) Total commercial and industrial 262,772 269,446 Consumer Secured 40,374 34,308 Unsecured 861 1,303 Deferred costs, net of unearned fees 12 8 Total consumer 41,247 35,619 Total loans $ 3,417,213 $ 3,319,106
Non-performing Loans Disaggregated by Loan Category	The following tables set forth information regarding non-performing loans disaggregated by loan category: March 31, 2022 Residential Commercial Home Commercial and Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 4,113 $ 463 $ 523 $ 107 $ 5,206 Troubled debt restructurings 636 — — 101 737 Total $ 4,749 $ 463 $ 523 $ 208 $ 5,943 December 31, 2021 Residential Commercial Home Commercial and Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 3,777 $ 517 $ 223 $ 111 $ 4,628 Troubled debt restructurings 652 — — 106 758 Total $ 4,429 $ 517 $ 223 $ 217 $ 5,386
Loans Receivable Disaggregated by Credit Quality Indicator	The following tables contain period-end balances of loans receivable disaggregated by credit quality indicator: Credit Quality Indicator - by Origination Year as of March 31, 2022 2022 2021 2020 2019 2018 Prior Revolving loans amortized cost basis Total (dollars in thousands) Residential Mortgage: Current $ 86,983 $ 536,375 $ 315,864 $ 129,036 $ 94,174 $ 279,960 $ — $ 1,442,392 Non-performing — — 148 — 492 4,109 — 4,749 Total $ 86,983 $ 536,375 $ 316,012 $ 129,036 $ 94,666 $ 284,069 $ — $ 1,447,141 Home equity: Current $ — $ — $ 397 $ 2,522 $ 3,791 $ 9,850 $ 69,476 $ 86,036 Non-performing — — — 523 — — — 523 Total $ — $ — $ 397 $ 3,045 $ 3,791 $ 9,850 $ 69,476 $ 86,559 Consumer: Current $ 9,746 $ 12,043 $ 7,746 $ 1,427 $ 2,640 $ 7,144 $ 501 $ 41,247 Non-performing — — — — — — — — Total $ 9,746 $ 12,043 $ 7,746 $ 1,427 $ 2,640 $ 7,144 $ 501 $ 41,247 Credit Quality Indicator - by Origination Year as of March 31, 2022 2022 2021 2020 2019 2018 Prior Revolving loans amortized cost basis Total (dollars in thousands) Commercial Mortgage: Credit risk profile by internally 1-6 (Pass) $ 106,176 $ 323,625 $ 238,962 $ 301,506 $ 153,681 $ 378,667 $ — $ 1,502,617 7 (Special Mention) — — 1,088 45,916 22,333 6,921 — 76,258 8 (Substandard) — — — — — 619 — 619 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 106,176 $ 323,625 $ 240,050 $ 347,422 $ 176,014 $ 386,207 $ — $ 1,579,494 Commercial and Industrial: Credit risk profile by internally 1-6 (Pass) $ 6,723 $ 77,584 $ 75,550 $ 37,872 $ 33,322 $ 20,795 $ 371 $ 252,217 7 (Special Mention) — 291 347 5,624 407 581 10 7,260 8 (Substandard) — — 729 2,324 101 138 3 3,295 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 6,723 $ 77,875 $ 76,626 $ 45,820 $ 33,830 $ 21,514 $ 384 $ 262,772 Credit Quality Indicator - by Origination Year as of December 31, 2021 2021 2020 2019 2018 2017 Prior Revolving loans amortized cost basis Total (dollars in thousands) Residential Mortgage: Current $ 535,071 $ 329,501 $ 135,139 $ 101,108 $ 77,702 $ 232,129 $ — $ 1,410,650 Non-performing — 151 — 330 54 3,894 — 4,429 Total $ 535,071 $ 329,652 $ 135,139 $ 101,438 $ 77,756 $ 236,023 $ — $ 1,415,079 Home equity: Current $ — $ 719 $ 3,088 $ 4,469 $ 5,060 $ 5,475 $ 68,926 $ 87,737 Non-performing — — 223 — — — — 223 Total $ — $ 719 $ 3,311 $ 4,469 $ 5,060 $ 5,475 $ 68,926 $ 87,960 Consumer: Current $ 14,427 $ 8,758 $ 1,544 $ 3,168 $ 1,838 $ 5,357 $ 527 $ 35,619 Non-performing — — — — — — — — Total $ 14,427 $ 8,758 $ 1,544 $ 3,168 $ 1,838 $ 5,357 $ 527 $ 35,619 Credit Quality Indicator - by Origination Year as of December 31, 2021 2021 2020 2019 2018 2017 Prior Revolving loans amortized cost basis Total (dollars in thousands) Commercial Mortgage: Credit risk profile by internally 1-6 (Pass) $ 319,633 $ 248,691 $ 320,189 $ 158,462 $ 93,016 $ 298,791 $ — $ 1,438,782 7 (Special Mention) — 1,096 40,879 22,471 2,913 4,131 — 71,490 8 (Substandard) — — — — — 730 — 730 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 319,633 $ 249,787 $ 361,068 $ 180,933 $ 95,929 $ 303,652 $ — $ 1,511,002 Commercial and Industrial: Credit risk profile by internally 1-6 (Pass) $ 83,614 $ 77,073 $ 38,299 $ 34,360 $ 19,727 $ 4,622 $ 353 $ 258,048 7 (Special Mention) 318 350 5,523 406 161 859 10 7,627 8 (Substandard) — 792 2,331 504 — 144 — 3,771 9 (Doubtful) — — — — — — — — 10 (Loss) — — — — — — — — Total $ 83,932 $ 78,215 $ 46,153 $ 35,270 $ 19,888 $ 5,625 $ 363 $ 269,446
Schedule of Loans Receivable Disaggregated by Past Due Status	The following tables contain period-end balances of loans receivable disaggregated by past due status: March 31, 2022 30-59 Days 60-89 Days 90 Days or greater Total Past Due Current Loans Total Amortized Cost 90+ Days Past Due and Accruing (dollars in thousands) Residential mortgage $ 7,521 $ — $ 1,083 $ 8,604 $ 1,438,537 $ 1,447,141 $ — Commercial mortgage — 5,148 — 5,148 1,574,346 1,579,494 — Home equity 628 — — 628 85,931 86,559 — Commercial and industrial 456 41 — 497 262,275 262,772 — Consumer 107 — — 107 41,140 41,247 — Total $ 8,712 $ 5,189 $ 1,083 $ 14,984 $ 3,402,229 $ 3,417,213 $ — December 31, 2021 30-59 Days 60-89 Days 90 Days Total Current Total Amortized Cost 90+ Days Past Due and Accruing (dollars in thousands) Residential mortgage $ 8,470 $ 415 $ 1,488 $ 10,373 $ 1,404,706 $ 1,415,079 $ — Commercial mortgage 476 — — 476 1,510,526 1,511,002 — Home equity 314 643 — 957 87,003 87,960 — Commercial and industrial 5 437 — 442 269,004 269,446 — Consumer — — — — 35,619 35,619 — Total $ 9,265 $ 1,495 $ 1,488 $ 12,248 $ 3,306,858 $ 3,319,106 $ —
Summary of Changes in Allowance for Credit Losses Disaggregated by Loan Category	The following table presents changes in the allowance for credit losses disaggregated by loan category: For the Three Months Ended March 31, 2022 Residential Commercial Home Commercial & Consumer Unfunded Commitments Total (dollars in thousands) Allowance for credit loss: Allowance for credit losses - loan Balance at December 31, 2021 $ 13,383 $ 17,133 $ 406 $ 2,989 $ 585 $ — $ 34,496 Charge-offs — — — — ( 25 ) — ( 25 ) Recoveries — — — 36 2 — 38 Provision for (release of) credit ( 190 ) 5 ( 29 ) ( 128 ) ( 57 ) — ( 399 ) Allowance for credit losses - $ 13,193 $ 17,138 $ 377 $ 2,897 $ 505 $ — $ 34,110 Allowance for credit losses - Balance at December 31, 2021 $ — $ — $ — $ — $ — $ 1,384 $ 1,384 Release of credit — — — — — ( 13 ) ( 13 ) Allowance for credit losses- $ — $ — $ — $ — $ — $ 1,371 $ 1,371 Total allowance for credit loss $ 13,193 $ 17,138 $ 377 $ 2,897 $ 505 $ 1,371 $ 35,481 For the Three Months Ended March 31, 2021 Residential Commercial Home Commercial & Consumer Unfunded Commitments Total (dollars in thousands) Allowance for credit loss: Allowance for credit losses - loan Balance at December 31, 2020 $ 13,067 $ 18,564 $ 552 $ 3,309 $ 524 $ — $ 36,016 Charge-offs — — — — ( 3 ) — ( 3 ) Recoveries — — — 19 4 — 23 Provision for (release of) credit 77 129 ( 189 ) ( 350 ) ( 57 ) — ( 390 ) Allowance for credit losses - $ 13,144 $ 18,693 $ 363 $ 2,978 $ 468 $ — $ 35,646 Allowance for credit losses - Balance at December 31, 2020 $ — $ — $ — $ — $ — $ 1,004 $ 1,004 Provision for credit — — — — — 184 184 Allowance for credit losses- — — — — — 1,188 1,188 Total allowance for credit loss $ 13,144 $ 18,693 $ 363 $ 2,978 $ 468 $ 1,188 $ 36,834

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	The components of income tax expense were as follows: Three Months Ended March 31, 2022 2021 (dollars in thousands) Current income tax expense Federal $ 1,095 $ 2,091 State 389 922 Total current income tax expense 1,484 3,013 Deferred income tax expense Federal $ 2,025 $ 1,182 State 935 548 Total deferred income tax expense 2,960 1,730 Total income tax expense $ 4,444 $ 4,743

Pension and Retirement Plans (T

Pension and Retirement Plans (Tables)	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Cost (Credit)	The components of net periodic benefit cost (credit) were as follows: Three Months Ended March 31, Pension Plan Supplemental Retirement Healthcare Plan 2022 2021 2022 2021 2022 2021 (dollars in thousands) Net periodic benefit cost (credit) Service cost $ — $ — $ 101 $ 106 $ 8 $ 9 Interest cost 310 303 59 57 5 4 Expected return on assets ( 936 ) ( 892 ) — — — — Amortization of prior service credit — ( 1 ) — — — — Amortization of net actuarial loss — — — 11 — — Net periodic benefit cost (credit) $ ( 626 ) $ ( 590 ) $ 160 $ 174 $ 13 $ 13

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2022
Schedule of Shares Issued and Fair Value of RSAs, RSUs	During the three months ended March 31, 2022 , the Company issued the following RSAs and RSUs pursuant to the Cambridge Bancorp 2017 Equity and Cash Incentive Plan (the “2017 Plan”). RSAs time-vest either over a three-year or five-year period. RSUs vest over a three-year -period. T he fair value of RSAs and RSUs are based upon the closing price of the Company's common stock on the date of the applicable grant. The holders of RSAs participate fully in the rewards of stock ownership of the Company, including voting and dividend rights. The holders of restricted stock units do not participate in the rewards of stock ownership of the Company until vested. For the Three Months Ended March 31, 2022 Weighted-Average Shares Granted Fair Value at Grant Date Type of Award 11,924 $ 87.00 RSAs 8,796 $ 88.18 RSUs
Schedule of Pre-tax Expense Associated with All Outstanding Non-vested RSAs, RSUs, Performance Based Restricted Stock Units and Related Tax Benefits	The following table presents the pre-tax expense associated with all outstanding non-vested RSAs, RSUs, and PRSUs, and the related tax benefits recognized: Three Months Ended March 31, 2022 2021 (dollars in thousands) Share based compensation expense $ 648 $ 1,375 Related tax benefits $ 181 $ 384

Financial Instruments with Of_2

Financial Instruments with Off-Balance-Sheet Risk (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Off-Balance-Sheet Financial Instruments with Contractual Amounts Include Present Credit Risk	Off-balance-sheet financial instruments with contractual amounts that present credit risk include the following: March 31, 2022 December 31, 2021 (dollars in thousands) Financial instruments whose contractual amount represents credit risk: Commitments to extend credit: Unused portion of existing lines of credit $ 823,005 $ 809,383 Origination of new loans 75,785 70,633 Standby letters of credit 19,346 18,880 Financial instruments whose notional amount exceeds the amount of credit risk: Commitments to sell residential mortgage loans 720 3,920

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2022
Leases [Abstract]
Summary of Components of Operating Lease Cost and Other Related Information	The components of operating lease cost and other related information are as follows: Three Months Ended March 31, 2022 2021 (dollars in thousands) Operating lease cost $ 1,744 $ 1,768 Variable lease cost (Cost excluded from lease payments) 1 — Sublease income ( 16 ) ( 16 ) Total Operating Lease Cost $ 1,729 $ 1,752 Other Information Cash paid for amounts included in the measurement of lease liabilities - $ 1,833 $ 1,854 Operating Lease - Operating cash flows (Liability reduction) $ 1,606 $ 1,597 Weighted average lease term - operating leases 5.96 Years 6.74 Years Weighted average discount rate - operating leases 2.95 % 3.00 %
Schedule of Total Minimum Lease Payments Due in Future Periods for Lease Agreements	The total minimum lease payments due in future periods for lease agreements in effect at March 31, 2022 were as follows: Future Minimum March 31, 2022 Lease Payments (dollars in thousands) Remainder of 2022 $ 7,144 2023 6,735 2024 5,739 2025 4,982 2026 3,254 Thereafter 7,399 Total minimum lease payments $ 35,253 Less: interest ( 2,982 ) Total lease liability $ 32,271

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Schedule of Minimum Capital Requirements Considered Well Capitalized by FRB and FDIC	As of March 31, 2022 and December 31, 2021, the Company and the Bank met all applicable minimum capital requirements and were considered “well-capitalized” by both the Federal Reserve Bank (“FRB”) and the Federal Deposit Insurance Corporation (“FDIC”). Actual Minimum Capital Minimum To Be Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At March 31, 2022 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 428,313 13.5 % $ 332,832 10.5 % N/A N/A Tier 1 capital (to risk-weighted assets) 392,831 12.4 % 269,435 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 392,831 12.4 % 221,888 7.0 % N/A N/A Tier 1 capital (to average assets) 392,831 8.0 % 196,394 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 412,721 13.0 % $ 332,802 10.5 % $ 316,954 10.0 % Tier 1 capital (to risk-weighted assets) 377,239 11.9 % 269,411 8.5 % 253,563 8.0 % Common equity tier I capital (to risk-weighted assets) 377,239 11.9 % 221,868 7.0 % 206,020 6.5 % Tier 1 capital (to average assets) 377,239 7.7 % 196,383 4.0 % 245,479 5.0 % Actual Minimum Capital Minimum To Be Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At December 31, 2021 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 420,398 13.6 % $ 325,617 10.5 % N/A N/A Tier 1 capital (to risk-weighted assets) 384,518 12.4 % 263,595 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 384,518 12.4 % 217,078 7.0 % N/A N/A Tier 1 capital (to average assets) 384,518 8.3 % 185,015 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 409,806 13.2 % $ 325,587 10.5 % $ 310,082 10.0 % Tier 1 capital (to risk-weighted assets) 373,926 12.1 % 263,570 8.5 % 248,066 8.0 % Common equity tier I capital (to risk-weighted assets) 373,926 12.1 % 217,058 7.0 % 201,554 6.5 % Tier 1 capital (to average assets) 373,926 8.1 % 185,003 4.0 % 231,254 5.0 %

Other Comprehensive Loss (Table

Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2022
Equity [Abstract]
Summary of Accumulated Other Comprehensive loss ("AOCL")	The following table presents the changes in accumulated other comprehensive loss (“AOCL”) during the period, by component, net of tax: Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 Before Tax Tax (Expense) Net-of-tax Before Tax Tax (Expense) Net-of-tax (dollars in thousands) Available for sale securities Unrealized holding losses $ ( 11,016 ) $ 2,789 $ ( 8,227 ) $ ( 3,923 ) $ 1,036 $ ( 2,887 ) Interest rate swaps designated as cash flow Unrealized holding losses ( 1,700 ) 474 ( 1,226 ) ( 447 ) 125 ( 322 ) Reclassification adjustment for losses recognized in net income ( 614 ) 173 ( 441 ) ( 630 ) 176 ( 454 ) Defined benefit retirement plans Net change in retirement liability — — — 11 ( 3 ) 8 Total other comprehensive loss $ ( 13,330 ) $ 3,436 $ ( 9,894 ) $ ( 4,989 ) $ 1,334 $ ( 3,655 )
Summary of Reclassifications out of Accumulated Other Comprehensive Loss ("AOCL")	Reclassifications out of AOCL that have an impact on net income are presented below: Three Months Ended Details about Accumulated Other Comprehensive Loss Components March 31, 2022 March 31, 2021 Affected Line Item in the (dollars in thousands) Unrealized gains on derivatives $ 614 $ 630 Interest on taxable loans Tax expense ( 173 ) ( 176 ) Income tax expense Net of tax $ 441 $ 454 Net income

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Summary of Reconciliation Between Basic and Diluted Earnings Per Share	The following represents a reconciliation between basic and diluted earnings per share: Three Months Ended March 31, 2022 2021 (dollars in thousands, except per share data) Earnings per common share - basic: Numerator: Net income $ 13,316 $ 13,499 Less dividends and undistributed earnings allocated ( 59 ) ( 57 ) Net income applicable to common shareholders $ 13,257 $ 13,442 Denominator: Weighted average common shares outstanding 6,948 6,908 Earnings per common share - basic $ 1.91 $ 1.95 Earnings per common share - diluted: Numerator: Net income $ 13,316 $ 13,499 Less dividends and undistributed earnings allocated ( 59 ) ( 57 ) Net income applicable to common shareholders $ 13,257 $ 13,442 Denominator: Weighted average common shares outstanding 6,948 6,908 Dilutive effect of common stock equivalents 63 79 Weighted average diluted common shares outstanding 7,011 6,987 Earnings per common share - diluted $ 1.89 $ 1.92

Derivative And Hedging Activi_2

Derivative And Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Fair Values of Derivative Instruments in the Company's Consolidated Balance Sheets	The following tables present the notional amount, the location, and fair values of derivative instruments in the Company’s consolidated balance sheets: March 31, 2022 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Fair Value Notional Amount Balance Sheet Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 1,133 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 1,133 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 193,561 Other Assets $ 4,949 $ 330,101 Other Liabilities $ 18,161 Mirror swaps with counterparties 330,101 Other Assets 18,161 193,561 Other Liabilities 4,949 Risk participation agreements-out to counterparties 47,696 Other Assets 76 — Other Liabilities — Risk participation agreements-in with counterparties — Other Assets — 109,082 Other Liabilities 186 Total derivatives not designated as hedging instruments $ 23,186 $ 23,296 December 31, 2021 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Fair Value Notional Amount Balance Sheet Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 3,513 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 3,513 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 522,581 Other Assets $ 23,431 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 522,581 Other Liabilities 23,431 Risk participation agreements-out to counterparties 47,988 Other Assets 107 — Other Liabilities — Risk participation agreements-in with counterparties — Other Assets — 109,510 Other Liabilities 293 Total derivatives not designated as hedging instruments $ 23,538 $ 23,724
Summary of Changes to AOCL as a Result of Cash Flow Hedge Accounting	The following tables present the changes to AOCL as a result of cash flow hedge accounting as of the periods presented: For the Three Months Ended March 31, 2022 Amount of Gain Amount of Gain Amount of Gain Location of Gain Amount of Gain Amount of Gain or (Loss) Reclassified from AOCL into Income Included Component Amount of Gain or (Loss) Reclassified from AOCL into Income Excluded Component (dollars in thousands) (dollars in thousands) Interest rate contracts $ ( 2,314 ) $ ( 2,528 ) $ 214 Interest Income $ 614 $ 662 $ ( 48 ) For the Three Months Ended March 31, 2021 Amount of Gain Amount of Gain Amount of Gain Location of Gain Amount of Gain Amount of Gain Amount of Gain (dollars in thousands) (dollars in thousands) Interest rate contracts $ ( 1,077 ) $ ( 1,156 ) $ 79 Interest Income $ 630 $ 678 $ ( 48 )
Summary of Derivative Financial Instruments Not Designated as Hedging Instruments on the Consolidated Statements of Income	The following table presents the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the consolidated statements of income as of the periods presented: Amount of Gain or (Loss) Recognized in Income on Derivatives Three Months Ended March 31, 2022 March 31, 2021 Location of Gain or (Loss) (dollars in thousands) Other contracts Loan related derivative income $ ( 77 ) $ 206
Schedule of Financial Instruments Eligible for Offset in Consolidated Balance Sheet	The following tables present the information about financial instruments that are eligible for offset in the consolidated balance sheets at March 31, 2022 and December 31, 2021: Gross Amounts Not Offset Gross Amounts Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount March 31, 2022 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 24,319 $ — $ 24,319 $ 4,950 $ ( 14,048 ) $ 5,321 Offsetting of Derivative Liabilities Derivative Liabilities $ 23,296 $ — $ 23,296 $ 4,950 $ — $ 18,346 Gross Amounts Not Offset Gross Amounts Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount December 31, 2021 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 27,051 $ — $ 27,051 $ 6,365 $ — $ 20,686 Offsetting of Derivative Liabilities Derivative Liabilities $ 23,724 $ — $ 23,724 $ 6,365 $ 14,011 $ 3,348

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Summary of Carrying Values and Estimated Fair Values of Financial Instruments	The following is a summary of the carrying values and estimated fair values of the Company’s significant financial instruments as of the dates indicated: March 31, 2022 December 31, 2021 Carrying Estimated Carrying Estimated (dollars in thousands) Financial assets Cash and cash equivalents $ 81,748 $ 81,748 $ 180,153 $ 180,153 Securities available for sale 188,205 188,205 197,803 197,803 Securities held to maturity 1,115,824 1,043,391 977,061 971,092 Loans, net 3,383,103 3,317,481 3,284,610 3,230,339 Loans held for sale 918 918 1,490 1,528 FHLB of Boston stock 4,816 4,816 4,816 4,816 Accrued interest receivable 9,718 9,718 9,162 9,162 Mortgage servicing rights 1,063 1,602 1,083 1,518 Interest rate contracts 1,133 1,133 3,513 3,513 Loan level interest rate swaps 23,110 23,110 23,431 23,431 Risk participation agreements out to counterparties 76 76 107 107 Financial liabilities Deposits 4,473,735 4,472,404 4,331,152 4,330,991 Borrowings 16,140 16,144 16,510 16,523 Loan level interest rate swaps 23,110 23,110 23,431 23,431 Risk participation agreements in with counterparties 186 186 293 293
Summary of Certain Assets and Liabilities Reported at Fair Value on a Recurring Basis	The following tables summarize certain assets and liabilities reported at fair value on a recurring basis: Fair Value as of March 31, 2022 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 21,668 $ — $ 21,668 Mortgage-backed securities — 164,779 — 164,779 Corporate debt securities — 1,758 — 1,758 Other assets Interest rate swaps with customers — 4,949 — 4,949 Mirror swaps with counterparties — 18,161 — 18,161 Risk participation agreements-out to counterparties — 76 — 76 Interest rate contracts — 1,133 — 1,133 Other liabilities Interest rate swaps with customers — 18,161 — 18,161 Mirror swaps with counterparties — 4,949 — 4,949 Risk participation agreements-in with counterparties — 186 — 186 Fair Value as of December 31, 2021 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 23,011 $ — $ 23,011 Mortgage-backed securities — 173,028 — 173,028 Corporate debt securities — 1,764 — 1,764 Other assets Interest rate swaps with customers — 23,431 — 23,431 Risk participation agreements-out to counterparties — 107 — 107 Interest rate contracts — 3,513 — 3,513 Other liabilities Mirror swaps with counterparties — 23,431 — 23,431 Risk participation agreements-in with counterparties — 293 — 293
Schedule of Carrying Value of Assets Measured at Fair Value on a Non-Recurring Basis	The following tables present the carrying value of assets held at March 31, 2022 and December 31, 2021, which were measured at fair value on a non-recurring basis: March 31, 2022 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a non-recurring basis Assets Individually evaluated collateral dependent loans $ — $ — $ 101 $ 101 Total $ — $ — $ 101 $ 101 December 31, 2021 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a non-recurring basis Assets Loans held for sale $ 1,490 $ — $ — $ 1,490 Individually evaluated collateral dependent loans — — 130 130 Total $ 1,490 $ — $ 130 $ 1,620

Cash and Cash Equivalents - Add

Cash and Cash Equivalents - Additional Information (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents	$ 81,748,000	$ 180,153,000
Cash pledged as collateral to derivative counterparties	0	13,300,000
Federal Reserve Bank of Boston
Cash And Cash Equivalents [Line Items]
Reserve balance of cash and due from banks	0	0
New Hampshire
Cash And Cash Equivalents [Line Items]
Pledged amount to federal banking department	$ 500,000	$ 500,000

Investment Securities - Summary

Investment Securities - Summary of Carrying Amounts of Securities and Their Approximate Fair Values (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		$ 202,688	$ 201,270
Available for sale securities, Gross Unrealized Gains		53	1,229
Available for sale securities, Gross Unrealized Losses		(14,536)	(4,696)
Total available for sale securities		188,205	197,803
Held to maturity securities, Amortized Cost		1,115,824	977,061
Held to maturity securities, Gross Unrealized Gains		1,413	7,805
Held to maturity securities, Gross Unrealized Losses		(73,846)	(13,774)
Held-to-maturity securities, fair value		1,043,391	971,092
Total, Amortized Cost		1,318,512	1,178,331
Total, Gross Unrealized Gains		1,466	9,034
Total, Gross Unrealized Losses		(88,382)	(18,470)
Total, Fair Value		1,231,596	1,168,895
U.S. Government Sponsored Enterprise Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		22,997	22,996
Available for sale securities, Gross Unrealized Gains			246
Available for sale securities, Gross Unrealized Losses		(1,329)	(231)
Total available for sale securities		21,668	23,011
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		1,743	1,743
Available for sale securities, Gross Unrealized Gains		21	24
Available for sale securities, Gross Unrealized Losses		(6)	(3)
Total available for sale securities		1,758	1,764
Held to maturity securities, Amortized Cost		2,498	6,997
Held to maturity securities, Gross Unrealized Gains		7	26
Held-to-maturity securities, fair value		2,505	7,023
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		177,948	176,531
Available for sale securities, Gross Unrealized Gains		32	959
Available for sale securities, Gross Unrealized Losses		(13,201)	(4,462)
Total available for sale securities	[1]	164,779	173,028
Held to maturity securities, Amortized Cost	[1]	1,009,206	864,983
Held to maturity securities, Gross Unrealized Gains		594	3,981
Held to maturity securities, Gross Unrealized Losses		(68,718)	(13,258)
Held-to-maturity securities, fair value		941,082	855,706
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Amortized Cost		104,120	105,081
Held to maturity securities, Gross Unrealized Gains		812	3,798
Held to maturity securities, Gross Unrealized Losses		(5,128)	(516)
Held-to-maturity securities, fair value		$ 99,804	$ 108,363
[1]	Includes agency mortgage-backed pass-through securities and collateralized mortgage obligations issued by U.S. Government Sponsored Enterprises ("GSEs") and U.S. government agencies, such as FNMA, FHLMC, and GNMA that are not rated by Moody’s or Standard & Poor's. Each security contains a guarantee by the issuing GSE or agency and therefore carries an implicit guarantee of the U.S. government. These have been categorized as AAA/AA/A.

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses of Aggregated by Investment Category and Length of Time that Individual Securities have been in Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Fair Value, Less than 12 months	$ 99,044	$ 80,365
Available for sale securities, Unrealized Losses, Less than 12 months	(4,683)	(2,371)
Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer, Total	85,592	52,755
Available for sale securities, Unrealized Losses, 12 months or longer	(9,853)	(2,325)
Available for sale securities, Fair Value	184,636	133,120
Available for sale securities, Unrealized Losses	(14,536)	(4,696)
Held to maturity securities, Fair Value, Less than 12 months	875,382	753,573
Held to maturity securities, Unrealized Losses, Less than 12 months	(64,611)	(12,703)
Held to maturity securities, Fair Value, 12 months or longer	68,369	21,061
Held to maturity securities, Unrealized Losses, 12 months or longer	(9,235)	(1,071)
Held to maturity securities, Fair Value	943,751	774,634
Held to maturity securities, Unrealized Losses	(73,846)	(13,774)
Fair Value, Less than 12 months	974,426	833,938
Unrealized Losses, Less than 12 months	(69,294)	(15,074)
Fair Value, 12 months or longer	153,961	73,816
Unrealized Losses, 12 months or longer	(19,088)	(3,396)
Fair Value	1,128,387	907,754
Unrealized Losses	88,382	(18,470)
U.S. Government Sponsored Enterprise Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Fair Value, Less than 12 months	12,318	4,881
Available for sale securities, Unrealized Losses, Less than 12 months	(682)	(115)
Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer, Total	9,350	4,884
Available for sale securities, Unrealized Losses, 12 months or longer	(647)	(116)
Available for sale securities, Fair Value	21,668	9,765
Available for sale securities, Unrealized Losses	(1,329)	(231)
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Fair Value, Less than 12 months	86,726	74,724
Available for sale securities, Unrealized Losses, Less than 12 months	(4,001)	(2,253)
Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer, Total	75,489	47,871
Available for sale securities, Unrealized Losses, 12 months or longer	(9,200)	(2,209)
Available for sale securities, Fair Value	162,215	122,595
Available for sale securities, Unrealized Losses	(13,201)	(4,462)
Held to maturity securities, Fair Value, Less than 12 months	837,728	740,966
Held to maturity securities, Unrealized Losses, Less than 12 months	(60,920)	(12,509)
Held to maturity securities, Fair Value, 12 months or longer	61,687	15,345
Held to maturity securities, Unrealized Losses, 12 months or longer	(7,798)	(749)
Held to maturity securities, Fair Value	899,415	756,311
Held to maturity securities, Unrealized Losses	(68,718)	(13,258)
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Fair Value, Less than 12 months		760
Available for sale securities, Unrealized Losses, Less than 12 months		(3)
Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer, Total	753
Available for sale securities, Unrealized Losses, 12 months or longer	(6)
Available for sale securities, Fair Value	753	760
Available for sale securities, Unrealized Losses	(6)	(3)
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Fair Value, Less than 12 months	37,654	12,607
Held to maturity securities, Unrealized Losses, Less than 12 months	(3,691)	(194)
Held to maturity securities, Fair Value, 12 months or longer	6,682	5,716
Held to maturity securities, Unrealized Losses, 12 months or longer	(1,437)	(322)
Held to maturity securities, Fair Value	44,336	18,323
Held to maturity securities, Unrealized Losses	$ (5,128)	$ (516)

Investment Securities - Additio

Investment Securities - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022USD ($)Security	Mar. 31, 2021USD ($)
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Number of debt securities with unrealized losses | Security	338
Aggregate depreciation percentage of gross unrealized losses from amortized cost	7.30%
Percentage of unrealized dollar loss on amortized cost	9.70%
Percentage of unrealized loss on amortized cost	22.20%
Unrealized dollar loss of amortized cost basis	$ 937,000
Unrealized loss of amortized cost basis	521,000
Net proceeds from securities sold	$ 0	$ 0

Investment Securities - Schedul

Investment Securities - Schedule of Amortized Cost and Fair Value of Debt Securities, Aggregated By Earlier of Guaranteed Call Date or Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Within One Year, Amortized Cost	$ 759
Available for sale securities, Within One Year, Fair Value	753
Available for sale securities, After One, But Within Five Years, Amortized Cost	20,359
Available for sale securities, After One, But Within Five Years, Fair Value	19,509
Available for sale securities, After Five, But Within Ten Years, Amortized Cost	52,145
Available for sale securities, After Five, But Within Ten Years, Fair Value	48,220
Available for sale securities, After Ten Years, Amortized Cost	129,425
Available for sale securities, After Ten Years, Fair Value	119,723
Available for sale securities, Total, Amortized Cost	202,688
Available for sale securities, Total, Fair Value	188,205
Held to maturity securities, Within One Year, Amortized Cost	7,800
Held to maturity securities, Within One Year, Fair Value	7,838
Held to maturity securities, After One, But Within Five Years, Amortized Cost	32,997
Held to maturity securities, After One, But Within Five Years, Fair Value	33,126
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	92,116
Held to maturity securities, After Five, But Within Ten Years, Fair Value	90,634
Held to maturity securities, After Ten Years, Amortized Cost	982,911
Held to maturity securities, After Ten Years, Fair Value	911,793
Held to maturity securities, Amortized Cost	1,115,824	$ 977,061
Held to maturity securities, Fair Value	1,043,391	971,092
Available for sale securities and Held to maturity securities, Within One Year, Amortized Cost	8,559
Available for sale securities and Held to maturity securities, Within One Year, Fair Value	8,591
Available for sale securities and Held to maturity securities, After One, But Within Five Years, Amortized Cost	53,356
Available for sale securities and Held to maturity securities, After One, But Within Five Years, Fair Value	52,635
Available for sale securities and Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	144,261
Available for sale securities and Held to maturity securities, After Five, But Within Ten Years, Fair Value	138,854
Available for sale securities and Held to maturity securities, After Ten Years, Amortized Cost	1,112,336
Available for sale securities and Held to maturity securities, After Ten Years, Fair Value	1,031,516
Available for sale securities and Held to maturity securities, Total, Amortized Cost	1,318,512
Available for sale securities and Held to maturity securities, Total, Fair Value	1,231,596
U.S. Government Sponsored Enterprise Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, After One, But Within Five Years, Amortized Cost	9,997
Available for sale securities, After One, But Within Five Years, Fair Value	9,350
Available for sale securities, After Five, But Within Ten Years, Amortized Cost	5,000
Available for sale securities, After Five, But Within Ten Years, Fair Value	4,811
Available for sale securities, After Ten Years, Amortized Cost	8,000
Available for sale securities, After Ten Years, Fair Value	7,507
Available for sale securities, Total, Amortized Cost	22,997
Available for sale securities, Total, Fair Value	21,668
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, After One, But Within Five Years, Amortized Cost	9,378
Available for sale securities, After One, But Within Five Years, Fair Value	9,154
Available for sale securities, After Five, But Within Ten Years, Amortized Cost	47,145
Available for sale securities, After Five, But Within Ten Years, Fair Value	43,409
Available for sale securities, After Ten Years, Amortized Cost	121,425
Available for sale securities, After Ten Years, Fair Value	112,216
Available for sale securities, Total, Amortized Cost	177,948
Available for sale securities, Total, Fair Value	164,779
Held to maturity securities, After One, But Within Five Years, Amortized Cost	15,139
Held to maturity securities, After One, But Within Five Years, Fair Value	15,049
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	56,143
Held to maturity securities, After Five, But Within Ten Years, Fair Value	54,324
Held to maturity securities, After Ten Years, Amortized Cost	937,924
Held to maturity securities, After Ten Years, Fair Value	871,709
Held to maturity securities, Amortized Cost	1,009,206
Held to maturity securities, Fair Value	941,082
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Within One Year, Amortized Cost	759
Available for sale securities, Within One Year, Fair Value	753
Available for sale securities, After One, But Within Five Years, Amortized Cost	984
Available for sale securities, After One, But Within Five Years, Fair Value	1,005
Available for sale securities, Total, Amortized Cost	1,743
Available for sale securities, Total, Fair Value	1,758
Held to maturity securities, Within One Year, Amortized Cost	2,498
Held to maturity securities, Within One Year, Fair Value	2,505
Held to maturity securities, Amortized Cost	2,498
Held to maturity securities, Fair Value	2,505
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Within One Year, Amortized Cost	5,302
Held to maturity securities, Within One Year, Fair Value	5,333
Held to maturity securities, After One, But Within Five Years, Amortized Cost	17,858
Held to maturity securities, After One, But Within Five Years, Fair Value	18,077
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	35,973
Held to maturity securities, After Five, But Within Ten Years, Fair Value	36,310
Held to maturity securities, After Ten Years, Amortized Cost	44,987
Held to maturity securities, After Ten Years, Fair Value	40,084
Held to maturity securities, Amortized Cost	104,120	105,081
Held to maturity securities, Fair Value	$ 99,804	$ 108,363

Investment Securities - Summa_2

Investment Securities - Summary of Credit Rating of Debt Securities Portfolio (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		$ 188,205	$ 197,803
Total held to maturity securities		1,115,824	977,061
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total held to maturity securities		104,120	105,081
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		1,758	1,764
Total held to maturity securities		2,498	6,997
U.S. Government Sponsored Enterprise Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		21,668	23,011
AAA/AA/A
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		187,200	196,798
Total held to maturity securities		1,115,824	977,061
AAA/AA/A | Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total held to maturity securities		104,120	105,081
AAA/AA/A | Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		753	759
Total held to maturity securities		2,498	6,997
AAA/AA/A | U.S. Government Sponsored Enterprise Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		21,668	23,011
BBB/BB/B
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		1,005	1,005
Total held to maturity securities			977,061
BBB/BB/B | Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total held to maturity securities			105,081
BBB/BB/B | Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities		1,005	1,005
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities	[1]	164,779	173,028
Total held to maturity securities	[1]	1,009,206	864,983
Mortgage Backed Securities | AAA/AA/A
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Total available for sale securities	[1]	164,779	173,028
Total held to maturity securities	[1]	$ 1,009,206	$ 864,983
[1]	Includes agency mortgage-backed pass-through securities and collateralized mortgage obligations issued by U.S. Government Sponsored Enterprises ("GSEs") and U.S. government agencies, such as FNMA, FHLMC, and GNMA that are not rated by Moody’s or Standard & Poor's. Each security contains a guarantee by the issuing GSE or agency and therefore carries an implicit guarantee of the U.S. government. These have been categorized as AAA/AA/A.

Loans and the Allowance for C_3

Loans and the Allowance for Credit Losses - Loans Outstanding by Category (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 3,417,213	$ 3,319,106
Residential Mortgage
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	8,208	5,936
Total loans	1,447,141	1,415,079
Residential Mortgage | Construction
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	21,722	13,012
Residential Mortgage | Mortgages - Fixed Rate
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	747,716	716,456
Residential Mortgage | Mortgages - Adjustable Rate
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	669,495	679,675
Commercial Mortgage
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	2,124	1,989
Total loans	1,579,494	1,511,002
Commercial Mortgage | Construction
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	89,200	86,246
Commercial Mortgage | Mortgages - Non-owner Occupied
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	1,336,997	1,272,135
Commercial Mortgage | Mortgages - Owner Occupied
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	151,173	150,632
Home Equity
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	313	304
Total loans	86,559	87,960
Home Equity | Home Equity - Lines of Credit
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	84,465	85,639
Home Equity | Home Equity - Term Loans
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	1,781	2,017
Commercial and Industrial
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	248,960	247,024
Unearned fees, net of deferred costs	(151)	(434)
Total loans	262,772	269,446
Commercial and Industrial | PPP Loans
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	13,963	22,856
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	12	8
Total loans	41,247	35,619
Consumer | Secured
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	40,374	34,308
Consumer | Unsecured
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	$ 861	$ 1,303

Loans and the Allowance for C_4

Loans and the Allowance for Credit Losses - Additional Information (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Modifications [Line Items]
Loans remaining in deferral	$ 4,400,000
Commitments to lend additional funds to borrowers whose loans were on non-accrual status	$ 0	$ 0

Loans and the Allowance for C_5

Loans and the Allowance for Credit Losses - Non-performing Loans Disaggregated by Loan Category (Details) - Non-Performing Loans - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	$ 5,206	$ 4,628
Troubled debt restructurings	737	758
Total	5,943	5,386
Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	4,113	3,777
Troubled debt restructurings	636	652
Total	4,749	4,429
Commercial Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	463	517
Total	463	517
Home Equity
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	523	223
Total	523	223
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	107	111
Troubled debt restructurings	101	106
Total	$ 208	$ 217

Loans and the Allowance for C_6

Loans and the Allowance for Credit Losses - Loans Receivable Disaggregated by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Residential Mortgage
Financing Receivable Recorded Investment [Line Items]
2022	$ 86,983	$ 535,071
2021	536,375	329,652
2020	316,012	135,139
2019	129,036	101,438
2018	94,666	77,756
Prior	284,069	236,023
Total	1,447,141	1,415,079
Residential Mortgage | Current
Financing Receivable Recorded Investment [Line Items]
2022	86,983	535,071
2021	536,375	329,501
2020	315,864	135,139
2019	129,036	101,108
2018	94,174	77,702
Prior	279,960	232,129
Total	1,442,392	1,410,650
Residential Mortgage | Non-Performing Loans
Financing Receivable Recorded Investment [Line Items]
2021		151
2020	148
2019		330
2018	492	54
Prior	4,109	3,894
Total	4,749	4,429
Home Equity
Financing Receivable Recorded Investment [Line Items]
2021		719
2020	397	3,311
2019	3,045	4,469
2018	3,791	5,060
Prior	9,850	5,475
Revolving loans amortized cost basis	69,476	68,926
Total	86,559	87,960
Home Equity | Current
Financing Receivable Recorded Investment [Line Items]
2021		719
2020	397	3,088
2019	2,522	4,469
2018	3,791	5,060
Prior	9,850	5,475
Revolving loans amortized cost basis	69,476	68,926
Total	86,036	87,737
Home Equity | Non-Performing Loans
Financing Receivable Recorded Investment [Line Items]
2020		223
2019	523
Total	523	223
Consumer
Financing Receivable Recorded Investment [Line Items]
2022	9,746	14,427
2021	12,043	8,758
2020	7,746	1,544
2019	1,427	3,168
2018	2,640	1,838
Prior	7,144	5,357
Revolving loans amortized cost basis	501	527
Total	41,247	35,619
Consumer | Current
Financing Receivable Recorded Investment [Line Items]
2022	9,746	14,427
2021	12,043	8,758
2020	7,746	1,544
2019	1,427	3,168
2018	2,640	1,838
Prior	7,144	5,357
Revolving loans amortized cost basis	501	527
Total	41,247	35,619
Commercial Mortgage
Financing Receivable Recorded Investment [Line Items]
2022	106,176	319,633
2021	323,625	249,787
2020	240,050	361,068
2019	347,422	180,933
2018	176,014	95,929
Prior	386,207	303,652
Total	1,579,494	1,511,002
Commercial Mortgage | 1-6 (Pass)
Financing Receivable Recorded Investment [Line Items]
2022	106,176	319,633
2021	323,625	248,691
2020	238,962	320,189
2019	301,506	158,462
2018	153,681	93,016
Prior	378,667	298,791
Total	1,502,617	1,438,782
Commercial Mortgage | 7 (Special Mention)
Financing Receivable Recorded Investment [Line Items]
2021		1,096
2020	1,088	40,879
2019	45,916	22,471
2018	22,333	2,913
Prior	6,921	4,131
Total	76,258	71,490
Commercial Mortgage | 8 (Substandard)
Financing Receivable Recorded Investment [Line Items]
Prior	619	730
Total	619	730
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
2022	6,723	83,932
2021	77,875	78,215
2020	76,626	46,153
2019	45,820	35,270
2018	33,830	19,888
Prior	21,514	5,625
Revolving loans amortized cost basis	384	363
Total	262,772	269,446
Commercial and Industrial | 1-6 (Pass)
Financing Receivable Recorded Investment [Line Items]
2022	6,723	83,614
2021	77,584	77,073
2020	75,550	38,299
2019	37,872	34,360
2018	33,322	19,727
Prior	20,795	4,622
Revolving loans amortized cost basis	371	353
Total	252,217	258,048
Commercial and Industrial | 7 (Special Mention)
Financing Receivable Recorded Investment [Line Items]
2022		318
2021	291	350
2020	347	5,523
2019	5,624	406
2018	407	161
Prior	581	859
Revolving loans amortized cost basis	10	10
Total	7,260	7,627
Commercial and Industrial | 8 (Substandard)
Financing Receivable Recorded Investment [Line Items]
2021		792
2020	729	2,331
2019	2,324	504
2018	101
Prior	138	144
Revolving loans amortized cost basis	3
Total	$ 3,295	$ 3,771

Loans and the Allowance for C_7

Loans and the Allowance for Credit Losses - Schedule of Loans Receivable Disaggregated by Past Due Status (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	$ 3,402,229	$ 3,306,858
Total loans	3,417,213	3,319,106
30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	8,712	9,265
60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	5,189	1,495
90 Days or Greater
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	1,083	1,488
Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	14,984	12,248
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	1,438,537	1,404,706
Total loans	1,447,141	1,415,079
Residential Mortgage | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	7,521	8,470
Residential Mortgage | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due		415
Residential Mortgage | 90 Days or Greater
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	1,083	1,488
Residential Mortgage | Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	8,604	10,373
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	1,574,346	1,510,526
Total loans	1,579,494	1,511,002
Commercial Mortgage | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due		476
Commercial Mortgage | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	5,148
Commercial Mortgage | Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	5,148	476
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	85,931	87,003
Total loans	86,559	87,960
Home Equity | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	628	314
Home Equity | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due		643
Home Equity | Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	628	957
Commercial and Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	262,275	269,004
Total loans	262,772	269,446
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	456	5
Commercial and Industrial | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	41	437
Commercial and Industrial | Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	497	442
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	41,140	35,619
Total loans	41,247	$ 35,619
Consumer | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	107
Consumer | Total Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Principal Balance/Past Due	$ 107

Loans and the Allowance for C_8

Loans and the Allowance for Credit Losses - Summary of Changes in Allowance for Credit Losses Disaggregated by Loan Category (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Provision for (Release of) credit losses - unfunded commitments	$ (412)	$ (206)
Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	34,496	36,016
Charge-offs	(25)	(3)
Recoveries	38	23
Provision for (release of) credit losses - loan portfolio	(399)	(390)
Allowance for credit losses-loan portfolio, Ending Balance	34,110	35,646
Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	1,384	1,004
Provision for (Release of) credit losses - unfunded commitments	(13)	184
Allowance for credit losses-unfunded commitments	1,371	1,188
Allowance for credit losses-loan portfolio, Ending Balance	35,481	36,834
Residential Mortgage | Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	13,383	13,067
Provision for (release of) credit losses - loan portfolio	(190)	77
Allowance for credit losses-loan portfolio, Ending Balance	13,193	13,144
Residential Mortgage | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Ending Balance	13,193	13,144
Commercial Mortgage | Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	17,133	18,564
Provision for (release of) credit losses - loan portfolio	5	129
Allowance for credit losses-loan portfolio, Ending Balance	17,138	18,693
Commercial Mortgage | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Ending Balance	17,138	18,693
Home Equity | Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	406	552
Provision for (release of) credit losses - loan portfolio	(29)	(189)
Allowance for credit losses-loan portfolio, Ending Balance	377	363
Home Equity | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Ending Balance	377	363
Commercial & Industrial | Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	2,989	3,309
Recoveries	36	19
Provision for (release of) credit losses - loan portfolio	(128)	(350)
Allowance for credit losses-loan portfolio, Ending Balance	2,897	2,978
Commercial & Industrial | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Ending Balance	2,897	2,978
Consumer | Funded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	585	524
Charge-offs	(25)	(3)
Recoveries	2	4
Provision for (release of) credit losses - loan portfolio	(57)	(57)
Allowance for credit losses-loan portfolio, Ending Balance	505	468
Consumer | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Ending Balance	505	468
Unfunded Commitments | Unfunded Commitments
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for credit losses-loan portfolio, Beginning Balance	1,384	1,004
Provision for (Release of) credit losses - unfunded commitments	(13)	184
Allowance for credit losses-unfunded commitments	1,371	1,188
Allowance for credit losses-loan portfolio, Ending Balance	$ 1,371	$ 1,188

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Effective tax rate	25.00%	26.00%
Net deferred tax assets	$ 10,460,000		$ 9,985,000
Deferred tax assets, valuation allowance	$ 0		$ 0

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Current income tax expense
Federal	$ 1,095	$ 2,091
State	389	922
Total current income tax expense	1,484	3,013
Deferred income tax expense
Federal	2,025	1,182
State	935	548
Total deferred income tax expense	2,960	1,730
Total income tax expense	$ 4,444	$ 4,743

Pension and Retirement Plans -

Pension and Retirement Plans - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Plan
Net periodic benefit cost (credit)
Interest cost	$ 310	$ 303
Expected return on assets	(936)	(892)
Amortization of prior service credit		(1)
Net periodic benefit cost (credit)	(626)	(590)
Supplemental Retirement Plan
Net periodic benefit cost (credit)
Service cost	101	106
Interest cost	59	57
Amortization of net actuarial loss		11
Net periodic benefit cost (credit)	160	174
Postretirement Healthcare Plan
Net periodic benefit cost (credit)
Service cost	8	9
Interest cost	5	4
Net periodic benefit cost (credit)	$ 13	$ 13

Pension and Retirement Plans _2

Pension and Retirement Plans - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2022
Profit Sharing Plan | 401(k)
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, maximum employee contribution, percent	100.00%
Profit Sharing Plan | 401(k) | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent	4.00%
Profit Sharing Plan | Discretionary Contribution
Defined Benefit Plan Disclosure [Line Items]
Normal retirement age of employees	65 years
Employee Stock Ownership Plan (ESOP)
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, minimum service period required for eligibility	12 months
Defined contribution plan, minimum number of hours of service per year required for eligibility	1000 hours
Employee Stock Ownership Plan (ESOP) | Minimum
Defined Benefit Plan Disclosure [Line Items]
Employee eligibility age under the plan	21 years
Profit Sharing and ESOP Plans
Defined Benefit Plan Disclosure [Line Items]
Contribution expense related to plans	$ 1,300,000	$ 1,100,000
Defined Contribution Supplemental Executive Retirement Plan ("DC SERP")
Defined Benefit Plan Disclosure [Line Items]
Contribution expense related to plans	$ 68,000	$ 50,000
Defined Contribution Supplemental Executive Retirement Plan ("DC SERP") | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent	10.00%
Qualified Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	$ 0
Qualified Defined Benefit Pension Plan | Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan			$ 0

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Shares Issued and Fair Value of RSAs and RSUs (Details) - 2017 Equity and Cash Incentive Plan	3 Months Ended
	Mar. 31, 2022$ / sharesshares
RSAs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Granted | shares	11,924
Weighted Average Fair Value at Grant Date | $ / shares	$ 87
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Granted | shares	8,796
Weighted Average Fair Value at Grant Date | $ / shares	$ 88.18

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - $ / shares	Feb. 15, 2022	Mar. 31, 2022
Restricted Stock | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options time-vest period		3 years
Restricted Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options time-vest period		5 years
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options time-vest period		3 years
Performance-Based Restricted Stock Units | 2017 Cash Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance-based restricted stock units performance period	3 years
Restricted stock units granted grant date fair value	$ 88.18
Restricted stock units granted	30,895

Stock Based Compensation - Sc_2

Stock Based Compensation - Schedule of Pre-tax Expense Associated with All Outstanding Non-vested RSAs, RSUs, Performance Based Restricted Stock Units and Related Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Payment Arrangement, Noncash Expense [Abstract]
Share based compensation expense	$ 648	$ 1,375
Related tax benefits	$ 181	$ 384

Financial Instruments with Of_3

Financial Instruments with Off-Balance-Sheet Risk - Summary of Off-Balance-Sheet Financial Instruments with Contractual Amounts Include Present Credit Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Standby Letters of Credit
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	$ 19,346	$ 18,880
Unused Portion of Existing Lines of Credit
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	823,005	809,383
Origination of New Loans
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	75,785	70,633
Commitments to Sell Residential Mortgage Loans
Financial instruments whose notional amount exceeds the amount of credit risk:
Financial instrument notional amount exceeds credit risk	$ 720	$ 3,920

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Leases [Abstract]
Description of operating lease expiration terms	operating leases and their terms expire between 2023 and 2032 and, in some instances, contain options to renew for periods up to
Renewal option period for operating leases	30 years
Existence of option to expire	true
Total rental expense	$ 1.8	$ 1.9

Leases - Summary of Components

Leases - Summary of Components of Operating Lease Cost and Other Related Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Leases [Abstract]
Operating lease cost	$ 1,744	$ 1,768
Variable lease cost (Cost excluded from lease payments)	1
Sublease income	(16)	(16)
Total Operating Lease Cost	1,729	1,752
Other Information
Cash paid for amounts included in the measurement of lease liabilities - operating cash flows for operating leases	1,833	1,854
Operating Lease - Operating cash flows (Liability reduction)	$ 1,606	$ 1,597
Weighted average lease term - operating leases	5 years 11 months 15 days	6 years 8 months 26 days
Weighted average discount rate - operating leases	2.95%	3.00%

Leases - Schedule of Total Mini

Leases - Schedule of Total Minimum Lease Payments Due in Future Periods for Lease Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2022	$ 7,144
2023	6,735
2024	5,739
2025	4,982
2026	3,254
Thereafter	7,399
Total minimum lease payments	35,253
Less: interest	(2,982)
Total lease liability	$ 32,271	$ 33,871

Shareholders' Equity - Minimum

Shareholders' Equity - Minimum Capital Requirements were Considered Well Capitalized by FRB and FDIC (Details)	Mar. 31, 2022USD ($)	Dec. 31, 2021USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 428,313,000	$ 420,398,000
Tier I capital (to risk-weighted assets), Actual, Amount	392,831,000	384,518,000
Common equity tier I capital (to risk-weighted assets), Actual, Amount	392,831,000	384,518,000
Tier I capital (to average assets), Actual, Amount	$ 392,831,000	$ 384,518,000
Total capital (to risk-weighted assets), Actual, Ratio	0.135	0.136
Tier I capital (to risk-weighted assets), Actual, Ratio	0.124	0.124
Common equity tier I capital (to risk-weighted assets), Actual, Ratio	0.124	0.124
Tier I capital (to average assets), Actual, Ratio	0.080	0.083
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	$ 332,832,000	$ 325,617,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	269,435,000	263,595,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	221,888,000	217,078,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	$ 196,394,000	$ 185,015,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.105	0.105
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.085	0.085
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.070	0.070
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.040	0.040
Cambridge Trust Company
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 412,721,000	$ 409,806,000
Tier I capital (to risk-weighted assets), Actual, Amount	377,239,000	373,926,000
Common equity tier I capital (to risk-weighted assets), Actual, Amount	377,239,000	373,926,000
Tier I capital (to average assets), Actual, Amount	$ 377,239,000	$ 373,926,000
Total capital (to risk-weighted assets), Actual, Ratio	0.130	0.132
Tier I capital (to risk-weighted assets), Actual, Ratio	0.119	0.121
Common equity tier I capital (to risk-weighted assets), Actual, Ratio	0.119	0.121
Tier I capital (to average assets), Actual, Ratio	0.077	0.081
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	$ 332,802,000	$ 325,587,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	269,411,000	263,570,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	221,868,000	217,058,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Amount	$ 196,383,000	$ 185,003,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.105	0.105
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.085	0.085
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.070	0.070
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer, Ratio	0.040	0.040
Cambridge Trust Company | Minimum
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 316,954,000	$ 310,082,000
Tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	253,563,000	248,066,000
Common equity tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	206,020,000	201,554,000
Tier I capital (to average assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 245,479,000	$ 231,254,000
Total capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.100	0.100
Tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.080	0.080
Common equity tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.065	0.065
Tier I capital (to average assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	0.050	0.050

Other Comprehensive Loss - Summ

Other Comprehensive Loss - Summary of Accumulated Other Comprehensive loss ("AOCL") (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Available for sale securities, before tax amount
Unrealized holding losses, before tax amount	$ (11,016)	$ (3,923)
Interest rate swaps designated as cash flow hedges, before tax amount
Unrealized holding losses, before tax amount	(1,700)	(447)
Reclassification adjustment for losses recognized in net income, before tax amount	(614)	(630)
Defined benefit retirement plans, before tax amount
Net change in retirement liability, before tax amount		11
Total other comprehensive income/(loss), before tax amount	(13,330)	(4,989)
Available for sale securities, tax (expense) or benefit
Unrealized holding losses, tax (expense) or benefit	2,789	1,036
Interest rate swaps designated as cash flow hedges, tax (expense) or benefit
Unrealized holding losses, tax (expense) or benefit	474	125
Reclassification adjustment for (losses) gains recognized in net income, tax (expense) or benefit	173	176
Defined benefit retirement plans, tax (expense) or benefit
Net change in retirement liability, tax (expense) or benefit		(3)
Total other comprehensive income/(loss), tax (expense) or benefit	3,436	1,334
Available for sale securities
Unrealized holding losses, net-of-tax amount	(8,227)	(2,887)
Interest rate swaps designated as cash flow hedges
Unrealized holding losses, net-of-tax amount	(1,226)	(322)
Reclassification adjustment for (losses) gains realized in net income	(441)	(454)
Defined benefit retirement plans
Change in retirement liabilities		8
Other comprehensive loss	$ (9,894)	$ (3,655)

Other Comprehensive Loss - Su_2

Other Comprehensive Loss - Summary of Reclassifications out of Accumulated Other Comprehensive Loss ("AOCL") (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Loss [Line Items]
Tax expense	$ (4,444)	$ (4,743)
Net income	13,316	13,499
Reclassifications out of Accumulated Other Comprehensive Loss
Reclassification Adjustment Out Of Accumulated Other Comprehensive Loss [Line Items]
Unrealized gains on derivatives	614	630
Tax expense	(173)	(176)
Net income	$ 441	$ 454

Earnings Per Share - Summary of

Earnings Per Share - Summary of Reconciliation Between Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income	$ 13,316	$ 13,499
Less dividends and undistributed earnings allocated to participating securities	(59)	(57)
Net income applicable to common shareholders	$ 13,257	$ 13,442
Denominator:
Weighted average number of shares outstanding, basic	6,948,040	6,907,861
Earnings per common share - basic	$ 1.91	$ 1.95
Numerator:
Net income	$ 13,316	$ 13,499
Less dividends and undistributed earnings allocated to participating securities	(59)	(57)
Net income applicable to common shareholders	$ 13,257	$ 13,442
Denominator:
Weighted average number of shares outstanding, basic	6,948,040	6,907,861
Dilutive effect of common stock equivalents	63,000	79,000
Weighted average diluted common shares outstanding	7,010,983	6,987,216
Earnings per common share - diluted	$ 1.89	$ 1.92

Derivative And Hedging Activi_3

Derivative And Hedging Activities - Summary of Fair Values of Derivative Instruments in the Company's Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	$ 24,319	$ 27,051
Derivative Liabilities, Fair value	23,296	23,724
Derivatives Designated as Hedging Instruments
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	1,133	3,513
Derivatives Designated as Hedging Instruments | Interest Rate Contracts
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Notional amount	150,000	150,000
Derivatives Designated as Hedging Instruments | Interest Rate Contracts | Other Assets
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	1,133	3,513
Derivatives Not Designated as Hedging Instruments
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	23,186	23,538
Derivative Liabilities, Fair value	23,296	23,724
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Interest Rate Swaps with Customers
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Notional amount	193,561	522,581
Derivative Liabilities, Notional Amount	330,101
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Interest Rate Swaps with Customers | Other Assets
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	4,949	23,431
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Interest Rate Swaps with Customers | Other Liabilities
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Liabilities, Fair value	18,161
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Mirror Swaps with Counterparties
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Notional amount	330,101
Derivative Liabilities, Notional Amount	193,561	522,581
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Mirror Swaps with Counterparties | Other Assets
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	18,161
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Mirror Swaps with Counterparties | Other Liabilities
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Liabilities, Fair value	4,949	23,431
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Risk Participation Agreements Out to Counterparties
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Notional amount	47,696	47,988
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Risk Participation Agreements Out to Counterparties | Other Assets
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	76	107
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Risk Participation Agreements with Counterparties
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Liabilities, Notional Amount	109,082	109,510
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Risk Participation Agreements with Counterparties | Other Liabilities
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Liabilities, Fair value	$ 186	$ 293

Derivative And Hedging Activi_4

Derivative And Hedging Activities - Summary of Changes to AOCL as a Result of Cash Flow Hedge Accounting (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Interest Income
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Reclassified from AOCL into Income	$ 614	$ 630
Amount of Gain or (Loss) Reclassified from AOCL into Income Included Component	662	678
Amount of Gain or (Loss) Reclassified from AOCL into Income Excluded Component	(48)	(48)
Interest Rate Contracts
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in OCI	(2,314)	(1,077)
Amount of Gain or (Loss) Recognized in OCI - Included Component	(2,528)	(1,156)
Amount of Gain or (Loss) Recognized in OCI - Excluded Component	$ 214	$ 79

Derivative And Hedging Activi_5

Derivative And Hedging Activities - Additional Information (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Estimated amount will be reclassified out of AOCL into earnings	$ 371,000
Fair value of derivative liability	23,296,000	$ 23,724,000
Minimum collateral posting threshold of derivative counterparties	0	13,300,000
Termination amount		14,000,000
Minimum
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Minimum collateral posting threshold of derivative counterparties		13,300,000
Accrued Interest
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Fair value of derivative liability	$ 0	$ 14,000,000

Derivative And Hedging Activi_6

Derivative And Hedging Activities - Summary of Derivative Financial Instruments Not Designated as Hedging Instruments on the Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Other contracts | Loan related derivative income | Derivatives Not Designated as Hedging Instruments
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (77)	$ 206

Derivative And Hedging Activi_7

Derivative And Hedging Activities - Schedule of Financial Instruments Eligible for Offset in Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Offsetting [Abstract]
Gross Amounts Recognized, Derivative assets	$ 24,319	$ 27,051
Net Amounts Recognized, Derivative Assets	24,319	27,051
Gross Amounts Not Offset, Financial Instruments, Derivative Assets	4,950	6,365
Gross Amounts Not Offset, Collateral Pledged (Received), Derivative Assets	(14,048)
Gross Amounts Not Offset, Net amount, Derivative Assets	5,321	20,686
Gross Amounts Recognized, Derivative Liabilities	23,296	23,724
Net Amounts Recognized, Derivative Liabilities	23,296	23,724
Gross Amounts Not Offset, Financial Instruments, Derivative Liabilities	4,950	6,365
Gross Amounts Not Offset, Collateral Pledged (Received), Derivative Liabilities		14,011
Gross Amounts Not Offset, Net amount, Derivative Liabilities	$ 18,346	$ 3,348

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial assets
Securities available for sale	$ 188,205	$ 197,803
Securities held to maturity	1,043,391	971,092
FHLB of Boston stock	4,816	4,816
Recurring Basis | Carrying Value
Financial assets
Cash and cash equivalents	81,748	180,153
Securities available for sale	188,205	197,803
Securities held to maturity	1,115,824	977,061
Loans, net	3,383,103	3,284,610
Loans held for sale	918	1,490
FHLB of Boston stock	4,816	4,816
Accrued interest receivable	9,718	9,162
Mortgage servicing rights	1,063	1,083
Interest rate contracts	1,133	3,513
Loan level interest rate swaps	23,110	23,431
Risk participation agreements out to counterparties	76	107
Financial liabilities
Deposits	4,473,735	4,331,152
Borrowings	16,140	16,510
Loan level interest rate swaps	23,110	23,431
Risk participation agreements in with counterparties	186	293
Recurring Basis | Estimated Fair Value
Financial assets
Cash and cash equivalents	81,748	180,153
Securities available for sale	188,205	197,803
Securities held to maturity	1,043,391	971,092
Loans, net	3,317,481	3,230,339
Loans held for sale	918	1,528
FHLB of Boston stock	4,816	4,816
Accrued interest receivable	9,718	9,162
Mortgage servicing rights	1,602	1,518
Interest rate contracts	1,133	3,513
Loan level interest rate swaps	23,110	23,431
Risk participation agreements out to counterparties	76	107
Financial liabilities
Deposits	4,472,404	4,330,991
Borrowings	16,144	16,523
Loan level interest rate swaps	23,110	23,431
Risk participation agreements in with counterparties	$ 186	$ 293

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Certain Assets and Liabilities Reported at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	$ 188,205	$ 197,803
U.S. GSE Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	21,668	23,011
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	1,758	1,764
Recurring Basis | U.S. GSE Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	21,668	23,011
Recurring Basis | U.S. GSE Obligations | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	21,668	23,011
Recurring Basis | Mortgage Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	164,779	173,028
Recurring Basis | Mortgage Backed Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	164,779	173,028
Recurring Basis | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	1,758	1,764
Recurring Basis | Corporate Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	1,758	1,764
Recurring Basis | Interest Rate Swaps with Customers
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	4,949	23,431
Other liabilities	18,161
Recurring Basis | Interest Rate Swaps with Customers | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	4,949	23,431
Other liabilities	18,161
Recurring Basis | Risk Participation Agreements Out to Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	76	107
Recurring Basis | Risk Participation Agreements Out to Counterparties | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	76	107
Recurring Basis | Interest Rate Contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	1,133	3,513
Recurring Basis | Interest Rate Contracts | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	1,133	3,513
Recurring Basis | Mirror Swaps with Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	18,161
Other liabilities	4,949	23,431
Recurring Basis | Mirror Swaps with Counterparties | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	18,161
Other liabilities	4,949	23,431
Recurring Basis | Risk Participation Agreements in With Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	186	293
Recurring Basis | Risk Participation Agreements in With Counterparties | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	$ 186	$ 293

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Carrying Value of Assets Measured at Fair Value on a Non-Recurring Basis (Details) - Non-recurring - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	$ 101	$ 1,620
Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis		1,490
Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	101	130
Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis		1,490
Loans Held for Sale | Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis		1,490
Individually Evaluated Collateral Dependent Loans
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	101	130
Individually Evaluated Collateral Dependent Loans | Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	$ 101	$ 130

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Transfers between levels	$ 0	$ 0

Mergers - Additional Informatio

Mergers - Additional Information (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill	$ 51,912	$ 51,912