Cambridge Bancorp (CATC) 10-Q 8 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
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		4,851,047
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-38184
Entity Tax Identification Number	042777442
Entity Address, Address Line One	1336 Massachusetts Avenue
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02138
City Area Code	(617)
Local Phone Number	876-5500

CONSOLIDATED BALANCE SHEETS (UN

CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 38,557,000	$ 18,473,000
Investment securities
Available for sale, at fair value (amortized cost $153,765 and $172,290, respectively)	153,053,000	168,163,000
Held to maturity, at amortized cost (fair value $291,993 and $281,310, respectively)	286,350,000	282,869,000
Total investment securities	439,403,000	451,032,000
Loans held for sale, at lower of cost or fair value	384,000
Loans
Residential mortgage	938,559,000	604,331,000
Commercial mortgage	905,442,000	757,957,000
Home equity	85,814,000	69,336,000
Commercial & Industrial	134,307,000	93,712,000
Consumer	32,428,000	34,436,000
Total loans	2,096,550,000	1,559,772,000
Less: allowance for loan losses	(17,099,000)	(16,768,000)
Net loans	2,079,451,000	1,543,004,000
Federal Home Loan Bank of Boston Stock, at cost	8,245,000	6,844,000
Bank owned life insurance	36,996,000	30,933,000
Banking premises and equipment, net	14,863,000	8,578,000
Deferred income taxes, net	7,267,000	8,717,000
Accrued interest receivable	7,485,000	5,762,000
Goodwill	31,206,000	412,000
Merger related intangibles	3,519,000
Other assets	73,932,000	27,629,000
Total assets	2,741,308,000	2,101,384,000
Deposits
Demand	587,030,000	494,492,000
Interest bearing checking	422,426,000	431,702,000
Money market	200,935,000	135,585,000
Savings	853,356,000	628,212,000
Certificates of deposit	265,918,000	121,419,000
Total deposits	2,329,665,000	1,811,410,000
Short-term borrowings	103,000,000	90,000,000
Long-term borrowings	3,323,000	3,409,000
Other liabilities	68,226,000	29,539,000
Total liabilities	2,504,214,000	1,934,358,000
Shareholders’ Equity
Common stock, par value $1.00; Authorized 10,000,000 shares; Outstanding: 4,850,230 shares and 4,107,051 shares, respectively	4,850,000	4,107,000
Additional paid-in capital	97,844,000	38,271,000
Retained earnings	137,036,000	131,135,000
Accumulated other comprehensive loss	(2,636,000)	(6,487,000)
Total shareholders’ equity	237,094,000	167,026,000
Total liabilities and shareholders’ equity	$ 2,741,308,000	$ 2,101,384,000

CONSOLIDATED BALANCE SHEETS (_2

CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Available for sale securities, amortized cost	$ 153,765	$ 172,290
Held-to-maturity securities, fair value	$ 291,993	$ 281,310
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares, outstanding	4,850,230	4,107,051

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest and dividend income
Interest on taxable loans	$ 21,355	$ 14,132	$ 37,639	$ 27,510
Interest on tax-exempt loans	124	92	213	188
Interest on taxable investment securities	2,116	1,920	4,096	3,634
Interest on tax-exempt investment securities	575	604	1,146	1,226
Dividends on FHLB of Boston stock	81	58	157	109
Interest on overnight investments	219	130	337	401
Total interest and dividend income	24,470	16,936	43,588	33,068
Interest expense
Interest on deposits	4,379	1,053	6,880	2,015
Interest on borrowed funds	315	29	671	46
Total interest expense	4,694	1,082	7,551	2,061
Net interest and dividend income	19,776	15,854	36,037	31,007
Provision for (Release of) Loan Losses	596	(79)	503	330
Net interest and dividend income after provision for loan losses	19,180	15,933	35,534	30,677
Noninterest income
Bank owned life insurance income	162	136	289	264
Gain (loss) on disposition of investment securities	6	2	(81)	2
Gain on loans held for sale	15	18	31	45
Loan related derivative income	5	112	441	584
Other income	316	353	643	757
Total noninterest income	8,145	7,844	16,102	16,022
Noninterest expense
Salaries and employee benefits	11,459	10,443	22,286	20,516
Occupancy and equipment	2,691	2,219	5,021	4,446
Data processing	1,534	1,289	2,880	2,519
Professional services	760	829	1,567	1,716
Marketing	508	336	912	774
FDIC insurance	278	135	278	286
Merger expenses	3,450		3,541
Other expenses	833	514	1,401	1,009
Total noninterest expense	21,513	15,765	37,886	31,266
Income before income taxes	5,812	8,012	13,750	15,433
Income tax expense	1,540	1,901	3,280	3,517
Net income	$ 4,272	$ 6,111	$ 10,470	$ 11,916
Share data:
Weighted average number of shares outstanding, basic	4,682,109	4,059,927	4,379,141	4,057,156
Weighted average number of shares outstanding, diluted	4,715,724	4,094,489	4,412,239	4,087,790
Basic earnings per share	$ 0.91	$ 1.49	$ 2.37	$ 2.91
Diluted earnings per share	$ 0.90	$ 1.48	$ 2.35	$ 2.89
Wealth Management Revenue
Noninterest income
Noninterest income	$ 6,419	$ 6,139	$ 12,543	$ 12,265
Deposit Account Fees
Noninterest income
Noninterest income	843	774	1,581	1,524
ATM/Debit Card Income
Noninterest income
Noninterest income	$ 379	$ 310	$ 655	$ 581

UNAUDITED CONSOLIDATED STATEMEN

UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,272	$ 6,111	$ 10,470	$ 11,916
Unrealized gains/(losses) on available for sale securities
Unrealized holding gains/(losses) arising during period	1,453	(423)	2,548	(1,775)
Less: reclassification adjustment for losses/(gains) included in net income	(4)	(2)	62	(2)
Total unrealized gains/(losses) on securities	1,449	(425)	2,610	(1,777)
Derivatives
Change in interest rate contracts	1,219		1,189
Defined benefit retirement plans
Change in retirement liabilities	26	10	52	20
Other comprehensive income/(loss)	2,694	(415)	3,851	(1,757)
Comprehensive income	$ 6,966	$ 5,696	$ 14,321	$ 10,159

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS EQUITY' (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2017	$ 147,957	$ 4,082	$ 35,663	$ 114,093	$ (5,881)
Cumulative effect of accounting changes				1,202	(1,202)
Net income	11,916			11,916
Other comprehensive income (loss)	(1,757)				(1,757)
Share based compensation	1,511	22	1,489
Dividends declared	(3,935)			(3,935)
Ending balance at Jun. 30, 2018	155,692	4,104	37,152	123,276	(8,840)
Beginning balance at Mar. 31, 2018	150,873	4,101	36,065	119,196	(8,489)
Cumulative effect of accounting changes				(64)	64
Net income	6,111			6,111
Other comprehensive income (loss)	(415)				(415)
Share based compensation	1,090	3	1,087
Dividends declared	(1,967)			(1,967)
Ending balance at Jun. 30, 2018	155,692	4,104	37,152	123,276	(8,840)
Beginning balance at Dec. 31, 2018	167,026	4,107	38,271	131,135	(6,487)
Net income	10,470			10,470
Other comprehensive income (loss)	3,851				3,851
Share based compensation	899	20	879
Dividends declared	(4,569)			(4,569)
Common stock issued for merger	59,417	723	58,694
Ending balance at Jun. 30, 2019	237,094	4,850	97,844	137,036	(2,636)
Beginning balance at Mar. 31, 2019	172,268	4,124	38,239	135,235	(5,330)
Net income	4,272			4,272
Other comprehensive income (loss)	2,694				2,694
Share based compensation	914	3	911
Dividends declared	(2,471)			(2,471)
Common stock issued for merger	59,417	723	58,694
Ending balance at Jun. 30, 2019	$ 237,094	$ 4,850	$ 97,844	$ 137,036	$ (2,636)

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retained Earnings
Dividends declared, per share	$ 0.51	$ 0.48	$ 1.02	$ 0.96

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 10,470	$ 11,916
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	503	330
Amortization of deferred charges and fees, net	255	459
Net (Accretion)/Amortization of merger-related intangibles	(247)
Depreciation and amortization	881	919
Bank owned life insurance income	(289)	(264)
Loss/(gain) on disposition of investment securities	81	(2)
Share based compensation	899	1,511
Change in accrued interest receivable	(595)	(151)
Deferred income tax (benefit)/expense	885	350
Change in other assets, net	(5,860)	(6,247)
Change in other liabilities, net	774	1,302
Change in loans held for sale	(384)	(566)
Net cash provided by operating activities	7,373	9,557
CASH FLOWS FROM INVESTING ACTIVITIES
Origination of loans	(273,385)	(245,108)
Proceeds from principal payments of loans	212,719	194,855
Proceeds from calls/maturities of securities available for sale	13,876	10,770
Proceeds from sales of securities available for sale	26,150	702
Proceeds from calls/maturities of securities held to maturity	32,216	17,200
Purchase of securities held to maturity	(35,958)	(64,960)
Proceeds from settlement of bank owned life insurance policies		676
Redemption (purchase) of FHLB of Boston stock	65	(271)
Purchase of banking premises and equipment	(880)	(726)
Net cash acquired in business combinations	2,063
Net cash (used in) provided by investing activities	(23,134)	(86,862)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in demand, interest bearing, money market and savings accounts	59,049	35,461
Change in certificates of deposit	(18,090)	(22,608)
Change in short-term borrowings	(459)
Repayment of long-term borrowings	(86)	(85)
Cash dividends paid on common stock	(4,569)	(3,935)
Net cash provided by (used in) financing activities	35,845	8,833
Net (decrease)/increase in cash and cash equivalents	20,084	(68,472)
Cash and cash equivalents at beginning of period	18,473	103,591
Cash and cash equivalents at end of period	38,557	35,119
Cash paid during the period for:
Interest	7,719	2,074
Income taxes	4,060	$ 4,160
Significant non-cash transactions
Right-of-use assets obtained in exchange for lessee operating lease liabilities	37,550
Other real estate owned	185
Common Stock issued to Optima shareholders	59,417
Fair value of assets acquired, net of cash acquired	548,801
Fair value of liabilities assumed	$ 491,447

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2019
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. We are a private bank offering a full range of private banking and wealth management services to our 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 June 30, 2019 and December 31, 2018, respectively, and the results of operations and cash flows for the interim periods presented in accordance with U.S. generally accepted accounting principles (“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, 2018, filed with the Securities and Exchange Commission.

Use of Estimates

Use of Estimates	6 Months Ended
	Jun. 30, 2019
Use Of Estimates [Abstract]
Use of Estimates	2. Use of Estimates The preparation of 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 financial statements. Actual results could differ from those estimates. The allowance for loan losses and the valuation of deferred tax assets are particularly subject to change.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	3. Subsequent Events Management has reviewed events occurring through August 8, 2019, the date the unaudited consolidated financial statements were available to be issued, and determined that no other subsequent events occurred requiring adjustment to or disclosure in these financial statements.

Mergers

Mergers	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Mergers	4. Mergers Optima Bank & Trust Company The Company completed its merger with Optima Bank & Trust Company (“Optima”) on April 17, 2019. Under the terms of the Agreement and Plan of Merger (the “Merger Agreement”), each outstanding share of Optima common stock was converted into $32.00 in cash or 0.3468 shares of the Company’s common stock, with the transaction structured as 95 percent common stock and 5 percent cash. As a result of the merger, former Optima shareholders received an aggregate of approximately 722,746 shares of the Company’s common stock and an aggregate of approximately $3.5 million in cash. The total consideration paid amounted to $64.3 million. The Company accounted for the merger using the acquisition method pursuant to the Business Combinations Topic of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”). Accordingly, the Company recorded merger expenses during the three months and six months ended June 30, 2019 of approximately $3.5 million. Additionally, the acquisition method requires the acquirer to recognize the assets acquired and the liabilities assumed at their fair values as of the acquisition date. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed as of the date of the acquisition: Net Assets Acquired at Fair Value (dollars in thousands) Assets Cash and cash equivalents $ 6,902 Investments 23,298 Loans 475,406 Premises and equipment 6,286 Goodwill 30,794 Core deposit and other intangibles 3,609 Other assets 9,408 Total assets acquired 555,703 Liabilities Deposits 477,189 Borrowings 13,459 Other liabilities 799 Total liabilities assumed 491,447 Purchase price $ 64,256 Fair value adjustments to assets acquired and liabilities assumed are generally amortized using either an effective yield or straight-line basis over periods consistent with the average life, useful life, and/or contractual term of the related assets and liabilities. Fair values of the major categories of assets acquired and liabilities assumed were determined as follows: Cash and Cash Equivalents The fair values of cash and cash equivalents approximate the respective carrying amounts because the instruments are payable on demand or have short-term maturities. Investments The fair values of securities were based on quoted market prices for identical securities received from an independent, nationally-recognized, third-party pricing service. Prices provided by the independent pricing service were based on recent trading activity and other observable information including, but not limited to, market interest rate curves, referenced credit spreads, and estimated prepayment rates where applicable. Loans The loans acquired were recorded at fair value without a carryover of the allowance for loan losses. Fair value of the loans portfolio is determined using market participant assumptions in estimating the amount and timing of both principal and interest cash flows expected to be collected, as adjusted for an estimate of future credit losses and prepayments, and then applying a market-based discount rate to those cash flows. The overall discount on the loans acquired in this transaction was due to anticipated credit loss, as well as considerations for liquidity and market interest rates. Premises and Equipment The fair value of the premises, including buildings and improvements, was determined based upon appraisals by licensed real estate appraisers. The appraisals were based upon the best and highest use of the property with final values determined based upon an analysis of the cost, sales comparison, and income capitalization approaches for each property appraised. Core Deposit Intangible The fair value of the core deposit intangible is derived by comparing the interest rate and servicing costs that the financial institution pays on the core deposit liability versus the current market rate for alternative sources of financing, while factoring in estimates over the remaining life and attrition rate of the deposit accounts. The intangible asset represents the stable and relatively low cost source of funds that the deposits and accompanying relationships provide the Company, when compared to alternative funding sources. Deposits The fair value of acquired savings and transaction deposit accounts was assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. The fair value of time deposits were determined based on the present value of the contractual cash flows over the remaining period to maturity using a market interest rate. Borrowings Federal Home Loan Bank (“FHLB”) borrowings were recorded at their carrying value which approximates fair value. Selected Pro Forma Results The following summarizes the unaudited pro forma results of operations as if the Company merged with Optima on January 1, 2019 (2018 amounts represent combined results for the Company and Optima). The selected pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the financial results of the combined companies had the acquisition actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full-year Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Net interest and dividend income after provision for loan losses $ 19,780 $ 19,364 $ 39,776 $ 37,737 Net Income 8,075 6,646 14,988 13,207 Excluded from the pro forma results of operations for the three months and six months ended June 30, 2019 are merger-related costs of approximately $3.5 million recognized by the Company. These costs were primarily made up of contract terminations arising due to the change in control, the acceleration of certain compensation and benefit costs, and other merger expenses.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Guidance	6 Months Ended
	Jun. 30, 2019
New Accounting Pronouncements And Changes In Accounting Principles [Abstract]
Recently Issued and Adopted Accounting Guidance	5. Recently Issued and Adopted Accounting Guidance Accounting Standards Update 2018-16 - Inclusion of the Secured Overnight Financing Rate (“SOFR”) Overnight Index Swap (“OIS”) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities Accounting Standards Update 2018-15 - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . Accounting Standards Update 2018-14 - Changes to the Disclosure Requirements for Defined Benefit Plans . Accounting Standards Update 2018-13 - Changes to the Disclosure Requirements for Fair Value Measurement . Accounting Standards Update 2018-07 - Improvements to Nonemployee Share-Based Payment Accounting Revenue from Contracts with Customers Accounting Standard Update No. Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities h is s e e s ta da r a a l l o c p a i e b t a l i e i e g a c c o n t i n a r i s a n a e ac t i v i t i es d c c o s a c m l e x i t a p l y i h d g a c c o n t i n T s ta d a r r q i r e c p a n i e c h a n h r c o n i t i a r s n t a t i o o t f c t h d g a c c o n ti b y • e li m i n a ti t q u i r e t s e a r a t l m a s r a p e g i e ff e c ti v n s s a n • re q i r i c m t p e s n a h l m n e a c o n i n a a e c e a a i n c m s t a e l i e d e i The standard also permits hedge accounting for strategies for which hedge accounting was not historically permitted and includes new alternatives for measuring the hedged item for fair value hedges of interest rate risk. Furthermore, the standard eases the requirements for effectiveness testing, hedge documentation, applying the critical terms match method, and introduces new alternatives that will permit companies to reduce the risk of material error corrections if they misapply the shortcut method. The new accounting standard was effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The new standard requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. The Company early adopted the standard during the fourth quarter of 2018, using a modified retrospective transition method, and it did not have an effect on our consolidated balance sheets, statements of income, and cash flows. See note 18 – DERIVATIVE AND HEDGING ACTIVITIES. Accounting Standards Update No. 2016-13 - Financial Instruments - Measurement of Credit Losses on Financial Instruments Accounting Standards Update No. 2016-02 - Leases Accounting Standards Update No. 2014-09 - Revenue from Contracts with Customers On January 1, 2018, the Company adopted ASU No. 2014-09 and all subsequent ASUs that modified Topic 606. Topic 606 is applicable to noninterest revenue streams such as trust and asset management income, deposit related fees, interchange fees, and merchant income. The Company completed its overall assessment of revenue streams and review of related contracts potentially affected by the ASU, including trust and asset management fees, deposit related fees, and other income within noninterest income. Based on this assessment, the Company concluded that ASU 2014-09 did not materially change the method in which the Company currently recognizes revenue for these revenue streams. The Company adopted ASU 2014-09 and its related amendments utilizing the modified retrospective approach. Since there was no net income impact upon adoption of the new guidance, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Noninterest income considered in-scope of Topic 606 is discussed below. Wealth Management and Trust Fees The Company earns wealth management fees for providing investment management, trust administration, and financial planning services to clients. The Company’s performance obligation under these contracts is satisfied over time as the wealth management services are provided. Fees are recognized monthly based on the average monthly value of the assets under management and the applicable fee rate, or at a fixed annual rate, depending on the terms of the contract. No performance-based incentives are earned on wealth management contracts. The Company earns trust fees for serving as trustee for certain clients. As trustee, the Company serves as a fiduciary, administers the client’s trust, and in some cases, manages the assets of the trust. The Company’s performance obligation under these agreements is satisfied over time as the administration and management services are provided. Fees are recognized monthly based on a percentage of the market value of the account or at a fixed annual rate as outlined in the agreement. The Company also earns fees for trust related activities. The Company’s performance obligation under these agreements is satisfied at a point in time and recognized when these services have been performed. All of the wealth management and trust fee income on the consolidated statement of income is considered in-scope of Topic 606. Other Banking Fee Income The Company charges a variety of fees to its clients for services provided on the deposit and deposit management related accounts. Each fee is either transaction-based or assessed monthly. The types of fees include service charges on accounts, overdraft fees, wire transfer fees, maintenance fees, ATM fee charges, and other miscellaneous charges related to the accounts. These fees are not governed by individual contracts with clients. They are charges to clients based on disclosures presented to clients upon opening these accounts along with updated disclosures when changes are made to the fee structures. The transaction-based fees are recognized in revenue when charged to the client based on specific activity on the client’s account. Monthly service and maintenance charges are recognized in the month they are earned and are charged directly to the client’s account.

Cash and Cash Equivalents

Cash and Cash Equivalents	6 Months Ended
	Jun. 30, 2019
Cash And Cash Equivalents [Abstract]
Cash and Cash Equivalents	6. Cash and cash equivalents At June 30, 2019 and December 31, 2018, cash and cash equivalents totaled $38.6 million and $18.5 million, respectively. Of this amount, $26.9 million and $12.7 million, respectively, were maintained to satisfy the reserve requirements of the Federal Reserve Bank of Boston (“FRB Boston”). Additionally, at June 30, 2019 and December 31, 2018, 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.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2019
Investments Debt And Equity Securities [Abstract]
Investment Securities	7. 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: June 30, 2019 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (dollars in thousands) Available for sale securities U.S. GSE obligations $ 50,000 $ 1 $ (186 ) $ 49,815 $ 75,004 $ — $ (965 ) $ 74,039 Mortgage-backed securities 103,765 358 (885 ) 103,238 92,271 118 (3,121 ) 89,268 Corporate debt securities — — — — 5,015 — (159 ) 4,856 Total available for sale securities $ 153,765 $ 359 $ (1,071 ) $ 153,053 $ 172,290 $ 118 $ (4,245 ) $ 168,163 Held to maturity securities U.S. GSE obligations $ 22,572 $ 3 $ (17 ) $ 22,558 $ 32,571 $ — $ (238 ) $ 32,333 Mortgage-backed securities 181,776 2,790 (138 ) 184,428 168,118 134 (2,290 ) 165,962 Corporate debt securities 6,977 92 — 7,069 6,972 — (107 ) 6,865 Municipal securities 75,025 2,913 — 77,938 75,208 1,297 (355 ) 76,150 Total held to maturity securities $ 286,350 $ 5,798 $ (155 ) $ 291,993 $ 282,869 $ 1,431 $ (2,990 ) $ 281,310 Total $ 440,115 $ 6,157 $ (1,226 ) $ 445,046 $ 455,159 $ 1,549 $ (7,235 ) $ 449,473 All of the Company’s mortgage-backed securities have been issued by, or are collateralized by securities issued by, either Government National Mortgage Association (Ginnie Mae), Federal National Mortgage Association (Fannie Mae), or Federal Home Loan Mortgage Corporation (Freddie Mac). The following tables show the Company’s securities with gross unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous loss position: June 30, 2019 Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (dollars in thousands) Temporarily Impaired Securities Available for sale securities U.S. GSE obligations $ — $ — $ 44,814 $ (186 ) $ 44,814 $ (186 ) Mortgage-backed securities 6,844 (41 ) 71,244 (844 ) 78,088 (885 ) Corporate debt securities — — — — — — Total available for sale securities $ 6,844 $ (41 ) $ 116,058 $ (1,030 ) $ 122,902 $ (1,071 ) Held to maturity securities U.S. GSE obligations $ — $ — $ 14,980 $ (17 ) $ 14,980 $ (17 ) Mortgage-backed securities — — 47,096 (138 ) 47,096 (138 ) Corporate debt securities — — — — — — Municipal securities — — 312 — 312 — Total held to maturity securities $ — $ — $ 62,388 $ (155 ) $ 62,388 $ (155 ) Total temporarily impaired securities $ 6,844 $ (41 ) $ 178,446 $ (1,185 ) $ 185,290 $ (1,226 ) December 31, 2018 Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (dollars in thousands) Temporarily Impaired Securities Available for sale securities U.S. GSE obligations $ — $ — $ 74,039 $ (965 ) $ 74,039 $ (965 ) Mortgage-backed securities — — 86,815 (3,121 ) 86,815 (3,121 ) Corporate debt securities 902 (98 ) 3,954 (61 ) 4,856 (159 ) Total available for sale securities $ 902 $ (98 ) $ 164,808 $ (4,147 ) $ 165,710 $ (4,245 ) Held to maturity securities U.S. GSE obligations $ 4,995 $ (5 ) $ 27,338 $ (233 ) $ 32,333 $ (238 ) Mortgage-backed securities 30,719 (216 ) 93,225 (2,074 ) 123,944 (2,290 ) Corporate debt securities 6,865 (107 ) — — 6,865 (107 ) Municipal securities 8,484 (82 ) 8,313 (273 ) 16,797 (355 ) Total held to maturity securities $ 51,063 $ (410 ) $ 128,876 $ (2,580 ) $ 179,939 $ (2,990 ) Total temporarily impaired securities $ 51,965 $ (508 ) $ 293,684 $ (6,727 ) $ 345,649 $ (7,235 ) Management evaluates securities for other-than-temporary impairment on at least a quarterly basis, and more frequently, when economic or market conditions warrant such evaluation. Consideration is given to: (1) the length of time and the extent to which the fair value has been less than cost; (2) the financial condition and near-term prospects of the issuer; and (3) the intent and ability of the Company to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value. As of June 30, 2019, 68 debt securities had gross unrealized losses, with an aggregate depreciation of 0.66% from the Company’s amortized cost basis. The largest unrealized loss percentage and largest unrealized loss dollar amount of any single security was 2.43%, or $79,000, of its amortized cost. As of December 31, 2018, 142 debt securities had gross unrealized losses, with an aggregate depreciation of 2.05% from the Company’s amortized cost basis. The largest unrealized loss percentage of any single security was 9.79%, or $98,000, of its amortized cost. The largest unrealized dollar loss of any single security was $189,000, or 5.34%, of its amortized cost. The Company believes that the nature and duration of impairment 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) that it is more likely than not that the Company will not be required to sell these securities before recovery, the Company does not consider these securities to be other-than-temporarily impaired as of June 30, 2019 and December 31, 2018. The amortized cost and fair value of debt securities, aggregated by the earlier of guaranteed 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 Within Five Years After Five, But Within Ten Years After Ten Years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value At June 30, 2019 (dollars in thousands) Available for sale securities U.S. GSE obligations $ 10,000 $ 9,971 $ 40,000 $ 39,844 $ — $ — $ — $ — $ 50,000 $ 49,815 Mortgage-backed securities — — 58 59 29,462 29,176 74,245 74,003 103,765 103,238 Corporate debt securities — — — — — — — — — — Total available for sale securities $ 10,000 $ 9,971 $ 40,058 $ 39,903 $ 29,462 $ 29,176 $ 74,245 $ 74,003 $ 153,765 $ 153,053 Held to maturity securities U.S. GSE obligations $ 4,997 $ 4,982 $ 17,575 $ 17,576 $ — $ — $ — $ — $ 22,572 $ 22,558 Mortgage-backed securities 8 8 — — 52,063 53,202 129,705 131,218 181,776 184,428 Corporate debt securities — — 6,977 7,069 — — — — 6,977 7,069 Municipal securities 2,424 2,445 12,746 12,970 43,956 46,051 15,899 16,472 75,025 77,938 Total held to maturity securities $ 7,429 $ 7,435 $ 37,298 $ 37,615 $ 96,019 $ 99,253 $ 145,604 $ 147,690 $ 286,350 $ 291,993 Total $ 17,429 $ 17,406 $ 77,356 $ 77,518 $ 125,481 $ 128,429 $ 219,849 $ 221,693 $ 440,115 $ 445,046 The following table sets forth information regarding sales of investment securities and the resulting gains (losses) from such sales: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Amortized cost of securities sold $ 10,231 $ 700 $ 26,231 $ 700 Gain/(loss) realized on securities sold 6 2 (81 ) 2 Net proceeds from securities sold $ 10,237 $ 702 $ 26,150 $ 702

Loans and the Allowance for Loa

Loans and the Allowance for Loan Losses	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Loans and the Allowance for Loan Losses	8. LOANS AND THE ALLOWANCE FOR LOAN LOSSES The Company’s lending activities are conducted primarily in Eastern Massachusetts and New Hampshire. The Company grants single- and multi-family residential loans, commercial & industrial (“C&I”), commercial real estate (“CRE”), construction loans, and a variety of consumer loans. Most of the loans granted by the Company are secured by real estate collateral. Repayment of the Company’s residential loans are generally dependent on the health of the employment market in the borrowers’ geographic areas and that of the general economy with liquidation of the underlying real estate collateral being typically viewed as the primary source of repayment in the event of borrower default. The repayment of C&I loans depends primarily on the cash flow and credit worthiness of the borrower and secondarily on the underlying collateral provided by the borrower. As borrower cash flow may be difficult to predict, liquidation of the underlying collateral securing these loans is typically viewed as the primary source of repayment in the event of borrower default. However, collateral typically consists of equipment, inventory, accounts receivable, or other business assets that may fluctuate in value, so the liquidation of collateral in the event of default is often an insufficient source of repayment. The Company’s CRE loans are primarily made based on the cash flow from the collateral property and secondarily on the underlying collateral provided by the borrower, with liquidation of the underlying real estate collateral typically being viewed as the primary source of repayment in the event of borrower default. The Company’s construction loans are primarily made based on the borrower’s expected ability to execute and the future completed value of the collateral property, with sale of the underlying real estate collateral typically being viewed as the primary source of repayment. Loans outstanding are detailed by category as follows: June 30, 2019 December 31, 2018 (dollars in thousands) Residential mortgage Mortgages - fixed rate $ 409,706 $ 293,267 Mortgages - adjustable rate 498,694 309,656 Construction 28,437 — Deferred costs net of unearned fees 1,722 1,408 Total residential mortgages 938,559 604,331 Commercial mortgage Mortgages - nonowner occupied 788,982 654,394 Mortgages - owner occupied 64,520 59,335 Construction 51,816 44,146 Deferred costs net of unearned fees 124 82 Total commercial mortgages 905,442 757,957 Home equity Home equity - lines of credit 79,814 63,421 Home equity - term loans 5,763 5,665 Deferred costs net of unearned fees 237 250 Total home equity 85,814 69,336 Commercial & industrial Commercial & industrial 134,338 93,728 Deferred costs (fees) net of unearned fees (31 ) (16 ) Total commercial & industrial 134,307 93,712 Consumer Secured 31,380 33,252 Unsecured 1,035 1,171 Deferred costs net of unearned fees 13 13 Total consumer 32,428 34,436 Total loans $ 2,096,550 $ 1,559,772 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. At June 30, 2019 and December 31, 2018, total loans outstanding to such directors and officers were $36,000 and $488,000, respectively. During the six months ended June 30, 2019, $67,000 of additions and $519,000 of repayments and other adjustments were made to these loans. There were $139,000 of additions and $167,000 of repayments during the year ended December 31, 2018. At June 30, 2019 and December 31, 2018, all of the loans to directors and officers were performing according to their original terms. The following tables set forth information regarding non-performing loans disaggregated by loan category: June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 507 $ 135 $ 12 $ 298 $ — $ 952 Loans past due >90 days, but still accruing — — — — — — Troubled debt restructurings 105 — — — — 105 Total $ 612 $ 135 $ 12 $ 298 $ — $ 1,057 December 31, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 512 $ — $ 13 $ — $ — $ 525 Loans past due >90 days, but still accruing — — — — — — Troubled debt restructurings 111 — — 6 — 117 Total $ 623 $ — $ 13 $ 6 $ — $ 642 There were no Troubled Debt Restructurings (“TDRs”) Loans are considered restructured in a troubled debt restructuring when the Company has granted concessions to a borrower due to the borrower’s financial condition that it otherwise would not have considered. These concessions may include modifications of the terms of the debt such as deferral of payments, extension of maturity, reduction of principal balance, reduction of the stated interest rate other than normal market rate adjustments, or a combination of these concessions. Debt may be bifurcated with separate terms for each tranche of the restructured debt. Restructuring a loan in lieu of aggressively enforcing the collection of the loan may benefit the Company by increasing the ultimate probability of collection. Restructured loans are classified as accruing or non-accruing based on management’s assessment of the collectability of the loan. Loans which are already on nonaccrual status at the time of the restructuring generally remain on nonaccrual status for approximately six months or longer before management considers such loans for return to accruing status. Accruing restructured loans are placed into nonaccrual status if and when the borrower fails to comply with the restructured terms and management deems it unlikely that the borrower will return to a status of compliance in the near term. Troubled debt restructurings are classified as impaired loans. The Company identifies loss allocations for impaired loans on an individual loan basis. There were no new TDRs during the three and six months ended June 30, 2019. At June 30, 2019, two loans were determined to be TDRs with a total carrying value of $105,000. One TDR loan was paid off during the first quarter of 2019. There were no TDR defaults during the three and six months ended June 30, 2019. There were no new TDRs during the year ended December 31, 2018. At December 31, 2018, three loans were determined to be TDRs with a total carrying value of $117,000. There were no TDR defaults during the year ended December 31, 2018. There were no specific allowances for TDRs at June 30, 2019 or December 31, 2018. As of June 30, 2019 and December 31, 2018, there were no significant commitments to lend additional funds to borrowers whose loans were restructured. Loans by Credit Quality Indicator. The following tables contain period-end balances of loans receivable disaggregated by credit quality indicator: June 30, 2019 Residential Mortgages Home Equity Consumer (dollars in thousands) Credit risk profile based on payment activity: Performing $ 937,947 $ 85,802 $ 32,428 Non-performing 612 12 — Total $ 938,559 $ 85,814 $ 32,428 Commercial Mortgages Commercial & Industrial Credit risk profile by internally assigned grade: 1-6 (Pass) $ 895,336 $ 125,763 7 (Special Mention) 9,571 3,487 8 (Substandard) 535 5,057 9 (Doubtful) — — 10 (Loss) — — Total $ 905,442 $ 134,307 December 31, 2018 Residential Mortgages Home Equity Consumer (dollars in thousands) Credit risk profile based on payment activity: Performing $ 603,708 $ 69,323 $ 34,436 Non-performing 623 13 — Total $ 604,331 $ 69,336 $ 34,436 Commercial Mortgages Commercial & Industrial Credit risk profile by internally assigned grade: 1-6 (Pass) $ 753,338 $ 85,821 7 (Special Mention) 4,619 4,186 8 (Substandard) — 3,705 9 (Doubtful) — — 10 (Loss) — — Total $ 757,957 $ 93,712 With respect to residential real estate mortgages, home equity, and consumer loans, the Bank 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 non-accrual, or are past due more than 90 days but are still accruing, or are restructured. These loans may contain greater than average risk. With respect to commercial real estate mortgages and commercial loans, the Bank 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: June 30, 2019 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Total Past Due Current Loans Total (dollars in thousands) Residential Mortgages $ 2,093 $ 721 $ 385 $ 3,199 $ 935,360 $ 938,559 Commercial Mortgages 1,943 — — 1,943 903,499 905,442 Home Equity — 12 — 12 85,802 85,814 Commercial & Industrial 425 — 159 584 133,723 134,307 Consumer loans 2 4 — 6 32,422 32,428 Total $ 4,463 $ 737 $ 544 $ 5,744 $ 2,090,806 $ 2,096,550 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Total Past Due Current Loans Total (dollars in thousands) Residential Mortgages $ 1,034 $ 121 $ 351 $ 1,506 $ 602,825 $ 604,331 Commercial Mortgages — — — — 757,957 757,957 Home Equity — — — — 69,336 69,336 Commercial & Industrial — — — — 93,712 93,712 Consumer loans 108 — — 108 34,328 34,436 Total $ 1,142 $ 121 $ 351 $ 1,614 $ 1,558,158 $ 1,559,772 There were no significant commitments to lend additional funds to borrowers whose loans were on nonaccrual status at June 30, 2019 and December 31, 2018. Foreclosure Proceedings Other Real Estate Owned (“OREO”) During the quarter ended June 30, 2019, the Company recorded other real estate owned assets of $185,000. OREO consists of real estate properties, which have primarily served as collateral to secure loans that are controlled or owned by the Bank. These properties are recorded at fair value less estimated costs to sell at the date control is established, resulting in a new cost basis. The amount by which the recorded investment in the loan exceeds the fair value (net of estimated costs to sell) of the foreclosed asset is charged to the allowance for loan losses. Subsequent declines in the fair value of the foreclosed asset below the new cost basis are recorded through the use of a valuation allowance. Subsequent increases in the fair value are recorded as reductions in the valuation allowance, but not below zero. All costs incurred thereafter in maintaining the property are generally charged to noninterest expense. In Process of Foreclosure As of June 30, 2019, there were no loans in process of foreclosure. As of December 31, 2018, one loan secured by one- to four-family residential property with a carrying value of $351,000 was in process of foreclosure. Impaired Loans Impaired loans are loans for which it is probable that the Company will not be able to collect all amounts due according to the contractual terms of the loan agreements and loans restructured in a troubled debt restructuring. The recorded investment in impaired loans consists of unpaid principal balance, net of charge-offs, interest payments received applied to principal, and unamortized deferred loan origination fees and costs. The following tables present information pertaining to impaired loans: For the Three Months Ended June 30, 2019 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ — $ — $ — $ — $ — Commercial mortgage — — — — — Residential mortgage 616 620 778 — 1 Home equity 96 97 133 — — Total 712 717 911 — 1 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage 616 620 778 — 1 Home equity 96 97 133 — — Total $ 712 $ 717 $ 911 $ — $ 1 For the Six Months Ended June 30, 2019 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ — $ — $ — $ — $ — Commercial mortgage — — — — — Residential mortgage 616 625 778 — 2 Home equity 96 97 133 — 1 Total 712 722 911 — 3 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage 616 625 778 — 2 Home equity 96 97 133 — 1 Total $ 712 $ 722 $ 911 $ — $ 3 For the Three Months Ended June 30, 2018 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ 17 $ 20 $ 17 $ — $ — Commercial mortgage 213 213 227 — — Residential mortgage 845 848 1,051 — — Home equity 66 67 98 — — Total 1,141 1,148 1,393 — — With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial 17 20 17 — — Commercial mortgage 213 213 227 — — Residential mortgage 845 848 1,051 — — Home equity 66 67 98 — — Total $ 1,141 $ 1,148 $ 1,393 $ — $ — For the Six Months Ended June 30, 2018 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ 17 $ 22 $ 17 $ — $ 1 Commercial mortgage 213 213 227 — — Residential mortgage 845 851 1,051 — — Home equity 66 68 98 — — Total 1,141 1,154 1,393 — 1 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial 17 22 17 — 1 Commercial mortgage 213 213 227 — — Residential mortgage 845 851 1,051 — — Home equity 66 68 98 — — Total $ 1,141 $ 1,154 $ 1,393 $ — $ 1 Allowance for Loan Losses The Company maintains an allowance for loan losses in an amount determined by management on the basis of the character of the loans, loan performance, financial condition of borrowers, the value of collateral securing loans, and other relevant factors. We provide for loan losses based upon the consistent application of our documented allowance for loan loss methodology. All loan losses are charged to the allowance for loan losses and all recoveries are credited to it. Additions to the allowance for loan losses are provided by charges to income based on various factors which, in our judgment, deserve current recognition in estimating probable losses. We regularly review the loan portfolio, including a review of our classified assets, and make provisions for loan losses in order to maintain the allowance for loan losses in accordance with GAAP. The allowance for loan losses consists primarily of two components: 1. Specific allowances established for impaired loans, as defined by GAAP. The amount of impairment provided for as a specific allowance is measured based on the deficiency, if any, between the present value of expected future cash flows discounted at the loan’s effective interest rate at the time of impairment or, as a practical expedient, at the loan’s observable market price, or the fair value of the collateral if the loan is collateral-dependent, and the carrying value of the loan; and 2. General allowances established for loan losses on a portfolio basis for loans that do not meet the definition of impaired loans. The portfolio is grouped into homogenous pools by similar risk characteristics, primarily by loan type and regulatory classification. We apply an estimated incurred loss rate to each loan group. The loss rates applied are based upon our historical loss experience over a designated look back period adjusted, as appropriate, for the quantitative, qualitative, and environmental factors discussed below. This evaluation is inherently subjective, as it requires material estimates that may be susceptible to significant revisions based upon changes in economic and real estate market conditions. Actual loan losses may be significantly more than the allowance for loan losses we have established, which could have a material negative effect on our financial results. The adjustments to historical loss experience are based on our evaluation of several quantitative, qualitative, and environmental factors, including: • the loss emergence period, which represents the average amount of time between when loss events occur for specific loan types and when such problem loans are identified and the related loss amounts are confirmed through charge-offs; • changes in any concentration of credit (including, but not limited to, concentrations by geography, industry, or collateral type); • changes in the number and amount of non-accrual loans and past due loans; • changes in national, state, and local economic trends; • changes in the types of loans in the loan portfolio; • changes in the experience and ability of personnel; • changes in lending strategies; and • changes in lending policies and procedures. In addition, we may establish an unallocated allowance to provide for probable losses that have been incurred as of the reporting date but are not reflected in the allocated allowance. We evaluate the allowance for loan losses based upon the combined total of the specific and general components. Generally, when the loan portfolio increases, absent other factors, the allowance for loan loss methodology results in a higher dollar amount of estimated probable losses than would be the case without the increase. Generally, when the loan portfolio decreases, absent other factors, the allowance for loan losses methodology results in a lower dollar amount of estimated probable losses than would be the case without the decrease. Periodically, management conducts an analysis to estimate the loss emergence period for various loan categories based on samples of historical charge-offs. Model output by loan category is reviewed to evaluate the reasonableness of the reserve levels in comparison to the estimated loss emergence period applied to historical loss experience. We evaluate the loan portfolio on a quarterly basis and the allowance is adjusted accordingly. While we use the best information available to make evaluations, future adjustments to the allowance may be necessary if conditions differ substantially from the information used in making the evaluations. In addition, various regulatory agencies, as an integral part of their examination process, will periodically review the allowance for loan losses. Such agencies may require us to recognize additions to the allowance based on their analysis of information available to them at the time of their examination. The following tables contain changes in the allowance for loan losses disaggregated by loan category June 30, 2019: For the Three Months Ended June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at March 31, 2019 $ 5,256 $ 9,369 $ 534 $ 1,245 $ 248 $ — $ 16,652 Charge-offs — (55 ) — (100 ) (9 ) — (164 ) Recoveries — — — 12 4 — 16 Provision for (Release of) 207 115 (3 ) 288 (12 ) — 595 Balance at June 30, 2019 $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ — $ 17,099 For the Six Months Ended June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at December 31, 2018 $ 4,946 $ 9,626 $ 517 $ 1,415 $ 264 $ — $ 16,768 Charge-offs — (55 ) — (130 ) (20 ) — (205 ) Recoveries — — — 25 8 — 33 Provision for (Release of) 517 (142 ) 14 135 (21 ) — 503 Balance at June 30, 2019 $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ — $ 17,099 For the Three Months Ended June 30, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at March 31, 2018 $ 4,692 $ 8,937 $ 570 $ 1,145 $ 298 $ 90 $ 15,732 Charge-offs — — — (6 ) (17 ) — (23 ) Recoveries — — — 12 3 — 15 Provision for (Release of) 187 (263 ) 31 44 12 (90 ) (79 ) Balance at June 30, 2018 $ 4,879 $ 8,674 $ 601 $ 1,195 $ 296 $ — $ 15,645 For the Six Months Ended June 30, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at December 31, 2017 $ 5,047 $ 8,289 $ 630 $ 946 $ 315 $ 93 $ 15,320 Charge-offs — — — (11 ) (21 ) — (32 ) Recoveries — — — 22 5 — 27 Provision for (Release of) (168 ) 385 (29 ) 238 (3 ) (93 ) 330 Balance at June 30, 2018 $ 4,879 $ 8,674 $ 601 $ 1,195 $ 296 $ — $ 15,645 The following tables contain period-end balances of the allowance for loan losses and related loans receivable disaggregated by impairment method: June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Allowance for loan losses Individually evaluated for impairment $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 5,463 9,429 531 1,445 231 17,099 Total $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ 17,099 Loans receivable Individually evaluated for impairment $ 616 $ — $ 96 $ — $ — $ 712 Collectively evaluated for impairment 937,943 905,442 85,718 134,307 32,428 2,095,838 Total $ 938,559 $ 905,442 $ 85,814 $ 134,307 $ 32,428 $ 2,096,550 December 31, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Allowance for loan losses Individually evaluated for impairment $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 4,946 9,626 517 1,415 264 16,768 Total $ 4,946 $ 9,626 $ 517 $ 1,415 $ 264 $ 16,768 Loans receivable Individually evaluated for impairment $ 647 $ — $ 88 $ 5 $ — $ 740 Collectively evaluated for impairment 603,684 757,957 69,248 93,707 34,436 1,559,032 Total $ 604,331 $ 757,957 $ 69,336 $ 93,712 $ 34,436 $ 1,559,772

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	9. GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill. As of June 30, 2019 and December 31, 2018, the carrying value of goodwill totaled $31.2 million and $412,000, respectively. The Company recorded additional goodwill of $30.8 million related to the Optima merger during the second quarter of 2019. Goodwill is tested for impairment, based on its fair value, at least annually. As of June 30, 2019 and December 31, 2018, no goodwill impairment has been recognized. Core deposit intangibles . During the second quarter of 2019, the Company recorded an asset for core deposit intangibles (“CDI”) of $3.6 million related to the Optima merger. Amortization of CDI assets totaled $90,000 for the three and six months ended June 30, 2019. As of June 30, 2019, the carrying value of CDI assets totaled $3.5 million. The weighted-average amortization period for CDI was approximately ten years at June 30, 2019. Mortgage servicing rights. Periodically, the Company sells certain residential mortgage loans to the secondary market. Generally, these loans are sold without recourse or other credit enhancements. As of June 30, 2019, loans held for sale totaled $384,000. The Company did not have any loans held for sale at and December 31, 2018. The Company sells loans and either releases or retains the servicing rights. For loans sold with servicing rights retained, we provide the servicing for the loans on a per-loan fee basis. Mortgage loans sold and servicing rights retained during the period ended June 30, 2019 and the year ended December 31, 2018 were $867,000 and $1.6 million, respectively. Total gain on loans held for sale were $15,000 and $18,000, for the three months ended June 30, 2019 and June 30, 2018, respectively. Total gain on loans held for sale were $31,000 and $45,000, for the six months ended June 30, 2019 and June 30, 2018, respectively. An analysis of mortgage servicing rights, which are included in other assets, follows: Mortgage Servicing Rights Valuation Allowance Total (dollars in thousands) Balance at December 31, 2017 $ 823 $ (30 ) $ 793 Mortgage servicing rights capitalized 5 — 5 Amortization charged against servicing income (70 ) — (70 ) Change in impairment reserve (30 ) 30 — Balance at June 30, 2018 $ 728 $ — $ 728 Balance at December 31, 2018 $ 666 $ — $ 666 Mortgage servicing rights acquired as a result of the merger 334 — 334 Mortgage servicing rights capitalized 7 — 7 Amortization charged against servicing income (106 ) — (106 ) Change in impairment reserve — (10 ) (10 ) Balance at June 30, 2019 $ 901 $ (10 ) $ 891 The fair value of our mortgage servicing rights (“MSR”) portfolio was $1.1 million and $1.0 million as of June 30, 2019 and June 30, 2018, respectively. The fair value of mortgage servicing rights is estimated based on the present value of expected cash flows, incorporating assumptions for discount rate, prepayment speed, and servicing cost. The weighted-average amortization period for the mortgage servicing rights portfolio was 6.0 years and 7.5 years at June 30, 2019 and December 31, 2018, respectively. The estimated aggregate future amortization expense for mortgage servicing rights for each of the next five years and thereafter is as follows: Future Amortization Expense (dollars in thousands) Remainder of 2019 $ 74 2020 133 2021 113 2022 96 2023 81 Thereafter 404 Total $ 901

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes The effective tax rate was 26.5% and 23.9% for the three and six months ended June 30, 2019, respectively, as compared to 23.7% and 22.8% for the three and six months ended June 30, 2018, respectively. Net deferred tax assets totaled $7.3 million at June 30, 2019 and $8.7 million at December 31, 2018. The Company recorded no valuation allowance for deferred tax assets at June 30, 2019 or December 31, 2018. The components of income tax expense were as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Current Federal $ 1,305 $ 1,642 $ 1,676 $ 2,235 State 552 679 719 932 Total current expense 1,857 2,321 2,395 3,167 Deferred Federal (217 ) (286 ) 601 238 State (100 ) (134 ) 284 112 Total deferred (317 ) (420 ) 885 350 Total income tax expense $ 1,540 $ 1,901 $ 3,280 $ 3,517

Pension and Retirement Plans

Pension and Retirement Plans	6 Months Ended
	Jun. 30, 2019
Compensation And Retirement Disclosure [Abstract]
Pension and Retirement Plans	11. Pension and Retirement Plans The components of net periodic benefit cost (credit) were as follows: Three Months Ended June 30, Pension Plan Supplemental Retirement Plan Retirement Healthcare Plan 2019 2018 2019 2018 2019 2018 (dollars in thousands) Net periodic benefit cost Service cost $ — $ — $ 75 $ 88 $ 5 $ 5 Interest cost 414 392 85 77 6 6 Expected return on assets (651 ) (722 ) — — — — Amortization of prior service cost (credit) (1 ) (1 ) — — — — Amortization of net actuarial loss 77 37 — 1 (1 ) (5 ) Net periodic benefit cost (credit) $ (161 ) $ (294 ) $ 160 $ 166 $ 10 $ 6 Six Months Ended June 30, Pension Plan Supplemental Retirement Plan Retirement Healthcare Plan 2019 2018 2019 2018 2019 2018 (dollars in thousands) Net periodic benefit cost Service cost $ — $ — 143 $ 177 10 $ 11 Interest cost 840 778 175 154 12 11 Expected return on assets (1,360 ) (1,445 ) — — — — Amortization of prior service (credit) (2 ) (2 ) — — — — Amortization of net actuarial loss 77 53 — 2 (2 ) — Net periodic benefit cost (credit) $ (445 ) $ (616 ) $ 318 $ 333 $ 20 $ 22 The Company made no contributions to the qualified defined benefit pension plan during the three and six months ended June 30, 2019. We do not expect to make any contributions to the qualified defined benefit plan during the remainder of 2019. 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. Beginning in 2018, the Company matched employee contributions up to 100% of the first 4% of each participant’s salary, eligible bonus, and eligible incentive, up from 3% in 2017. 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. In 2018, employees were eligible to participate in the discretionary contribution portion of the PSP after completing 12 months of employment and 1,000 hours of service. The employee 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. Effective in 2019, employees are eligible to participate in the discretionary contribution portion of the PSP on the first day of their initial date of service. Employee Stock Ownership Plan The Company has an Employee Stock Ownership Plan (“ESOP”) for its eligible employees. Employees are eligible to participate in the ESOP on January 1 or July 1 following the completion of 12 months of service consisting of at least 1,000 hours and upon the attainment of age 21. Purchases of the Company’s 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 June 30, 2019 and June 30, 2018 amounted to approximately $552,000 and $584,000, respectively. Total expenses related to the PSP and ESOP for the six months ended June 30, 2019 . Defined Contribution SERP Plan For executives participating in the Defined Contribution SERP Plan (“DC SERP”), the Company made a discretionary contribution of 10% of each executive’s base salary and bonus to his or her account. Total expenses related to the DC SERP for the three months ended June 30, 2019 and June 30, 2018 amounted to approximately $43,000 and $75,000, respectively. Total expenses related to the DC SERP for the six months ended June 30, 2019 and June 30, 2018 amounted to approximately $86,000 and $126,000, respectively.

Stock Based Compensation

Stock Based Compensation	6 Months Ended
	Jun. 30, 2019
Share Based Compensation [Abstract]
Stock Based Compensation	12. STOCK BASED COMPENSATION Time Vested Restricted Stock Awards (“RSAs”) and Time Vested Restricted Stock Units (“RSUs”) During the three months ended June 30, 2019, the Company issued the following RSAs from the 2017 Equity and Cash Incentive Plan. T he fair value of RSAs is based upon the Company’s common stock closing share price on the date of the grant. The holders of RSAs participate fully in the rewards of stock ownership of the Company, including voting and dividend rights. There were no RSUs issued during the three months ended Weighted- Average Shares Granted Fair Value at Grant Date Type of Award 950 $ 84.66 RSAs Performance-Based Restricted Stock Units (“PRSUs”) There were no PRSUs issued during the three months ended June 30, 2019 The following table presents the pre-tax expense associated with all outstanding non-vested RSAs, RSUs, PRSUs, and the related tax benefits recognized: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Stock based compensation expense $ 699 $ 807 $ 1,318 $ 1,347 Related tax benefits $ 197 $ 227 $ 370 $ 379

Financial Instruments with Off-

Financial Instruments with Off-Balance-Sheet Risk	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Financial Instruments with Off-Balance-Sheet Risk	13. 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, derivatives contracts, risk participation agreements, 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 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: June 30, 2019 December 31, 2018 (dollars in thousands) Financial instruments whose contractual amount represents credit risk: Commitments to extend credit: Unused portion of existing lines of credit $ 405,900 $ 368,410 Origination of new loans 59,930 24,505 Standby letters of credit 8,439 8,752 Financial instruments whose notional amount exceeds the amount of credit risk: Commitments to sell residential mortgage loans 3,188 —

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	14. LEASES The Company is obligated under various lease agreements covering its main office, private banking offices, and other locations. These agreements are accounted for as operating leases and their terms expire between 2019 and 2030 and, in some instances, contain options to renew for periods up to 30 years. The Company adopted Accounting Standards Update No. 2016-02 - Leases The following table summarizes information related to the Company’s right-of-use asset and net lease liability: June 30, 2019 Operating Leases Balance Sheet Location (dollars in thousands) Right-of-use asset $ 35,604 Other assets Lease liability $ 36,982 Other liabilities Operating lease expenses are comprised of operating lease costs and variable lease costs, net of sublease income. The pattern and measurement of expense recognition of these costs were not significantly impacted by ASU 2016-02 and subsequent ASUs issued to amend this Topic. Variable lease payments that are not dependent on an index or a rate or changes in variable payments based on an index or rate after the commencement date are excluded from the measurement of the lease liability, recognized in the period incurred and included within variable lease costs below. The Company determines whether a contract contains a lease based on whether a contract, or a part of a contract, conveys the right to control the use of an identified asset for a period of time in exchange for consideration. The discount rate is determined as either the rate implicit in the lease or when a rate cannot be readily determined, the Company’s incremental borrowing rate. The incremental borrowing rate is the rate of interest that the Company would have to pay to borrow on a collateralized basis over a similar term. The components of operating lease cost and other related information are as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2019 (dollars in thousands) Operating lease cost $ 1,321 $ 2,501 Short-term lease cost — — Variable lease cost (Cost excluded from lease payments) — — Sublease income (16 ) (32 ) Total Operating Lease Cost $ 1,305 $ 2,469 Other Information Cash paid for amounts included in the measurement of lease liabilities - operating cash flows from operating leases $ 1,231 $ 2,308 Operating Lease - Operating Cash Flows (Liability reduction) 937 1,744 Right-of-use assets obtained in exchange for new operating lease liabilities 4,656 4,656 Weighted average lease term - operating Leases 8.56 Years 8.56 Years Weighted average discount Rate - operating leases 3.38 % 3.38 % The Company recorded additional ROU assets of $4.7 million during the second quarter of 2019 associated with leases acquired from the merger with Optima. The total minimum rentals due in future periods under these agreements in effect at June 30, 2019 and December 31, 2018 were as follows: Future Minimum June 30, 2019 Lease Payments (dollars in thousands) Remainder of 2019 5,426 2020 5,527 2021 5,428 2022 5,181 2023 4,864 Thereafter 16,380 Total minimum lease payments 42,806 Less: interest (5,824 ) Total lease liability $ 36,982 Year Ended Future Minimum December 31, Lease Payments (dollars in thousands) 2019 4,448 2020 4,661 2021 4,662 2022 4,553 2023 4,455 Thereafter 17,128 Total minimum lease payments $ 39,907 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 $1.4 million and $1.1 million for the quarter ended June 30, 2019 and June 30, 2018, respectively. Total rental expense was $2.7 million and $2.2 million for the six months ended June 30, 2019 and June 30, 2018, respectively. Under the terms of the Company’s sole sublease agreement, the Company will receive minimum annual rental payments of approximately $32,000. This agreement expired on July 31, 2019. Total rental income was $16,000 for the quarters ended June 30, 2019 and June 30, 2018. Total rental income was $32,000 for the six months ended June 30, 2019 and June 30, 2018.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Shareholders' Equity	15. Shareholders’ Equity As of June 30, 2019 and December 31, 2018, the Company and the Bank met all applicable minimum capital requirements and were considered “well-capitalized” by both the FRB and the FDIC. Actual Minimum Capital Required For Capital Adequacy Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer (1) Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At June 30, 2019 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 222,152 11.8 % $ 150,732 8.0 % $ 197,836 10.5 % N/A N/A Tier I capital (to risk-weighted assets) 205,002 10.9 % 113,049 6.0 % 160,153 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 205,002 10.9 % 84,787 4.5 % 131,891 7.0 % N/A N/A Tier I capital (to average assets) 205,002 7.9 % 103,327 4.0 % 103,327 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 218,012 11.6 % $ 150,732 8.0 % $ 197,836 10.5 % $ 188,415 10.0 % Tier I capital (to risk-weighted assets) 200,862 10.7 % 113,049 6.0 % 160,153 8.5 % 150,732 8.0 % Common equity tier I capital (to risk-weighted assets) 200,862 10.7 % 84,787 4.5 % 131,891 7.0 % 122,470 6.5 % Tier I capital (to average assets) 200,862 7.8 % 103,327 4.0 % 103,327 4.0 % 129,158 5.0 % (1) The 2013 Capital Rules adopted by the Federal Reserve, Office of the Comptroller of the Currency, and the Federal Deposit Insurance Corporation implementing Basel III were fully phased-in effective January 1, 2019. Actual Minimum Capital Required For Capital Adequacy Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At December 31, 2018 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 189,888 13.2 % $ 114,666 8.0 % $ 141,541 9.875 % $ 150,500 10.5 % N/A N/A Tier I capital (to risk-weighted assets) 173,070 12.1 % 86,000 6.0 % 112,875 7.875 % 121,833 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 173,070 12.1 % 64,500 4.5 % 91,375 6.375 % 100,333 7.0 % N/A N/A Tier I capital (to average assets) 173,070 8.5 % 81,507 4.0 % 81,507 4.000 % 81,507 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 185,507 12.9 % $ 114,666 8.0 % $ 141,541 9.875 % $ 150,500 10.5 % $ 143,333 10.0 % Tier I capital (to risk-weighted assets) 168,689 11.8 % 86,000 6.0 % 112,875 7.875 % 121,833 8.5 % 114,666 8.0 % Common equity tier I capital (to risk-weighted assets) 168,689 11.8 % 64,500 4.5 % 91,375 6.375 % 100,333 7.0 % 93,166 6.5 % Tier I capital (to average assets) 168,689 8.3 % 81,507 4.0 % 81,507 4.000 % 81,507 4.0 % 101,884 5.0 %

Other Comprehensive Income

Other Comprehensive Income	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Other Comprehensive Income	16. Other Comprehensive Income The following table presents the changes in accumulated other comprehensive income (loss) during the period, by component, net of tax: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount (dollars in thousands) Unrealized (losses)/gains on available for sale securities Unrealized holding (losses)/gains arising during period $ 1,909 $ (456 ) $ 1,453 $ (550 ) $ 127 $ (423 ) Reclassification adjustment for (gains)/losses recognized in net income (6 ) 2 (4 ) (2 ) — (2 ) Derivatives Change in interest rate contracts 1,696 (477 ) 1,219 — — — Defined benefit retirement plans Change in retirement liability 36 (10 ) 26 15 (5 ) 10 Total Other Comprehensive (Loss)/Income $ 3,635 $ (941 ) $ 2,694 $ (537 ) $ 122 $ (415 ) Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount (dollars in thousands) Unrealized (losses)/gains on available for sale securities Unrealized holding (losses)/gains arising during period $ 3,334 $ (786 ) $ 2,548 $ (2,228 ) $ 453 $ (1,775 ) Reclassification adjustment for (gains)/losses recognized in net income 81 (19 ) 62 (2 ) — (2 ) Derivatives Change in interest rate contracts 1,654 (465 ) 1,189 — — — Defined benefit retirement plans Change in retirement liability 72 (20 ) 52 29 (9 ) 20 Total Other Comprehensive (Loss)/Income $ 5,141 $ (1,290 ) $ 3,851 $ (2,201 ) $ 444 $ (1,757 ) Reclassifications out of Accumulated Other Comprehensive Income (“AOCI”) that have an impact on net income are presented below: Three Months Ended June 30, Details about Accumulated Other Comprehensive Income Components 2019 2018 Affected Line Item in the Statement where Net Income is Presented (dollars in thousands) Unrealized gains and losses on available for sale securities $ 6 $ 2 Gain/(loss) on disposition of investment securities Tax benefit or (expense) (2 ) — Provision for income taxes Net of tax $ 4 $ 2 Net income Six Months Ended June 30, Details about Accumulated Other Comprehensive Income Components 2019 2018 Affected Line Item in the Statement where Net Income is Presented (dollars in thousands) Unrealized gains and losses on available for sale securities $ (81 ) $ 2 Gain/(loss) on disposition of investment securities Tax benefit or (expense) 19 — Provision for income taxes Net of tax $ (62 ) $ 2 Net income

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	17. Earnings per Share The following represents a reconciliation between basic and diluted earnings per share: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands, except per share data) Earnings per common share - basic: Numerator: Net income $ 4,272 $ 6,111 $ 10,470 $ 11,916 Less dividends and undistributed earnings allocated to participating securities (35 ) (60 ) (94 ) (121 ) Net income applicable to common shareholders $ 4,237 $ 6,051 $ 10,376 $ 11,795 Denominator: Weighted average common shares outstanding 4,682 4,060 4,379 4,057 Earnings per common share - basic $ 0.91 $ 1.49 $ 2.37 $ 2.91 Earnings per common share - diluted: Numerator: Net income $ 4,272 $ 6,111 $ 10,470 $ 11,916 Less dividends and undistributed earnings allocated to participating securities (35 ) (60 ) (94 ) (121 ) Net income applicable to common shareholders $ 4,237 $ 6,051 $ 10,376 $ 11,795 Denominator: Weighted average common shares outstanding 4,682 4,060 4,379 4,057 Dilutive effect of common stock equivalents 34 34 33 31 Weighted average diluted common shares outstanding 4,716 4,094 4,412 4,088 Earnings per common share - diluted $ 0.90 $ 1.48 $ 2.35 $ 2.89

Derivative And Hedging Activiti

Derivative And Hedging Activities	6 Months Ended
	Jun. 30, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative And Hedging Activities	18. 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 our 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 accumulated other comprehensive income and subsequently reclassed into interest income in the same period(s) during which the hedged transaction affects earnings. The earnings recognition of excluded components is presented in interest income. Amounts reported in accumulated other comprehensive income related to derivatives will be reclassed to interest income as the Company receives interest payments on its variable-rate assets. 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 Bank 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 client’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 in other 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 only enters into interest rate agreements with highly rated counterparties that management believes to be creditworthy. 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 with a corresponding offset within other assets or other liabilities. 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 and pays a fee 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 and receives a fee 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: June 30, 2019 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 3,528 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 3,528 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 181,291 Other Assets $ 12,348 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 181,291 Other Liabilities 12,348 Risk participation agreements out to counterparties 19,000 Other Assets 46 — Other Liabilities — Risk participation agreements in with counterparties — Other Assets — 78,700 Other Liabilities 459 Total derivatives not designated as hedging instruments $ 12,394 $ 12,807 December 31, 2018 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 1,970 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 1,970 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 150,489 Other Assets $ 5,782 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 150,489 Other Liabilities 5,782 Risk participation agreements out to counterparties 19,000 Other Assets 28 — Other Liabilities — Risk participation agreements in with counterparties — Other Assets — 63,825 Other Liabilities 179 Total derivatives not designated as hedging instruments $ 5,810 $ 5,961 The following table presents the effect of cash flow hedge accounting on accumulated other comprehensive income (“AOCI”) at June 30, 2019: Amount of Gain or (Loss) Recognized in OCI Amount of Gain or (Loss) Recognized in OCI Included Component Amount of Gain or (Loss) Recognized in OCI Excluded Component Location of Gain or (Loss) Amount of Gain or (Loss) Reclassified from AOCI into Income Amount of Gain or (Loss) Reclassified from AOCI into Income Included Component Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component Three Months Ended June 30, 2019 Three Months Ended June 30, 2019 (dollars in thousands) (dollars in thousands) Interest rate contracts $ 1,647 $ 2,080 $ (433 ) Interest Income $ (48 ) $ — $ (48 ) Total $ 1,647 $ 2,080 $ (433 ) $ (48 ) $ — $ (48 ) Amount of Gain or (Loss) Recognized in OCI Amount of Gain or (Loss) Recognized in OCI Included Component Amount of Gain or (Loss) Recognized in OCI Excluded Component Location of Gain or (Loss) Amount of Gain or (Loss) Reclassified from AOCI into Income Amount of Gain or (Loss) Reclassified from AOCI into Income Included Component Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component Six Months Ended June 30, 2019 Six Months Ended June 30, 2019 (dollars in thousands) (dollars in thousands) Interest rate contracts $ 1,558 $ 2,080 $ (522 ) Interest Income $ (96 ) $ — $ (96 ) Total $ 1,558 $ 2,080 $ (522 ) $ (96 ) $ — $ (96 ) Over the next 12 months, the Company estimates that an additional $28,000 will be reclassified out of AOCI into earnings, as a reduction to interest income. The following table presents the effect of the Company’s derivative financial instruments on the Income Statement at June 30, 2019: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Interest Income Interest Income (dollars in thousands) Total amount of income presented in the income statement in which the effects of fair value or cash flow hedges are recorded $ (48 ) $ (96 ) The effects of fair value and cash flow hedging: Gain or (loss) on cash flow hedging relationships in Subtopic 815-20 Interest rate contracts Amount of gain or (loss) reclassed from AOCI into income $ (48 ) $ (96 ) Amount of gain or (loss) reclassed from AOCI into income - Included Component — — Amount of gain or (loss) reclassed from AOCI into income - Excluded Component $ (48 ) $ (96 ) The following tables present the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the Income Statement as of the periods presented: Amount of Gain or (Loss) Recognized in Income on Derivative Three Months Ended June 30, Three Months Ended June 30, 2019 2018 Location of Gain or (Loss) (dollars in thousands) Other contracts Other income $ (61 ) $ 12 Total $ (61 ) $ 12 Amount of Gain or (Loss) Recognized in Income on Derivative Six Months Ended June 30, Six Months Ended June 30, 2019 2018 Location of Gain or (Loss) (dollars in thousands) Other contracts Other income $ 13 $ 40 Total $ 13 $ 40 Credit-risk-related Contingent Features By using derivatives, the Company is exposed to credit risk to the extent that counterparties to the derivative contracts do not perform as required. Should a counterparty fail to perform under the terms of a derivative contract, the Company’s credit exposure on interest rate swaps is limited to the net positive fair value and accrued interest of all swaps with each counterparty. 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 positions, and the Company would be required to settle its obligations under the agreements. As of June 30, 2019, 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 $8.5 million. As of June 30, 2019, the Company has minimum collateral posting thresholds with certain of its derivative counterparties and has posted collateral of $8.4 million. If the Company had breached any of these provisions at June 30, 2019, then it could have been required to settle its obligations under the agreements at their termination value of $8.5 million. 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 sheet as June 30, 2019 and December 31, 2018: Gross Amounts Not Offset Gross Amounts of Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount June 30, 2019 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 15,922 $ — $ 15,922 $ 3,663 $ — $ 12,259 Offsetting of Derivative Liabilities Derivative Liabilities $ 12,807 $ — $ 12,807 $ 3,663 $ 8,428 $ 716 Gross Amounts Not Offset Gross Amounts of Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount December 31, 2018 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 7,780 $ — $ 7,780 $ 3,099 $ (743 ) $ 3,938 Offsetting of Derivative Liabilities Derivative Liabilities $ 5,961 $ — $ 5,961 $ 3,099 $ 260 $ 2,602

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	19. 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: June 30, 2019 December 31, 2018 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (dollars in thousands) Financial assets Cash and cash equivalents $ 38,557 $ 38,557 $ 18,473 $ 18,473 Securities available for sale 153,053 153,053 168,163 168,163 Securities held to maturity 286,350 291,993 282,869 281,310 Loans, net 2,079,451 2,036,666 1,543,004 1,484,905 Loans held for sale 384 384 — — FHLB Boston stock 8,245 8,245 6,844 6,844 Accrued interest receivable 7,485 7,485 5,762 5,762 Mortgage servicing rights 891 1,105 666 941 Interest rate contracts 3,528 3,528 1,970 1,970 Loan level interest rate swaps 12,348 12,348 5,782 5,782 Risk participation agreements out to counterparties 46 46 28 28 Financial liabilities Deposits 2,329,665 2,328,568 1,811,410 1,809,051 Short-term borrowings 103,000 103,031 90,000 90,000 Long-term borrowings 3,323 3,316 3,409 3,363 Loan level interest rate swaps 12,348 12,348 5,782 5,782 Risk participation agreements in with counterparties 459 459 179 179 The Company follows ASC 820, “Fair Value Measurements and Disclosures,” • 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 collateral dependent impaired loans. In accordance with the requirements of ASU 2016-01, the Company uses an exit price notion for its fair value disclosures as of June 30, 2019. The following tables summarize certain assets reported at fair value on a recurring basis: Fair Value as of June 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 49,815 $ — $ 49,815 Mortgage-backed securities — 103,238 — 103,238 Corporate debt securities — — — — Other assets Interest rate swaps with customers — 12,348 — 12,348 Risk participation agreements out to counterparties — 46 — 46 Interest rate contracts — 3,528 — 3,528 Other liabilities Mirror swaps with counterparties — 12,348 — 12,348 Risk participation agreements in with counterparties — 459 — 459 Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 74,039 $ — $ 74,039 Mortgage-backed securities — 89,268 — 89,268 Corporate debt securities — 4,856 — 4,856 Other assets Interest rate swaps with customers — 5,782 — 5,782 Risk participation agreements out to counterparties — 28 — 28 Interest rate contracts — 1,970 — 1,970 Other liabilities Mirror swaps with counterparties — 5,782 — 5,782 Risk participation agreements in with counterparties — 179 — 179 The following table presents the carrying value of assets held at June 30, 2019, which were measured at fair value on a non-recurring basis during the three and six months ended June 30, 2019: June 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a nonrecurring basis Assets Collateral dependent impaired loans $ — $ — $ — $ — Loans held for sale — — 384 384 Other real estate owned — — 185 185 Total $ — $ — $ 569 $ 569 During the three months ended June 30, 2019, the Company recorded total OREO of $185,000. These properties are recorded at fair value less estimated costs to sell at the date control is established. There were no assets measured at fair value on a non-recurring basis during the year ended December 31, 2018. There were no transfers between levels for the three and six months ended June 30, 2019 and the three and six months ended June 30, 2018. 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 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. Long-Term 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 Bank 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 Bank 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 Bank will charge fees in exchange for its commitment. While these commitment fees have value, the Bank 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 Bank’s portfolio of loans serviced for itself, and the intangible value inherent in the Bank’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)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of 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 financial statements. Actual results could differ from those estimates. The allowance for loan losses and the valuation of deferred tax assets are particularly subject to change.
Recently Issued and Adopted Accounting Guidance	Recently Issued and Adopted Accounting Guidance Accounting Standards Update 2018-16 - Inclusion of the Secured Overnight Financing Rate (“SOFR”) Overnight Index Swap (“OIS”) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities Accounting Standards Update 2018-15 - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract . Accounting Standards Update 2018-14 - Changes to the Disclosure Requirements for Defined Benefit Plans . Accounting Standards Update 2018-13 - Changes to the Disclosure Requirements for Fair Value Measurement . Accounting Standards Update 2018-07 - Improvements to Nonemployee Share-Based Payment Accounting Revenue from Contracts with Customers Accounting Standard Update No. Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities h is s e e s ta da r a a l l o c p a i e b t a l i e i e g a c c o n t i n a r i s a n a e ac t i v i t i es d c c o s a c m l e x i t a p l y i h d g a c c o n t i n T s ta d a r r q i r e c p a n i e c h a n h r c o n i t i a r s n t a t i o o t f c t h d g a c c o n ti b y • e li m i n a ti t q u i r e t s e a r a t l m a s r a p e g i e ff e c ti v n s s a n • re q i r i c m t p e s n a h l m n e a c o n i n a a e c e a a i n c m s t a e l i e d e i The standard also permits hedge accounting for strategies for which hedge accounting was not historically permitted and includes new alternatives for measuring the hedged item for fair value hedges of interest rate risk. Furthermore, the standard eases the requirements for effectiveness testing, hedge documentation, applying the critical terms match method, and introduces new alternatives that will permit companies to reduce the risk of material error corrections if they misapply the shortcut method. The new accounting standard was effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years. The new standard requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. The Company early adopted the standard during the fourth quarter of 2018, using a modified retrospective transition method, and it did not have an effect on our consolidated balance sheets, statements of income, and cash flows. See note 18 – DERIVATIVE AND HEDGING ACTIVITIES. Accounting Standards Update No. 2016-13 - Financial Instruments - Measurement of Credit Losses on Financial Instruments Accounting Standards Update No. 2016-02 - Leases Accounting Standards Update No. 2014-09 - Revenue from Contracts with Customers On January 1, 2018, the Company adopted ASU No. 2014-09 and all subsequent ASUs that modified Topic 606. Topic 606 is applicable to noninterest revenue streams such as trust and asset management income, deposit related fees, interchange fees, and merchant income. The Company completed its overall assessment of revenue streams and review of related contracts potentially affected by the ASU, including trust and asset management fees, deposit related fees, and other income within noninterest income. Based on this assessment, the Company concluded that ASU 2014-09 did not materially change the method in which the Company currently recognizes revenue for these revenue streams. The Company adopted ASU 2014-09 and its related amendments utilizing the modified retrospective approach. Since there was no net income impact upon adoption of the new guidance, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Noninterest income considered in-scope of Topic 606 is discussed below. Wealth Management and Trust Fees The Company earns wealth management fees for providing investment management, trust administration, and financial planning services to clients. The Company’s performance obligation under these contracts is satisfied over time as the wealth management services are provided. Fees are recognized monthly based on the average monthly value of the assets under management and the applicable fee rate, or at a fixed annual rate, depending on the terms of the contract. No performance-based incentives are earned on wealth management contracts. The Company earns trust fees for serving as trustee for certain clients. As trustee, the Company serves as a fiduciary, administers the client’s trust, and in some cases, manages the assets of the trust. The Company’s performance obligation under these agreements is satisfied over time as the administration and management services are provided. Fees are recognized monthly based on a percentage of the market value of the account or at a fixed annual rate as outlined in the agreement. The Company also earns fees for trust related activities. The Company’s performance obligation under these agreements is satisfied at a point in time and recognized when these services have been performed. All of the wealth management and trust fee income on the consolidated statement of income is considered in-scope of Topic 606. Other Banking Fee Income The Company charges a variety of fees to its clients for services provided on the deposit and deposit management related accounts. Each fee is either transaction-based or assessed monthly. The types of fees include service charges on accounts, overdraft fees, wire transfer fees, maintenance fees, ATM fee charges, and other miscellaneous charges related to the accounts. These fees are not governed by individual contracts with clients. They are charges to clients based on disclosures presented to clients upon opening these accounts along with updated disclosures when changes are made to the fee structures. The transaction-based fees are recognized in revenue when charged to the client based on specific activity on the client’s account. Monthly service and maintenance charges are recognized in the month they are earned and are charged directly to the client’s account.

Mergers (Tables)

Mergers (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed as of the date of the acquisition: Net Assets Acquired at Fair Value (dollars in thousands) Assets Cash and cash equivalents $ 6,902 Investments 23,298 Loans 475,406 Premises and equipment 6,286 Goodwill 30,794 Core deposit and other intangibles 3,609 Other assets 9,408 Total assets acquired 555,703 Liabilities Deposits 477,189 Borrowings 13,459 Other liabilities 799 Total liabilities assumed 491,447 Purchase price $ 64,256
Summary of Selected Pro Forma Financial Information	The selected pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the financial results of the combined companies had the acquisition actually been completed at the beginning of the periods presented, nor does it indicate future results for any other interim or full-year Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Net interest and dividend income after provision for loan losses $ 19,780 $ 19,364 $ 39,776 $ 37,737 Net Income 8,075 6,646 14,988 13,207

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (dollars in thousands) Available for sale securities U.S. GSE obligations $ 50,000 $ 1 $ (186 ) $ 49,815 $ 75,004 $ — $ (965 ) $ 74,039 Mortgage-backed securities 103,765 358 (885 ) 103,238 92,271 118 (3,121 ) 89,268 Corporate debt securities — — — — 5,015 — (159 ) 4,856 Total available for sale securities $ 153,765 $ 359 $ (1,071 ) $ 153,053 $ 172,290 $ 118 $ (4,245 ) $ 168,163 Held to maturity securities U.S. GSE obligations $ 22,572 $ 3 $ (17 ) $ 22,558 $ 32,571 $ — $ (238 ) $ 32,333 Mortgage-backed securities 181,776 2,790 (138 ) 184,428 168,118 134 (2,290 ) 165,962 Corporate debt securities 6,977 92 — 7,069 6,972 — (107 ) 6,865 Municipal securities 75,025 2,913 — 77,938 75,208 1,297 (355 ) 76,150 Total held to maturity securities $ 286,350 $ 5,798 $ (155 ) $ 291,993 $ 282,869 $ 1,431 $ (2,990 ) $ 281,310 Total $ 440,115 $ 6,157 $ (1,226 ) $ 445,046 $ 455,159 $ 1,549 $ (7,235 ) $ 449,473
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 aggregated by investment category and length of time that individual securities have been in a continuous loss position: June 30, 2019 Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (dollars in thousands) Temporarily Impaired Securities Available for sale securities U.S. GSE obligations $ — $ — $ 44,814 $ (186 ) $ 44,814 $ (186 ) Mortgage-backed securities 6,844 (41 ) 71,244 (844 ) 78,088 (885 ) Corporate debt securities — — — — — — Total available for sale securities $ 6,844 $ (41 ) $ 116,058 $ (1,030 ) $ 122,902 $ (1,071 ) Held to maturity securities U.S. GSE obligations $ — $ — $ 14,980 $ (17 ) $ 14,980 $ (17 ) Mortgage-backed securities — — 47,096 (138 ) 47,096 (138 ) Corporate debt securities — — — — — — Municipal securities — — 312 — 312 — Total held to maturity securities $ — $ — $ 62,388 $ (155 ) $ 62,388 $ (155 ) Total temporarily impaired securities $ 6,844 $ (41 ) $ 178,446 $ (1,185 ) $ 185,290 $ (1,226 ) December 31, 2018 Less than 12 months 12 months or longer Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (dollars in thousands) Temporarily Impaired Securities Available for sale securities U.S. GSE obligations $ — $ — $ 74,039 $ (965 ) $ 74,039 $ (965 ) Mortgage-backed securities — — 86,815 (3,121 ) 86,815 (3,121 ) Corporate debt securities 902 (98 ) 3,954 (61 ) 4,856 (159 ) Total available for sale securities $ 902 $ (98 ) $ 164,808 $ (4,147 ) $ 165,710 $ (4,245 ) Held to maturity securities U.S. GSE obligations $ 4,995 $ (5 ) $ 27,338 $ (233 ) $ 32,333 $ (238 ) Mortgage-backed securities 30,719 (216 ) 93,225 (2,074 ) 123,944 (2,290 ) Corporate debt securities 6,865 (107 ) — — 6,865 (107 ) Municipal securities 8,484 (82 ) 8,313 (273 ) 16,797 (355 ) Total held to maturity securities $ 51,063 $ (410 ) $ 128,876 $ (2,580 ) $ 179,939 $ (2,990 ) Total temporarily impaired securities $ 51,965 $ (508 ) $ 293,684 $ (6,727 ) $ 345,649 $ (7,235 )
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 guaranteed 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 Within Five Years After Five, But Within Ten Years After Ten Years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value At June 30, 2019 (dollars in thousands) Available for sale securities U.S. GSE obligations $ 10,000 $ 9,971 $ 40,000 $ 39,844 $ — $ — $ — $ — $ 50,000 $ 49,815 Mortgage-backed securities — — 58 59 29,462 29,176 74,245 74,003 103,765 103,238 Corporate debt securities — — — — — — — — — — Total available for sale securities $ 10,000 $ 9,971 $ 40,058 $ 39,903 $ 29,462 $ 29,176 $ 74,245 $ 74,003 $ 153,765 $ 153,053 Held to maturity securities U.S. GSE obligations $ 4,997 $ 4,982 $ 17,575 $ 17,576 $ — $ — $ — $ — $ 22,572 $ 22,558 Mortgage-backed securities 8 8 — — 52,063 53,202 129,705 131,218 181,776 184,428 Corporate debt securities — — 6,977 7,069 — — — — 6,977 7,069 Municipal securities 2,424 2,445 12,746 12,970 43,956 46,051 15,899 16,472 75,025 77,938 Total held to maturity securities $ 7,429 $ 7,435 $ 37,298 $ 37,615 $ 96,019 $ 99,253 $ 145,604 $ 147,690 $ 286,350 $ 291,993 Total $ 17,429 $ 17,406 $ 77,356 $ 77,518 $ 125,481 $ 128,429 $ 219,849 $ 221,693 $ 440,115 $ 445,046
Summary of Gains (Losses) from Sale of Investment Securities	The following table sets forth information regarding sales of investment securities and the resulting gains (losses) from such sales: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Amortized cost of securities sold $ 10,231 $ 700 $ 26,231 $ 700 Gain/(loss) realized on securities sold 6 2 (81 ) 2 Net proceeds from securities sold $ 10,237 $ 702 $ 26,150 $ 702

Loans and the Allowance for L_2

Loans and the Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Loans Outstanding by Category	Loans outstanding are detailed by category as follows: June 30, 2019 December 31, 2018 (dollars in thousands) Residential mortgage Mortgages - fixed rate $ 409,706 $ 293,267 Mortgages - adjustable rate 498,694 309,656 Construction 28,437 — Deferred costs net of unearned fees 1,722 1,408 Total residential mortgages 938,559 604,331 Commercial mortgage Mortgages - nonowner occupied 788,982 654,394 Mortgages - owner occupied 64,520 59,335 Construction 51,816 44,146 Deferred costs net of unearned fees 124 82 Total commercial mortgages 905,442 757,957 Home equity Home equity - lines of credit 79,814 63,421 Home equity - term loans 5,763 5,665 Deferred costs net of unearned fees 237 250 Total home equity 85,814 69,336 Commercial & industrial Commercial & industrial 134,338 93,728 Deferred costs (fees) net of unearned fees (31 ) (16 ) Total commercial & industrial 134,307 93,712 Consumer Secured 31,380 33,252 Unsecured 1,035 1,171 Deferred costs net of unearned fees 13 13 Total consumer 32,428 34,436 Total loans $ 2,096,550 $ 1,559,772
Non-performing Loans Disaggregated by Loan Category	The following tables set forth information regarding non-performing loans disaggregated by loan category: June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 507 $ 135 $ 12 $ 298 $ — $ 952 Loans past due >90 days, but still accruing — — — — — — Troubled debt restructurings 105 — — — — 105 Total $ 612 $ 135 $ 12 $ 298 $ — $ 1,057 December 31, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Non-performing loans: Non-accrual loans $ 512 $ — $ 13 $ — $ — $ 525 Loans past due >90 days, but still accruing — — — — — — Troubled debt restructurings 111 — — 6 — 117 Total $ 623 $ — $ 13 $ 6 $ — $ 642
Loans Receivable Disaggregated by Credit Quality Indicator	. The following tables contain period-end balances of loans receivable disaggregated by credit quality indicator: June 30, 2019 Residential Mortgages Home Equity Consumer (dollars in thousands) Credit risk profile based on payment activity: Performing $ 937,947 $ 85,802 $ 32,428 Non-performing 612 12 — Total $ 938,559 $ 85,814 $ 32,428 Commercial Mortgages Commercial & Industrial Credit risk profile by internally assigned grade: 1-6 (Pass) $ 895,336 $ 125,763 7 (Special Mention) 9,571 3,487 8 (Substandard) 535 5,057 9 (Doubtful) — — 10 (Loss) — — Total $ 905,442 $ 134,307 December 31, 2018 Residential Mortgages Home Equity Consumer (dollars in thousands) Credit risk profile based on payment activity: Performing $ 603,708 $ 69,323 $ 34,436 Non-performing 623 13 — Total $ 604,331 $ 69,336 $ 34,436 Commercial Mortgages Commercial & Industrial Credit risk profile by internally assigned grade: 1-6 (Pass) $ 753,338 $ 85,821 7 (Special Mention) 4,619 4,186 8 (Substandard) — 3,705 9 (Doubtful) — — 10 (Loss) — — Total $ 757,957 $ 93,712
Schedule of Loans Receivable Disaggregated by Past Due Status	The following tables contain period-end balances of loans receivable disaggregated by past due status: June 30, 2019 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Total Past Due Current Loans Total (dollars in thousands) Residential Mortgages $ 2,093 $ 721 $ 385 $ 3,199 $ 935,360 $ 938,559 Commercial Mortgages 1,943 — — 1,943 903,499 905,442 Home Equity — 12 — 12 85,802 85,814 Commercial & Industrial 425 — 159 584 133,723 134,307 Consumer loans 2 4 — 6 32,422 32,428 Total $ 4,463 $ 737 $ 544 $ 5,744 $ 2,090,806 $ 2,096,550 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Total Past Due Current Loans Total (dollars in thousands) Residential Mortgages $ 1,034 $ 121 $ 351 $ 1,506 $ 602,825 $ 604,331 Commercial Mortgages — — — — 757,957 757,957 Home Equity — — — — 69,336 69,336 Commercial & Industrial — — — — 93,712 93,712 Consumer loans 108 — — 108 34,328 34,436 Total $ 1,142 $ 121 $ 351 $ 1,614 $ 1,558,158 $ 1,559,772
Information Pertaining to Impaired Loans	The following tables present information pertaining to impaired loans: For the Three Months Ended June 30, 2019 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ — $ — $ — $ — $ — Commercial mortgage — — — — — Residential mortgage 616 620 778 — 1 Home equity 96 97 133 — — Total 712 717 911 — 1 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage 616 620 778 — 1 Home equity 96 97 133 — — Total $ 712 $ 717 $ 911 $ — $ 1 For the Six Months Ended June 30, 2019 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ — $ — $ — $ — $ — Commercial mortgage — — — — — Residential mortgage 616 625 778 — 2 Home equity 96 97 133 — 1 Total 712 722 911 — 3 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage 616 625 778 — 2 Home equity 96 97 133 — 1 Total $ 712 $ 722 $ 911 $ — $ 3 For the Three Months Ended June 30, 2018 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ 17 $ 20 $ 17 $ — $ — Commercial mortgage 213 213 227 — — Residential mortgage 845 848 1,051 — — Home equity 66 67 98 — — Total 1,141 1,148 1,393 — — With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial 17 20 17 — — Commercial mortgage 213 213 227 — — Residential mortgage 845 848 1,051 — — Home equity 66 67 98 — — Total $ 1,141 $ 1,148 $ 1,393 $ — $ — For the Six Months Ended June 30, 2018 Carrying Value Average Carrying Value Unpaid Principal Balance Related Allowance Interest Income Recognized (dollars in thousands) With no required reserve recorded: Commercial and industrial $ 17 $ 22 $ 17 $ — $ 1 Commercial mortgage 213 213 227 — — Residential mortgage 845 851 1,051 — — Home equity 66 68 98 — — Total 1,141 1,154 1,393 — 1 With required reserve recorded: Commercial and industrial — — — — — Commercial mortgage — — — — — Residential mortgage — — — — — Home equity — — — — — Total — — — — — Total: Commercial and industrial 17 22 17 — 1 Commercial mortgage 213 213 227 — — Residential mortgage 845 851 1,051 — — Home equity 66 68 98 — — Total $ 1,141 $ 1,154 $ 1,393 $ — $ 1
Summary of Changes in Allowance for Loan Losses Disaggregated by Loan Type	The following tables contain changes in the allowance for loan losses disaggregated by loan category June 30, 2019: For the Three Months Ended June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at March 31, 2019 $ 5,256 $ 9,369 $ 534 $ 1,245 $ 248 $ — $ 16,652 Charge-offs — (55 ) — (100 ) (9 ) — (164 ) Recoveries — — — 12 4 — 16 Provision for (Release of) 207 115 (3 ) 288 (12 ) — 595 Balance at June 30, 2019 $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ — $ 17,099 For the Six Months Ended June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at December 31, 2018 $ 4,946 $ 9,626 $ 517 $ 1,415 $ 264 $ — $ 16,768 Charge-offs — (55 ) — (130 ) (20 ) — (205 ) Recoveries — — — 25 8 — 33 Provision for (Release of) 517 (142 ) 14 135 (21 ) — 503 Balance at June 30, 2019 $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ — $ 17,099 For the Three Months Ended June 30, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at March 31, 2018 $ 4,692 $ 8,937 $ 570 $ 1,145 $ 298 $ 90 $ 15,732 Charge-offs — — — (6 ) (17 ) — (23 ) Recoveries — — — 12 3 — 15 Provision for (Release of) 187 (263 ) 31 44 12 (90 ) (79 ) Balance at June 30, 2018 $ 4,879 $ 8,674 $ 601 $ 1,195 $ 296 $ — $ 15,645 For the Six Months Ended June 30, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Impaired Total (dollars in thousands) Allowance for loan losses: Balance at December 31, 2017 $ 5,047 $ 8,289 $ 630 $ 946 $ 315 $ 93 $ 15,320 Charge-offs — — — (11 ) (21 ) — (32 ) Recoveries — — — 22 5 — 27 Provision for (Release of) (168 ) 385 (29 ) 238 (3 ) (93 ) 330 Balance at June 30, 2018 $ 4,879 $ 8,674 $ 601 $ 1,195 $ 296 $ — $ 15,645
Summary of Allowance for Loan Losses and Related Loans Receivable Disaggregated by Impairment Method	The following tables contain period-end balances of the allowance for loan losses and related loans receivable disaggregated by impairment method: June 30, 2019 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Allowance for loan losses Individually evaluated for impairment $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 5,463 9,429 531 1,445 231 17,099 Total $ 5,463 $ 9,429 $ 531 $ 1,445 $ 231 $ 17,099 Loans receivable Individually evaluated for impairment $ 616 $ — $ 96 $ — $ — $ 712 Collectively evaluated for impairment 937,943 905,442 85,718 134,307 32,428 2,095,838 Total $ 938,559 $ 905,442 $ 85,814 $ 134,307 $ 32,428 $ 2,096,550 December 31, 2018 Residential Mortgages Commercial Mortgages Home Equity Commercial & Industrial Consumer Total (dollars in thousands) Allowance for loan losses Individually evaluated for impairment $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 4,946 9,626 517 1,415 264 16,768 Total $ 4,946 $ 9,626 $ 517 $ 1,415 $ 264 $ 16,768 Loans receivable Individually evaluated for impairment $ 647 $ — $ 88 $ 5 $ — $ 740 Collectively evaluated for impairment 603,684 757,957 69,248 93,707 34,436 1,559,032 Total $ 604,331 $ 757,957 $ 69,336 $ 93,712 $ 34,436 $ 1,559,772

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Schedule of Mortgage Servicing Rights	An analysis of mortgage servicing rights, which are included in other assets, follows: Mortgage Servicing Rights Valuation Allowance Total (dollars in thousands) Balance at December 31, 2017 $ 823 $ (30 ) $ 793 Mortgage servicing rights capitalized 5 — 5 Amortization charged against servicing income (70 ) — (70 ) Change in impairment reserve (30 ) 30 — Balance at June 30, 2018 $ 728 $ — $ 728 Balance at December 31, 2018 $ 666 $ — $ 666 Mortgage servicing rights acquired as a result of the merger 334 — 334 Mortgage servicing rights capitalized 7 — 7 Amortization charged against servicing income (106 ) — (106 ) Change in impairment reserve — (10 ) (10 ) Balance at June 30, 2019 $ 901 $ (10 ) $ 891
Mortgage Servicing Rights
Schedule of Aggregate Estimated Future Amortization Expense	The estimated aggregate future amortization expense for mortgage servicing rights for each of the next five years and thereafter is as follows: Future Amortization Expense (dollars in thousands) Remainder of 2019 $ 74 2020 133 2021 113 2022 96 2023 81 Thereafter 404 Total $ 901

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	The components of income tax expense were as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Current Federal $ 1,305 $ 1,642 $ 1,676 $ 2,235 State 552 679 719 932 Total current expense 1,857 2,321 2,395 3,167 Deferred Federal (217 ) (286 ) 601 238 State (100 ) (134 ) 284 112 Total deferred (317 ) (420 ) 885 350 Total income tax expense $ 1,540 $ 1,901 $ 3,280 $ 3,517

Pension and Retirement Plans (T

Pension and Retirement Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Compensation And Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost (Credit)	The components of net periodic benefit cost (credit) were as follows: Three Months Ended June 30, Pension Plan Supplemental Retirement Plan Retirement Healthcare Plan 2019 2018 2019 2018 2019 2018 (dollars in thousands) Net periodic benefit cost Service cost $ — $ — $ 75 $ 88 $ 5 $ 5 Interest cost 414 392 85 77 6 6 Expected return on assets (651 ) (722 ) — — — — Amortization of prior service cost (credit) (1 ) (1 ) — — — — Amortization of net actuarial loss 77 37 — 1 (1 ) (5 ) Net periodic benefit cost (credit) $ (161 ) $ (294 ) $ 160 $ 166 $ 10 $ 6 Six Months Ended June 30, Pension Plan Supplemental Retirement Plan Retirement Healthcare Plan 2019 2018 2019 2018 2019 2018 (dollars in thousands) Net periodic benefit cost Service cost $ — $ — 143 $ 177 10 $ 11 Interest cost 840 778 175 154 12 11 Expected return on assets (1,360 ) (1,445 ) — — — — Amortization of prior service (credit) (2 ) (2 ) — — — — Amortization of net actuarial loss 77 53 — 2 (2 ) — Net periodic benefit cost (credit) $ (445 ) $ (616 ) $ 318 $ 333 $ 20 $ 22

Stock Based Compensation (Table

Stock Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Share Based Compensation [Abstract]
Schedule of Shares Issued and Fair Value of RSAs	During the three months ended June 30, 2019, the Company issued the following RSAs from the 2017 Equity and Cash Incentive Plan. T he fair value of RSAs is based upon the Company’s common stock closing share price on the date of the grant. The holders of RSAs participate fully in the rewards of stock ownership of the Company, including voting and dividend rights. There were no RSUs issued during the three months ended Weighted- Average Shares Granted Fair Value at Grant Date Type of Award 950 $ 84.66 RSAs
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, PRSUs, and the related tax benefits recognized: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands) Stock based compensation expense $ 699 $ 807 $ 1,318 $ 1,347 Related tax benefits $ 197 $ 227 $ 370 $ 379

Financial Instruments with Of_2

Financial Instruments with Off-Balance-Sheet Risk (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 (dollars in thousands) Financial instruments whose contractual amount represents credit risk: Commitments to extend credit: Unused portion of existing lines of credit $ 405,900 $ 368,410 Origination of new loans 59,930 24,505 Standby letters of credit 8,439 8,752 Financial instruments whose notional amount exceeds the amount of credit risk: Commitments to sell residential mortgage loans 3,188 —

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Summary of Right-of-Use Asset and Net Lease Liability	The following table summarizes information related to the Company’s right-of-use asset and net lease liability: June 30, 2019 Operating Leases Balance Sheet Location (dollars in thousands) Right-of-use asset $ 35,604 Other assets Lease liability $ 36,982 Other liabilities
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 June 30, Six Months Ended June 30, 2019 2019 (dollars in thousands) Operating lease cost $ 1,321 $ 2,501 Short-term lease cost — — Variable lease cost (Cost excluded from lease payments) — — Sublease income (16 ) (32 ) Total Operating Lease Cost $ 1,305 $ 2,469 Other Information Cash paid for amounts included in the measurement of lease liabilities - operating cash flows from operating leases $ 1,231 $ 2,308 Operating Lease - Operating Cash Flows (Liability reduction) 937 1,744 Right-of-use assets obtained in exchange for new operating lease liabilities 4,656 4,656 Weighted average lease term - operating Leases 8.56 Years 8.56 Years Weighted average discount Rate - operating leases 3.38 % 3.38 %
Schedule of Total Minimum Rentals Due in Future Periods under Lease Agreements	The total minimum rentals due in future periods under these agreements in effect at June 30, 2019 and December 31, 2018 were as follows: Future Minimum June 30, 2019 Lease Payments (dollars in thousands) Remainder of 2019 5,426 2020 5,527 2021 5,428 2022 5,181 2023 4,864 Thereafter 16,380 Total minimum lease payments 42,806 Less: interest (5,824 ) Total lease liability $ 36,982 Year Ended Future Minimum December 31, Lease Payments (dollars in thousands) 2019 4,448 2020 4,661 2021 4,662 2022 4,553 2023 4,455 Thereafter 17,128 Total minimum lease payments $ 39,907

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Schedule of Minimum Capital Requirements Considered Well Capitalized by FRB and FDIC	As of June 30, 2019 and December 31, 2018, the Company and the Bank met all applicable minimum capital requirements and were considered “well-capitalized” by both the FRB and the FDIC. Actual Minimum Capital Required For Capital Adequacy Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer (1) Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At June 30, 2019 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 222,152 11.8 % $ 150,732 8.0 % $ 197,836 10.5 % N/A N/A Tier I capital (to risk-weighted assets) 205,002 10.9 % 113,049 6.0 % 160,153 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 205,002 10.9 % 84,787 4.5 % 131,891 7.0 % N/A N/A Tier I capital (to average assets) 205,002 7.9 % 103,327 4.0 % 103,327 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 218,012 11.6 % $ 150,732 8.0 % $ 197,836 10.5 % $ 188,415 10.0 % Tier I capital (to risk-weighted assets) 200,862 10.7 % 113,049 6.0 % 160,153 8.5 % 150,732 8.0 % Common equity tier I capital (to risk-weighted assets) 200,862 10.7 % 84,787 4.5 % 131,891 7.0 % 122,470 6.5 % Tier I capital (to average assets) 200,862 7.8 % 103,327 4.0 % 103,327 4.0 % 129,158 5.0 % (1) The 2013 Capital Rules adopted by the Federal Reserve, Office of the Comptroller of the Currency, and the Federal Deposit Insurance Corporation implementing Basel III were fully phased-in effective January 1, 2019. Actual Minimum Capital Required For Capital Adequacy Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) At December 31, 2018 Cambridge Bancorp: Total capital (to risk-weighted assets) $ 189,888 13.2 % $ 114,666 8.0 % $ 141,541 9.875 % $ 150,500 10.5 % N/A N/A Tier I capital (to risk-weighted assets) 173,070 12.1 % 86,000 6.0 % 112,875 7.875 % 121,833 8.5 % N/A N/A Common equity tier I capital (to risk-weighted assets) 173,070 12.1 % 64,500 4.5 % 91,375 6.375 % 100,333 7.0 % N/A N/A Tier I capital (to average assets) 173,070 8.5 % 81,507 4.0 % 81,507 4.000 % 81,507 4.0 % N/A N/A Cambridge Trust Company: Total capital (to risk-weighted assets) $ 185,507 12.9 % $ 114,666 8.0 % $ 141,541 9.875 % $ 150,500 10.5 % $ 143,333 10.0 % Tier I capital (to risk-weighted assets) 168,689 11.8 % 86,000 6.0 % 112,875 7.875 % 121,833 8.5 % 114,666 8.0 % Common equity tier I capital (to risk-weighted assets) 168,689 11.8 % 64,500 4.5 % 91,375 6.375 % 100,333 7.0 % 93,166 6.5 % Tier I capital (to average assets) 168,689 8.3 % 81,507 4.0 % 81,507 4.000 % 81,507 4.0 % 101,884 5.0 %

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Summary of Other Comprehensive Income	The following table presents the changes in accumulated other comprehensive income (loss) during the period, by component, net of tax: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount (dollars in thousands) Unrealized (losses)/gains on available for sale securities Unrealized holding (losses)/gains arising during period $ 1,909 $ (456 ) $ 1,453 $ (550 ) $ 127 $ (423 ) Reclassification adjustment for (gains)/losses recognized in net income (6 ) 2 (4 ) (2 ) — (2 ) Derivatives Change in interest rate contracts 1,696 (477 ) 1,219 — — — Defined benefit retirement plans Change in retirement liability 36 (10 ) 26 15 (5 ) 10 Total Other Comprehensive (Loss)/Income $ 3,635 $ (941 ) $ 2,694 $ (537 ) $ 122 $ (415 ) Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount Before Tax Amount Tax (Expense) or Benefit Net-of-tax Amount (dollars in thousands) Unrealized (losses)/gains on available for sale securities Unrealized holding (losses)/gains arising during period $ 3,334 $ (786 ) $ 2,548 $ (2,228 ) $ 453 $ (1,775 ) Reclassification adjustment for (gains)/losses recognized in net income 81 (19 ) 62 (2 ) — (2 ) Derivatives Change in interest rate contracts 1,654 (465 ) 1,189 — — — Defined benefit retirement plans Change in retirement liability 72 (20 ) 52 29 (9 ) 20 Total Other Comprehensive (Loss)/Income $ 5,141 $ (1,290 ) $ 3,851 $ (2,201 ) $ 444 $ (1,757 )
Summary of Reclassifications out of Accumulated Other Comprehensive Income ("AOCI")	Reclassifications out of Accumulated Other Comprehensive Income (“AOCI”) that have an impact on net income are presented below: Three Months Ended June 30, Details about Accumulated Other Comprehensive Income Components 2019 2018 Affected Line Item in the Statement where Net Income is Presented (dollars in thousands) Unrealized gains and losses on available for sale securities $ 6 $ 2 Gain/(loss) on disposition of investment securities Tax benefit or (expense) (2 ) — Provision for income taxes Net of tax $ 4 $ 2 Net income Six Months Ended June 30, Details about Accumulated Other Comprehensive Income Components 2019 2018 Affected Line Item in the Statement where Net Income is Presented (dollars in thousands) Unrealized gains and losses on available for sale securities $ (81 ) $ 2 Gain/(loss) on disposition of investment securities Tax benefit or (expense) 19 — Provision for income taxes Net of tax $ (62 ) $ 2 Net income

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 (dollars in thousands, except per share data) Earnings per common share - basic: Numerator: Net income $ 4,272 $ 6,111 $ 10,470 $ 11,916 Less dividends and undistributed earnings allocated to participating securities (35 ) (60 ) (94 ) (121 ) Net income applicable to common shareholders $ 4,237 $ 6,051 $ 10,376 $ 11,795 Denominator: Weighted average common shares outstanding 4,682 4,060 4,379 4,057 Earnings per common share - basic $ 0.91 $ 1.49 $ 2.37 $ 2.91 Earnings per common share - diluted: Numerator: Net income $ 4,272 $ 6,111 $ 10,470 $ 11,916 Less dividends and undistributed earnings allocated to participating securities (35 ) (60 ) (94 ) (121 ) Net income applicable to common shareholders $ 4,237 $ 6,051 $ 10,376 $ 11,795 Denominator: Weighted average common shares outstanding 4,682 4,060 4,379 4,057 Dilutive effect of common stock equivalents 34 34 33 31 Weighted average diluted common shares outstanding 4,716 4,094 4,412 4,088 Earnings per common share - diluted $ 0.90 $ 1.48 $ 2.35 $ 2.89

Derivative And Hedging Activi_2

Derivative And Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 3,528 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 3,528 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 181,291 Other Assets $ 12,348 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 181,291 Other Liabilities 12,348 Risk participation agreements out to counterparties 19,000 Other Assets 46 — Other Liabilities — Risk participation agreements in with counterparties — Other Assets — 78,700 Other Liabilities 459 Total derivatives not designated as hedging instruments $ 12,394 $ 12,807 December 31, 2018 Derivative Assets Derivative Liabilities Notional Amount Balance Sheet Location Fair Value Notional Amount Balance Sheet Location Fair Value (dollars in thousands) (dollars in thousands) Derivatives designated as hedging instruments Interest rate contracts $ 150,000 Other Assets $ 1,970 $ — Other Liabilities $ — Total derivatives designated as hedging instruments $ 1,970 $ — Derivatives not designated as hedging instruments Loan related derivative contracts Interest rate swaps with customers $ 150,489 Other Assets $ 5,782 $ — Other Liabilities $ — Mirror swaps with counterparties — Other Assets — 150,489 Other Liabilities 5,782 Risk participation agreements out to counterparties 19,000 Other Assets 28 — Other Liabilities — Risk participation agreements in with counterparties — Other Assets — 63,825 Other Liabilities 179 Total derivatives not designated as hedging instruments $ 5,810 $ 5,961
Summary of Cash Flow Hedge Accounting on Accumulated Other Comprehensive Income	The following table presents the effect of cash flow hedge accounting on accumulated other comprehensive income (“AOCI”) at June 30, 2019: Amount of Gain or (Loss) Recognized in OCI Amount of Gain or (Loss) Recognized in OCI Included Component Amount of Gain or (Loss) Recognized in OCI Excluded Component Location of Gain or (Loss) Amount of Gain or (Loss) Reclassified from AOCI into Income Amount of Gain or (Loss) Reclassified from AOCI into Income Included Component Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component Three Months Ended June 30, 2019 Three Months Ended June 30, 2019 (dollars in thousands) (dollars in thousands) Interest rate contracts $ 1,647 $ 2,080 $ (433 ) Interest Income $ (48 ) $ — $ (48 ) Total $ 1,647 $ 2,080 $ (433 ) $ (48 ) $ — $ (48 ) Amount of Gain or (Loss) Recognized in OCI Amount of Gain or (Loss) Recognized in OCI Included Component Amount of Gain or (Loss) Recognized in OCI Excluded Component Location of Gain or (Loss) Amount of Gain or (Loss) Reclassified from AOCI into Income Amount of Gain or (Loss) Reclassified from AOCI into Income Included Component Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component Six Months Ended June 30, 2019 Six Months Ended June 30, 2019 (dollars in thousands) (dollars in thousands) Interest rate contracts $ 1,558 $ 2,080 $ (522 ) Interest Income $ (96 ) $ — $ (96 ) Total $ 1,558 $ 2,080 $ (522 ) $ (96 ) $ — $ (96 )
Summary of Derivative Financial Instruments Income Statement	The following table presents the effect of the Company’s derivative financial instruments on the Income Statement at June 30, 2019: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Interest Income Interest Income (dollars in thousands) Total amount of income presented in the income statement in which the effects of fair value or cash flow hedges are recorded $ (48 ) $ (96 ) The effects of fair value and cash flow hedging: Gain or (loss) on cash flow hedging relationships in Subtopic 815-20 Interest rate contracts Amount of gain or (loss) reclassed from AOCI into income $ (48 ) $ (96 ) Amount of gain or (loss) reclassed from AOCI into income - Included Component — — Amount of gain or (loss) reclassed from AOCI into income - Excluded Component $ (48 ) $ (96 )
Summary of Derivative Financial Instruments Not Designated as Hedging Instruments	The following tables present the effect of the Company’s derivative financial instruments that are not designated as hedging instruments on the Income Statement as of the periods presented: Amount of Gain or (Loss) Recognized in Income on Derivative Three Months Ended June 30, Three Months Ended June 30, 2019 2018 Location of Gain or (Loss) (dollars in thousands) Other contracts Other income $ (61 ) $ 12 Total $ (61 ) $ 12 Amount of Gain or (Loss) Recognized in Income on Derivative Six Months Ended June 30, Six Months Ended June 30, 2019 2018 Location of Gain or (Loss) (dollars in thousands) Other contracts Other income $ 13 $ 40 Total $ 13 $ 40
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 sheet as June 30, 2019 and December 31, 2018: Gross Amounts Not Offset Gross Amounts of Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount June 30, 2019 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 15,922 $ — $ 15,922 $ 3,663 $ — $ 12,259 Offsetting of Derivative Liabilities Derivative Liabilities $ 12,807 $ — $ 12,807 $ 3,663 $ 8,428 $ 716 Gross Amounts Not Offset Gross Amounts of Recognized Gross Amounts Offset Net Amounts Recognized Financial Instruments Collateral Pledged (Received) Net Amount December 31, 2018 (dollars in thousands) Offsetting of Derivative Assets Derivative Assets $ 7,780 $ — $ 7,780 $ 3,099 $ (743 ) $ 3,938 Offsetting of Derivative Liabilities Derivative Liabilities $ 5,961 $ — $ 5,961 $ 3,099 $ 260 $ 2,602

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
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: June 30, 2019 December 31, 2018 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (dollars in thousands) Financial assets Cash and cash equivalents $ 38,557 $ 38,557 $ 18,473 $ 18,473 Securities available for sale 153,053 153,053 168,163 168,163 Securities held to maturity 286,350 291,993 282,869 281,310 Loans, net 2,079,451 2,036,666 1,543,004 1,484,905 Loans held for sale 384 384 — — FHLB Boston stock 8,245 8,245 6,844 6,844 Accrued interest receivable 7,485 7,485 5,762 5,762 Mortgage servicing rights 891 1,105 666 941 Interest rate contracts 3,528 3,528 1,970 1,970 Loan level interest rate swaps 12,348 12,348 5,782 5,782 Risk participation agreements out to counterparties 46 46 28 28 Financial liabilities Deposits 2,329,665 2,328,568 1,811,410 1,809,051 Short-term borrowings 103,000 103,031 90,000 90,000 Long-term borrowings 3,323 3,316 3,409 3,363 Loan level interest rate swaps 12,348 12,348 5,782 5,782 Risk participation agreements in with counterparties 459 459 179 179
Summary of Certain Assets Reported at Fair Value on a Recurring Basis	The following tables summarize certain assets reported at fair value on a recurring basis: Fair Value as of June 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 49,815 $ — $ 49,815 Mortgage-backed securities — 103,238 — 103,238 Corporate debt securities — — — — Other assets Interest rate swaps with customers — 12,348 — 12,348 Risk participation agreements out to counterparties — 46 — 46 Interest rate contracts — 3,528 — 3,528 Other liabilities Mirror swaps with counterparties — 12,348 — 12,348 Risk participation agreements in with counterparties — 459 — 459 Fair Value as of December 31, 2018 Level 1 Level 2 Level 3 Total (dollars in thousands) Measured on a recurring basis Securities available for sale U.S. GSE obligations $ — $ 74,039 $ — $ 74,039 Mortgage-backed securities — 89,268 — 89,268 Corporate debt securities — 4,856 — 4,856 Other assets Interest rate swaps with customers — 5,782 — 5,782 Risk participation agreements out to counterparties — 28 — 28 Interest rate contracts — 1,970 — 1,970 Other liabilities Mirror swaps with counterparties — 5,782 — 5,782 Risk participation agreements in with counterparties — 179 — 179
Schedule of Carrying Value of Assets Measured at Fair Value on a Non-Recurring Basis	The following table presents the carrying value of assets held at June 30, 2019, which were measured at fair value on a non-recurring basis during the three and six months ended June 30, 2019: June 30, 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Items recorded at fair value on a nonrecurring basis Assets Collateral dependent impaired loans $ — $ — $ — $ — Loans held for sale — — 384 384 Other real estate owned — — 185 185 Total $ — $ — $ 569 $ 569

Mergers - Additional Informatio

Mergers - Additional Information (Details) $ / shares in Units, $ in Thousands	Apr. 17, 2019USD ($)$ / sharesshares	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)
Business Acquisition [Line Items]
Merger expenses		$ 3,450	$ 3,541
Optima Bank And Trust Company
Business Acquisition [Line Items]
Business combination, conversion price per share | $ / shares	$ 32
Business combination, share conversion ratio	0.3468
Business combination percentage of common stock transaction	95.00%
Business combination percentage of cash transaction	5.00%
Common stock issued related to merger | shares	722,746
Cash payment related to merger	$ 3,500
Total consideration paid	$ 64,300
Merger expenses		3,500	3,500
Merger-related costs		$ 3,500	$ 3,500

Mergers - Summary of Estimated

Mergers - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($)	Jun. 30, 2019	Apr. 17, 2019	Dec. 31, 2018
Assets
Goodwill	$ 31,206,000		$ 412,000
Optima Bank And Trust Company
Assets
Cash and cash equivalents		$ 6,902,000
Investments		23,298,000
Loans		475,406,000
Premises and equipment		6,286,000
Goodwill	$ 30,800,000	30,794,000
Core deposit and other intangibles		3,609,000
Other assets		9,408,000
Total assets acquired		555,703,000
Liabilities
Deposits		477,189,000
Borrowings		13,459,000
Other liabilities		799,000
Total liabilities assumed		491,447,000
Purchase price		$ 64,256,000

Mergers - Summary of Selected P

Mergers - Summary of Selected Pro Forma Financial Information (Details) - Optima Bank And Trust Company - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Net interest and dividend income after provision for loan losses	$ 19,780	$ 19,364	$ 39,776	$ 37,737
Net Income	$ 8,075	$ 6,646	$ 14,988	$ 13,207

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Standards - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Right-of-use asset	$ 35,604
Accounting Standards Update 2016-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Right-of-use asset		$ 32,900

Cash and Cash Equivalents - Add

Cash and Cash Equivalents - Additional Information (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Cash And Cash Equivalents [Line Items]
Cash and cash equivalents	$ 38,557,000	$ 18,473,000	$ 35,119,000	$ 103,591,000
Federal Reserve Bank of Boston
Cash And Cash Equivalents [Line Items]
Reserve balance of cash and due from banks	26,900,000	12,700,000
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	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	$ 153,765	$ 172,290
Available for sale securities, Gross Unrealized Gains	359	118
Available for sale securities, Gross Unrealized Losses	(1,071)	(4,245)
Available for sale securities, Fair Value	153,053	168,163
Held to maturity securities, Amortized Cost	286,350	282,869
Held to maturity securities, Gross Unrealized Gains	5,798	1,431
Held to maturity securities, Gross Unrealized Losses	(155)	(2,990)
Held to maturity securities, Fair Value	291,993	281,310
Total, Amortized Cost	440,115	455,159
Total, Gross Unrealized Gains	6,157	1,549
Total, Gross Unrealized Losses	(1,226)	(7,235)
Total, Fair Value	445,046	449,473
U.S. GSE Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	50,000	75,004
Available for sale securities, Gross Unrealized Gains	1
Available for sale securities, Gross Unrealized Losses	(186)	(965)
Available for sale securities, Fair Value	49,815	74,039
Held to maturity securities, Amortized Cost	22,572	32,571
Held to maturity securities, Gross Unrealized Gains	3
Held to maturity securities, Gross Unrealized Losses	(17)	(238)
Held to maturity securities, Fair Value	22,558	32,333
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost		5,015
Available for sale securities, Gross Unrealized Losses		(159)
Available for sale securities, Fair Value		4,856
Held to maturity securities, Amortized Cost	6,977	6,972
Held to maturity securities, Gross Unrealized Gains	92
Held to maturity securities, Gross Unrealized Losses		(107)
Held to maturity securities, Fair Value	7,069	6,865
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Amortized Cost	103,765	92,271
Available for sale securities, Gross Unrealized Gains	358	118
Available for sale securities, Gross Unrealized Losses	(885)	(3,121)
Available for sale securities, Fair Value	103,238	89,268
Held to maturity securities, Amortized Cost	181,776	168,118
Held to maturity securities, Gross Unrealized Gains	2,790	134
Held to maturity securities, Gross Unrealized Losses	(138)	(2,290)
Held to maturity securities, Fair Value	184,428	165,962
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Amortized Cost	75,025	75,208
Held to maturity securities, Gross Unrealized Gains	2,913	1,297
Held to maturity securities, Gross Unrealized Losses		(355)
Held to maturity securities, Fair Value	$ 77,938	$ 76,150

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	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Temporarily Impaired Securities, Available for sale securities, Fair Value, Less than 12 months	$ 6,844	$ 902
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, Less than 12 months	(41)	(98)
Temporarily Impaired Securities, Available for sale securities, Fair Value, 12 months or longer	116,058	164,808
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, 12 months or longer	(1,030)	(4,147)
Temporarily Impaired Securities, Available for sale securities, Fair Value	122,902	165,710
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses	(1,071)	(4,245)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, Less than 12 months		51,063
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, Less than 12 months		(410)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, 12 months or longer	62,388	128,876
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, 12 months or longer	(155)	(2,580)
Temporarily Impaired Securities, Held to maturity securities, Fair Value	62,388	179,939
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses	(155)	(2,990)
Temporarily Impaired Securities, Fair Value, Less than 12 months	6,844	51,965
Temporarily Impaired Securities, Unrealized Losses, Less than 12 months	(41)	(508)
Temporarily Impaired Securities, Fair Value, 12 months or longer	178,446	293,684
Temporarily Impaired Securities, Unrealized Losses, 12 months or longer	(1,185)	(6,727)
Temporarily Impaired Securities, Fair Value	185,290	345,649
Temporarily Impaired Securities, Unrealized Losses	(1,226)	(7,235)
U.S. GSE Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Temporarily Impaired Securities, Available for sale securities, Fair Value, 12 months or longer	44,814	74,039
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, 12 months or longer	(186)	(965)
Temporarily Impaired Securities, Available for sale securities, Fair Value	44,814	74,039
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses	(186)	(965)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, Less than 12 months		4,995
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, Less than 12 months		(5)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, 12 months or longer	14,980	27,338
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, 12 months or longer	(17)	(233)
Temporarily Impaired Securities, Held to maturity securities, Fair Value	14,980	32,333
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses	(17)	(238)
Mortgage Backed Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Temporarily Impaired Securities, Available for sale securities, Fair Value, Less than 12 months	6,844
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, Less than 12 months	(41)
Temporarily Impaired Securities, Available for sale securities, Fair Value, 12 months or longer	71,244	86,815
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, 12 months or longer	(844)	(3,121)
Temporarily Impaired Securities, Available for sale securities, Fair Value	78,088	86,815
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses	(885)	(3,121)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, Less than 12 months		30,719
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, Less than 12 months		(216)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, 12 months or longer	47,096	93,225
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, 12 months or longer	(138)	(2,074)
Temporarily Impaired Securities, Held to maturity securities, Fair Value	47,096	123,944
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses	(138)	(2,290)
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Temporarily Impaired Securities, Available for sale securities, Fair Value, Less than 12 months		902
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, Less than 12 months		(98)
Temporarily Impaired Securities, Available for sale securities, Fair Value, 12 months or longer		3,954
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses, 12 months or longer		(61)
Temporarily Impaired Securities, Available for sale securities, Fair Value		4,856
Temporarily Impaired Securities, Available for sale securities, Unrealized Losses		(159)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, Less than 12 months		6,865
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, Less than 12 months		(107)
Temporarily Impaired Securities, Held to maturity securities, Fair Value		6,865
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses		(107)
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Temporarily Impaired Securities, Held to maturity securities, Fair Value, Less than 12 months		8,484
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, Less than 12 months		(82)
Temporarily Impaired Securities, Held to maturity securities, Fair Value, 12 months or longer	312	8,313
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses, 12 months or longer		(273)
Temporarily Impaired Securities, Held to maturity securities, Fair Value	$ 312	16,797
Temporarily Impaired Securities, Held to maturity securities, Unrealized Losses		$ (355)

Investment Securities - Additio

Investment Securities - Additional Information (Details)	Jun. 30, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Number of debt securities with unrealized losses | Security	68	142
Aggregate depreciation percentage of gross unrealized losses from amortized cost	0.66%	2.05%
Maximum
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Percentage of unrealized loss on amortized cost	2.43%	9.79%
Unrealized dollar loss of amortized cost basis	$ 79,000	$ 189,000
Unrealized loss of amortized cost basis		$ 98,000
Percentage of unrealized dollar loss on amortized cost		5.34%

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	Jun. 30, 2019	Dec. 31, 2018
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Within One Year, Amortized Cost	$ 10,000
Available for sale securities, Within One Year, Fair Value	9,971
Available for sale securities, After One, But Within Five Years, Amortized Cost	40,058
Available for sale securities, After One, But Within Five Years, Fair Value	39,903
Available for sale securities, After Five, But Within Ten Years, Amortized Cost	29,462
Available for sale securities, After Five, But Within Ten Years, Fair Value	29,176
Available for sale securities, After Ten Years, Amortized Cost	74,245
Available for sale securities, After Ten Years, Fair Value	74,003
Available for sale securities, Total, Amortized Cost	153,765
Available for sale securities, Total, Fair Value	153,053
Held to maturity securities, Within One Year, Amortized Cost	7,429
Held to maturity securities, Within One Year, Fair Value	7,435
Held to maturity securities, After One, But Within Five Years, Amortized Cost	37,298
Held to maturity securities, After One, But Within Five Years, Fair Value	37,615
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	96,019
Held to maturity securities, After Five, But Within Ten Years, Fair Value	99,253
Held to maturity securities, After Ten Years, Amortized Cost	145,604
Held to maturity securities, After Ten Years, Fair Value	147,690
Held to maturity securities, Amortized Cost	286,350	$ 282,869
Held to maturity securities, Fair Value	291,993	281,310
Available for sale securities and Held to maturity securities, Within One Year, Amortized Cost	17,429
Available for sale securities and Held to maturity securities, Within One Year, Fair Value	17,406
Available for sale securities and Held to maturity securities, After One, But Within Five Years, Amortized Cost	77,356
Available for sale securities and Held to maturity securities, After One, But Within Five Years, Fair Value	77,518
Available for sale securities and Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	125,481
Available for sale securities and Held to maturity securities, After Five, But Within Ten Years, Fair Value	128,429
Available for sale securities and Held to maturity securities, After Ten Years, Amortized Cost	219,849
Available for sale securities and Held to maturity securities, After Ten Years, Fair Value	221,693
Available for sale securities and Held to maturity securities, Total, Amortized Cost	440,115
Available for sale securities and Held to maturity securities, Total, Fair Value	445,046
U.S. GSE Obligations
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Available for sale securities, Within One Year, Amortized Cost	10,000
Available for sale securities, Within One Year, Fair Value	9,971
Available for sale securities, After One, But Within Five Years, Amortized Cost	40,000
Available for sale securities, After One, But Within Five Years, Fair Value	39,844
Available for sale securities, Total, Amortized Cost	50,000
Available for sale securities, Total, Fair Value	49,815
Held to maturity securities, Within One Year, Amortized Cost	4,997
Held to maturity securities, Within One Year, Fair Value	4,982
Held to maturity securities, After One, But Within Five Years, Amortized Cost	17,575
Held to maturity securities, After One, But Within Five Years, Fair Value	17,576
Held to maturity securities, Amortized Cost	22,572
Held to maturity securities, Fair Value	22,558
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	58
Available for sale securities, After One, But Within Five Years, Fair Value	59
Available for sale securities, After Five, But Within Ten Years, Amortized Cost	29,462
Available for sale securities, After Five, But Within Ten Years, Fair Value	29,176
Available for sale securities, After Ten Years, Amortized Cost	74,245
Available for sale securities, After Ten Years, Fair Value	74,003
Available for sale securities, Total, Amortized Cost	103,765
Available for sale securities, Total, Fair Value	103,238
Held to maturity securities, Within One Year, Amortized Cost	8
Held to maturity securities, Within One Year, Fair Value	8
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	52,063
Held to maturity securities, After Five, But Within Ten Years, Fair Value	53,202
Held to maturity securities, After Ten Years, Amortized Cost	129,705
Held to maturity securities, After Ten Years, Fair Value	131,218
Held to maturity securities, Amortized Cost	181,776
Held to maturity securities, Fair Value	184,428
Corporate Debt Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, After One, But Within Five Years, Amortized Cost	6,977
Held to maturity securities, After One, But Within Five Years, Fair Value	7,069
Held to maturity securities, Amortized Cost	6,977
Held to maturity securities, Fair Value	7,069
Municipal Securities
Schedule of Available for Sale Securities and Held to Maturity Securities [Line Items]
Held to maturity securities, Within One Year, Amortized Cost	2,424
Held to maturity securities, Within One Year, Fair Value	2,445
Held to maturity securities, After One, But Within Five Years, Amortized Cost	12,746
Held to maturity securities, After One, But Within Five Years, Fair Value	12,970
Held to maturity securities, After Five, But Within Ten Years, Amortized Cost	43,956
Held to maturity securities, After Five, But Within Ten Years, Fair Value	46,051
Held to maturity securities, After Ten Years, Amortized Cost	15,899
Held to maturity securities, After Ten Years, Fair Value	16,472
Held to maturity securities, Amortized Cost	75,025	75,208
Held to maturity securities, Fair Value	$ 77,938	$ 76,150

Investment Securities - Summa_2

Investment Securities - Summary of Gains (Losses) from Sale of Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Amortized cost of securities sold	$ 10,231	$ 700	$ 26,231	$ 700
Gain/(loss) realized on securities sold	6	2	(81)	2
Net proceeds from securities sold	$ 10,237	$ 702	$ 26,150	$ 702

Loans and the Allowance for L_3

Loans and the Allowance for Loan Losses - Loans Outstanding by Category (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loans And Leases Receivable Disclosure [Line Items]
Total loans	$ 2,096,550	$ 1,559,772
Residential Mortgage
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	1,722	1,408
Total loans	938,559	604,331
Residential Mortgage | Construction
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	28,437
Residential Mortgage | Mortgages - Fixed Rate
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	409,706	293,267
Residential Mortgage | Mortgages - Adjustable Rate
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	498,694	309,656
Commercial Mortgage
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	124	82
Total loans	905,442	757,957
Commercial Mortgage | Construction
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	51,816	44,146
Commercial Mortgage | Mortgages - Nonowner Occupied
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	788,982	654,394
Commercial Mortgage | Mortgages - Owner Occupied
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	64,520	59,335
Home Equity
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	237	250
Total loans	85,814	69,336
Home Equity | Home Equity - Lines of Credit
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	79,814	63,421
Home Equity | Home Equity - Term Loans
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	5,763	5,665
Commercial & Industrial
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	134,338	93,728
Deferred costs (fees) net of unearned fees	(31)	(16)
Total loans	134,307	93,712
Consumer
Loans And Leases Receivable Disclosure [Line Items]
Deferred costs (fees) net of unearned fees	13	13
Total loans	32,428	34,436
Consumer | Secured
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	31,380	33,252
Consumer | Unsecured
Loans And Leases Receivable Disclosure [Line Items]
Loans outstanding by category gross	$ 1,035	$ 1,171

Loans and the Allowance for L_4

Loans and the Allowance for Loan Losses - Additional Information (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)Loan	Jun. 30, 2019USD ($)Loan	Dec. 31, 2018USD ($)Loan
Receivables [Abstract]
Loans outstanding to directors and officers	$ 36,000	$ 36,000	$ 488,000
Loans to directors and officers, additions		67,000	139,000
Loans to directors and officers, repayments		519,000	167,000
Commitments to lend additional funds to borrowers whose loans were on non-accrual status	$ 0	$ 0	$ 0
Number of TDRs defaulted during the period | Loan	0	0	0
Number of loans determined to be troubled debt restructurings | Loan		2	3
Troubled debt restructuring carrying value	$ 105,000	$ 105,000	$ 117,000
Number of loans modified as troubled debt restructuring | Loan	0	0	0
Specific allowances for troubled debt restructurings	$ 0	$ 0	$ 0
Other real estate owned	185,000	185,000
Loans secured by one- to-four family residential properties in process of foreclosure	$ 0	$ 0	$ 351,000

Loans and the Allowance for L_5

Loans and the Allowance for Loan Losses - Non-performing Loans Disaggregated by Loan Category (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Troubled debt restructurings	$ 105,000	$ 117,000
Non-Performing Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	952,000	525,000
Troubled debt restructurings	105,000	117,000
Total	1,057,000	642,000
Non-Performing Loans | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	507,000	512,000
Troubled debt restructurings	105,000	111,000
Total	612,000	623,000
Non-Performing Loans | Commercial Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	135,000
Total	135,000
Non-Performing Loans | Home Equity
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	12,000	13,000
Total	12,000	13,000
Non-Performing Loans | Commercial & Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Non-accrual loans	298,000
Troubled debt restructurings		6,000
Total	$ 298,000	$ 6,000

Loans and the Allowance for L_6

Loans and the Allowance for Loan Losses - Loans Receivable Disaggregated by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Loans receivable	$ 2,096,550	$ 1,559,772
Residential Mortgage
Financing Receivable Recorded Investment [Line Items]
Loans receivable	938,559	604,331
Residential Mortgage | Performing
Financing Receivable Recorded Investment [Line Items]
Loans receivable	937,947	603,708
Residential Mortgage | Non-Performing Loans
Financing Receivable Recorded Investment [Line Items]
Loans receivable	612	623
Home Equity
Financing Receivable Recorded Investment [Line Items]
Loans receivable	85,814	69,336
Home Equity | Performing
Financing Receivable Recorded Investment [Line Items]
Loans receivable	85,802	69,323
Home Equity | Non-Performing Loans
Financing Receivable Recorded Investment [Line Items]
Loans receivable	12	13
Consumer
Financing Receivable Recorded Investment [Line Items]
Loans receivable	32,428	34,436
Consumer | Performing
Financing Receivable Recorded Investment [Line Items]
Loans receivable	32,428	34,436
Commercial Mortgage
Financing Receivable Recorded Investment [Line Items]
Loans receivable	905,442	757,957
Commercial Mortgage | 1-6 (Pass)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	895,336	753,338
Commercial Mortgage | 7 (Special Mention)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	9,571	4,619
Commercial Mortgage | 8 (Substandard)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	535
Commercial & Industrial
Financing Receivable Recorded Investment [Line Items]
Loans receivable	134,307	93,712
Commercial & Industrial | 1-6 (Pass)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	125,763	85,821
Commercial & Industrial | 7 (Special Mention)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	3,487	4,186
Commercial & Industrial | 8 (Substandard)
Financing Receivable Recorded Investment [Line Items]
Loans receivable	$ 5,057	$ 3,705

Loans and the Allowance for L_7

Loans and the Allowance for Loan Losses - Schedule of Loans Receivable Disaggregated by Past Due Status (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	$ 5,744	$ 1,614
Current Loans	2,090,806	1,558,158
Total loans	2,096,550	1,559,772
30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	4,463	1,142
60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	737	121
90 Days or Greater
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	544	351
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	3,199	1,506
Current Loans	935,360	602,825
Total loans	938,559	604,331
Residential Mortgage | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	2,093	1,034
Residential Mortgage | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	721	121
Residential Mortgage | 90 Days or Greater
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	385	351
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	1,943
Current Loans	903,499	757,957
Total loans	905,442	757,957
Commercial Mortgage | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	1,943
Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	584
Current Loans	133,723	93,712
Total loans	134,307	93,712
Commercial & Industrial | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	425
Commercial & Industrial | 90 Days or Greater
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	159
Consumer loans
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	6	108
Current Loans	32,422	34,328
Total loans	32,428	34,436
Consumer loans | 30-59 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	2	108
Consumer loans | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	4
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	12
Current Loans	85,802	69,336
Total loans	85,814	$ 69,336
Home Equity | 60-89 Days Past Due
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	$ 12

Loans and the Allowance for L_8

Loans and the Allowance for Loan Losses - Information Pertaining to Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	$ 712	$ 1,141	$ 712	$ 1,141
With no required reserve recorded, Average Carrying Value	717	1,148	722	1,154
With no required reserve recorded, Unpaid Principal Balance	911	1,393	911	1,393
With no required reserve recorded, Interest Income Recognized	1		3	1
Carrying Value	712	1,141	712	1,141
Average Carrying Value	717	1,148	722	1,154
Unpaid Principal Balance	911	1,393	911	1,393
Interest Income Recognized	1		3	1
Commercial and Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value		17		17
With no required reserve recorded, Average Carrying Value		20		22
With no required reserve recorded, Unpaid Principal Balance		17		17
With no required reserve recorded, Interest Income Recognized				1
Carrying Value		17		17
Average Carrying Value		20		22
Unpaid Principal Balance		17		17
Interest Income Recognized				1
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value		213		213
With no required reserve recorded, Average Carrying Value		213		213
With no required reserve recorded, Unpaid Principal Balance		227		227
Carrying Value		213		213
Average Carrying Value		213		213
Unpaid Principal Balance		227		227
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	616	845	616	845
With no required reserve recorded, Average Carrying Value	620	848	625	851
With no required reserve recorded, Unpaid Principal Balance	778	1,051	778	1,051
With no required reserve recorded, Interest Income Recognized	1		2
Carrying Value	616	845	616	845
Average Carrying Value	620	848	625	851
Unpaid Principal Balance	778	1,051	778	1,051
Interest Income Recognized	1		2
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	96	66	96	66
With no required reserve recorded, Average Carrying Value	97	67	97	68
With no required reserve recorded, Unpaid Principal Balance	133	98	133	98
With no required reserve recorded, Interest Income Recognized			1
Carrying Value	96	66	96	66
Average Carrying Value	97	67	97	68
Unpaid Principal Balance	$ 133	$ 98	133	$ 98
Interest Income Recognized			$ 1

Loans and the Allowance for L_9

Loans and the Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses Disaggregated by Loan Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	$ 16,652	$ 15,732	$ 16,768	$ 15,320
Charge-offs	(164)	(23)	(205)	(32)
Recoveries	16	15	33	27
Provision for (Release of)	595	(79)	503	330
Allowance for loan losses, Ending balance	17,099	15,645	17,099	15,645
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	5,256	4,692	4,946	5,047
Provision for (Release of)	207	187	517	(168)
Allowance for loan losses, Ending balance	5,463	4,879	5,463	4,879
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	9,369	8,937	9,626	8,289
Charge-offs	(55)		(55)
Provision for (Release of)	115	(263)	(142)	385
Allowance for loan losses, Ending balance	9,429	8,674	9,429	8,674
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	534	570	517	630
Provision for (Release of)	(3)	31	14	(29)
Allowance for loan losses, Ending balance	531	601	531	601
Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	1,245	1,145	1,415	946
Charge-offs	(100)	(6)	(130)	(11)
Recoveries	12	12	25	22
Provision for (Release of)	288	44	135	238
Allowance for loan losses, Ending balance	1,445	1,195	1,445	1,195
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	248	298	264	315
Charge-offs	(9)	(17)	(20)	(21)
Recoveries	4	3	8	5
Provision for (Release of)	(12)	12	(21)	(3)
Allowance for loan losses, Ending balance	$ 231	296	$ 231	296
Impaired
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		90		93
Provision for (Release of)		$ (90)		$ (93)

Loans and the Allowance for _10

Loans and the Allowance for Loan Losses - Summary of Allowance for Loan Losses and Related Loans Receivable Disaggregated by Impairment Method (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	$ 17,099		$ 16,768
Allowance for loan losses	17,099	$ 16,652	16,768	$ 15,645	$ 15,732	$ 15,320
Individually evaluated for impairment	712		740
Collectively evaluated for impairment	2,095,838		1,559,032
Total loans	2,096,550		1,559,772
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	5,463		4,946
Allowance for loan losses	5,463	5,256	4,946	4,879	4,692	5,047
Individually evaluated for impairment	616		647
Collectively evaluated for impairment	937,943		603,684
Total loans	938,559		604,331
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	9,429		9,626
Allowance for loan losses	9,429	9,369	9,626	8,674	8,937	8,289
Collectively evaluated for impairment	905,442		757,957
Total loans	905,442		757,957
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	531		517
Allowance for loan losses	531	534	517	601	570	630
Individually evaluated for impairment	96		88
Collectively evaluated for impairment	85,718		69,248
Total loans	85,814		69,336
Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	1,445		1,415
Allowance for loan losses	1,445	1,245	1,415	1,195	1,145	946
Individually evaluated for impairment			5
Collectively evaluated for impairment	134,307		93,707
Total loans	134,307		93,712
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Collectively evaluated for impairment	231		264
Allowance for loan losses	231	$ 248	264	$ 296	$ 298	$ 315
Collectively evaluated for impairment	32,428		34,436
Total loans	$ 32,428		$ 34,436

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Apr. 17, 2019
Finite Lived Intangible Assets [Line Items]
Carrying value of goodwill	$ 31,206,000		$ 31,206,000		$ 412,000
Impairment of goodwill recognized			0		$ 0
Carrying value of intangible asset	3,519,000		$ 3,519,000
Mortgage Servicing Rights
Finite Lived Intangible Assets [Line Items]
Weighted average amortization period			6 years		7 years 6 months
Loans held for sale	384,000		$ 384,000		$ 0
Amount of mortgage loans sold and servicing rights retained			867,000		$ 1,600,000
Net gains recognized in gain on loans held for sale	15,000	$ 18,000	31,000	$ 45,000
Fair value of mortgage servicing rights portfolio	1,100,000	$ 1,000,000	1,100,000	$ 1,000,000
Optima Bank And Trust Company
Finite Lived Intangible Assets [Line Items]
Carrying value of goodwill	30,800,000		30,800,000			$ 30,794,000
Optima Bank And Trust Company | Core Deposit Intangibles
Finite Lived Intangible Assets [Line Items]
Intangible assets acquired	3,600,000
Amortization of intangible asset	90,000		90,000
Carrying value of intangible asset	$ 3,500,000		$ 3,500,000
Weighted average amortization period			10 years

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Mortgage Servicing Rights (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance, Mortgage servicing rights	$ 666	$ 823
Mortgage servicing rights acquired as a result of the merger, Mortgage servicing rights	334
Mortgage servicing rights capitalized, Mortgage servicing rights	7	5
Amortization charged against servicing income, Mortgage servicing rights	(106)	(70)
Change in impairment reserve, Mortgage servicing rights		(30)
Ending Balance, Mortgage servicing rights	901	728
Beginning Balance, Valuation allowance		(30)
Change in impairment reserve, Valuation allowance	(10)	30
Ending Balance, Valudation allowance	(10)
Beginning Balance, Total	666	793
Mortgage servicing rights acquired as a result of the merger, Total	334
Mortgage servicing rights capitalized, Total	7	5
Amortization charged against servicing income, Total	(106)	(70)
Change in impairment reserve, Total	(10)
Ending Balance, Total	$ 891	$ 728

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Schedule of Aggregate Estimated Future Amortization Expense (Details) - Mortgage Servicing Rights $ in Thousands	Jun. 30, 2019USD ($)
Future Amortization Expense
Remainder of 2019	$ 74
2020	133
2021	113
2022	96
2023	81
Thereafter	404
Total	$ 901

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Effective tax rate	26.50%	23.70%	23.90%	22.80%
Net deferred tax assets	$ 7,267,000		$ 7,267,000		$ 8,717,000
Deferred tax assets, valuation allowance	$ 0		$ 0		$ 0

Income Taxes - Components of In

Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Current
Federal	$ 1,305	$ 1,642	$ 1,676	$ 2,235
State	552	679	719	932
Total current expense	1,857	2,321	2,395	3,167
Deferred
Federal	(217)	(286)	601	238
State	(100)	(134)	284	112
Total deferred	(317)	(420)	885	350
Total income tax expense	$ 1,540	$ 1,901	$ 3,280	$ 3,517

Pension and Retirement Plans -

Pension and Retirement Plans - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Plan
Net periodic benefit cost
Interest cost	$ 414	$ 392	$ 840	$ 778
Expected return on assets	(651)	(722)	(1,360)	(1,445)
Amortization of prior service cost (credit)	(1)	(1)	(2)	(2)
Amortization of net actuarial loss	77	37	77	53
Net periodic benefit cost (credit)	(161)	(294)	(445)	(616)
Supplemental Retirement Plan
Net periodic benefit cost
Service cost	75	88	143	177
Interest cost	85	77	175	154
Amortization of net actuarial loss		1		2
Net periodic benefit cost (credit)	160	166	318	333
Postretirement Healthcare Plan
Net periodic benefit cost
Service cost	5	5	10	11
Interest cost	6	6	12	11
Amortization of net actuarial loss	(1)	(5)	(2)
Net periodic benefit cost (credit)	$ 10	$ 6	$ 20	$ 22

Pension and Retirement Plans _2

Pension and Retirement Plans - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
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 | 401(k) | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent							3.00%
Profit Sharing Plan | Discretionary Contribution
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, minimum number of hours of service per year required for eligibility						1000 hours
Defined contribution plan, minimum service period required for eligibility						12 months
Normal retirement age of employees						65 years
Employee Stock Ownership Plan (ESOP)
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, minimum number of hours of service per year required for eligibility				1000 hours
Defined contribution plan, minimum service period required for eligibility				12 months
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	$ 552,000	$ 584,000		$ 1,100,000	$ 1,400,000
Defined Contribution SERP Plan (“DC SERP”)
Defined Benefit Plan Disclosure [Line Items]
Contribution expense related to plans	43,000	$ 75,000		$ 86,000	$ 126,000
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			$ 0
Qualified Defined Benefit Pension Plan | Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan			$ 0

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - 2017 Equity and Cash Incentive Plan	3 Months Ended
	Jun. 30, 2019shares
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	0
Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued	0

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Shares Issued and Fair Value of RSAs (Details) - RSAs - 2017 Equity and Cash Incentive Plan	3 Months Ended
	Jun. 30, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Granted | shares	950
Weighted Average Fair Value at Grant Date | $ / shares	$ 84.66

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation [Abstract]
Stock based compensation expense	$ 699	$ 807	$ 1,318	$ 1,347
Related tax benefits	$ 197	$ 227	$ 370	$ 379

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	Jun. 30, 2019	Dec. 31, 2018
Standby Letters of Credit
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	$ 8,439	$ 8,752
Unused Portion of Existing Lines of Credit
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	405,900	368,410
Origination of New Loans
Financial instruments whose contractual amount represents credit risk:
Financial instruments with off-balance-sheet risk	59,930	$ 24,505
Commitments to Sell Residential Mortgage Loans
Financial instruments whose notional amount exceeds the amount of credit risk:
Financial instrument notional amount exceeds credit risk	$ 3,188

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lessee Lease Description [Line Items]
Description of operating lease expiration terms			operating leases and their terms expire between 2019 and 2030 and, in some instances, contain options to renew for periods up to 30 years.
Renewal option period for operating leases	30 years		30 years
Existence of option to expire			true
Right-of-use asset	$ 35,604,000		$ 35,604,000
Total rental expense	1,400,000	$ 1,100,000	2,700,000	$ 2,200,000
Operating leases, minimum annual rental payments, receivable under sublease			$ 32,000
Operating leases minimum annual rental payments receivable under sublease agreement expired date			Jul. 31, 2019
Operating leases, rental income under sublease	16,000	$ 16,000	$ 32,000	$ 32,000
Optima Bank And Trust Company
Lessee Lease Description [Line Items]
Right-of-use asset	$ 4,700,000		$ 4,700,000

Leases - Summary of Right-of-Us

Leases - Summary of Right-of-Use Asset and Net Lease Liability (Details) $ in Thousands	Jun. 30, 2019USD ($)
Leases [Abstract]
Right-of-use asset	$ 35,604
Operating lease, right-of-use asset, statement of financial position [extensible list]	us-gaap:OtherAssetsMember
Lease liability	$ 36,982
Operating lease, liability, statement of financial position [extensible list]	us-gaap:OtherLiabilitiesMember

Leases - Summary of Components

Leases - Summary of Components of Operating Lease Cost and Other Related Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Leases [Abstract]
Operating lease cost	$ 1,321,000		$ 2,501,000
Sublease income	(16,000)	$ (16,000)	(32,000)	$ (32,000)
Total Operating Lease Cost	1,305,000		2,469,000
Other Information
Cash paid for amounts included in the measurement of lease liabilities - operating cash flows from operating leases	1,231,000		2,308,000
Operating Lease - Operating Cash Flows (Liability reduction)	937,000		1,744,000
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 4,656,000		$ 4,656,000
Weighted average lease term - operating Leases	8 years 6 months 21 days		8 years 6 months 21 days
Weighted average discount Rate - operating leases	3.38%		3.38%

Leases - Schedule of Total Mini

Leases - Schedule of Total Minimum Rentals Due in Future Periods under Lease Agreements (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Operating Leases Future Minimum Payments Due [Abstract]
Remainder of 2019	$ 5,426
2020	5,527
2021	5,428
2022	5,181
2023	4,864
Thereafter	16,380
Total minimum lease payments	42,806
Less: interest	(5,824)
Total lease liability	$ 36,982
2019		$ 4,448
2020		4,661
2021		4,662
2022		4,553
2023		4,455
Thereafter		17,128
Total minimum lease payments		$ 39,907

Shareholders' Equity - Minimum

Shareholders' Equity - Minimum Capital Requirements were Considered Well Capitalized by FRB and FDIC (Details) - USD ($)	Jun. 30, 2019		Dec. 31, 2018
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 222,152,000		$ 189,888,000
Tier I capital (to risk-weighted assets), Actual, Amount	205,002,000		173,070,000
Common equity tier I capital (to risk-weighted assets), Actual, Amount	205,002,000		173,070,000
Tier I capital (to average assets), Actual, Amount	$ 205,002,000		$ 173,070,000
Total capital (to risk-weighted assets), Actual, Ratio	11.80%		13.20%
Tier I capital (to risk-weighted assets), Actual, Ratio	10.90%		12.10%
Common equity tier I capital (to risk-weighted assets), Actual, Ratio	10.90%		12.10%
Tier I capital (to average assets), Actual, Ratio	7.90%		8.50%
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	$ 150,732,000		$ 114,666,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	113,049,000		86,000,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	84,787,000		64,500,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy, Amount	$ 103,327,000		$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	8.00%		8.00%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	6.00%		6.00%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	4.50%		4.50%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy, Ratio	4.00%		4.00%
Minimum
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			$ 141,541,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			112,875,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			91,375,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			9.875%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			7.875%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			6.375%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			4.00%
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	$ 197,836,000	[1]	$ 150,500,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	160,153,000	[1]	121,833,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	131,891,000	[1]	100,333,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	$ 103,327,000	[1]	$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	10.50%	[1]	10.50%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	8.50%	[1]	8.50%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	7.00%	[1]	7.00%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	4.00%	[1]	4.00%
Cambridge Trust Company
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Actual, Amount	$ 218,012,000		$ 185,507,000
Tier I capital (to risk-weighted assets), Actual, Amount	200,862,000		168,689,000
Common equity tier I capital (to risk-weighted assets), Actual, Amount	200,862,000		168,689,000
Tier I capital (to average assets), Actual, Amount	$ 200,862,000		$ 168,689,000
Total capital (to risk-weighted assets), Actual, Ratio	11.60%		12.90%
Tier I capital (to risk-weighted assets), Actual, Ratio	10.70%		11.80%
Common equity tier I capital (to risk-weighted assets), Actual, Ratio	10.70%		11.80%
Tier I capital (to average assets), Actual, Ratio	7.80%		8.30%
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	$ 150,732,000		$ 114,666,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	113,049,000		86,000,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Amount	84,787,000		64,500,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy, Amount	$ 103,327,000		$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	8.00%		8.00%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	6.00%		6.00%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy, Ratio	4.50%		4.50%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy, Ratio	4.00%		4.00%
Cambridge Trust Company | Minimum
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			$ 141,541,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			112,875,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			91,375,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Amount			$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			9.875%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			7.875%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			6.375%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Phase-In Schedule, Ratio			4.00%
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	$ 197,836,000	[1]	$ 150,500,000
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	160,153,000	[1]	121,833,000
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	131,891,000	[1]	100,333,000
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Amount	$ 103,327,000	[1]	$ 81,507,000
Total capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	10.50%	[1]	10.50%
Tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	8.50%	[1]	8.50%
Common equity tier I capital (to risk-weighted assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	7.00%	[1]	7.00%
Tier I capital (to average assets), Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Basel III Fully Phased In, Ratio	4.00%	[1]	4.00%
Total capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 188,415,000		$ 143,333,000
Tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	150,732,000		114,666,000
Common equity tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	122,470,000		93,166,000
Tier I capital (to average assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Amount	$ 129,158,000		$ 101,884,000
Total capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%		10.00%
Tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%		8.00%
Common equity tier I capital (to risk-weighted assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%		6.50%
Tier I capital (to average assets), Minimum To Be Well-Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%		5.00%
[1]	The 2013 Capital Rules adopted by the Federal Reserve, Office of the Comptroller of the Currency, and the Federal Deposit Insurance Corporation implementing Basel III were fully phased-in effective January 1, 2019.

Other Comprehensive Income - Su

Other Comprehensive Income - Summary of Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Unrealized (losses)/gains on available for sale securities, before tax amount
Unrealized holding (losses)/gains arising during the period, before tax amount	$ 1,909	$ (550)	$ 3,334	$ (2,228)
Reclassification adjustment for (gains)/losses recognized in net income, before tax amount	(6)	(2)	81	(2)
Derivatives, before tax amount
Change in interest rate contracts, before tax amount	1,696		1,654
Defined benefit retirement plans, before tax amount
Change in retirement liability, before tax amount	36	15	72	29
Total Other Comprehensive (Loss)/Income, before tax amount	3,635	(537)	5,141	(2,201)
Unrealized (losses)/gains on available for sale securities, tax (expense) or benefit
Unrealized holding (losses)/gains arising during the period, tax (expense) or benefit	(456)	127	(786)	453
Reclassification adjustment for (gains)/losses recognized in net income, tax (expense) or benefit	2		(19)
Derivatives, tax (expense) or benefit
Change in interest rate contracts, tax (expense) or benefit	(477)		(465)
Defined benefit retirement plans, tax (expense) or benefit
Change in retirement liability, tax (expense) or benefit	(10)	(5)	(20)	(9)
Total Other Comprehensive (Loss)/Income, tax (expense) or benefit	(941)	122	(1,290)	444
Unrealized (losses)/gains on available for sale securities, net-of-tax amount
Unrealized holding (losses)/gains arising during the period, net-of-tax amount	1,453	(423)	2,548	(1,775)
Reclassification adjustment for (gains)/losses recognized in net income, net-of-tax amount	(4)	(2)	62	(2)
Derivatives, net-of-tax amount
Change in interest rate contracts, net-of-tax amount	1,219		1,189
Defined benefit retirement plans, net-of-tax amount
Change in retirement liability, net-of-tax amount	26	10	52	20
Other comprehensive income/(loss)	$ 2,694	$ (415)	$ 3,851	$ (1,757)

Other Comprehensive Income - _2

Other Comprehensive Income - Summary of Reclassifications out of Accumulated Other Comprehensive Income ("AOCI") (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale securities	$ 6	$ 2	$ (81)	$ 2
Tax benefit or (expense)	(1,540)	(1,901)	(3,280)	(3,517)
Net income	4,272	6,111	10,470	11,916
Reclassifications out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale securities	6	2	(81)	2
Tax benefit or (expense)	(2)		19
Net income	$ 4	$ 2	$ (62)	$ 2

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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income	$ 4,272	$ 6,111	$ 10,470	$ 11,916
Less dividends and undistributed earnings allocated to participating securities	(35)	(60)	(94)	(121)
Net income applicable to common shareholders	$ 4,237	$ 6,051	$ 10,376	$ 11,795
Denominator:
Weighted average number of shares outstanding, basic	4,682,109	4,059,927	4,379,141	4,057,156
Earnings per common share - basic	$ 0.91	$ 1.49	$ 2.37	$ 2.91
Numerator:
Net income	$ 4,272	$ 6,111	$ 10,470	$ 11,916
Less dividends and undistributed earnings allocated to participating securities	(35)	(60)	(94)	(121)
Net income applicable to common shareholders	$ 4,237	$ 6,051	$ 10,376	$ 11,795
Denominator:
Weighted average number of shares outstanding, basic	4,682,109	4,059,927	4,379,141	4,057,156
Dilutive effect of common stock equivalents	34,000	34,000	33,000	31,000
Weighted average diluted common shares outstanding	4,715,724	4,094,489	4,412,239	4,087,790
Earnings per common share - diluted	$ 0.90	$ 1.48	$ 2.35	$ 2.89

Derivative And Hedging Activite

Derivative And Hedging Activites - Summary of Fair Values of Derivative Instruments in the Company's Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	$ 15,922	$ 7,780
Derivative Liabilities, Fair value	12,807	5,961
Derivatives Designated as Hedging Instruments
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	3,528	1,970
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	3,528	1,970
Derivatives Not Designated as Hedging Instruments
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Assets, Fair value	12,394	5,810
Derivative Liabilities, Fair value	12,807	5,961
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	181,291	150,489
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	12,348	5,782
Derivatives Not Designated as Hedging Instruments | Loan Related Derivative Contracts | Mirror Swaps with Counterparties
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative Liabilities, Notional Amount	181,291	150,489
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	12,348	5,782
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	19,000	19,000
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	46	28
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	78,700	63,825
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	$ 459	$ 179

Derivative And Hedging Activi_3

Derivative And Hedging Activites - Summary of Cash Flow Hedge Accounting on Accumulated Other Comprehensive Income (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in OCI	$ 1,647	$ 1,558
Amount of Gain or (Loss) Recognized in OCI Included Component	2,080	2,080
Amount of Gain or (Loss) Recognized in OCI Excluded Component	(433)	(522)
Amount of Gain or (Loss) Reclassified from AOCI into Income	(48)	(96)
Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component	(48)	(96)
Interest Income
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Reclassified from AOCI into Income	(48)	(96)
Amount of Gain or (Loss) Reclassified from AOCI into Income Excluded Component	(48)	(96)
Interest Rate Contracts
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in OCI	1,647	1,558
Amount of Gain or (Loss) Recognized in OCI Included Component	2,080	2,080
Amount of Gain or (Loss) Recognized in OCI Excluded Component	$ (433)	$ (522)

Derivative And Hedging Activi_4

Derivative And Hedging Activites - Additional Information (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Fair value of derivative liability		$ 12,807,000	$ 5,961,000
Notional amount		8,500,000
Minimum
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Minimum collateral posting threshold of derivative counterparties		8,400,000
Accrued Interest
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Fair value of derivative liability		$ 8,500,000
Scenario Forecast
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Estimated amount will be reclassified out of AOCI in to earnings	$ 28,000

Derivative And Hedging Activi_5

Derivative And Hedging Activites - Summary of Derivative Financial Instruments Income Statement (Details) - Interest Income - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Total amount of income presented in the income statement in which the effects of fair value or cash flow hedges are recorded	$ (48)	$ (96)
Interest Rate Contracts
The effects of fair value and cash flow hedging:
Amount of gain or (loss) reclassed from AOCI into income	(48)	(96)
Amount of gain or (loss) reclassed from AOCI into income - Excluded Component	$ (48)	$ (96)

Derivative And Hedging Activi_6

Derivative And Hedging Activites - Summary of Derivative Financial Instruments Not Designated as Hedging Instruments (Details) - Derivatives Not Designated as Hedging Instruments - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (61)	$ 12	$ 13	$ 40
Other contracts | Other Income
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (61)	$ 12	$ 13	$ 40

Derivative And Hedging Activi_7

Derivative And Hedging Activites - Schedule of Financial Instruments Eligible for Offset in Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Offsetting [Abstract]
Gross Amounts of Recognized, Derivative assets	$ 15,922	$ 7,780
Net Amounts Recognized, Derivative Assets	15,922	7,780
Gross Amounts Not Offset, Financial Instruments, Derivative Assets	3,663	3,099
Gross Amounts Not Offset, Collateral Pledged (Received), Derivative Assets		(743)
Gross Amounts Not Offset, Net amount, Derivative Assets	12,259	3,938
Gross Amounts of Recognized, Derivative Liablities	12,807	5,961
Net Amounts Recognized, Derivative Liablities	12,807	5,961
Gross Amounts Not Offset, Financial Instruments, Derivative Liablities	3,663	3,099
Gross Amounts Not Offset, Collateral Pledged (Received), Derivative Liablities	8,428	260
Gross Amounts Not Offset, Net amount, Derivative Liablities	$ 716	$ 2,602

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Carrying Values and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial assets
Securities available for sale	$ 153,053	$ 168,163
Securities held to maturity	291,993	281,310
FHLB Boston stock	8,245	6,844
Recurring Basis | Carrying Value
Financial assets
Cash and cash equivalents	38,557	18,473
Securities available for sale	153,053	168,163
Securities held to maturity	286,350	282,869
Loans, net	2,079,451	1,543,004
Loans held for sale	384
FHLB Boston stock	8,245	6,844
Accrued interest receivable	7,485	5,762
Mortgage servicing rights	891	666
Interest rate contracts	3,528	1,970
Loan level interest rate swaps	12,348	5,782
Risk participation agreements out to counterparties	46	28
Financial liabilities
Deposits	2,329,665	1,811,410
Short-term borrowings	103,000	90,000
Long-term borrowings	3,323	3,409
Loan level interest rate swaps	12,348	5,782
Risk participation agreements in with counterparties	459	179
Recurring Basis | Estimated Fair Value
Financial assets
Cash and cash equivalents	38,557	18,473
Securities available for sale	153,053	168,163
Securities held to maturity	291,993	281,310
Loans, net	2,036,666	1,484,905
Loans held for sale	384
FHLB Boston stock	8,245	6,844
Accrued interest receivable	7,485	5,762
Mortgage servicing rights	1,105	941
Interest rate contracts	3,528	1,970
Loan level interest rate swaps	12,348	5,782
Risk participation agreements out to counterparties	46	28
Financial liabilities
Deposits	2,328,568	1,809,051
Short-term borrowings	103,031	90,000
Long-term borrowings	3,316	3,363
Loan level interest rate swaps	12,348	5,782
Risk participation agreements in with counterparties	$ 459	$ 179

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Certain Assets Reported at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	$ 153,053	$ 168,163
U.S. GSE Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	49,815	74,039
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale		4,856
Recurring Basis | U.S. GSE Obligations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	49,815	74,039
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	49,815	74,039
Recurring Basis | Mortgage Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	103,238	89,268
Recurring Basis | Mortgage Backed Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale	103,238	89,268
Recurring Basis | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale		4,856
Recurring Basis | Corporate Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available for sale		4,856
Recurring Basis | Interest Rate Swaps with Customers
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	12,348	5,782
Recurring Basis | Interest Rate Swaps with Customers | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	12,348	5,782
Recurring Basis | Risk Participation Agreements Out to Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	46	28
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	46	28
Recurring Basis | Interest Rate Contracts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	3,528	1,970
Recurring Basis | Interest Rate Contracts | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other assets	3,528	1,970
Recurring Basis | Mirror Swaps with Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	12,348	5,782
Recurring Basis | Mirror Swaps with Counterparties | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	12,348	5,782
Recurring Basis | Risk Participation Agreements in With Counterparties
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other liabilities	459	179
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	$ 459	$ 179

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Carrying Value of Assets Measured at Fair Value on a Non-Recurring Basis (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis		$ 0
Non-recurring
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	$ 569,000
Non-recurring | Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	384,000
Non-recurring | Other Real Estate Owned
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	185,000
Level 3 | Non-recurring
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	569,000
Level 3 | Non-recurring | Loans Held for Sale
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	384,000
Level 3 | Non-recurring | Other Real Estate Owned
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value, non-recurring basis	$ 185,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Other real estate owned	$ 185,000		$ 185,000
Assets, fair value, non-recurring basis					$ 0
Transfers between levels	$ 0	$ 0	$ 0	$ 0