Randolph Bancorp (RNDB) 10-K 10 Mar 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 28, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Trading Symbol	RNDB
Entity Registrant Name	Randolph Bancorp, Inc.
Entity Central Index Key	0001667161
Current Fiscal Year End Date	--12-31
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	false
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, par value $.01 per share
Entity Incorporation, State or Country Code	MA
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		5,180,670
Entity Shell Company	false
Entity File Number	001-37780
Entity Tax Identification Number	81-1844402
Entity Address, Address Line One	2 Batterymarch Park
Entity Address, Address Line Two	Suite 301
Entity Address, City or Town	Quincy
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02169
City Area Code	781
Local Phone Number	963-2100
Document Annual Report	true
Document Transition Report	false
Entity Public Float			$ 92,148,669
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	Portions of the Registrant’s Proxy Statement for its 2021 Annual Meeting of Shareholders are incorporated by reference into Part III of this Form 10-K.
Auditor Name	Crowe LLP
Auditor Location	New York, New York
Auditor Firm ID	173

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash and due from banks	$ 3,501	$ 4,206
Interest-bearing deposits	111,948	9,568
Total cash and cash equivalents	115,449	13,774
Securities available for sale, at fair value	51,666	55,366
Loans held for sale, at fair value	44,766	119,112
Loans, net of allowance for loan losses of $6,289 in 2021 and $6,784 in 2020	544,621	483,644
Federal Home Loan Bank of Boston stock, at cost	2,940	3,576
Accrued interest receivable	1,500	1,562
Mortgage servicing rights, net	15,616	12,377
Premises and equipment, net	7,684	4,781
Bank-owned life insurance	8,784	8,622
Foreclosed real estate, net		132
Other assets	10,252	18,126
Total assets	803,278	721,072
Deposits:
Noninterest-bearing	145,666	96,731
Interest bearing	492,481	431,576
Total deposits	638,147	528,307
Federal Reserve Bank advances		11,431
Federal Home Loan Bank of Boston advances	50,000	61,895
Mortgagors' escrow accounts	2,128	2,338
Post-employment benefit obligations	2,222	2,382
Other liabilities	9,878	14,900
Total liabilities	702,375	621,253
Commitments and contingencies (Note 16)
Stockholders' Equity:
Preferred stock, no par value; authorized: 1,000,000 shares; issued: none
Common stock, $.01 par value; authorized: 15,000,000 shares; issued and outstanding: 5,113,825 shares at December 31, 2021 and 5,495,514 shares at December 31, 2020	50	54
Additional paid-in capital	44,078	50,937
Retained earnings	60,524	51,689
ESOP-Unearned compensation	(3,568)	(3,756)
Accumulated other comprehensive income (loss), net of tax	(181)	895
Total stockholders' equity	100,903	99,819
Total liabilities and stockholders' equity	$ 803,278	$ 721,072

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Loans, allowance for loan losses	$ 6,289	$ 6,784
Preferred stock, par value	$ 0	$ 0
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	5,113,825	5,495,514
Common stock, shares outstanding	5,113,825	5,495,514

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Interest and dividend income:
Loans	$ 23,162	$ 22,212
Securities-taxable	899	1,273
Securities-tax exempt	20	28
Interest-bearing deposits and certificates of deposit	32	75
Total interest and dividend income	24,113	23,588
Interest expense:
Deposits	1,390	3,778
Federal Reserve Bank and Federal Home Loan Bank of Boston advances	763	943
Total interest expense	2,153	4,721
Net interest income	21,960	18,867
Provision (credit) for loan losses	(438)	2,553
Net interest income after provision (credit) for loan losses	22,398	16,314
Non-interest income:
Customer service fees	1,618	1,283
Gain on loan origination and sale activities, net	27,685	54,236
Mortgage servicing fees, net	1,691	(1,153)
Increase in cash surrender value of life insurance	163	181
Other	766	864
Total non-interest income	31,923	55,411
Non-interest expenses:
Salaries and employee benefits	28,212	33,161
Occupancy and equipment	2,792	3,545
Data processing	1,168	943
Professional fees	1,699	1,277
Marketing	749	689
FDIC insurance	217	187
Other	6,821	6,514
Total non-interest expenses	41,658	46,316
Income before income taxes	12,663	25,409
Income tax expense	3,062	5,477
Net income	$ 9,601	$ 19,932
Earnings per common share:
Basic	$ 1.96	$ 3.89
Diluted	$ 1.88	$ 3.86
Weighted average shares outstanding
Basic	4,896,641	5,126,561
Diluted	5,108,738	5,163,042

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 9,601	$ 19,932
Securities available for sale:
Unrealized holding gains (losses)		(1,464)	1,546
Related tax effects		249
Net-of-tax amount		(1,215)	1,546
Supplemental retirement plan:
Actuarial gains	[1]	48	45
Prior service credits recognized	[1]	(32)	(57)
Actuarial gains (losses) arising during the year		18	(105)
Net change in supplemental retirement plan		34	(117)
Related tax effects		105
Net-of-tax amount		139	(117)
Total other comprehensive income (loss)		(1,076)	1,429
Comprehensive income		$ 8,525	$ 21,361
[1]	Amounts are included in other non-interest expenses in the consolidated statements of operations.

Consolidated Statements Changes

Consolidated Statements Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Unearned Compensation ESOP [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance at Dec. 31, 2019	$ 78,462	$ 56	$ 51,127	$ 31,757	$ (3,944)	$ (534)
Beginning balance, shares at Dec. 31, 2019		5,576,855
Net income	19,932			19,932
Other comprehensive income (loss)	1,429					1,429
Stock repurchased	(1,749)	$ (2)	(1,747)
Stock repurchased, shares		(131,388)
Restricted stock awards granted, shares		65,630
Restricted stock awards forfeited, shares		(9,251)
Share redemption for tax withholdings for restricted stock vesting	(75)		(75)
Share redemption for tax withholdings for restricted stock vesting, shares		(6,332)
Stock-based compensation	1,564		1,564
ESOP shares committed to be released	256		68		188
Ending balance at Dec. 31, 2020	99,819	$ 54	50,937	51,689	(3,756)	895
Ending balance, shares at Dec. 31, 2020		5,495,514
Net income	9,601			9,601
Common stock dividends paid	(766)			(766)
Other comprehensive income (loss)	(1,076)					(1,076)
Stock repurchased	(8,529)	$ (4)	(8,525)
Stock repurchased, shares		(415,894)
Restricted stock awards granted, shares		19,750
Restricted stock awards forfeited, shares		(2,112)
Share redemption for tax withholdings for restricted stock vesting	(39)		(39)
Share redemption for tax withholdings for restricted stock vesting, shares		(2,709)
Stock-based compensation	1,231		1,231
ESOP shares committed to be released	401		213		188
Proceeds from exercise of options, net	$ 261		261
Proceeds from exercise of options, net, shares	19,276	19,276
Ending balance at Dec. 31, 2021	$ 100,903	$ 50	$ 44,078	$ 60,524	$ (3,568)	$ (181)
Ending balance, shares at Dec. 31, 2021		5,113,825

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 9,601,000	$ 19,932,000
Adjustments to reconcile net income to net cash used in operating activities:
Provision (credit) for loan losses	(438,000)	2,553,000
Loans originated for sale	(1,298,647,000)	(1,564,552,000)
Net gain on sales of mortgage loans	(27,685,000)	(54,236,000)
Proceeds from sales of mortgage loans	1,436,418,000	1,560,043,000
Net amortization of securities	364,000	307,000
Net change in deferred loan costs and fees, and purchase premiums	51,000	284,000
Depreciation and amortization	707,000	1,508,000
Loss on sale of foreclosed real estate	(5,000)
Stock-based compensation	1,231,000	1,564,000
ESOP expense	339,000	256,000
Increase in cash surrender value of life insurance	(162,000)	(182,000)
Amortization of mortgage servicing rights	3,197,000	2,544,000
Increase (decrease) in valuation allowance of mortgage servicing rights	(438,000)	(2,067,000)
Loss on disposal of assets		49,000
Other, net	574,000	(11,296,000)
Net cash provided by (used in) operating activities	125,117,000	(43,293,000)
Cash flows from investing activities:
Redemptions of certificates of deposit		490,000
Securities available for sale:
Calls/maturities	1,945,000	4,650,000
Purchases	(13,196,000)	(15,493,000)
Principal payments on mortgage-backed securities	13,124,000	14,218,000
Loan originations, net of principal repayments	(121,703,000)	(10,224,000)
Proceeds from sale of portfolio loans	48,597,000
Loan purchases and participations	(26,632,000)	(1,803,000)
Redemptions (purchases) of Federal Home Loan Bank of Boston stock, net	636,000	(1,159,000)
Proceeds from sale of foreclosed real estate	127,000
Purchases of premises and equipment	(3,694,000)	(589,000)
Loss on disposal of fixed assets	84,000
Net cash provided by (used in) investing activities	(100,712,000)	(9,910,000)
Cash flows from financing activities:
Net increase in non-interest bearing deposits	48,935,000	35,128,000
Net increase (decrease) in interest bearing deposits	60,905,000	(3,863,000)
Net increase (decrease) in Federal Reserve Bank borrowings	(11,431,000)	11,431,000
Net increase (decrease) in short-term Federal Home Loan Bank of Boston borrowings	5,000,000	(19,822,000)
Issuance of long-term Federal Home Loan Bank of Boston advances	5,000,000	40,000,000
Repayments of long-term Federal Home Loan Bank of Boston advances	(21,895,000)	(2,686,000)
Net increase (decrease) in mortgagors' escrow accounts	(210,000)	286,000
Repurchases of common stock	(8,529,000)	(1,749,000)
Proceeds from exercise of stock options	261,000
Common stock dividends paid	(766,000)
Net cash provided by financing activities	77,270,000	58,725,000
Net change in cash and cash equivalents	101,675,000	5,522,000
Cash and cash equivalents at beginning of year	13,774,000	8,252,000
Cash and cash equivalents at end of year	115,449,000	13,774,000
Supplemental cash flow information:
Interest paid on deposits and borrowed funds	2,305,000	5,018,000
Income taxes paid, net	3,914,000	4,225,000
Non-cash items:
Transfer of held for sale loans to portfolio	9,449,000	3,262,000
Transfer of portfolio loans to held for sale	$ 48,597,000
Transfer of portfolio loans to foreclosed real estate		$ 132,000

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	1. BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations Randolph Bancorp, Inc. (the “Company”) is a bank holding company whose principal subsidiary is the Bank. The Bank provides a variety of financial services to individuals and small businesses through its five branch offices in Massachusetts and six loan production offices and lending centers located throughout Massachusetts and Southern New Hampshire. The Bank’s primary deposit products are checking, savings and term certificate accounts and its primary lending products are residential and commercial mortgage loans. The Bank is also actively involved in the sale and servicing of residential mortgage loans in the secondary market. The Federal Deposit Insurance Corporation (“FDIC”) provides insurance coverage on all deposits up to $250,000 per depositor. As an FDIC insured institution, the Bank is subject to supervision, examination and regulation by the FDIC. Additionally, as a Massachusetts chartered savings bank, the Bank’s depositors are also insured by the Depositors Insurance Fund (“DIF”), a private industry-sponsored insurance company. The DIF insures bank deposits in excess of the FDIC insurance limits. Basis of Presentation The consolidated financial statements include the accounts of Randolph Bancorp, Inc. (a Massachusetts corporation) and its wholly-owned subsidiary, Envision Bank (together, the “Company”). The Bank has subsidiaries involved in owning investment securities and foreclosed real estate and a subsidiary which provides loan closing services. All intercompany accounts and transactions have been eliminated in consolidation. The following significant accounting and reporting policies of the Company conform to U.S. generally accepted accounting principles (“GAAP”) and are used in preparing and presenting these consolidated financial statements. Use of estimates In preparing consolidated financial statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the consolidated balance sheet and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash and cash equivalents Cash equivalents include amounts due from banks, federal funds sold on a daily basis and interest-bearing deposits with original maturities of ninety days or less. Certificates of deposit Certificates of deposit have original maturities ranging from one to five years and are carried at cost. Fair value hierarchy The Company groups its assets and liabilities that are measured at fair value in three levels based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. Level 1 – Valuation is based on quoted prices in active markets for identical assets and liabilities. Valuations are obtained from readily available pricing sources. Level 2 – Valuation is based on observable inputs other than Level 1 prices, such as quoted prices for similar assets and liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets and liabilities. Level 3 – Valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. Level 3 assets and liabilities include those for which the value is determined using unobservable inputs to pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. Transfers between levels are recognized at the end of a reporting period, if applicable. Securities All securities are classified as available for sale and are recorded at fair value, with unrealized gains and losses excluded from earnings and reported in other comprehensive income/loss. Purchase premiums and discounts are recognized in interest income using the level yield method over the terms of the securities. Anticipated prepayments on mortgage-backed securities are used in applying this method. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. On a quarterly basis, the Company evaluates all securities with a decline in fair value below the amortized cost of the investment to determine whether or not the impairment is deemed to be other than temporary (“OTTI”). OTTI is required to be recognized: (1) if the Company intends to sell the security; (2) if it is “more likely than not” that the Company will be required to sell the security before recovery of its amortized cost basis; or (3) for debt securities, if the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For all impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the decline in fair value is recognized as OTTI through earnings. For all other impaired debt securities, credit-related OTTI is recognized through earnings and non-credit related OTTI is recognized in other comprehensive income/loss, net of applicable taxes. Because the Company’s assessments are based on available factual information as well as subjective information, the determination as to whether an OTTI exists and, if so, the amount of impairment, is subjective and, therefore, the timing and amount of OTTI constitute material estimates that are subject to significant change. Federal Home Loan Bank of Boston stock The Bank, as a member of the Federal Home Loan Bank of Boston (“FHLBB”), is required to maintain an investment in capital stock of the FHLBB. Based on redemption provisions of the FHLBB, the stock has no quoted market value and is carried at cost. The Company periodically evaluates for impairment based on ultimate recovery of its cost basis in the FHLBB stock. Loans held for sale and related derivatives The origination of residential mortgage loans is an integral part of the Company’s business. The Company generally sells its originations of such loans in the secondary market to either government-sponsored enterprises (“GSEs”) or other financial institutions. The servicing of loans sold to GSEs is generally retained while loans sold to other financial institutions are generally done on a servicing released basis. The Bank utilizes the fair value option pursuant to Accounting Standards Codification (“ASC”) 825, “Financial Instruments” for its residential mortgage loans being held for sale. Fair value is determined based on either commitments in effect from investors or prevailing market price and include the value of mortgage servicing rights. Gains and losses on the sales of loans are determined using the specific identification method. In determining the amount of the gain or loss the Company takes into consideration the direct costs of originating the loan. Also included in the net gain on loan origination and sale activities presented in the accompanying statements of operations are fair value adjustments for mortgage banking derivatives (interest rate lock commitments with borrowers, and forward loan sale commitments with investors for the delivery of mortgage loans to third party investors including To Be Announced securities (“TBAs”)) and loans held for sale. Loans The Company grants residential real estate, commercial real estate, construction, commercial and consumer loans to customers. A substantial portion of the loan portfolio is represented by mortgage loans in Massachusetts and Rhode Island. The ability of the Company’s borrowers to honor their contracts is affected by real estate values and general economic conditions in these markets. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, and net deferred loan origination fees and costs and purchase premiums. Interest income is accrued on the unpaid principal balance. Certain direct loan origination costs and purchase premiums, net of origination fees, are deferred and recognized in interest income using the level yield method without anticipating prepayments. Interest is not accrued on loans which are ninety days or more past due, or when, in the judgment of management, the collectability of the principal or interest becomes doubtful. Past due status is based on contractual terms of the loan. Interest income previously accrued on such loans is reversed against current period earnings. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured. The Company periodically may agree to modify the contractual terms of loans. When a loan is modified and a concession is made to a borrower experiencing financial difficulty, the modification is considered a TDR. All TDRs are initially classified as impaired and placed on nonaccrual status. Generally, a nonaccrual loan that is restructured remains on nonaccrual for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower’s ability to meet the revised terms is not reasonably assured, the loan remains on nonaccrual status. Allowance for loan losses The allowance for loan losses is a valuation allowance for probable incurred credit losses. Loan losses are charged against the allowance when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses is evaluated on a regular basis and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as either additional information becomes available or circumstances change. The allowance for loan losses is allocated to loan types using both a formula-based approach applied to groups of loans (general component) and an analysis of certain individual loans for impairment (allocated component). General component The general component of the allowance for loan losses covers loans that are collectively evaluated for impairment and is based on historical loss experience adjusted for qualitative factors stratified by loan segments. Management uses a rolling average of historical losses based on a trailing 48 month time frame appropriate to capture relevant loss data for each loan segment. This historical loss factor is supplemented by the following qualitative factors: changes in the volume and severity of past due loans and adversely classified or graded loans, the volume of nonaccrual loans and trends in charge-offs and recoveries; changes in the nature and volume of the portfolio and in the terms of loans; changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices not considered elsewhere in estimating credit losses; changes in the experience, ability, and depth of lending management and other relevant staff; changes in international, national, regional and local economic and business conditions and developments that affect the collectability of the portfolio, including the condition of various market segments; changes in the quality of the institution’s review system; the effect of other external factors such as competition and legal and regulatory requirements on the level of estimated credit losses in the institution’s existing portfolio; changes in the value of underlying collateral-dependent loans; and the existence of concentrations of credit, and changes in the level of such concentrations. The qualitative factors are determined based on the various risk characteristics of each loan segment. Risk characteristics relevant to each portfolio segment are as follows: Residential one- to four-family real estate – The Company generally does not originate loans with a loan-to-value ratio greater than 80 percent. All loans in this segment are collateralized by one- to four-family owner, and non-owner-occupied, residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Second mortgages and home equity lines of credit (“HELOC”) – Loans in this segment are primarily secured by second-position liens, and the Company may or may not also have a first-position lien. Regardless of which creditor is in first position, the Company does not originate loans with a combined loan-to-value ratio greater than 80 percent. All loans in this segment are collateralized by owner-occupied residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Commercial real estate – Loans in this segment consist of owner-occupied and non-owner-occupied property primarily located in Massachusetts and Rhode Island. The underlying cash flows generated by the operating entities of owner-occupied real estate support the associated debt. Rental cash flows, for which management obtains periodic rent rolls, support the debt associated with non-owner-occupied real estate and can be negatively impacted by increased vacancy rates. Construction – Loans in this segment primarily include residential real estate development loans for which payment is derived from sale of the property. Credit risk is affected by cost overruns, time to sell at an adequate price, and market conditions. Commercial and Industrial – Loans in this segment are made to businesses and are generally secured by assets of the business. Repayment is expected from the cash flows of the business. A weakened economy, and resultant decreased consumer spending, would have an effect on the credit quality in this segment. As of December 31, 2021, the Company funded 385 PPP loans totaling $26.4 million. The Company had $3.6 million of Paycheck Protection Program (“PPP”) loans outstanding at December 31, 2021. These loans are fully guaranteed by the SBA and the Company does not reserve for these loans. Consumer – Loans in this segment primarily include personal unsecured loans, refinanced student loans and auto loans purchased from third party lenders. Repayment is dependent on the credit quality of the individual borrower. Allocated component The allocated component of the allowance for loan losses relates to loans that are individually classified as impaired. Residential real estate, commercial and industrial, commercial real estate and construction loans are evaluated for impairment on a loan-by-loan basis. Impairment is measured by either the present value of expected future cash flows discounted at the loan’s effective interest rate, or the fair value of the collateral if the loan is collateral dependent. An allowance is established when the discounted cash flows (or collateral value) of the impaired loan are lower than the carrying value of that loan. Large groups of smaller balance homogeneous loans are collectively evaluated for impairment. Accordingly, the Company does not generally identify individual consumer loans or second mortgages and HELOCs for impairment disclosures unless such loans are 90 days past due or are classified as a TDR. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. Bank-owned life insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at their cash surrender value net of charges or other amounts that are probable at settlement. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income in the consolidated statements of operations and are not subject to income taxes, unless such policies are surrendered prior to the death of the insured individuals. Mortgage servicing rights The Company services mortgage loans for others. Mortgage servicing rights are recognized as separate assets at fair value when rights are acquired through purchase or through sale of financial assets (“MSRs”). Capitalized servicing rights are amortized into mortgage servicing income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets. MSRs are evaluated for impairment based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights by predominant risk characteristics, such as interest rates and terms. Fair value is based on a valuation model that calculates the present value of estimated future net servicing income, using market-based assumptions. Impairment is recognized through a valuation allowance for an individual stratum, to the extent that fair value is less than the capitalized amount for the stratum. Changes in the valuation allowance, if any, are reported in mortgage servicing income. Premises and equipment Land is carried at cost. Buildings, equipment and leasehold improvements are stated at cost, less accumulated depreciation and amortization computed predominantly on the straight-line method over the estimated useful lives of the assets or the expected terms of the leases, if shorter. Expected terms include lease option periods to the extent that the exercise of such options is reasonably assured. Premises and equipment held for sale are stated at the lower of amortized cost or fair value less costs to sell. Transfers of financial assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. During the normal course of business, the Company may transfer a portion of a financial asset, for example, a participation loan. In order to be eligible for sales treatment, all cash flows from the loan must be divided proportionately, the rights of each loan holder must have the same priority, the loan holders must have no recourse to the transferor other than standard representations and warranties, and no loan holder can have the right to pledge or exchange the entire loan. In certain cases, the Company may have an obligation to repurchase mortgage loans sold to third parties and to refund fees to the purchaser if a payment default or prepayment occurs, in each case within a prescribed time period not exceeding four months after the sale date, or in the case of a violation of its representations and warranties under the provisions of its loan sale agreements. The Company evaluates its obligations under these provisions and recognizes a liability for the fair value of its recourse obligations. At December 31, 2021 and 2020, the Company determined that its obligations in connection with the recourse provisions of its loan sale agreements were insignificant. Foreclosed real estate Real estate acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value, less costs to sell, at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, valuations are periodically performed by management and the assets are carried at the lower of carrying amount or fair value less costs to sell. Revenue and expenses from operations, changes in the valuation allowance and any direct write-downs are included in foreclosed real estate expense. Supplemental retirement plan The Company accounts for its supplemental retirement plan using an actuarial model that allocates cost over the service period of participants in the plan. The Company accounts for the over-funded or under-funded status of the plan as an asset or liability in its consolidated balance sheets and recognizes changes in the funded status in the year in which the changes occur through other comprehensive income/loss. Employee Stock Ownership Plan Compensation expense for the Employee Stock Ownership Plan (“ESOP”) is computed based on the number of shares allocated to participants during the period multiplied by the average fair market value of the Company’s shares. This expense is recognized ratably throughout the year based on the expected allocation of shares for the year. Unearned compensation applicable to the ESOP is reflected as a reduction of stockholders’ equity. The difference between the average fair market value and cost of the shares allocated by the ESOP is recorded as an adjustment to additional paid-in capital. Stock-based compensation The fair value of restricted stock and stock options is determined on the date of grant and amortized to compensation expense with a corresponding increase to additional paid-in capital over the required service period, but in no event beyond the date of an employee’s or director’s date of termination. Forfeitures of unvested awards and grants are recorded as incurred. Advertising costs Advertising costs are expensed as incurred. Income taxes Deferred income tax assets and liabilities are determined using the liability (or balance sheet) method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the temporary differences between the book and tax basis of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. A valuation allowance is established against deferred tax assets when, based upon available evidence including historical and projected taxable income, that some or all of the deferred tax assets will not be realized. A tax position is recognized as a benefit if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company does not have any uncertain tax positions at December 31, 2021 and 2020 which require accrual or disclosure. The Company records interest and penalties as part of income tax expense. No material interest or penalties were recorded for the years ended December 31, 2021 and 2020. Comprehensive income (loss) Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income (loss). Although certain changes in assets and liabilities are reported as a separate component of equity, such items, along with net income (loss), are components of accumulated other comprehensive income (loss) (“AOCI”). The components of AOCI, included in stockholders’ equity, are as follows: December 31, December 31, 2021 2020 (In thousands) Securities available for sale: Net unrealized gain $ 249 $ 1,713 Tax effect (64 ) (313 ) Net-of-tax amount 185 1,400 Supplemental retirement plan Unrecognized net actuarial loss (646 ) (712 ) Unrecognized net prior service credit 222 254 (424 ) (458 ) Tax effect 58 (47 ) Net-of-tax amount (366 ) (505 ) Accumulated other comprehensive income (loss) $ (181 ) $ 895 In 2022, the Company expects to recognize $45,000 in prior service credits and $55,000 in net actuarial losses as components of cost for the supplemental retirement plan. These amounts are included in AOCI at December 31, 2021. Prior service credits and net actuarial gains and losses are amortized to periodic pension cost over varying periods based on the plan participants to whom they relate. Segment reporting An operating segment is defined as a component of a business for which separate financial information is available that is evaluated regularly by the chief operating decision-maker in determining how to allocate resources and evaluate performance. The Company has two reporting business segments, namely, “Envision Bank” and “Envision Mortgage”. Management allocates indirect costs, such as IT, Marketing, Accounting and Administration, to each business segment in order to fully measure each segment’s results of operations. See Note 18 for disclosure of the Company’s segment information. Earnings per share Basic earnings per share represents income available to common stockholders divided by the weighted average of common shares outstanding during the period. Unvested restricted shares of common stock having dividend rights are treated as “participating securities” and, accordingly, are considered outstanding in computing basic earnings per share. Unallocated ESOP shares are not considered outstanding in computing earnings per share. Diluted earnings per share reflects additional common shares that would have been outstanding if dilutive potential shares had been issued. Stock options represent potential dilutive shares with the number of such shares computed using the treasury stock method. Business combinations We account for business combinations under the acquisition method of accounting. The application of this method of accounting requires the use of significant estimates and assumptions in the determination of the fair value of tangible and identified intangible assets acquired and liabilities assumed in order to properly allocate purchase price consideration between assets from those that are recorded as goodwill. Our estimates of the fair values of assets acquired and liabilities assumed are based upon assumptions that we believe to be reasonable, and whenever necessary, include assistance from independent third-party appraisal and valuation firms. Costs incurred to consummate a business combination are expensed as incurred. Leases The Company leases office space, certain loan production offices and certain branch locations under noncancelable operating leases, several of which have renewal options to extend lease terms. Upon commencement of a new lease, the Company will recognize a right of use (“ROU”) asset and corresponding lease liability. The Company makes the decision on whether to renew an option to extend a lease by considering various factors. The Company will recognize an adjustment to its ROU asset and lease liability when lease agreements are amended and executed. The discount rate used in determining the present value of lease payments in based on the Company’s incremental borrowing rate for borrowings with terms similar to each lease at commencement date. The Company has lease agreements with lease and non-lease components, which are generally accounted for separately. For real estate leases, non-lease components and other non-components, such as common area maintenance charges, real estate taxes, and insurance are not included in the measurement of the lease liability since they are generally able to be separated. The Company has elected the short-term lease recognition exemption for all leases that qualify. Recent accounting pronouncements In February 2016, FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses In December 2019, FASB issued ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes

Securities Available for Sale

Securities Available for Sale	12 Months Ended
	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Securities Available for Sale	2 . SECURITIES AVAILABLE FOR SALE The amortized cost and fair value of securities available for sale, including gross unrealized gains and losses, are as follows: Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value (In thousands) December 31, 2021 U.S. Treasury $ 10,939 $ — $ (168 ) $ 10,771 U.S. Government-sponsored enterprises 1,995 — (17 ) 1,978 Corporate 2,510 33 (7 ) 2,536 Municipal 351 2 — 353 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 23,349 324 (194 ) 23,479 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 8,733 223 — 8,956 U.S. Government-guaranteed 103 — — 103 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 796 14 — 810 U.S. Government-guaranteed 2,641 39 — 2,680 Total securities available for sale $ 51,417 $ 635 $ (386 ) $ 51,666 December 31, 2020 U.S. Government-sponsored enterprises $ 1,993 $ 3 $ — $ 1,996 Corporate 4,300 56 — 4,356 Municipal 595 5 — 600 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 32,538 919 — 33,457 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 8,857 525 — 9,382 U.S. Government-guaranteed 977 24 — 1,001 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 996 52 — 1,048 U.S. Government-guaranteed 3,398 128 — 3,526 Total securities available for sale $ 53,654 $ 1,712 $ — $ 55,366 The amortized cost and fair value of debt securities by contractual maturity at December 31, 2021 are presented below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Fair Cost Value (In thousands) Within 1 year $ — $ — After 1 year through 5 years 10,073 9,974 After 5 years through 10 years 5,722 5,664 15,795 15,638 Mortgage-backed securities and collateralized mortgage obligations 35,622 36,028 $ 51,417 $ 51,666 Obligations of U.S. Government-sponsored enterprises consist primarily of securities issued by the Federal Home Loan Mortgage Corporation and the Federal National Mortgage Association. At December 31, 2021 and 2020, investment securities having a fair value of $1,979,000 and $1,958,000, respectively, were pledged as collateral for a line of credit with the Federal Reserve Bank of Boston (the “FRB”). There were no individual holdings of investment securities at December 31, 2021 and 2020, other than holdings of the U.S. Government and its agencies, which exceeded 10% of the Company’s stockholders’ equity as of such dates. The Company had 17 securities in a loss position at December 31, 2021, and no securities in a loss position at December 31, 2020. Information pertaining to securities with gross unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: Less Over Twelve Months Gross Gross Unrealized Fair Unrealized Fair Losses Value Losses Value December 31, 2021 Debt securities: U.S. Treasury $ (168 ) $ 10,771 $ — $ — U.S. Government-sponsored enterprises (17 ) 1,978 — — Corporate (7 ) 723 — — Residential mortgage-backed securities: U.S. Government-sponsored enterprises (194 ) 11,477 — — Total debt securities $ (386 ) $ 24,949 $ — $ — The Company currently does not believe it is probable that it will be unable to collect all amounts due according to the contractual terms of its investments. Therefore, it is expected that the securities would not be settled at a price less than the par value of the investment. Because the Company does not intend to sell any debt securities and it is more likely than not that the Company will not be required to sell any debt securities before recovery of its amortized cost basis, it does not consider its investments to be other-than-temporarily impaired at December 31, 2021. There were no security sales for the year ended December 31, 2021 and 2020.

Loans

Loans	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Loans	3 . LOANS A summary of the loan portfolio is as follows: December 31, 2021 2020 (In thousands) Mortgage loans on real estate: Residential: One- to four-family $ 236,364 $ 235,648 Home equity loans and lines of credit 57,295 48,166 Commercial 197,423 143,893 Construction 33,961 31,050 Total real estate loans 525,043 458,757 Commercial and industrial 17,242 20,259 Consumer 7,552 10,289 Total loans 549,837 489,305 Allowance for loan losses (6,289 ) (6,784 ) Net deferred loan costs and fees, and purchase premiums 1,073 1,123 Total loans, net $ 544,621 $ 483,644 The Company periodically transfers a portion of its originated commercial real estate loans to participating lenders. The amounts transferred have been accounted for as sales and are therefore not included in the Company’s accompanying consolidated balance sheets. The Company continues to service the loans on behalf of the participating lenders and, as such, collects cash payments from the borrowers, remits payments to participating lenders and disburses required escrow funds to relevant parties. At December 31, 2021 and 2020, the Company was servicing loans for participants aggregating $6,222,000 and $2,410,000, respectively. See Note 4 for information relating to the Company’s servicing of residential mortgage loans for others. The following tables present activity in the allowance for loan losses, by loan category, for the years ended December 31, 2021 and 2020 and allocation of the allowance to each category as of such dates: Second Residential Mortgages Commercial Commercial 1-4 Family and HELOC Real Estate Construction and Industrial Consumer Total (In thousands) Allowance for loan losses Balance at December 31, 2019 1,096 289 1,840 692 235 128 4,280 Provision for loan losses 543 156 1,562 59 179 54 2,553 Loans charged-off — (3 ) — — — (68 ) (71 ) Recoveries 7 — — — 2 13 22 Balance at December 31, 2020 $ 1,646 $ 442 $ 3,402 $ 751 $ 416 $ 127 $ 6,784 Provision (credit) for loan losses (558 ) 20 49 (54 ) 81 24 (438 ) Loans charged-off — — — — — (67 ) (67 ) Recoveries 5 — — — 2 3 10 Balance at December 31, 2021 $ 1,093 $ 462 $ 3,451 $ 697 $ 499 $ 87 $ 6,289 Second Residential Mortgages Commercial Commercial 1-4 Family and HELOC Real Estate Construction and Industrial (1) Consumer Total December 31, 2021 Allowance for impaired loans $ 81 $ 19 $ — $ — $ — $ — $ 100 Allowance for non-impaired loans 1,012 443 3,451 697 499 87 6,189 Total allowance for loan losses $ 1,093 $ 462 $ 3,451 $ 697 $ 499 $ 87 $ 6,289 Impaired loans $ 3,255 $ 603 $ - $ — $ — $ — $ 3,858 Non-impaired loans 233,109 56,692 197,423 33,961 17,242 7,552 545,979 Total loans $ 236,364 $ 57,295 $ 197,423 $ 33,961 $ 17,242 $ 7,552 $ 549,837 December 31, 2020 Allowance for impaired loans $ 133 $ — $ — $ — $ — $ — $ 133 Allowance for non-impaired loans 1,513 442 3,402 751 416 127 6,651 Total allowance for loan losses $ 1,646 $ 442 $ 3,402 $ 751 $ 416 $ 127 $ 6,784 Impaired loans $ 3,575 $ 623 $ 4,751 $ — $ — $ — $ 8,949 Non-impaired loans 232,073 47,543 139,142 31,050 20,259 10,289 480,356 Total loans $ 235,648 $ 48,166 $ 143,893 $ 31,050 $ 20,259 $ 10,289 $ 489,305 (1) Non-impaired loan balance includes $3.6 million and $10.9 million of PPP loans as of December 31, 2021 and 2020, respectively, for which no allowance is provided due to the full guarantee from the SBA. The following table presents past due and non-accrual loans, by loan category, at December 31, 2021 and 2020: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due (1) Non-accrual Loans (In thousands) December 31, 2021 Residential one- to four-family $ 701 $ 193 $ — $ 894 $ 2,133 Home equity loans and lines of credit 186 215 — 401 491 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer 76 9 — 85 — Total $ 963 $ 417 $ — $ 1,380 $ 2,624 December 31, 2020 Residential one- to four-family $ — $ — $ — $ — $ 1,876 Home equity loans and lines of credit 95 — 317 412 584 Commercial real estate — — 26 26 4,713 Construction — — — — — Commercial and industrial — — — — — Consumer 38 64 — 102 — Total $ 133 $ 64 $ 343 $ 540 $ 7,173 (1) Excludes non-accrual loans which are separately presented. Further information pertaining to impaired loans, which includes both non-accrual loans and TDRs, follows: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) December 31, 2021 Impaired loans without a valuation allowance: Residential one- to four-family $ 2,364 $ 2,377 $ — Home equity loans and lines of credit 479 485 — Total 2,843 2,862 — Impaired loans with a valuation allowance: Residential one- to four-family 874 878 81 Home equity loans and lines of credit 108 118 19 Total 982 996 100 Total impaired loans $ 3,825 $ 3,858 $ 100 December 31, 2020 Impaired loans without a valuation allowance: Residential one- to four-family $ 2,160 $ 2,181 $ — Home equity loans and lines of credit 626 623 — Commercial real estate 4,753 4,751 — Total 7,539 7,555 — Impaired loans with a valuation allowance: Residential one- to four-family 1,382 1,394 133 Total 1,382 1,394 133 Total impaired loans $ 8,921 $ 8,949 $ 133 Information related to the average balances of impaired loans and the interest income recognized on such loans, follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Year Ended December 31, 2021 Residential one- to four-family $ 3,132 $ 202 $ 125 Home equity loans and lines of credit 525 30 4 Commercial real estate 2,491 - — Total $ 6,148 $ 232 $ 129 Year Ended December 31, 2020 Residential one- to four-family $ 3,550 $ 399 $ 159 Home equity loans and lines of credit 588 60 — Commercial real estate 2,838 8 — Total $ 6,976 $ 467 $ 159 No additional funds are committed to be advanced in connection with impaired loans. Troubled Debt Restructurings The Company periodically grants concessions to borrowers experiencing financial difficulties. The Company’s TDRs consist primarily of interest rate concessions for periods of three months to thirty years for residential real estate loans and home equity loans, and for periods up to one year for commercial real estate loans. Number of Contracts TDRs Listed as Accrual Number of Contracts TDRs Listed as Non-accrual Total Number of Contracts Total TDRs (In thousands) December 31, 2021 Residential one- to four-family 9 $ 1,103 3 $ 919 12 $ 2,022 Home equity loans and lines of credit 2 97 1 109 3 206 Total 11 $ 1,200 4 $ 1,028 15 $ 2,228 December 31, 2020 Residential one- to four-family $ 12 $ 1,666 $ 4 $ 1,167 16 $ 2,833 Home equity loans and lines of credit 1 42 — — 1 42 Commercial real estate 1 40 — — 1 40 Total 14 1,748 4 $ 1,167 18 $ 2,915 For the year ended December 31, 2021, the Company entered into one loan modification meeting the criteria of a TDR in which a long term concession was granted to a borrower. For the year ended December 31, 2020, the Company also entered into one loan modification meeting the criteria of a TDR. Management performs a discounted cash flow calculation to determine the amount of impairment reserve required on each of the TDRs. Any reserve is recorded as part of the allowance for loan losses. At December 31, 2021 and 2020, the Company had allowances of $100,000 and $133,000, respectively, related to TDRs. During the years ended December 31, 2021 and 2020, there were no TDRs that defaulted (over 30 days past due) within twelve months of the restructuring date. No additional funds are committed to be advanced on loans being accounted for as TDRs. At December 31, 2021 there was one residential real estate troubled debt restructuring that was granted a payment deferral plan. That loan, totaling $213,000, was not performing in accordance with its modified terms. Credit Quality Information The Company utilizes an eight-grade internal loan rating system for commercial real estate, construction and commercial loans, as follows: Loans rated 1 – 3A are considered “pass” rated loans with low to average risk. Loans rated 4 are considered “special mention.” These loans are starting to show signs of potential weakness and are being closely monitored by management. Loans rated 5 are considered “substandard” and are inadequately protected by the current net worth and paying capacity of the obligors and/or the collateral pledged. There is a distinct possibility that the Company will sustain some loss if the weakness is not corrected. Loans rated 6 are considered “doubtful” and have all the weaknesses inherent in those classified substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, highly questionable and improbable. Loans rated 7 are considered uncollectible (“loss”) and of such little value that their continuance as loans is not warranted. On an annual basis, or more often if needed, the Company formally reviews the ratings on all commercial real estate, construction and commercial loans. Annually, the Company engages an independent third party to review a significant portion of loans within these segments. Management uses the results of these reviews as part of its annual review process. The following table presents the Company’s loans by risk rating at December 31, 2021 and 2020: Residential 1-4 Family Second Mortgages and HELOC Commercial Real Estate Construction Commercial and Industrial Consumer Total (In thousands) December 31, 2021 Not Rated $ 234,225 $ 56,797 $ — $ — $ — $ 7,552 $ 298,574 Loans rated 1 - 3A (Pass rated) — — 186,774 33,961 16,910 — 237,645 Loans rated 4 361 381 7,106 — 332 — 8,180 Loans rated 5 1,778 117 3,543 — — — 5,438 Total $ 236,364 $ 57,295 $ 197,423 $ 33,961 $ 17,242 $ 7,552 $ 549,837 December 31, 2020 Not Rated $ 233,773 $ 47,582 $ — $ — $ — $ 10,289 $ 291,644 Loans rated 1 - 3A (Pass rated) — — 129,925 31,050 19,828 — 180,803 Loans rated 4 803 584 9,257 — 431 — 11,075 Loans rated 5 1,072 — 4,711 — - — 5,783 Total $ 235,648 $ 48,166 $ 143,893 $ 31,050 $ 20,259 $ 10,289 $ 489,305 Residential mortgages, home equity loans and lines of credit, and consumer loans are monitored for credit quality based primarily on their payment status. When one of these loans becomes more than 90 days delinquent it is assigned an internal loan rating.

Loan Servicing

Loan Servicing	12 Months Ended
	Dec. 31, 2021
Transfers And Servicing [Abstract]
Loan Servicing	4 . LOAN SERVICING Mortgage loans serviced for others are not included in the accompanying consolidated balance sheets. The unpaid principal balances of mortgage loans serviced for others were $1,975,876,000 and $1,760,306,000 at December 31, 2021 and 2020, respectively. In connection with these serviced loans, we maintained $16.6 million and $14.2 million of custodial escrow balances at December 31, 2021 and 2020, respectively. The following table summarizes the activity in the Company’s MSRs for the indicated periods: For the Years Ended December 31, 2021 2020 Mortgage servicing rights: (In thousands) Balance at beginning of year $ 15,372 $ 9,484 Additions through originations 5,998 8,432 Amortization (3,197 ) (2,544 ) Balance at end of year $ 18,173 $ 15,372 Valuation allowance: Balance at beginning of year $ 2,995 $ 928 Provision (credit) (438 ) 2,067 Balance at end of year $ 2,557 $ 2,995 Mortgage servicing rights, amortized cost $ 15,616 $ 12,377 Mortgage servicing rights, fair value $ 16,355 $ 12,490 At December 31, 2021 and 2020, the fair value of MSRs was determined using a discount rate of 12% and projected annual prepayment speeds ranging from 15% to 18% for 2021 and 19% to 27% for 2020. During the year ended December 31, 2021 the Company decreased the valuation allowance for its MSRs by $438,000 and the Company increased the valuation allowance for its MSRs by $2,067,000 for the year ended December 31, 2020. Such adjustments were due to changes in fair value caused by the impact of interest rate movements on actual and expected loan prepayments. Contractually specified servicing fees for the years ended December 31, 2021 and 2020 amounted to $5,012,000 and $3,458,000, respectively, and are included in mortgage servicing fees, net.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Premises and Equipment	5 . PREMISES AND EQUIPMENT A summary of the cost and accumulated depreciation and amortization of premises and equipment is as follows: December 31, Estimated 2021 2020 Useful Life (In thousands) (In years) Land and improvements $ 953 $ 953 Buildings and improvements 6,325 3,343 5 to 50 Leasehold improvements 1,097 2,236 3 to 10 Furniture and equipment 4,295 5,558 3 to 10 Construction-in-progress - 145 12,670 12,235 Less accumulated depreciation and amortization (4,986 ) (7,454 ) $ 7,684 $ 4,781 Total depreciation and amortization expense for the years ended December 31, 2021 and 2020 amounted to $707,000 and $1,508,000, respectively.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2021
Deposits [Abstract]
Deposits	6 . DEPOSITS A summary of deposit balances, by type, is as follows: December 31, 2021 2020 (In thousands) Demand deposits $ 145,666 $ 96,731 NOW accounts 53,996 53,530 Money market deposits 90,544 77,393 Regular and other savings accounts 191,712 185,481 Brokered deposits 10,061 10,056 Total non-certificate accounts 491,979 423,191 Term certificates less than $250,000 85,877 60,026 Term certificates of $250,000 or more 20,235 23,418 Term certificates - brokered 40,056 21,672 Total certificate accounts 146,168 105,116 $ 638,147 $ 528,307 A summary of term certificates, including brokered deposits, by maturity is as follows: December 31, 2021 December 31, 2020 Weighted Weighted Average Average Maturing during: Amount Rate Amount Rate (Dollars in thousands) 2021 $ — — % $ 81,320 0.95 % 2022 95,232 0.53 20,122 1.46 2023 31,966 0.30 2,269 1.06 2024 17,464 0.30 781 1.15 2025 755 0.53 624 0.64 2026 751 0.27 — — $ 146,168 0.45 % $ 105,116 1.05 %

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Borrowings	7 . BORROWINGS A summary of borrowings from the FHLBB at December 31, 2021 and 2020 is as follows: 2021 2020 Weighted Weighted Average Average Amount Rate Amount Rate (Dollars in thousands) Fixed-rate advances maturing: 2021* $ — — % 21,895 1.27 2022 5,000 0.30 10,000 2.20 2023 5,000 0.46 — — 2024 — — — — 2025 40,000 1.39 30,000 1.35 $ 50,000 1.18 % $ 61,895 1.46 % * Includes amortizing advances which require monthly principal and interest payments. There were no overnight advances or advances having a one-month maturity at December 31, 2021 and 2020. Selected information for such short-term borrowings for the years presented is as follows (in 000’s): 2021 2020 Average daily balance $ 4,357 $ 2,265 Maximum outstanding at any month end 28,032 16,181 Advances from the FHLBB are secured by a blanket pledge agreement on the Bank’s qualified collateral, defined principally as 75% of the carrying value of pledged first mortgage loans on owner-occupied residential property and 65% on pledged commercial real estate loans. Available borrowing capacity at December 31, 2021 was $111.5 million. At December 31, 2021, the Bank was in compliance with the FHLBB collateral requirements. The Bank also has a $4,195,000 available line of credit with the FHLBB at an interest rate that adjusts daily. Borrowings under the line are limited to 2% of the Bank’s total assets. At December 31, 2021 and 2020, there were no advances outstanding. The Bank also has a $2,000,000 available line of credit with the FRB and a $12,500,000 available line of credit with a correspondent bank. No advances were outstanding under either of these lines at December 31, 2021 and 2020. As a participating lender in the PPP, the Company had access to borrowing capacity through the Federal Reserve’s Paycheck Protection Program Lending Facility (the “PPPLF”). Only loans issued through the PPP could be pledged as collateral. At December 31, 2020, the bank had $11.4 million in outstanding advances. The bank prepaid all remaining outstanding PPPLF advances during 2021. The bank had no outstanding advances at December 31, 2021.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	8 . INCOME TAXES Allocation of federal and state income taxes between current and deferred portions is as follows (in thousands): Years Ended December 31, 2021 2020 Current tax expense: Federal $ 2,797 $ 789 State 1,384 1,393 Total current tax expense 4,181 2,182 Deferred tax expense (benefit): Federal (301 ) 4,174 State (287 ) 887 (588 ) 5,061 Change in valuation allowance (531 ) (1,766 ) Total deferred tax expense (benefit) (1,119 ) 3,295 Total tax expense $ 3,062 $ 5,477 The reasons for the differences between the statutory federal income tax expense (benefit) and the actual tax expense are summarized as follows (in thousands): Years Ended December 31, 2021 2020 Statutory federal tax rate of 21% $ 2,659 $ 5,341 Increase (decrease) resulting from: State taxes, net of federal tax effect 867 1,801 Bank-owned life insurance (34 ) (38 ) Tax-exempt income (4 ) (6 ) Change in valuation allowance (531 ) (1,766 ) Other, net 105 145 Total tax expense $ 3,062 $ 5,477 The components of the net deferred tax asset are as follows (in thousands): December 31, 2021 2020 Deferred tax assets: Federal $ 3,977 $ 2,962 State 1,867 1,286 5,844 4,248 Valuation allowance - (531 ) 5,844 3,717 Deferred tax liabilities: Federal (5,160 ) (4,837 ) State (2,423 ) (2,175 ) (7,583 ) (7,012 ) Net deferred tax liability $ (1,739 ) $ (3,295 ) The tax effects of items giving rise to deferred tax assets (liabilities) are as follows (in thousands): December 31, 2021 2020 Employee benefit plans $ 729 $ 785 Allowance for loan losses 1,938 2,071 Funded status of post-retirement benefits 143 (47 ) Securities available for sale (64 ) (313 ) Depreciation and amortization 62 144 Net deferred loan origination costs (276 ) (281 ) Mortgage servicing rights (4,390 ) (3,479 ) Charitable contribution carryforward — 531 Derivatives (374 ) (2,722 ) Right-of-use asset (508 ) — Lease liability 508 — Stock-based compensation 390 290 Other, net 103 257 (1,739 ) (2,764 ) Valuation allowance on net deferred tax assets — (531 ) Net deferred tax liability $ (1,739 ) $ (3,295 ) From 2014 to June 30, 2019, the Company has maintained a valuation allowance on its net deferred tax asset based on a determination that it was more likely than not that such assets would not be realized. This determination was based on the Company's net operating loss carryforward position, its current period operating results exclusive of non-recurring items and its expectations for the upcoming year. As a result, the 100% valuation allowance for deferred tax assets relating to the net operating loss carryforwards was maintained. Due to the level of income earned during the year ended 2020 and the Company being in a net deferred tax liability position at December 31, 2020, the full amount of the Company’s net operating loss carryforwards was absorbed and the previously held valuation allowance was reversed. At December 31, 2020, the Company had a charitable contribution valuation allowance carryforward of $531,000 which was reversed during 2021. There was no charitable contribution valuation allowance carryforward at December 31, 2021. The federal income tax reserve for loan losses at the Company’s base year amounted to $2,033,000. If any portion of the reserve is used for purposes other than to absorb the losses for which it was established, approximately 150% of the amount actually used (limited to the amount of the reserve) would be subject to taxation in the fiscal year in which used. As the Company intends to use the reserve only to absorb loan losses, a deferred income tax liability of $571,000 has not been provided. The Company’s income tax returns are subject to review and examination by federal and state taxing authorities. The Company is currently open to audit under the applicable statutes of limitations by the Internal Revenue Service for the years ended December 31, 2018 through 2021. The years open to examination by state taxing authorities vary by jurisdiction; no years prior to 2016 are open.

On-Balance Sheet Derivative Ins

On-Balance Sheet Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2021
Derivative Instruments And Hedging Activities Disclosure [Abstract]
On-Balance Sheet Derivative Instruments and Hedging Activities	9 . ON-BALANCE SHEET DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Derivative Loan Commitments Mortgage loan interest rate lock commitments qualify as derivative loan commitments if the loan that will result from exercise of the commitment will be held for sale upon funding. The Company enters into commitments to fund residential mortgage loans at specified rates and times in the future, with the intention that these loans will subsequently be sold in the secondary market or to other financial institutions. Outstanding derivative loan commitments expose the Company to the risk that the price of the loans arising from exercise of the loan commitment might decline from inception of the rate lock to funding of the loan due to an increase in mortgage interest rates. If interest rates increase, the value of these loan commitments decreases. Conversely, if interest rates decrease, the value of these loan commitments increases. The notional amount of derivative loan commitments was $85,887,000 and $396,551,000 at December 31, 2021 and 2020 , respectively. The fair value of such commitments at December 31, 2021 and 2020 was an asset of $ and $ , respectively, and is included in other assets in the accompanying consolidated balance sheets. During the year ended December 31, 2021 , the decrease in aggregate fair value of $ 10,457,000 and the increase in aggregate fair value of $ for the year ended December 31, 2020 , related to interest rate lock commitments w ere recognized and included in the net gain on loan origination and sales activities in the accompanying consolidated statements of operations. Forward Loan Sale Commitments The Company utilizes both “mandatory delivery” and “best efforts” forward loan sale commitments and, effective in the fourth quarter of 2018, TBA securities to hedge the financial impact of changes in interest rates on the value of loans that would result from the exercise of the derivative loan commitments. With a “mandatory delivery” contract, the Company commits to deliver a certain principal amount of mortgage loans to an investor at a specified price on or before a specified date. If the Company fails to deliver the amount of mortgages necessary to fulfill the commitment by the specified date, it may be obligated to pay a “pair-off” fee, based on then-current market prices, to the investor to compensate the investor in the event of a loss in value. With a “best efforts” contract, the Company commits to deliver an individual mortgage loan of a specified principal amount and quality to an investor if the loan to the underlying borrower closes. Generally, the price the investor will pay the seller for an individual loan is specified prior to the loan being funded (e.g., on the same day the lender commits to lend funds to a potential borrower). The Company expects that these forward loan sale commitments and TBA securities will experience changes in fair value that serve to substantially offset the change in fair value of derivative loan commitments the degree to which depends on the notional amount of such sale commitments. The aggregate notional amount of forward loan sale commitments and TBA securities was $80,407,000 and $390,248,000 at December 31, 2021 and 2020, respectively. The fair value of such commitments at December 31, 2021 and 2020 consisted of liabilities of $84,000 and $2,180,000, respectively, included in other liabilities in the consolidated balance sheets and assets of $50,000 and $44,000, respectively, included in other assets in the consolidated balance sheets. During the years ended December 31, 2021 and 2020, net increases (reductions) in the aggregate fair value liability of $(2,102,000) and $2,007,000, respectively, related to forward loan sale commitments and TBA securities were recognized and included in net gain on loan originations and sales activities in the accompanying consolidated statements of operations.

Minimum Regulatory Capital Requ

Minimum Regulatory Capital Requirements	12 Months Ended
	Dec. 31, 2021
Banking And Thrifts [Abstract]
Minimum Regulatory Capital Requirements	1 0 . MINIMUM REGULATORY CAPITAL REQUIREMENTS The Bank is subject to various regulatory capital requirements administered by federal banking agencies. Capital adequacy guidelines and prompt corrective actions regulations involve qualitative measures of assets, liabilities, and certain off-balance sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgement by regulators. Failure to meet capital requirements can initiate regulatory action. The final rules implementing Basel Committee on Banking Supervision’s capital guidelines for U.S. banks (Basel III rules) became effective for the Bank on January 1, 2015. Under BASEL III, community banking institutions must maintain a capital conservation buffer of common equity tier 1 capital in an amount greater than 2.5% of total risk-weighted assets to avoid being subject to limitations on capital distributions and discretionary bonuses. Quantitative measures established by regulation to ensure capital adequacy require the Bank to maintain minimum amounts and ratios (set forth in the following tables) of total, Tier 1 capital and common equity Tier 1 capital to risk weighted assets, and Tier 1 capital to average assets (all as defined). Management believes, as of December 31, 2021 and 2020, that the Bank met all capital adequacy requirements to which it is subject. As of December 31, 2021, the most recent notification from the FDIC categorized the Bank as well capitalized under the regulatory framework for prompt corrective action. To be categorized as well capitalized, the Bank must maintain minimum total risk-based, Tier 1 risk-based, common equity Tier 1 and Tier 1 leverage ratios as set forth in the following tables. There are no conditions or events since the notification that management believes have changed the Bank’s category. The Bank’s actual and minimum capital amounts and ratios, exclusive of the capital conservation buffer, are presented in the following table: Minimum To Be Well For Minimum Capitalized Under Capital Prompt Corrective Actual Adequacy Purposes Action Provisions Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) December 31, 2021 Total capital (to risk weighted assets) $ 100,180 17.4 % $ 45,956 8.0 % $ 57,445 10.0 % Tier 1 capital (to risk weighted assets) 93,288 16.2 34,467 6.0 45,956 8.0 Common equity Tier 1 capital (to risk weighted assets) 93,288 16.2 25,850 4.5 37,339 6.5 Tier 1 capital (to average assets) 93,288 12.3 30,355 4.0 37,943 5.0 December 31, 2020 Total capital (to risk weighted assets) $ 97,406 15.7 % $ 49,682 8.0 % $ 62,102 10.0 % Tier 1 capital (to risk weighted assets) 90,037 14.5 37,261 6.0 49,682 8.0 Common equity Tier 1 capital (to risk weighted assets) 90,037 14.5 27,946 4.5 40,366 6.5 Tier 1 capital (to average assets) 90,037 12.7 28,466 4.0 35,582 5.0

Post-retirement Plans

Post-retirement Plans	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Post-retirement Plans	1 1 . POST-RETIREMENT PLANS Supplemental retirement agreements The Company maintains supplemental retirement agreements with certain officers and directors that provide for supplemental benefits commencing with retirement. The present value of future benefits payable is accrued over the terms of employment or anticipated term of each participating director’s position, as applicable, taking into consideration the vesting provisions in the agreements. At December 31, 2021 and 2020, the accrued benefits related to the agreements amounted to $391,000 and $453,000, respectively. Total expense, included in other non-interest expenses, related to these supplemental agreements amounted to $152,000 and $65,000 for the years ended December 31, 2021 and 2020, respectively. Supplemental retirement plan The Company has a master supplemental retirement plan (“Plan”) which covers certain officers and directors of the Company. In 2021 and 2020, the only active participants in the Plan were certain directors, as the Plan is frozen to new participants. Information pertaining to activity in the Plan follows: Years Ended December 31, 2021 2020 (In thousands) Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Employer contributions 201 201 Benefits paid (201 ) (201 ) Fair value of plan assets at end of year — — Change in benefit obligation: Benefit obligation at beginning of year 1,457 1,506 Service cost 13 11 Interest cost 17 36 Actuarial (gain) loss (19 ) 105 Benefits paid (201 ) (201 ) Benefit obligation at end of year 1,267 1,457 Unfunded status and accrued supplemental pension cost at year end $ (1,267 ) $ (1,457 ) Accumulated benefit obligation at year end $ 1,267 $ 1,457 The assumptions used to determine the benefit obligation are as follows: December 31, 2021 2020 Discount rate 1.90 % 1.25 % Annual inflation factor 1.00 % 1.00 % Net periodic benefit cost, included in other non-interest expenses, attributable to the Plan for the years ended December 31, 2021 and 2020, consists of the following: 2021 2020 (In thousands) Service cost $ 13 $ 11 Interest cost 17 36 Amortization of net actuarial loss 62 45 Amortization of prior service credit (45 ) (57 ) $ 47 $ 35 The following assumptions were used to determine the net periodic benefit cost for the years ended December 31, 2021 and 2020: 2021 2020 Discount rate 1.25 % 2.50 % Annual inflation factor 1.00 % 1.00 % Estimated future benefit payments, which reflect expected future services, as appropriate, are as follows: Years Ending December 31, Amount (In thousands) 2022 $ 209 2023 345 2024 204 2025 200 2026 90 2027-2031 187 Endorsement split-dollar life insurance arrangements The Company is the sole owner of life insurance policies pertaining to certain of the Company’s current and former directors and executives. The Company has entered into agreements with these directors and executives whereby the Company will pay to the directors’ and executives’ estates or beneficiaries a portion of the death benefit that the Company will receive as beneficiary of such policies. Expense associated with this post-retirement benefit for the years ended December 31, 2021 and 2020 amounted to $14,000 and $20,000, respectively. At December 31, 2021 and 2020, the accrued benefits related to the split-dollar arrangements amounted to $486,000 and $472,000, respectively. 401(k) Plan The Company maintains a 401(k) Plan whereby each employee reaching the age of 21 automatically becomes a participant in the plan. Employees may contribute up to 15% of their compensation subject to certain limits based on federal tax laws. All employees who have worked for one year or 1,000 hours are eligible for an automatic employer contribution of 3% of employees’ compensation, which requires no vesting period. The Company also matches 50% of the first 2% of an eligible employee’s contributions, allowing for a total employer contribution of 4% of employees’ compensation. Matching contributions vest over a four-year

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	1 2 . STOCK-BASED COMPENSATION Under the Randolph Bancorp, Inc. 2017 Stock Option and Incentive Plan (the “2017 Equity Plan”), the Company may grant options, restricted stock, restricted units or performance awards to its directors, officers and employees. Both incentive stock options and non-qualified stock options may be granted under the Equity Plan with 586,872 shares reserved for options. The exercise price of each option equals the market price of the Company’s stock on the date of the grant and the maximum term of each option is 10 years. The total number of shares reserved for restricted stock is 234,749. Options and awards generally vest ratably over three to five years. In addition, the Company granted 15,000 shares of restricted stock and 44,118 options in 2020 as an inducement for senior executives to accept employment (the “2020 Inducement Plan”). The inducement awards and options vest ratably over five years. The fair value of shares awarded is based on the market price at the date of grant. At the Annual Meeting of Shareholders held on May 24, 2021, the Company’s shareholders approved the 2021 Equity Incentive Plan (the “2021 Equity Plan”). The 2021 Equity Plan permits equity awards to employees and directors in the form of stock options, restricted stock and other forms of compensation. The maximum number of shares of common stock that may be issued under the 2021 Equity Plan is 100,000. On August 13, 2021, the Company granted 18,000 performance-based restricted stock unit awards to certain senior level employees. These performance-based restricted stock unit awards were issued from the 2021 Equity Plan and were determined to have a grant fair value per share of $20.15. The number of stock units to be vested is contingent upon the attainment of certain performance criteria to be measured at the end of a three-year Stock Options The fair value of each option grant is estimated on the date of the grant using the Black-Scholes option-pricing model with the following assumptions: • Volatility incorporates peer group volatility because the Company does not have a sufficient trading history. • Expected life represents the period of time that the option is expected to be outstanding, taking into account the contractual term, and the vesting period. • Expected dividend yield is based on the Company's history and expectation of dividend payouts. • The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for a period equivalent to the expected life of the option. The Company made the following grants of options to purchase shares of common stock during the years ended December 31, 2021 and 2020: 2021 2020 Options granted 40,491 333,118 Vesting period (years) 5 3 - 5 Expiration period (years) 10 10 Expected volatility 30.98 % 24.94% - 29.87% Expected life (years) 6.2 6 - 6.5 Expected dividend yield — — Risk free interest rate 0.64 % 0.44%-1.47% Option fair value $ 6.20 $2.69 - $4.87 The following table presents the activity and certain other information related to stock option grants under the 2017 Equity Plan and the 2020 Inducement Plan for the year ended December 31, 2021: Options Stock Option Grants Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Balance at January 1, 2021 587,168 $ 13.32 8.40 $ — Granted 40,491 20.06 Exercised (19,276 ) 13.48 Forfeited (9,000 ) 11.48 Balance at December 31, 2021 599,383 $ 13.80 8.50 $ 6,115,920 Exercisable at December 31, 2021 261,733 $ 14.26 7.61 $ 2,548,314 Unrecognized compensation cost (inclusive of directors' options) $ 1,072,768 Weighted average remaining recognition period (years) 2.08 For the years ended December 31, 2021 and 2020, stock-based compensation expense applicable to stock options was $591,000 and $703,000, respectively. Restricted Stock Shares issued upon vesting may be either authorized but unissued shares or reacquired shares held by the Company. Any shares not issued because vesting requirements are not met will again be available for issuance under the plan. The fair market value of shares awarded, based on the market price at the date of grant, is recorded as unearned compensation and amortized over the applicable vesting period. The following table presents the activity and certain other information related to restricted stock awards under the Equity Plan for the year ended December 31, 2021: Restricted Stock Awards Weighted Average Grant Price Performance-Based Restricted Stock Units (1) Weighted Average Grant Price Total Restricted Stock Awards and Performance-Based Restricted Stock Units Weighted Average Grant Price Restricted stock awards at January 1, 2021 122,012 $ 12.72 — $ — 122,012 $ 12.72 Granted 19,750 20.15 18,000 20.15 37,750 20.15 Vested (40,165 ) 13.44 — — (40,165 ) 13.44 Forfeited (2,112 ) 11.48 — — (2,112 ) 11.48 Non-vested stock awards at December 31, 2021 99,485 $ 13.93 18,000 $ 20.15 117,485 $ 14.89 Unrecognized compensation cost $ 1,124,787 $ 310,355 $ 1,435,142 Weighted average remaining recognition period (years) 2.60 2.29 2.55 (1) Performance-based restricted stock units granted reflects the estimated number able to be earned under a given award. The maximum number of shares that could vest is 27,000. Estimates are based on the most recent performance assumption available and is adjusted as assumptions change. Total expense for the restricted stock awards was $641,000 and $891,000 for the years ended December 31, 2021 and 2020, respectively.

Employee Stock Ownership Plan

Employee Stock Ownership Plan	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee Stock Ownership Plan	1 3 . EMPLOYEE STOCK OWNERSHIP PLAN The Company maintains an Employee Stock Ownership Plan (“ESOP”), which is a tax-qualified retirement plan providing eligible employees the opportunity to own Company stock. The Company granted a loan to the ESOP for the purchase of 469,498 shares of its common stock at $10.00 per share. The loan is payable annually over 25 years with interest at the prime rate to be reset each January 1 st Shares are committed to be released on a monthly basis and allocated as of December 31 st

Share Repurchase Program

Share Repurchase Program	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Share Repurchase Program	1 4 . SHARE REPURCHASE PROGRAM In September 2017, the Company’s Board of Directors adopted a share repurchase program under which the Company may repurchase up to 10%, or 586,854 shares of its then outstanding common shares. Repurchases under the program may be made in open market or in privately negotiated transactions and pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities and Exchange Commission. Any repurchased shares will be held by the Company as authorized but unissued shares. The repurchase program expired on September 14, 2020, at which time, the Company had repurchased 568,403 shares at a cost of $8,452,000 in connection with this program. In October 2020, the Company’s Board of Directors adopted a share repurchase program under which the Company may repurchase up to 10%, or 552,000 shares of its then outstanding common shares. Repurchases under the program may be made in open market or in privately negotiated transactions and pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities and Exchange Commission. Any repurchased shares will be held by the Company as authorized but unissued shares. The repurchase expired on October 29, 2021, at which time, the Company had repurchased 435,601 shares at a cost of $8,819,000 in connection with this program. In October 2021, the Company announced a new share repurchase program under which the Company may repurchase up to 10%, or 510,000 of its then outstanding shares. Repurchases under the program may be made in open market or in privately negotiated transactions and pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities and Exchange Commission. Any repurchased shares will be held by the Company as authorized but unissued shares. As of December 31, 2021, the Company had repurchased 4,337 shares at a cost of $100,000 in connection with this program. On January 25, 2022, the Company announced a modification to this program. The modification changes the program so that the Company may purchase up to 62,000 shares, or approximately 1% of the Company’s outstanding common stock.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	15. EARNINGS PER SHARE Basic earnings per share represents net income divided by the weighted average of common shares outstanding during the period. Unvested restricted shares of common stock having dividend rights are treated as “participating securities” and, accordingly, are considered outstanding in computing basic earnings per share. Unallocated ESOP shares are not considered to be outstanding for purposes of computing earnings per share. The following table sets forth the calculation of the average number of shares outstanding used to calculate the basic and diluted earnings per share for the periods indicated: 2021 2020 Average number of common shares outstanding 5,262,824 5,511,524 Less: Average unallocated ESOP shares (366,183 ) (384,963 ) Average number of common shares outstanding used to calculate basic earnings per share 4,896,641 5,126,561 Effect of dilutive stock options 212,097 36,481 Average number of common shares outstanding used to calculate dilutive earnings per share 5,108,738 5,163,042

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 6 . COMMITMENTS AND CONTINGENCIES In the normal course of business, there are outstanding commitments and contingencies which are not reflected in the accompanying consolidated financial statements: Loan commitments The Company is a party to financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit. These instruments involve, to varying degrees, elements of market, credit and interest rate risk which are not recognized in the consolidated financial statements. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. The Company uses the same credit policies in making commitments and conditional obligations as it does for on-balance-sheet instruments. At December 31, 2021 and 2020, the following financial instruments were outstanding whose contract amounts represent credit risk: 2021 2020 (In thousands) Commitments to originate loans $ 107,889 $ 411,401 Unused lines and letters of credit 79,012 71,458 Unadvanced funds on construction loans 13,879 9,110 Overdraft lines of credit 7,967 7,969 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. The commitments for lines of credit may expire without being drawn upon. Therefore, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The majority of these financial instruments are collateralized by real estate. Employment Arrangement and Change in Control Agreements The Company has entered into an employment arrangement with its President and Chief Executive Officer that provides for three years of salary continuation in the event his employment is terminated without cause or he resigns for good reason, subject to his providing a release of claims and complying with a non-solicitation and non-disclosure agreement. The Company has also entered into change in control agreements with five members of senior management which provide that if, within two years of a change of control of the Company or the Bank, the executive is involuntarily terminated other than for cause, disability or death, or voluntarily resigns for good reason, the executive will be entitled to a lump-sum payment equal to two times salary plus bonus. The Company has also entered into change in control agreements with four members of senior management which provide that if, within one year of a change of control of the Company or the Bank, the executive is involuntarily terminated other than for cause, disability or death, or voluntarily resigns for good reason, the executive will be entitled to a lump-sum payment equal to one times salary plus bonus. Other contingencies The Company is not currently a party to any pending legal proceedings that it believes would have a material adverse effect on its financial condition, results of operations or cash flows.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	1 7 . FAIR VALUE OF ASSETS AND LIABILITIES Determination of fair value The Company uses fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined based upon quoted market prices. However, in many instances, there are no quoted market prices for the Company’s various assets and liabilities. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. Accordingly, the fair value estimates may not be realized in an immediate settlement of the asset or liability. The following methods and assumptions were used by the Company in estimating fair value disclosures: Cash and cash equivalents Certificates of deposit Securities Federal Home Loan Bank of Boston stock Loans held for sale Loans Mortgage servicing rights Deposit liabilities FHLBB advances Accrued interest On-balance-sheet derivatives Off-balance sheet credit-related instruments Assets and liabilities measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis are summarized below. Total Level 1 Level 2 Level 3 Fair December 31, 2021 (In thousands) Assets: Securities available for sale $ — $ 51,666 $ — $ 51,666 Portfolio loans (fair value option) 13,780 — 13,780 Loans held for sale (fair value option) — 44,766 — 44,766 Derivative loan commitments — 1,364 — 1,364 Forward loan sale commitments — 50 — 50 Liabilities: Forward loan sale commitments, including TBAs — 84 — 84 December 31, 2020 Assets: Securities available for sale: Debt securities $ — $ 55,366 $ — $ 55,366 Portfolio loans (fair value option) — 13,780 — 13,780 Loans held for sale (fair value option) — 119,112 — 119,112 Derivative loan commitments — 11,821 — 11,821 Forward loan sale commitments — 44 — 44 Liabilities: Forward loan sale commitments, including TBAs — 2,180 — 2,180 There were no transfers between levels for assets and liabilities recorded at fair value on a recurring basis during 2021 or 2020. Assets and liabilities measured at fair value on a non-recurring basis The Company may also be required, from time to time, to measure certain other assets on a non-recurring basis in accordance with U.S. generally accepted accounting principles. These adjustments to fair value usually result from application of lower-of-cost-or-market accounting or write-downs of individual assets and liabilities. The following table summarizes the fair value hierarchy used to determine each adjustment and the carrying value of the related assets and liabilities as of December 31, 2021 and 2020. The gains and losses represent the amounts recorded during 2021 and 2020 on the assets and liabilities held at year-end. There no liabilities recorded at fair value on a non-recurring basis as of December 31, 2021 and 2020. Year Ended December 31, 2021 December 31, 2021 Level 1 Level 2 Level 3 Total Assets: (In thousands) Collateral dependent impaired loans $ — $ — $ 2,551 $ — Mortgage servicing rights — 15,616 — 438 $ — $ 15,616 $ 2,551 $ 438 Year Ended December 31, 2020 December 31, 2020 Level 1 Level 2 Level 3 Total Gains (Losses) (In thousands) Collateral dependent impaired loans $ — $ — $ 6,318 $ — Mortgage servicing rights — 12,377 — (2,067 ) Foreclosed real estate — — 132 — $ — $ 12,377 $ 6,450 $ (2,067 ) Gains or losses applicable to impaired loans are based on the appraised value of the underlying collateral, discounted as necessary due to management’s estimates of changes in market conditions, less estimated selling costs, and are not recorded directly to current earnings but rather as a component in determining the allowance for loan losses. The Company utilizes an independent valuation from a third party which uses a discounted cash flow model to estimate the fair value of mortgage servicing rights. The model utilizes loan prepayment assumptions based on current market conditions and applies a discount rate based on indicated rates of return required by market participants. During the year ended December 31, 2021, the valuation allowance decreased due to slower actual and projected loan prepayment speeds attributable to the increase in interest rates on residential mortgage loans during the period. During the year ended December 31, 2020, the valuation allowance increased due to faster actual and projected loan prepayment speeds attributable to the decrease in interest rates on residential mortgage loans during the period. Summary of fair values of financial instruments The estimated fair values, and related carrying amounts, of the Company’s financial instruments are presented below. Certain financial instruments and all non-financial instruments are exempt from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein do not represent the underlying fair value of the Company. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include mortgagor’s escrow accounts and accrued interest payable. December 31, 2021 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Securities available for sale 51,666 51,666 — 51,666 — Loans held for sale 44,766 44,766 — 44,766 — Loans, net 544,621 549,674 — — 549,674 Derivative assets 1,414 1,414 — 1,414 — Financial liabilities: Deposits $ 638,147 $ 637,538 $ — $ 637,538 $ — FHLBB advances 50,000 50,001 — 50,001 — Derivative liabilities 84 84 — 84 — December 31, 2020 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Securities available for sale $ 55,366 $ 55,366 $ — $ 55,366 $ — Loans held for sale 119,112 119,112 — 119,112 — Loans, net 483,644 490,914 — — 490,914 Derivative assets 11,865 11,865 — 11,865 — Financial liabilities: Deposits $ 528,307 $ 528,786 $ — $ 528,786 $ — FRB advances 11,431 11,431 — 11,431 — FHLBB advances 61,895 63,071 — 63,071 — Derivative liabilities 2,180 2,180 — 2,180 —

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Segment Information	18. SEGMENT INFORMATION The Company reports its activities in one of two business segments, namely Envision Bank (“EB”) and Envision Mortgage (“EM”). EB operations primarily consist of accepting deposits from customers within the communities surrounding the Bank’s five full service branch offices, through the internet, and investing those funds in residential and commercial real estate loans, home equity lines of credit, construction loans, commercial and industrial loans, and consumer loans. EM’s operations primarily consist of the origination and sale of residential mortgage loans and the servicing of loans sold to government-sponsored entities. A portion of the loans originated by EM are held in the loan portfolio of EB. Segment information as of and for the year ended December 31, 2021, follows: For the Year Ended December 31, 2021 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 18,894 $ 3,066 $ 21,960 Provision (credit) for loan losses (438 ) — (438 ) Net interest income after provision (credit) for loan losses 19,332 3,066 22,398 Non-interest income: Customer service fees 1,538 80 1,618 Gain on loan origination and sale activities, net (1) — 30,347 30,347 Mortgage servicing fees, net (622 ) 2,313 1,691 Other 428 501 929 Total non-interest income 1,344 33,241 34,585 Non-interest expenses: Salaries and employee benefits 7,031 21,181 28,212 Occupancy and equipment 1,825 967 2,792 Other non-interest expenses 4,435 6,219 10,654 Total non-interest expenses 13,291 28,367 41,658 Income before income taxes and elimination of inter-segment profit $ 7,385 $ 7,940 15,325 Elimination of inter-segment profit (2,662 ) Income before income taxes 12,663 Income tax expense 3,062 Net income $ 9,601 Total assets, December 31, 2021 $ 708,631 $ 94,647 $ 803,278 (1) Before elimination of inter-segment profit The information above was derived from the internal management reporting system used by management to measure performance of the segments. The Company’s internal transfer pricing arrangements determined by management primarily consist of the following: 1. EM’s cost of funds is based on the weighted average rate of overnight advances from the FHLBB for the period. 2. EM is credited with service released premiums and a sales premium totaling 1.50% for new loans transferred to EB’s loans held for investment, and a 1.00% fee for HELOC originations. This income for the year ended December 31, 2021 totaled $2,662,000. 3. Loan servicing fees are charged to EB by EM based on the balance of residential mortgage loans held in portfolio at a rate of 0.14% per annum for the first six months of 2021. The rate was changed to 0.25% per annum for the last six months of the year and will be used thereafter. These loan servicing fees amounted to $622,000 for the year ended December 31, 2021. 4. Certain cost centers provide services to both business segments. The cost centers include Accounting, Marketing, IT and Administration. Costs which are common to both business segments are referred to as “indirect costs” and are allocated using relevant benchmarks, e.g. headcount, number of accounts, etc. Segment information as of and for the year ended December 31, 2020 follows: For the Year Ended December 31, 2020 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 16,235 $ 2,632 $ 18,867 Provision for loan losses 2,553 — 2,553 Net interest income after provision for loan losses 13,682 2,632 16,314 Non-interest income: Customer service fees 1,180 103 1,283 Gain on loan origination and sale activities, net (1) — 55,729 55,729 Mortgage servicing fees, net (381 ) (772 ) (1,153 ) Other 465 580 1,045 Total non-interest income 1,264 55,640 56,904 Non-interest expenses: Salaries and employee benefits 9,161 24,000 33,161 Occupancy and equipment 1,770 1,775 3,545 Other non-interest expenses 5,228 4,382 9,610 Total non-interest expenses 16,159 30,157 46,316 Income (loss) before income taxes and elimination of inter-segment profit $ (1,213 ) $ 28,115 26,902 Elimination of inter-segment profit (1,493 ) Income before income taxes 25,409 Income tax expense 5,477 Net income $ 19,932 Total assets, December 31, 2020 $ 537,722 $ 183,350 $ 721,072 (1) Before elimination of inter-segment profit The information above was derived from the internal management reporting system used by management to measure performance of the segments. The Company’s internal transfer pricing arrangements determined by management primarily consist of the following: 1. EM’s cost of funds is based on the weighted average rate of overnight advances from the FHLBB for the period. 2. E M is credited with service released premiums and a sales premium totaling 1.50 % for new loans transferred to EB’s loans held for investment, and a 1.00 % fee for HELOC originations. This income for the year ended December 31, 2020 totaled $ . 3. Loan servicing fees are charged to EB by EM based on the balance of residential mortgage loans held in portfolio at a rate of 0.14% per annum and amounted to $381,000 for the year ended December 31, 2020. 4. Certain cost centers provide services to both business segments. The cost centers include Accounting, Marketing, IT and Administration. Costs which are common to both business segments are referred to as “indirect costs” and are allocated using relevant benchmarks, e.g. headcount, number of accounts, etc.

Other Non-Interest Expenses

Other Non-Interest Expenses	12 Months Ended
	Dec. 31, 2021
Other Income And Expenses [Abstract]
Other Non-Interest Expenses	1 9 . OTHER NON-INTEREST EXPENSES Included in other non-interest expenses in 2021 and 2020 are certain items exceeding 1% of the Company’s total interest and non-interest income as follows: 2021 2020 (In thousands) Software amortization, licenses and maintenance $ 1,667 $ 1,303 Credit reports 769 820 Card related expenses 468 429 Data communication and telephone 397 391 Directors' fees, including stock-based compensation 777 579

Global Pandemic Affecting Rando

Global Pandemic Affecting Randolph Bancorp, Inc.	12 Months Ended
	Dec. 31, 2021
Risks And Uncertainties [Abstract]
Global Pandemic Affecting Randolph Bancorp, Inc.	20 . GLOBAL PANDEMIC AFFECTING RANDOLPH BANCORP, INC. The following summarizes the more significant financial repercussions of this national emergency for the Company. Credit Quality and Allowance for Loan Losses The Company increased the allowance for loan losses during 2020 directly related to its estimate, based on available information, of probable incurred losses resulting from the impact of the COVID-19 pandemic. As the Company acquires additional information on overall economic prospects together with further assessments of the impact on individual borrowers, the loss estimated will be revised as needed, and these revisions could be material. The Company’s approach to estimating the impact of this pandemic on credit quality is presented in Note 3 – “Loans and Allowance for Loan Losses.” Disaster Response Plan Costs The Company implemented its disaster response plans when the national emergency was declared and a stay-at-home order was issued in the Commonwealth of Massachusetts. To operate in this mode the Company incurred expenses for, among other things, compensation for front-line and quarantined employees, buying equipment for a remote workforce, cleaning of office and branch buildings, and communications with customers regarding the status of the Company’s operations. These plan costs amounted to $229,000 for the year ended December 31, 2020. Loan Payment Deferral and Paycheck Protection Program In response to the pandemic’s effect on our customers, the Company implemented a series of measures, including participating in the PPP and granting payment deferrals for residential mortgage, home equity and certain commercial borrowers who were current in their payments. The table below summarizes lending activity and outstanding balances of PPP loans and the associated pledges to the PPPLF: PPP Loan Balance FRB Advances PPP Loans Outstanding at Amount Pledged Outstanding at Originated December 31, 2021 to PPPLF December 31, 2021 (1) (In thousands) 2020 PPP loans $ 15,387 $ 16 $ 15,387 $ - 2021 PPP loans 10,967 3,569 - - Total Activity $ 26,354 $ 3,585 $ 15,387 $ - (1) FRB advances were fully repaid during the first quarter of 2021 and the associated PPP loans are no longer pledged. The Company has granted short-term loan payment deferrals for residential mortgage, home equity and certain commercial borrowers who were current on their payment and experiencing a hardship due to the COVID-19 pandemic. In accordance with interagency guidance issued in March 2020 and/or the CARES Act enacted in March 2020 and as modified by the Consolidated Appropriations Act, these short-term deferrals are not considered TDR s, provided the loan modification is made between March 1, 2020 and as modified by the Consolidated Appropriations Act, the earlier of January 1, 2022 or 60 days after the end of the coronavirus emergency declaration and the applicable loan was not more than 30 days past due as of December 31, 2019. The Company has agreed to loan payment deferrals on commercial loans totaling $37.5 million, residential real estate loans in portfolio totaling $19.1 million and residential real estate loans serviced for others totaling $68.4 million as of December 31, 2021. The commercial loan payment deferrals are concentrated in the hotel and hospitality, restaurant and retail service industries. The qualifying residential real estate and commercial loan borrowers were required to contact the Company to receive loan payment deferrals. The table below summarizes the status of the bank’s loan deferral activity: Deferrals Suspended/ Resumed Full Granted (1) Reduced Payment (2) Payment (2) Payoff (3) (In thousands) December 31, 2021 Real estate loans: Residential: One- to-four family $ 15,771 $ 1,949 $ 8,063 $ 5,759 Home equity loans and lines of credit 2,936 42 1,458 1,436 Construction 341 — 341 — Commercial 34,176 — 26,463 7,713 Total real estate loans 53,224 1,991 36,325 14,908 Commercial and industrial 3,362 — 1,352 2,010 Consumer 58 — 58 — Total $ 56,644 $ 1,991 $ 37,735 $ 16,918 December 31, 2020 Real estate loans: Residential: One-to-four family $ 15,514 $ 12,974 $ 2,109 $ 431 Home equity loans and lines of credit 3,179 626 1,287 1,266 Construction 350 350 — — Commercial 34,754 6,544 25,406 2,804 Total real estate loans 53,797 20,494 28,802 4,501 Commercial and industrial 3,645 — 1,635 2,010 Consumer 68 68 — — Total $ 57,510 $ 20,562 $ 30,437 $ 6,511 (1) (2) (3) The payment deferral programs were applied prospectively from the respective dates of the events and did not change the delinquency status of the loans as of such dates. Accordingly, if all payments were current at the date of the event, the loan will not be reported as past due during the deferral period. Furthermore, for loans subject to the deferral programs on which payments were past due prior to the event, the delinquency status of such loans was frozen to the status that existed at the date of the event until the end of the deferral period. Accordingly, the table below summarizes the risk rating and for all loans that were granted deferral, and any loans that were listed in nonaccrual status: Pass Rated / Special Sub- Non- Not Rated Mention standard (1) accrual (1)(2) (In thousands) December 31, 2021 Real estate loans: Residential: One- to four-family $ 8,678 $ 212 $ 1,122 $ 1,334 Home equity loans and lines of credit 1,500 — — — Construction 341 — — — Commercial 16,004 6,916 3,543 — Total real estate loans 26,523 7,128 4,665 1,334 Commercial and industrial 1,020 332 — — Consumer 58 — — — Total $ 27,601 $ 7,460 $ 4,665 $ 1,334 December 31, 2020 Real estate loans: Residential: One- to four-family $ 14,887 $ 196 $ — $ 196 Home equity loans and lines of credit 1,913 — — — Construction 350 — — — Commercial 19,020 8,748 4,182 4,182 Total real estate loans 36,170 8,944 4,182 4,378 Commercial and industrial 1,204 431 — — Consumer 68 — — — Total $ 37,442 $ 9,375 $ 4,182 $ 4,378 (1) These three columns indicate the risk rating and subsequent outstanding balance of loans that have received a deferral. The Pass Rated/Not Rated, Special Mention and Substandard columns reconcile to the Suspended Payment/Reduced Payment columns in the preceding table. (2) Nonaccrual loans are risk rated as either special mention or substandard and are included as a balance in those columns.

Parent Company Condensed Financ

Parent Company Condensed Financial Statements	12 Months Ended
	Dec. 31, 2021
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Parent Company Condensed Financial Statements	21 . PARENT COMPANY CONDENSED FINANCIAL STATEMENTS Financial information as of December 31, 2021 and 2020 and for the years then ended pertaining to Randolph Bancorp, Inc. is as follows: BALANCE SHEETS December 31, December 31, 2021 2020 Assets Cash and due from bank $ 3,240 $ 4,829 Investment in Envision Bank 93,126 90,959 Income taxes receivable 661 - ESOP loan 3,895 4,042 Total assets $ 100,922 $ 99,830 Liabilities Income taxes payable $ — $ 8 Due to Envision Bank 4 3 Other liabilities 15 — Total liabilities 19 11 Stockholders' Equity Common stock 50 54 Additional paid-in capital 44,078 50,937 Retained earnings 60,524 51,689 ESOP-Unearned compensation (3,568 ) (3,756 ) Accumulated other comprehensive loss, net of tax (181 ) 895 Total stockholders' equity 100,903 99,819 Total liabilities and stockholders' equity $ 100,922 $ 99,830 STATEMENTS OF OPERATIONS Years Ended December 31, 2021 2020 Interest income $ 131 $ 198 Dividend income 8,000 5,000 Operating expenses 191 171 Income before incomes taxes and equity in undistributed net income of Envision Bank 7,940 5,027 Applicable income tax (credit) (12 ) 7 Income before equity in undistributed net income of Envision Bank 7,952 5,020 Equity in undistributed net income of Envision Bank 1,649 14,912 Net income $ 9,601 $ 19,932 STATEMENTS OF CASH FLOWS Years Ended December 31, 2021 2020 Cash flows from operating activities: Net income $ 9,601 $ 19,932 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Equity in undistributed net income of Envision Bank (1,649 ) (14,912 ) Dividends received from Envision Bank (8,000 ) (5,000 ) Increase (decrease) in income taxes payable (receivable) (669 ) 8 Increase in other liabilities 15 — Change in intercompany receivable/payable — (15 ) Net cash provided by (used in) operating activities (702 ) 13 Cash flows from investing activities: Principal payments received on ESOP loan 147 120 Dividends received from Envision Bank 8,000 5,000 Net cash provided by investing activities 8,147 5,120 Cash flows from financing activities: Stock repurchases (8,529 ) (1,749 ) Stock repurchase payable — — Proceeds from the exercise of options, net 261 — Common stock dividend paid (766 ) — Net cash used in financing activities (9,034 ) (1,749 ) Net change in cash and due from bank (1,589 ) 3,384 Cash and due from bank at the beginning of year 4,829 1,445 Cash and due from bank at end of year $ 3,240 $ 4,829

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	22. LEASES The Company adopted the new lease accounting standard (“the lease standard”) under Accounting Standards Codification 842 (“ASC 842”) using the modified retrospective transition method with an effective date as of January 1, 2021. Therefore, periods prior to that date were not restated, and accordingly disclosures are not presented on a comparable basis. The Company elected the package of practical expedients, which permits the Company not to reassess prior conclusions about lease identifications, lease classification and direct costs. The Company did not elect to apply the hindsight expedient pertaining to using hindsight knowledge as of the effective date when determining lease terms and impairment. As of December 31, 2021, the Company had entered into 10 noncancelable operating lease agreements for office space and branch locations, several of which contain renewal options to extend lease terms for a period of 1 to 10 years. The Company had no financing leases outstanding and no leases with residual value guarantees. The Company’s ROU asset related to operating leases totaled $1.8 million at December 31, 2021 and is recognized in the Company’s Consolidated Balance Sheet in other assets. The Company’s operating lease cost for 2021 was $834,000. As of December 31, 2021, the weighted average remaining lease term for operating leases was 4.5 years and the weighted average discount rate used in the measurement of operating lease liabilities was 1.99%. The following table sets forth the undiscounted cash flows of base rent related to operating leases outstanding at December 31, 2021 with payments scheduled over the next five years and thereafter, including a reconciliation to the operating lease liability recognized in the Company’s Consolidated Balance Sheet in other liabilities. (In thousands) 2022 $ 619 2023 396 2024 309 2025 245 2026 226 Thereafter 95 Total minimum lease payments 1,890 Less: amount representing interest (84 ) Present value of future minimum lease payments $ 1,806

Mortgage Banking Income

Mortgage Banking Income	12 Months Ended
	Dec. 31, 2021
Mortgage Banking [Abstract]
Mortgage Banking Income	23. MORTGAGE BANKING INCOME The components of gain on loan origination and sale activities and mortgage servicing fees for the years ended December 31, 2021 and 2020 are as follows: For the Year Ended December 31, 2021 2020 (In thousands) Gain on loan origination and sale activities, net Gain on sale of mortgage loans and realized gain from derivative financial instruments, net $ 33,578 $ 34,203 Net change in fair value of loans held for sale and portfolio loans accounted for at fair value (3,536 ) 3,263 Capitalized residential mortgage loan servicing rights 5,998 8,428 Net change in fair value of derivative loan commitments and forward loan sale commitments (8,355 ) 8,342 Gain on loan origination and sales activities, net $ 27,685 $ 54,236 Mortgage servicing fees, net Residential mortgage loan servicing fees $ 5,012 $ 3,458 Amortization of residential mortgage loan servicing rights (3,197 ) (2,543 ) Release (provision) to the valuation allowance of mortgage loan servicing rights 438 (2,068 ) Sub-servicer expenses (1) (562 ) - Mortgage servicing fees, net $ 1,691 $ (1,153 ) Total gain on loan origination and sales activities and mortgage servicing fees, net $ 29,376 $ 53,083 (1) Sub-servicer expenses were first incurred during the third quarter of 2021, due to the conversion of the Company’s mortgage loan servicing activities. Previously, all expenses related to servicing mortgage loans serviced for others were included in non-interest expenses.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Randolph Bancorp, Inc. (the “Company”) is a bank holding company whose principal subsidiary is the Bank. The Bank provides a variety of financial services to individuals and small businesses through its five branch offices in Massachusetts and six loan production offices and lending centers located throughout Massachusetts and Southern New Hampshire. The Bank’s primary deposit products are checking, savings and term certificate accounts and its primary lending products are residential and commercial mortgage loans. The Bank is also actively involved in the sale and servicing of residential mortgage loans in the secondary market. The Federal Deposit Insurance Corporation (“FDIC”) provides insurance coverage on all deposits up to $250,000 per depositor. As an FDIC insured institution, the Bank is subject to supervision, examination and regulation by the FDIC. Additionally, as a Massachusetts chartered savings bank, the Bank’s depositors are also insured by the Depositors Insurance Fund (“DIF”), a private industry-sponsored insurance company. The DIF insures bank deposits in excess of the FDIC insurance limits.
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Randolph Bancorp, Inc. (a Massachusetts corporation) and its wholly-owned subsidiary, Envision Bank (together, the “Company”). The Bank has subsidiaries involved in owning investment securities and foreclosed real estate and a subsidiary which provides loan closing services. All intercompany accounts and transactions have been eliminated in consolidation. The following significant accounting and reporting policies of the Company conform to U.S. generally accepted accounting principles (“GAAP”) and are used in preparing and presenting these consolidated financial statements.
Use of Estimates	Use of estimates In preparing consolidated financial statements in conformity with GAAP, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the consolidated balance sheet and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and cash equivalents Cash equivalents include amounts due from banks, federal funds sold on a daily basis and interest-bearing deposits with original maturities of ninety days or less.
Certificates of Deposit	Certificates of deposit Certificates of deposit have original maturities ranging from one to five years and are carried at cost.
Fair Value Hierarchy	Fair value hierarchy The Company groups its assets and liabilities that are measured at fair value in three levels based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. Level 1 – Valuation is based on quoted prices in active markets for identical assets and liabilities. Valuations are obtained from readily available pricing sources. Level 2 – Valuation is based on observable inputs other than Level 1 prices, such as quoted prices for similar assets and liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets and liabilities. Level 3 – Valuation is based on unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets and liabilities. Level 3 assets and liabilities include those for which the value is determined using unobservable inputs to pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. Transfers between levels are recognized at the end of a reporting period, if applicable.
Securities	Securities All securities are classified as available for sale and are recorded at fair value, with unrealized gains and losses excluded from earnings and reported in other comprehensive income/loss. Purchase premiums and discounts are recognized in interest income using the level yield method over the terms of the securities. Anticipated prepayments on mortgage-backed securities are used in applying this method. Gains and losses on the sale of securities are recorded on the trade date and are determined using the specific identification method. On a quarterly basis, the Company evaluates all securities with a decline in fair value below the amortized cost of the investment to determine whether or not the impairment is deemed to be other than temporary (“OTTI”). OTTI is required to be recognized: (1) if the Company intends to sell the security; (2) if it is “more likely than not” that the Company will be required to sell the security before recovery of its amortized cost basis; or (3) for debt securities, if the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For all impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the decline in fair value is recognized as OTTI through earnings. For all other impaired debt securities, credit-related OTTI is recognized through earnings and non-credit related OTTI is recognized in other comprehensive income/loss, net of applicable taxes. Because the Company’s assessments are based on available factual information as well as subjective information, the determination as to whether an OTTI exists and, if so, the amount of impairment, is subjective and, therefore, the timing and amount of OTTI constitute material estimates that are subject to significant change.
Federal Home Loan Bank of Boston Stock	Federal Home Loan Bank of Boston stock The Bank, as a member of the Federal Home Loan Bank of Boston (“FHLBB”), is required to maintain an investment in capital stock of the FHLBB. Based on redemption provisions of the FHLBB, the stock has no quoted market value and is carried at cost. The Company periodically evaluates for impairment based on ultimate recovery of its cost basis in the FHLBB stock.
Loans Held for Sale and related derivatives	Loans held for sale and related derivatives The origination of residential mortgage loans is an integral part of the Company’s business. The Company generally sells its originations of such loans in the secondary market to either government-sponsored enterprises (“GSEs”) or other financial institutions. The servicing of loans sold to GSEs is generally retained while loans sold to other financial institutions are generally done on a servicing released basis. The Bank utilizes the fair value option pursuant to Accounting Standards Codification (“ASC”) 825, “Financial Instruments” for its residential mortgage loans being held for sale. Fair value is determined based on either commitments in effect from investors or prevailing market price and include the value of mortgage servicing rights. Gains and losses on the sales of loans are determined using the specific identification method. In determining the amount of the gain or loss the Company takes into consideration the direct costs of originating the loan. Also included in the net gain on loan origination and sale activities presented in the accompanying statements of operations are fair value adjustments for mortgage banking derivatives (interest rate lock commitments with borrowers, and forward loan sale commitments with investors for the delivery of mortgage loans to third party investors including To Be Announced securities (“TBAs”)) and loans held for sale.
Loans	Loans The Company grants residential real estate, commercial real estate, construction, commercial and consumer loans to customers. A substantial portion of the loan portfolio is represented by mortgage loans in Massachusetts and Rhode Island. The ability of the Company’s borrowers to honor their contracts is affected by real estate values and general economic conditions in these markets. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, and net deferred loan origination fees and costs and purchase premiums. Interest income is accrued on the unpaid principal balance. Certain direct loan origination costs and purchase premiums, net of origination fees, are deferred and recognized in interest income using the level yield method without anticipating prepayments. Interest is not accrued on loans which are ninety days or more past due, or when, in the judgment of management, the collectability of the principal or interest becomes doubtful. Past due status is based on contractual terms of the loan. Interest income previously accrued on such loans is reversed against current period earnings. Loans are returned to accrual status when all principal and interest amounts contractually due are brought current and future payments are reasonably assured. The Company periodically may agree to modify the contractual terms of loans. When a loan is modified and a concession is made to a borrower experiencing financial difficulty, the modification is considered a TDR. All TDRs are initially classified as impaired and placed on nonaccrual status. Generally, a nonaccrual loan that is restructured remains on nonaccrual for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower’s ability to meet the revised terms is not reasonably assured, the loan remains on nonaccrual status.
Allowance for Loan Losses	Allowance for loan losses The allowance for loan losses is a valuation allowance for probable incurred credit losses. Loan losses are charged against the allowance when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance. The allowance for loan losses is evaluated on a regular basis and is based upon management’s periodic review of the collectability of the loans in light of historical experience, the nature and volume of the loan portfolio, adverse situations that may affect the borrower’s ability to repay, estimated value of any underlying collateral and prevailing economic conditions. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as either additional information becomes available or circumstances change. The allowance for loan losses is allocated to loan types using both a formula-based approach applied to groups of loans (general component) and an analysis of certain individual loans for impairment (allocated component). General component The general component of the allowance for loan losses covers loans that are collectively evaluated for impairment and is based on historical loss experience adjusted for qualitative factors stratified by loan segments. Management uses a rolling average of historical losses based on a trailing 48 month time frame appropriate to capture relevant loss data for each loan segment. This historical loss factor is supplemented by the following qualitative factors: changes in the volume and severity of past due loans and adversely classified or graded loans, the volume of nonaccrual loans and trends in charge-offs and recoveries; changes in the nature and volume of the portfolio and in the terms of loans; changes in lending policies and procedures, including changes in underwriting standards and collection, charge-off, and recovery practices not considered elsewhere in estimating credit losses; changes in the experience, ability, and depth of lending management and other relevant staff; changes in international, national, regional and local economic and business conditions and developments that affect the collectability of the portfolio, including the condition of various market segments; changes in the quality of the institution’s review system; the effect of other external factors such as competition and legal and regulatory requirements on the level of estimated credit losses in the institution’s existing portfolio; changes in the value of underlying collateral-dependent loans; and the existence of concentrations of credit, and changes in the level of such concentrations. The qualitative factors are determined based on the various risk characteristics of each loan segment. Risk characteristics relevant to each portfolio segment are as follows: Residential one- to four-family real estate – The Company generally does not originate loans with a loan-to-value ratio greater than 80 percent. All loans in this segment are collateralized by one- to four-family owner, and non-owner-occupied, residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Second mortgages and home equity lines of credit (“HELOC”) – Loans in this segment are primarily secured by second-position liens, and the Company may or may not also have a first-position lien. Regardless of which creditor is in first position, the Company does not originate loans with a combined loan-to-value ratio greater than 80 percent. All loans in this segment are collateralized by owner-occupied residential real estate and repayment is dependent on the credit quality of the individual borrower. The overall health of the economy, including unemployment rates and housing prices, will have an effect on the credit quality in this segment. Commercial real estate – Loans in this segment consist of owner-occupied and non-owner-occupied property primarily located in Massachusetts and Rhode Island. The underlying cash flows generated by the operating entities of owner-occupied real estate support the associated debt. Rental cash flows, for which management obtains periodic rent rolls, support the debt associated with non-owner-occupied real estate and can be negatively impacted by increased vacancy rates. Construction – Loans in this segment primarily include residential real estate development loans for which payment is derived from sale of the property. Credit risk is affected by cost overruns, time to sell at an adequate price, and market conditions. Commercial and Industrial – Loans in this segment are made to businesses and are generally secured by assets of the business. Repayment is expected from the cash flows of the business. A weakened economy, and resultant decreased consumer spending, would have an effect on the credit quality in this segment. As of December 31, 2021, the Company funded 385 PPP loans totaling $26.4 million. The Company had $3.6 million of Paycheck Protection Program (“PPP”) loans outstanding at December 31, 2021. These loans are fully guaranteed by the SBA and the Company does not reserve for these loans. Consumer – Loans in this segment primarily include personal unsecured loans, refinanced student loans and auto loans purchased from third party lenders. Repayment is dependent on the credit quality of the individual borrower. Allocated component The allocated component of the allowance for loan losses relates to loans that are individually classified as impaired. Residential real estate, commercial and industrial, commercial real estate and construction loans are evaluated for impairment on a loan-by-loan basis. Impairment is measured by either the present value of expected future cash flows discounted at the loan’s effective interest rate, or the fair value of the collateral if the loan is collateral dependent. An allowance is established when the discounted cash flows (or collateral value) of the impaired loan are lower than the carrying value of that loan. Large groups of smaller balance homogeneous loans are collectively evaluated for impairment. Accordingly, the Company does not generally identify individual consumer loans or second mortgages and HELOCs for impairment disclosures unless such loans are 90 days past due or are classified as a TDR. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed.
Bank-owned Life Insurance	Bank-owned life insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at their cash surrender value net of charges or other amounts that are probable at settlement. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income in the consolidated statements of operations and are not subject to income taxes, unless such policies are surrendered prior to the death of the insured individuals.
Mortgage Servicing Rights	Mortgage servicing rights The Company services mortgage loans for others. Mortgage servicing rights are recognized as separate assets at fair value when rights are acquired through purchase or through sale of financial assets (“MSRs”). Capitalized servicing rights are amortized into mortgage servicing income in proportion to, and over the period of, the estimated future net servicing income of the underlying financial assets. MSRs are evaluated for impairment based upon the fair value of the rights as compared to amortized cost. Impairment is determined by stratifying rights by predominant risk characteristics, such as interest rates and terms. Fair value is based on a valuation model that calculates the present value of estimated future net servicing income, using market-based assumptions. Impairment is recognized through a valuation allowance for an individual stratum, to the extent that fair value is less than the capitalized amount for the stratum. Changes in the valuation allowance, if any, are reported in mortgage servicing income.
Premises and Equipment	Premises and equipment Land is carried at cost. Buildings, equipment and leasehold improvements are stated at cost, less accumulated depreciation and amortization computed predominantly on the straight-line method over the estimated useful lives of the assets or the expected terms of the leases, if shorter. Expected terms include lease option periods to the extent that the exercise of such options is reasonably assured. Premises and equipment held for sale are stated at the lower of amortized cost or fair value less costs to sell.
Transfers of Financial Assets	Transfers of financial assets Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when (1) the assets have been isolated from the Company, (2) the transferee obtains the right to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity. During the normal course of business, the Company may transfer a portion of a financial asset, for example, a participation loan. In order to be eligible for sales treatment, all cash flows from the loan must be divided proportionately, the rights of each loan holder must have the same priority, the loan holders must have no recourse to the transferor other than standard representations and warranties, and no loan holder can have the right to pledge or exchange the entire loan. In certain cases, the Company may have an obligation to repurchase mortgage loans sold to third parties and to refund fees to the purchaser if a payment default or prepayment occurs, in each case within a prescribed time period not exceeding four months after the sale date, or in the case of a violation of its representations and warranties under the provisions of its loan sale agreements. The Company evaluates its obligations under these provisions and recognizes a liability for the fair value of its recourse obligations. At December 31, 2021 and 2020, the Company determined that its obligations in connection with the recourse provisions of its loan sale agreements were insignificant.
Foreclosed Real Estate	Foreclosed real estate Real estate acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value, less costs to sell, at the date of foreclosure, establishing a new cost basis. Subsequent to foreclosure, valuations are periodically performed by management and the assets are carried at the lower of carrying amount or fair value less costs to sell. Revenue and expenses from operations, changes in the valuation allowance and any direct write-downs are included in foreclosed real estate expense.
Supplemental Retirement Plans	Supplemental retirement plan The Company accounts for its supplemental retirement plan using an actuarial model that allocates cost over the service period of participants in the plan. The Company accounts for the over-funded or under-funded status of the plan as an asset or liability in its consolidated balance sheets and recognizes changes in the funded status in the year in which the changes occur through other comprehensive income/loss.
Employee Stock Ownership Plan	Employee Stock Ownership Plan Compensation expense for the Employee Stock Ownership Plan (“ESOP”) is computed based on the number of shares allocated to participants during the period multiplied by the average fair market value of the Company’s shares. This expense is recognized ratably throughout the year based on the expected allocation of shares for the year. Unearned compensation applicable to the ESOP is reflected as a reduction of stockholders’ equity. The difference between the average fair market value and cost of the shares allocated by the ESOP is recorded as an adjustment to additional paid-in capital.
Stock-Based Compensation	Stock-based compensation The fair value of restricted stock and stock options is determined on the date of grant and amortized to compensation expense with a corresponding increase to additional paid-in capital over the required service period, but in no event beyond the date of an employee’s or director’s date of termination. Forfeitures of unvested awards and grants are recorded as incurred.
Advertising Cost	Advertising costs Advertising costs are expensed as incurred.
Income Taxes	Income taxes Deferred income tax assets and liabilities are determined using the liability (or balance sheet) method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the temporary differences between the book and tax basis of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. A valuation allowance is established against deferred tax assets when, based upon available evidence including historical and projected taxable income, that some or all of the deferred tax assets will not be realized. A tax position is recognized as a benefit if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company does not have any uncertain tax positions at December 31, 2021 and 2020 which require accrual or disclosure. The Company records interest and penalties as part of income tax expense. No material interest or penalties were recorded for the years ended December 31, 2021 and 2020.
Comprehensive Income (Loss)	Comprehensive income (loss) Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income (loss). Although certain changes in assets and liabilities are reported as a separate component of equity, such items, along with net income (loss), are components of accumulated other comprehensive income (loss) (“AOCI”). The components of AOCI, included in stockholders’ equity, are as follows: December 31, December 31, 2021 2020 (In thousands) Securities available for sale: Net unrealized gain $ 249 $ 1,713 Tax effect (64 ) (313 ) Net-of-tax amount 185 1,400 Supplemental retirement plan Unrecognized net actuarial loss (646 ) (712 ) Unrecognized net prior service credit 222 254 (424 ) (458 ) Tax effect 58 (47 ) Net-of-tax amount (366 ) (505 ) Accumulated other comprehensive income (loss) $ (181 ) $ 895 In 2022, the Company expects to recognize $45,000 in prior service credits and $55,000 in net actuarial losses as components of cost for the supplemental retirement plan. These amounts are included in AOCI at December 31, 2021. Prior service credits and net actuarial gains and losses are amortized to periodic pension cost over varying periods based on the plan participants to whom they relate.
Segment Reporting	Segment reporting An operating segment is defined as a component of a business for which separate financial information is available that is evaluated regularly by the chief operating decision-maker in determining how to allocate resources and evaluate performance. The Company has two reporting business segments, namely, “Envision Bank” and “Envision Mortgage”. Management allocates indirect costs, such as IT, Marketing, Accounting and Administration, to each business segment in order to fully measure each segment’s results of operations. See Note 18 for disclosure of the Company’s segment information.
Earnings Per Share	Earnings per share Basic earnings per share represents income available to common stockholders divided by the weighted average of common shares outstanding during the period. Unvested restricted shares of common stock having dividend rights are treated as “participating securities” and, accordingly, are considered outstanding in computing basic earnings per share. Unallocated ESOP shares are not considered outstanding in computing earnings per share. Diluted earnings per share reflects additional common shares that would have been outstanding if dilutive potential shares had been issued. Stock options represent potential dilutive shares with the number of such shares computed using the treasury stock method.
Business Combinations	Business combinations We account for business combinations under the acquisition method of accounting. The application of this method of accounting requires the use of significant estimates and assumptions in the determination of the fair value of tangible and identified intangible assets acquired and liabilities assumed in order to properly allocate purchase price consideration between assets from those that are recorded as goodwill. Our estimates of the fair values of assets acquired and liabilities assumed are based upon assumptions that we believe to be reasonable, and whenever necessary, include assistance from independent third-party appraisal and valuation firms. Costs incurred to consummate a business combination are expensed as incurred.
Leases	Leases The Company leases office space, certain loan production offices and certain branch locations under noncancelable operating leases, several of which have renewal options to extend lease terms. Upon commencement of a new lease, the Company will recognize a right of use (“ROU”) asset and corresponding lease liability. The Company makes the decision on whether to renew an option to extend a lease by considering various factors. The Company will recognize an adjustment to its ROU asset and lease liability when lease agreements are amended and executed. The discount rate used in determining the present value of lease payments in based on the Company’s incremental borrowing rate for borrowings with terms similar to each lease at commencement date. The Company has lease agreements with lease and non-lease components, which are generally accounted for separately. For real estate leases, non-lease components and other non-components, such as common area maintenance charges, real estate taxes, and insurance are not included in the measurement of the lease liability since they are generally able to be separated. The Company has elected the short-term lease recognition exemption for all leases that qualify.
Recent Accounting Pronouncements	Recent accounting pronouncements In February 2016, FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses In December 2019, FASB issued ASU 2019-12, Income Taxes – Simplifying the Accounting for Income Taxes

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Components of Accumulated Other Comprehensive Loss (AOCI) and Related Tax Effects	The components of AOCI, included in stockholders’ equity, are as follows: December 31, December 31, 2021 2020 (In thousands) Securities available for sale: Net unrealized gain $ 249 $ 1,713 Tax effect (64 ) (313 ) Net-of-tax amount 185 1,400 Supplemental retirement plan Unrecognized net actuarial loss (646 ) (712 ) Unrecognized net prior service credit 222 254 (424 ) (458 ) Tax effect 58 (47 ) Net-of-tax amount (366 ) (505 ) Accumulated other comprehensive income (loss) $ (181 ) $ 895

Securities Available for Sale (

Securities Available for Sale (Tables)	12 Months Ended
	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Schedule of Amortized Cost and Fair Value of Securities	The amortized cost and fair value of securities available for sale, including gross unrealized gains and losses, are as follows: Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value (In thousands) December 31, 2021 U.S. Treasury $ 10,939 $ — $ (168 ) $ 10,771 U.S. Government-sponsored enterprises 1,995 — (17 ) 1,978 Corporate 2,510 33 (7 ) 2,536 Municipal 351 2 — 353 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 23,349 324 (194 ) 23,479 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 8,733 223 — 8,956 U.S. Government-guaranteed 103 — — 103 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 796 14 — 810 U.S. Government-guaranteed 2,641 39 — 2,680 Total securities available for sale $ 51,417 $ 635 $ (386 ) $ 51,666 December 31, 2020 U.S. Government-sponsored enterprises $ 1,993 $ 3 $ — $ 1,996 Corporate 4,300 56 — 4,356 Municipal 595 5 — 600 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 32,538 919 — 33,457 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 8,857 525 — 9,382 U.S. Government-guaranteed 977 24 — 1,001 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 996 52 — 1,048 U.S. Government-guaranteed 3,398 128 — 3,526 Total securities available for sale $ 53,654 $ 1,712 $ — $ 55,366
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of debt securities by contractual maturity at December 31, 2021 are presented below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Fair Cost Value (In thousands) Within 1 year $ — $ — After 1 year through 5 years 10,073 9,974 After 5 years through 10 years 5,722 5,664 15,795 15,638 Mortgage-backed securities and collateralized mortgage obligations 35,622 36,028 $ 51,417 $ 51,666
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	The Company had 17 securities in a loss position at December 31, 2021, and no securities in a loss position at December 31, 2020. Information pertaining to securities with gross unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous loss position follows: Less Over Twelve Months Gross Gross Unrealized Fair Unrealized Fair Losses Value Losses Value December 31, 2021 Debt securities: U.S. Treasury $ (168 ) $ 10,771 $ — $ — U.S. Government-sponsored enterprises (17 ) 1,978 — — Corporate (7 ) 723 — — Residential mortgage-backed securities: U.S. Government-sponsored enterprises (194 ) 11,477 — — Total debt securities $ (386 ) $ 24,949 $ — $ —

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Summary of Loan Portfolio	A summary of the loan portfolio is as follows: December 31, 2021 2020 (In thousands) Mortgage loans on real estate: Residential: One- to four-family $ 236,364 $ 235,648 Home equity loans and lines of credit 57,295 48,166 Commercial 197,423 143,893 Construction 33,961 31,050 Total real estate loans 525,043 458,757 Commercial and industrial 17,242 20,259 Consumer 7,552 10,289 Total loans 549,837 489,305 Allowance for loan losses (6,289 ) (6,784 ) Net deferred loan costs and fees, and purchase premiums 1,073 1,123 Total loans, net $ 544,621 $ 483,644 The table below summarizes the status of the bank’s loan deferral activity: Deferrals Suspended/ Resumed Full Granted (1) Reduced Payment (2) Payment (2) Payoff (3) (In thousands) December 31, 2021 Real estate loans: Residential: One- to-four family $ 15,771 $ 1,949 $ 8,063 $ 5,759 Home equity loans and lines of credit 2,936 42 1,458 1,436 Construction 341 — 341 — Commercial 34,176 — 26,463 7,713 Total real estate loans 53,224 1,991 36,325 14,908 Commercial and industrial 3,362 — 1,352 2,010 Consumer 58 — 58 — Total $ 56,644 $ 1,991 $ 37,735 $ 16,918 December 31, 2020 Real estate loans: Residential: One-to-four family $ 15,514 $ 12,974 $ 2,109 $ 431 Home equity loans and lines of credit 3,179 626 1,287 1,266 Construction 350 350 — — Commercial 34,754 6,544 25,406 2,804 Total real estate loans 53,797 20,494 28,802 4,501 Commercial and industrial 3,645 — 1,635 2,010 Consumer 68 68 — — Total $ 57,510 $ 20,562 $ 30,437 $ 6,511 (1) (2) (3)
Summary of Activity in the Allowance for Loan Losses by Loan Category	The following tables present activity in the allowance for loan losses, by loan category, for the years ended December 31, 2021 and 2020 and allocation of the allowance to each category as of such dates: Second Residential Mortgages Commercial Commercial 1-4 Family and HELOC Real Estate Construction and Industrial Consumer Total (In thousands) Allowance for loan losses Balance at December 31, 2019 1,096 289 1,840 692 235 128 4,280 Provision for loan losses 543 156 1,562 59 179 54 2,553 Loans charged-off — (3 ) — — — (68 ) (71 ) Recoveries 7 — — — 2 13 22 Balance at December 31, 2020 $ 1,646 $ 442 $ 3,402 $ 751 $ 416 $ 127 $ 6,784 Provision (credit) for loan losses (558 ) 20 49 (54 ) 81 24 (438 ) Loans charged-off — — — — — (67 ) (67 ) Recoveries 5 — — — 2 3 10 Balance at December 31, 2021 $ 1,093 $ 462 $ 3,451 $ 697 $ 499 $ 87 $ 6,289
Summary of Additional Information Pertaining to the Allowance for Loan Losses	Second Residential Mortgages Commercial Commercial 1-4 Family and HELOC Real Estate Construction and Industrial (1) Consumer Total December 31, 2021 Allowance for impaired loans $ 81 $ 19 $ — $ — $ — $ — $ 100 Allowance for non-impaired loans 1,012 443 3,451 697 499 87 6,189 Total allowance for loan losses $ 1,093 $ 462 $ 3,451 $ 697 $ 499 $ 87 $ 6,289 Impaired loans $ 3,255 $ 603 $ - $ — $ — $ — $ 3,858 Non-impaired loans 233,109 56,692 197,423 33,961 17,242 7,552 545,979 Total loans $ 236,364 $ 57,295 $ 197,423 $ 33,961 $ 17,242 $ 7,552 $ 549,837 December 31, 2020 Allowance for impaired loans $ 133 $ — $ — $ — $ — $ — $ 133 Allowance for non-impaired loans 1,513 442 3,402 751 416 127 6,651 Total allowance for loan losses $ 1,646 $ 442 $ 3,402 $ 751 $ 416 $ 127 $ 6,784 Impaired loans $ 3,575 $ 623 $ 4,751 $ — $ — $ — $ 8,949 Non-impaired loans 232,073 47,543 139,142 31,050 20,259 10,289 480,356 Total loans $ 235,648 $ 48,166 $ 143,893 $ 31,050 $ 20,259 $ 10,289 $ 489,305 (1) Non-impaired loan balance includes $3.6 million and $10.9 million of PPP loans as of December 31, 2021 and 2020, respectively, for which no allowance is provided due to the full guarantee from the SBA.
Schedule of Past Due and Non-Accrual Loans by Loan Category	The following table presents past due and non-accrual loans, by loan category, at December 31, 2021 and 2020: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due (1) Non-accrual Loans (In thousands) December 31, 2021 Residential one- to four-family $ 701 $ 193 $ — $ 894 $ 2,133 Home equity loans and lines of credit 186 215 — 401 491 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer 76 9 — 85 — Total $ 963 $ 417 $ — $ 1,380 $ 2,624 December 31, 2020 Residential one- to four-family $ — $ — $ — $ — $ 1,876 Home equity loans and lines of credit 95 — 317 412 584 Commercial real estate — — 26 26 4,713 Construction — — — — — Commercial and industrial — — — — — Consumer 38 64 — 102 — Total $ 133 $ 64 $ 343 $ 540 $ 7,173 (1) Excludes non-accrual loans which are separately presented. Accordingly, the table below summarizes the risk rating and for all loans that were granted deferral, and any loans that were listed in nonaccrual status: Pass Rated / Special Sub- Non- Not Rated Mention standard (1) accrual (1)(2) (In thousands) December 31, 2021 Real estate loans: Residential: One- to four-family $ 8,678 $ 212 $ 1,122 $ 1,334 Home equity loans and lines of credit 1,500 — — — Construction 341 — — — Commercial 16,004 6,916 3,543 — Total real estate loans 26,523 7,128 4,665 1,334 Commercial and industrial 1,020 332 — — Consumer 58 — — — Total $ 27,601 $ 7,460 $ 4,665 $ 1,334 December 31, 2020 Real estate loans: Residential: One- to four-family $ 14,887 $ 196 $ — $ 196 Home equity loans and lines of credit 1,913 — — — Construction 350 — — — Commercial 19,020 8,748 4,182 4,182 Total real estate loans 36,170 8,944 4,182 4,378 Commercial and industrial 1,204 431 — — Consumer 68 — — — Total $ 37,442 $ 9,375 $ 4,182 $ 4,378 (1) These three columns indicate the risk rating and subsequent outstanding balance of loans that have received a deferral. The Pass Rated/Not Rated, Special Mention and Substandard columns reconcile to the Suspended Payment/Reduced Payment columns in the preceding table. (2) Nonaccrual loans are risk rated as either special mention or substandard and are included as a balance in those columns.
Summary of Impaired Loans and Information Related to Average Balances of Impaired Loans and Interest Income Recognized	Further information pertaining to impaired loans, which includes both non-accrual loans and TDRs, follows: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) December 31, 2021 Impaired loans without a valuation allowance: Residential one- to four-family $ 2,364 $ 2,377 $ — Home equity loans and lines of credit 479 485 — Total 2,843 2,862 — Impaired loans with a valuation allowance: Residential one- to four-family 874 878 81 Home equity loans and lines of credit 108 118 19 Total 982 996 100 Total impaired loans $ 3,825 $ 3,858 $ 100 December 31, 2020 Impaired loans without a valuation allowance: Residential one- to four-family $ 2,160 $ 2,181 $ — Home equity loans and lines of credit 626 623 — Commercial real estate 4,753 4,751 — Total 7,539 7,555 — Impaired loans with a valuation allowance: Residential one- to four-family 1,382 1,394 133 Total 1,382 1,394 133 Total impaired loans $ 8,921 $ 8,949 $ 133 Information related to the average balances of impaired loans and the interest income recognized on such loans, follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Year Ended December 31, 2021 Residential one- to four-family $ 3,132 $ 202 $ 125 Home equity loans and lines of credit 525 30 4 Commercial real estate 2,491 - — Total $ 6,148 $ 232 $ 129 Year Ended December 31, 2020 Residential one- to four-family $ 3,550 $ 399 $ 159 Home equity loans and lines of credit 588 60 — Commercial real estate 2,838 8 — Total $ 6,976 $ 467 $ 159
Summary of Financing Receivable, Troubled Debt Restructuring	The Company’s TDRs consist primarily of interest rate concessions for periods of three months to thirty years for residential real estate loans and home equity loans, and for periods up to one year for commercial real estate loans. Number of Contracts TDRs Listed as Accrual Number of Contracts TDRs Listed as Non-accrual Total Number of Contracts Total TDRs (In thousands) December 31, 2021 Residential one- to four-family 9 $ 1,103 3 $ 919 12 $ 2,022 Home equity loans and lines of credit 2 97 1 109 3 206 Total 11 $ 1,200 4 $ 1,028 15 $ 2,228 December 31, 2020 Residential one- to four-family $ 12 $ 1,666 $ 4 $ 1,167 16 $ 2,833 Home equity loans and lines of credit 1 42 — — 1 42 Commercial real estate 1 40 — — 1 40 Total 14 1,748 4 $ 1,167 18 $ 2,915
Summary of Company's Loans by Risk Rating	The following table presents the Company’s loans by risk rating at December 31, 2021 and 2020: Residential 1-4 Family Second Mortgages and HELOC Commercial Real Estate Construction Commercial and Industrial Consumer Total (In thousands) December 31, 2021 Not Rated $ 234,225 $ 56,797 $ — $ — $ — $ 7,552 $ 298,574 Loans rated 1 - 3A (Pass rated) — — 186,774 33,961 16,910 — 237,645 Loans rated 4 361 381 7,106 — 332 — 8,180 Loans rated 5 1,778 117 3,543 — — — 5,438 Total $ 236,364 $ 57,295 $ 197,423 $ 33,961 $ 17,242 $ 7,552 $ 549,837 December 31, 2020 Not Rated $ 233,773 $ 47,582 $ — $ — $ — $ 10,289 $ 291,644 Loans rated 1 - 3A (Pass rated) — — 129,925 31,050 19,828 — 180,803 Loans rated 4 803 584 9,257 — 431 — 11,075 Loans rated 5 1,072 — 4,711 — - — 5,783 Total $ 235,648 $ 48,166 $ 143,893 $ 31,050 $ 20,259 $ 10,289 $ 489,305

Loan Servicing (Tables)

Loan Servicing (Tables)	12 Months Ended
	Dec. 31, 2021
Transfers And Servicing [Abstract]
Summary of Activity Relating to Mortgage Servicing Rights	The following table summarizes the activity in the Company’s MSRs for the indicated periods: For the Years Ended December 31, 2021 2020 Mortgage servicing rights: (In thousands) Balance at beginning of year $ 15,372 $ 9,484 Additions through originations 5,998 8,432 Amortization (3,197 ) (2,544 ) Balance at end of year $ 18,173 $ 15,372 Valuation allowance: Balance at beginning of year $ 2,995 $ 928 Provision (credit) (438 ) 2,067 Balance at end of year $ 2,557 $ 2,995 Mortgage servicing rights, amortized cost $ 15,616 $ 12,377 Mortgage servicing rights, fair value $ 16,355 $ 12,490

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Summary of Cost and Accumulated Depreciation and Amortization of Premises and Equipment	A summary of the cost and accumulated depreciation and amortization of premises and equipment is as follows: December 31, Estimated 2021 2020 Useful Life (In thousands) (In years) Land and improvements $ 953 $ 953 Buildings and improvements 6,325 3,343 5 to 50 Leasehold improvements 1,097 2,236 3 to 10 Furniture and equipment 4,295 5,558 3 to 10 Construction-in-progress - 145 12,670 12,235 Less accumulated depreciation and amortization (4,986 ) (7,454 ) $ 7,684 $ 4,781

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2021
Deposits [Abstract]
Summary of Deposit Balances by Type	A summary of deposit balances, by type, is as follows: December 31, 2021 2020 (In thousands) Demand deposits $ 145,666 $ 96,731 NOW accounts 53,996 53,530 Money market deposits 90,544 77,393 Regular and other savings accounts 191,712 185,481 Brokered deposits 10,061 10,056 Total non-certificate accounts 491,979 423,191 Term certificates less than $250,000 85,877 60,026 Term certificates of $250,000 or more 20,235 23,418 Term certificates - brokered 40,056 21,672 Total certificate accounts 146,168 105,116 $ 638,147 $ 528,307
Summary of Term Certificates, Including Brokered Deposits, by Maturity	A summary of term certificates, including brokered deposits, by maturity is as follows: December 31, 2021 December 31, 2020 Weighted Weighted Average Average Maturing during: Amount Rate Amount Rate (Dollars in thousands) 2021 $ — — % $ 81,320 0.95 % 2022 95,232 0.53 20,122 1.46 2023 31,966 0.30 2,269 1.06 2024 17,464 0.30 781 1.15 2025 755 0.53 624 0.64 2026 751 0.27 — — $ 146,168 0.45 % $ 105,116 1.05 %

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Summary of Borrowings from FHLBB	A summary of borrowings from the FHLBB at December 31, 2021 and 2020 is as follows: 2021 2020 Weighted Weighted Average Average Amount Rate Amount Rate (Dollars in thousands) Fixed-rate advances maturing: 2021* $ — — % 21,895 1.27 2022 5,000 0.30 10,000 2.20 2023 5,000 0.46 — — 2024 — — — — 2025 40,000 1.39 30,000 1.35 $ 50,000 1.18 % $ 61,895 1.46 % * Includes amortizing advances which require monthly principal and interest payments.
Summary of Outstanding Balances of Short Term Borrowings from FHLBB	There were no overnight advances or advances having a one-month maturity at December 31, 2021 and 2020. Selected information for such short-term borrowings for the years presented is as follows (in 000’s): 2021 2020 Average daily balance $ 4,357 $ 2,265 Maximum outstanding at any month end 28,032 16,181

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Allocation of Federal and State Income Taxes Between Current and Deferred Portions	Allocation of federal and state income taxes between current and deferred portions is as follows (in thousands): Years Ended December 31, 2021 2020 Current tax expense: Federal $ 2,797 $ 789 State 1,384 1,393 Total current tax expense 4,181 2,182 Deferred tax expense (benefit): Federal (301 ) 4,174 State (287 ) 887 (588 ) 5,061 Change in valuation allowance (531 ) (1,766 ) Total deferred tax expense (benefit) (1,119 ) 3,295 Total tax expense $ 3,062 $ 5,477
Summary of Differences Between Statutory Federal Income Tax Expense (Benefit) and Actual Tax Expense	The reasons for the differences between the statutory federal income tax expense (benefit) and the actual tax expense are summarized as follows (in thousands): Years Ended December 31, 2021 2020 Statutory federal tax rate of 21% $ 2,659 $ 5,341 Increase (decrease) resulting from: State taxes, net of federal tax effect 867 1,801 Bank-owned life insurance (34 ) (38 ) Tax-exempt income (4 ) (6 ) Change in valuation allowance (531 ) (1,766 ) Other, net 105 145 Total tax expense $ 3,062 $ 5,477
Summary of Components of Net Deferred Tax Asset	The components of the net deferred tax asset are as follows (in thousands): December 31, 2021 2020 Deferred tax assets: Federal $ 3,977 $ 2,962 State 1,867 1,286 5,844 4,248 Valuation allowance - (531 ) 5,844 3,717 Deferred tax liabilities: Federal (5,160 ) (4,837 ) State (2,423 ) (2,175 ) (7,583 ) (7,012 ) Net deferred tax liability $ (1,739 ) $ (3,295 )
Summary of Deferred Tax Assets (Liabilities)	The tax effects of items giving rise to deferred tax assets (liabilities) are as follows (in thousands): December 31, 2021 2020 Employee benefit plans $ 729 $ 785 Allowance for loan losses 1,938 2,071 Funded status of post-retirement benefits 143 (47 ) Securities available for sale (64 ) (313 ) Depreciation and amortization 62 144 Net deferred loan origination costs (276 ) (281 ) Mortgage servicing rights (4,390 ) (3,479 ) Charitable contribution carryforward — 531 Derivatives (374 ) (2,722 ) Right-of-use asset (508 ) — Lease liability 508 — Stock-based compensation 390 290 Other, net 103 257 (1,739 ) (2,764 ) Valuation allowance on net deferred tax assets — (531 ) Net deferred tax liability $ (1,739 ) $ (3,295 )

Minimum Regulatory Capital Re_2

Minimum Regulatory Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2021
Banking And Thrifts [Abstract]
Summary of Actual and Minimum Capital Amounts and Ratios Exclusive of Capital Conservation Buffer	The Bank’s actual and minimum capital amounts and ratios, exclusive of the capital conservation buffer, are presented in the following table: Minimum To Be Well For Minimum Capitalized Under Capital Prompt Corrective Actual Adequacy Purposes Action Provisions Amount Ratio Amount Ratio Amount Ratio (Dollars in thousands) December 31, 2021 Total capital (to risk weighted assets) $ 100,180 17.4 % $ 45,956 8.0 % $ 57,445 10.0 % Tier 1 capital (to risk weighted assets) 93,288 16.2 34,467 6.0 45,956 8.0 Common equity Tier 1 capital (to risk weighted assets) 93,288 16.2 25,850 4.5 37,339 6.5 Tier 1 capital (to average assets) 93,288 12.3 30,355 4.0 37,943 5.0 December 31, 2020 Total capital (to risk weighted assets) $ 97,406 15.7 % $ 49,682 8.0 % $ 62,102 10.0 % Tier 1 capital (to risk weighted assets) 90,037 14.5 37,261 6.0 49,682 8.0 Common equity Tier 1 capital (to risk weighted assets) 90,037 14.5 27,946 4.5 40,366 6.5 Tier 1 capital (to average assets) 90,037 12.7 28,466 4.0 35,582 5.0

Post-retirement Plans (Tables)

Post-retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Summary of Information Pertaining to Activity in Plan	The Company has a master supplemental retirement plan (“Plan”) which covers certain officers and directors of the Company. In 2021 and 2020, the only active participants in the Plan were certain directors, as the Plan is frozen to new participants. Information pertaining to activity in the Plan follows: Years Ended December 31, 2021 2020 (In thousands) Change in plan assets: Fair value of plan assets at beginning of year $ — $ — Employer contributions 201 201 Benefits paid (201 ) (201 ) Fair value of plan assets at end of year — — Change in benefit obligation: Benefit obligation at beginning of year 1,457 1,506 Service cost 13 11 Interest cost 17 36 Actuarial (gain) loss (19 ) 105 Benefits paid (201 ) (201 ) Benefit obligation at end of year 1,267 1,457 Unfunded status and accrued supplemental pension cost at year end $ (1,267 ) $ (1,457 ) Accumulated benefit obligation at year end $ 1,267 $ 1,457
Summary of Assumptions Used to Determine Benefit Obligation	The assumptions used to determine the benefit obligation are as follows: December 31, 2021 2020 Discount rate 1.90 % 1.25 % Annual inflation factor 1.00 % 1.00 % The following assumptions were used to determine the net periodic benefit cost for the years ended December 31, 2021 and 2020: 2021 2020 Discount rate 1.25 % 2.50 % Annual inflation factor 1.00 % 1.00 %
Summary of Net Periodic Benefit Cost Included in Salaries and Employee Benefits Expense	Net periodic benefit cost, included in other non-interest expenses, attributable to the Plan for the years ended December 31, 2021 and 2020, consists of the following: 2021 2020 (In thousands) Service cost $ 13 $ 11 Interest cost 17 36 Amortization of net actuarial loss 62 45 Amortization of prior service credit (45 ) (57 ) $ 47 $ 35
Summary of Estimated Future Benefit Payments Expected Future Services	Estimated future benefit payments, which reflect expected future services, as appropriate, are as follows: Years Ending December 31, Amount (In thousands) 2022 $ 209 2023 345 2024 204 2025 200 2026 90 2027-2031 187

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Grants of Options to Purchase Shares of Common Stock	The Company made the following grants of options to purchase shares of common stock during the years ended December 31, 2021 and 2020: 2021 2020 Options granted 40,491 333,118 Vesting period (years) 5 3 - 5 Expiration period (years) 10 10 Expected volatility 30.98 % 24.94% - 29.87% Expected life (years) 6.2 6 - 6.5 Expected dividend yield — — Risk free interest rate 0.64 % 0.44%-1.47% Option fair value $ 6.20 $2.69 - $4.87
Summary of Activity and Certain Other Information Related to Stock Options Grants Under 2017 Equity Plan and 2020 Inducement Plan	The following table presents the activity and certain other information related to stock option grants under the 2017 Equity Plan and the 2020 Inducement Plan for the year ended December 31, 2021: Options Stock Option Grants Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Balance at January 1, 2021 587,168 $ 13.32 8.40 $ — Granted 40,491 20.06 Exercised (19,276 ) 13.48 Forfeited (9,000 ) 11.48 Balance at December 31, 2021 599,383 $ 13.80 8.50 $ 6,115,920 Exercisable at December 31, 2021 261,733 $ 14.26 7.61 $ 2,548,314 Unrecognized compensation cost (inclusive of directors' options) $ 1,072,768 Weighted average remaining recognition period (years) 2.08
Summary of Activity and Certain Other Information Related to Restricted Stock Awards Under Equity Plan	The following table presents the activity and certain other information related to restricted stock awards under the Equity Plan for the year ended December 31, 2021: Restricted Stock Awards Weighted Average Grant Price Performance-Based Restricted Stock Units (1) Weighted Average Grant Price Total Restricted Stock Awards and Performance-Based Restricted Stock Units Weighted Average Grant Price Restricted stock awards at January 1, 2021 122,012 $ 12.72 — $ — 122,012 $ 12.72 Granted 19,750 20.15 18,000 20.15 37,750 20.15 Vested (40,165 ) 13.44 — — (40,165 ) 13.44 Forfeited (2,112 ) 11.48 — — (2,112 ) 11.48 Non-vested stock awards at December 31, 2021 99,485 $ 13.93 18,000 $ 20.15 117,485 $ 14.89 Unrecognized compensation cost $ 1,124,787 $ 310,355 $ 1,435,142 Weighted average remaining recognition period (years) 2.60 2.29 2.55

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Calculation of Average Number of Shares Outstanding Used to Calculate Basic and Diluted Earnings Per Share	The following table sets forth the calculation of the average number of shares outstanding used to calculate the basic and diluted earnings per share for the periods indicated: 2021 2020 Average number of common shares outstanding 5,262,824 5,511,524 Less: Average unallocated ESOP shares (366,183 ) (384,963 ) Average number of common shares outstanding used to calculate basic earnings per share 4,896,641 5,126,561 Effect of dilutive stock options 212,097 36,481 Average number of common shares outstanding used to calculate dilutive earnings per share 5,108,738 5,163,042

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding Contract Amounts Represent Credit Risk	At December 31, 2021 and 2020, the following financial instruments were outstanding whose contract amounts represent credit risk: 2021 2020 (In thousands) Commitments to originate loans $ 107,889 $ 411,401 Unused lines and letters of credit 79,012 71,458 Unadvanced funds on construction loans 13,879 9,110 Overdraft lines of credit 7,967 7,969

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized below. Total Level 1 Level 2 Level 3 Fair December 31, 2021 (In thousands) Assets: Securities available for sale $ — $ 51,666 $ — $ 51,666 Portfolio loans (fair value option) 13,780 — 13,780 Loans held for sale (fair value option) — 44,766 — 44,766 Derivative loan commitments — 1,364 — 1,364 Forward loan sale commitments — 50 — 50 Liabilities: Forward loan sale commitments, including TBAs — 84 — 84 December 31, 2020 Assets: Securities available for sale: Debt securities $ — $ 55,366 $ — $ 55,366 Portfolio loans (fair value option) — 13,780 — 13,780 Loans held for sale (fair value option) — 119,112 — 119,112 Derivative loan commitments — 11,821 — 11,821 Forward loan sale commitments — 44 — 44 Liabilities: Forward loan sale commitments, including TBAs — 2,180 — 2,180
Schedule of Assets Measured at Fair Value on a Non-Recurring Basis	The following table summarizes the fair value hierarchy used to determine each adjustment and the carrying value of the related assets and liabilities as of December 31, 2021 and 2020. The gains and losses represent the amounts recorded during 2021 and 2020 on the assets and liabilities held at year-end. There no liabilities recorded at fair value on a non-recurring basis as of December 31, 2021 and 2020. Year Ended December 31, 2021 December 31, 2021 Level 1 Level 2 Level 3 Total Assets: (In thousands) Collateral dependent impaired loans $ — $ — $ 2,551 $ — Mortgage servicing rights — 15,616 — 438 $ — $ 15,616 $ 2,551 $ 438 Year Ended December 31, 2020 December 31, 2020 Level 1 Level 2 Level 3 Total Gains (Losses) (In thousands) Collateral dependent impaired loans $ — $ — $ 6,318 $ — Mortgage servicing rights — 12,377 — (2,067 ) Foreclosed real estate — — 132 — $ — $ 12,377 $ 6,450 $ (2,067 )
Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments	The estimated fair values, and related carrying amounts, of the Company’s financial instruments are presented below. Certain financial instruments and all non-financial instruments are exempt from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein do not represent the underlying fair value of the Company. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include mortgagor’s escrow accounts and accrued interest payable. December 31, 2021 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Securities available for sale 51,666 51,666 — 51,666 — Loans held for sale 44,766 44,766 — 44,766 — Loans, net 544,621 549,674 — — 549,674 Derivative assets 1,414 1,414 — 1,414 — Financial liabilities: Deposits $ 638,147 $ 637,538 $ — $ 637,538 $ — FHLBB advances 50,000 50,001 — 50,001 — Derivative liabilities 84 84 — 84 — December 31, 2020 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Securities available for sale $ 55,366 $ 55,366 $ — $ 55,366 $ — Loans held for sale 119,112 119,112 — 119,112 — Loans, net 483,644 490,914 — — 490,914 Derivative assets 11,865 11,865 — 11,865 — Financial liabilities: Deposits $ 528,307 $ 528,786 $ — $ 528,786 $ — FRB advances 11,431 11,431 — 11,431 — FHLBB advances 61,895 63,071 — 63,071 — Derivative liabilities 2,180 2,180 — 2,180 —

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Summary of Segment Information	Segment information as of and for the year ended December 31, 2021, follows: For the Year Ended December 31, 2021 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 18,894 $ 3,066 $ 21,960 Provision (credit) for loan losses (438 ) — (438 ) Net interest income after provision (credit) for loan losses 19,332 3,066 22,398 Non-interest income: Customer service fees 1,538 80 1,618 Gain on loan origination and sale activities, net (1) — 30,347 30,347 Mortgage servicing fees, net (622 ) 2,313 1,691 Other 428 501 929 Total non-interest income 1,344 33,241 34,585 Non-interest expenses: Salaries and employee benefits 7,031 21,181 28,212 Occupancy and equipment 1,825 967 2,792 Other non-interest expenses 4,435 6,219 10,654 Total non-interest expenses 13,291 28,367 41,658 Income before income taxes and elimination of inter-segment profit $ 7,385 $ 7,940 15,325 Elimination of inter-segment profit (2,662 ) Income before income taxes 12,663 Income tax expense 3,062 Net income $ 9,601 Total assets, December 31, 2021 $ 708,631 $ 94,647 $ 803,278 (1) Before elimination of inter-segment profit Segment information as of and for the year ended December 31, 2020 follows: For the Year Ended December 31, 2020 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 16,235 $ 2,632 $ 18,867 Provision for loan losses 2,553 — 2,553 Net interest income after provision for loan losses 13,682 2,632 16,314 Non-interest income: Customer service fees 1,180 103 1,283 Gain on loan origination and sale activities, net (1) — 55,729 55,729 Mortgage servicing fees, net (381 ) (772 ) (1,153 ) Other 465 580 1,045 Total non-interest income 1,264 55,640 56,904 Non-interest expenses: Salaries and employee benefits 9,161 24,000 33,161 Occupancy and equipment 1,770 1,775 3,545 Other non-interest expenses 5,228 4,382 9,610 Total non-interest expenses 16,159 30,157 46,316 Income (loss) before income taxes and elimination of inter-segment profit $ (1,213 ) $ 28,115 26,902 Elimination of inter-segment profit (1,493 ) Income before income taxes 25,409 Income tax expense 5,477 Net income $ 19,932 Total assets, December 31, 2020 $ 537,722 $ 183,350 $ 721,072 (1) Before elimination of inter-segment profit

Other Non-Interest Expenses (Ta

Other Non-Interest Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Other Income And Expenses [Abstract]
Schedule of Company's Total Interest and Non-Interest Income Included in Other Non-Interest Expenses	Included in other non-interest expenses in 2021 and 2020 are certain items exceeding 1% of the Company’s total interest and non-interest income as follows: 2021 2020 (In thousands) Software amortization, licenses and maintenance $ 1,667 $ 1,303 Credit reports 769 820 Card related expenses 468 429 Data communication and telephone 397 391 Directors' fees, including stock-based compensation 777 579

Global Pandemic Affecting Ran_2

Global Pandemic Affecting Randolph Bancorp, Inc. (Tables)	12 Months Ended
	Dec. 31, 2021
Risks And Uncertainties [Abstract]
Summary of Lending Activity and Outstanding Balances of PPP Loans and The Associated Pledges	The table below summarizes lending activity and outstanding balances of PPP loans and the associated pledges to the PPPLF: PPP Loan Balance FRB Advances PPP Loans Outstanding at Amount Pledged Outstanding at Originated December 31, 2021 to PPPLF December 31, 2021 (1) (In thousands) 2020 PPP loans $ 15,387 $ 16 $ 15,387 $ - 2021 PPP loans 10,967 3,569 - - Total Activity $ 26,354 $ 3,585 $ 15,387 $ - (1) FRB advances were fully repaid during the first quarter of 2021 and the associated PPP loans are no longer pledged.
Summary of Loan Portfolio	A summary of the loan portfolio is as follows: December 31, 2021 2020 (In thousands) Mortgage loans on real estate: Residential: One- to four-family $ 236,364 $ 235,648 Home equity loans and lines of credit 57,295 48,166 Commercial 197,423 143,893 Construction 33,961 31,050 Total real estate loans 525,043 458,757 Commercial and industrial 17,242 20,259 Consumer 7,552 10,289 Total loans 549,837 489,305 Allowance for loan losses (6,289 ) (6,784 ) Net deferred loan costs and fees, and purchase premiums 1,073 1,123 Total loans, net $ 544,621 $ 483,644 The table below summarizes the status of the bank’s loan deferral activity: Deferrals Suspended/ Resumed Full Granted (1) Reduced Payment (2) Payment (2) Payoff (3) (In thousands) December 31, 2021 Real estate loans: Residential: One- to-four family $ 15,771 $ 1,949 $ 8,063 $ 5,759 Home equity loans and lines of credit 2,936 42 1,458 1,436 Construction 341 — 341 — Commercial 34,176 — 26,463 7,713 Total real estate loans 53,224 1,991 36,325 14,908 Commercial and industrial 3,362 — 1,352 2,010 Consumer 58 — 58 — Total $ 56,644 $ 1,991 $ 37,735 $ 16,918 December 31, 2020 Real estate loans: Residential: One-to-four family $ 15,514 $ 12,974 $ 2,109 $ 431 Home equity loans and lines of credit 3,179 626 1,287 1,266 Construction 350 350 — — Commercial 34,754 6,544 25,406 2,804 Total real estate loans 53,797 20,494 28,802 4,501 Commercial and industrial 3,645 — 1,635 2,010 Consumer 68 68 — — Total $ 57,510 $ 20,562 $ 30,437 $ 6,511 (1) (2) (3)
Schedule of Past Due and Non-Accrual Loans by Loan Category	The following table presents past due and non-accrual loans, by loan category, at December 31, 2021 and 2020: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due (1) Non-accrual Loans (In thousands) December 31, 2021 Residential one- to four-family $ 701 $ 193 $ — $ 894 $ 2,133 Home equity loans and lines of credit 186 215 — 401 491 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer 76 9 — 85 — Total $ 963 $ 417 $ — $ 1,380 $ 2,624 December 31, 2020 Residential one- to four-family $ — $ — $ — $ — $ 1,876 Home equity loans and lines of credit 95 — 317 412 584 Commercial real estate — — 26 26 4,713 Construction — — — — — Commercial and industrial — — — — — Consumer 38 64 — 102 — Total $ 133 $ 64 $ 343 $ 540 $ 7,173 (1) Excludes non-accrual loans which are separately presented. Accordingly, the table below summarizes the risk rating and for all loans that were granted deferral, and any loans that were listed in nonaccrual status: Pass Rated / Special Sub- Non- Not Rated Mention standard (1) accrual (1)(2) (In thousands) December 31, 2021 Real estate loans: Residential: One- to four-family $ 8,678 $ 212 $ 1,122 $ 1,334 Home equity loans and lines of credit 1,500 — — — Construction 341 — — — Commercial 16,004 6,916 3,543 — Total real estate loans 26,523 7,128 4,665 1,334 Commercial and industrial 1,020 332 — — Consumer 58 — — — Total $ 27,601 $ 7,460 $ 4,665 $ 1,334 December 31, 2020 Real estate loans: Residential: One- to four-family $ 14,887 $ 196 $ — $ 196 Home equity loans and lines of credit 1,913 — — — Construction 350 — — — Commercial 19,020 8,748 4,182 4,182 Total real estate loans 36,170 8,944 4,182 4,378 Commercial and industrial 1,204 431 — — Consumer 68 — — — Total $ 37,442 $ 9,375 $ 4,182 $ 4,378 (1) These three columns indicate the risk rating and subsequent outstanding balance of loans that have received a deferral. The Pass Rated/Not Rated, Special Mention and Substandard columns reconcile to the Suspended Payment/Reduced Payment columns in the preceding table. (2) Nonaccrual loans are risk rated as either special mention or substandard and are included as a balance in those columns.

Parent Company Condensed Fina_2

Parent Company Condensed Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2021
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Balance Sheets	Financial information as of December 31, 2021 and 2020 and for the years then ended pertaining to Randolph Bancorp, Inc. is as follows: BALANCE SHEETS December 31, December 31, 2021 2020 Assets Cash and due from bank $ 3,240 $ 4,829 Investment in Envision Bank 93,126 90,959 Income taxes receivable 661 - ESOP loan 3,895 4,042 Total assets $ 100,922 $ 99,830 Liabilities Income taxes payable $ — $ 8 Due to Envision Bank 4 3 Other liabilities 15 — Total liabilities 19 11 Stockholders' Equity Common stock 50 54 Additional paid-in capital 44,078 50,937 Retained earnings 60,524 51,689 ESOP-Unearned compensation (3,568 ) (3,756 ) Accumulated other comprehensive loss, net of tax (181 ) 895 Total stockholders' equity 100,903 99,819 Total liabilities and stockholders' equity $ 100,922 $ 99,830
Statements of Operations	STATEMENTS OF OPERATIONS Years Ended December 31, 2021 2020 Interest income $ 131 $ 198 Dividend income 8,000 5,000 Operating expenses 191 171 Income before incomes taxes and equity in undistributed net income of Envision Bank 7,940 5,027 Applicable income tax (credit) (12 ) 7 Income before equity in undistributed net income of Envision Bank 7,952 5,020 Equity in undistributed net income of Envision Bank 1,649 14,912 Net income $ 9,601 $ 19,932
Statements of Cash Flows	STATEMENTS OF CASH FLOWS Years Ended December 31, 2021 2020 Cash flows from operating activities: Net income $ 9,601 $ 19,932 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Equity in undistributed net income of Envision Bank (1,649 ) (14,912 ) Dividends received from Envision Bank (8,000 ) (5,000 ) Increase (decrease) in income taxes payable (receivable) (669 ) 8 Increase in other liabilities 15 — Change in intercompany receivable/payable — (15 ) Net cash provided by (used in) operating activities (702 ) 13 Cash flows from investing activities: Principal payments received on ESOP loan 147 120 Dividends received from Envision Bank 8,000 5,000 Net cash provided by investing activities 8,147 5,120 Cash flows from financing activities: Stock repurchases (8,529 ) (1,749 ) Stock repurchase payable — — Proceeds from the exercise of options, net 261 — Common stock dividend paid (766 ) — Net cash used in financing activities (9,034 ) (1,749 ) Net change in cash and due from bank (1,589 ) 3,384 Cash and due from bank at the beginning of year 4,829 1,445 Cash and due from bank at end of year $ 3,240 $ 4,829

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Undiscounted Cash Flows of Base Rent Related to Operating Leases with Payments	The following table sets forth the undiscounted cash flows of base rent related to operating leases outstanding at December 31, 2021 with payments scheduled over the next five years and thereafter, including a reconciliation to the operating lease liability recognized in the Company’s Consolidated Balance Sheet in other liabilities. (In thousands) 2022 $ 619 2023 396 2024 309 2025 245 2026 226 Thereafter 95 Total minimum lease payments 1,890 Less: amount representing interest (84 ) Present value of future minimum lease payments $ 1,806

Mortgage Banking Income (Tables

Mortgage Banking Income (Tables)	12 Months Ended
	Dec. 31, 2021
Mortgage Banking [Abstract]
Components of Gain on Loan Origination and Sale Activities and Mortgage Servicing Fees	The components of gain on loan origination and sale activities and mortgage servicing fees for the years ended December 31, 2021 and 2020 are as follows: For the Year Ended December 31, 2021 2020 (In thousands) Gain on loan origination and sale activities, net Gain on sale of mortgage loans and realized gain from derivative financial instruments, net $ 33,578 $ 34,203 Net change in fair value of loans held for sale and portfolio loans accounted for at fair value (3,536 ) 3,263 Capitalized residential mortgage loan servicing rights 5,998 8,428 Net change in fair value of derivative loan commitments and forward loan sale commitments (8,355 ) 8,342 Gain on loan origination and sales activities, net $ 27,685 $ 54,236 Mortgage servicing fees, net Residential mortgage loan servicing fees $ 5,012 $ 3,458 Amortization of residential mortgage loan servicing rights (3,197 ) (2,543 ) Release (provision) to the valuation allowance of mortgage loan servicing rights 438 (2,068 ) Sub-servicer expenses (1) (562 ) - Mortgage servicing fees, net $ 1,691 $ (1,153 ) Total gain on loan origination and sales activities and mortgage servicing fees, net $ 29,376 $ 53,083 (1) Sub-servicer expenses were first incurred during the third quarter of 2021, due to the conversion of the Company’s mortgage loan servicing activities. Previously, all expenses related to servicing mortgage loans serviced for others were included in non-interest expenses.

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)LoanSegment	Dec. 31, 2020USD ($)	Dec. 31, 2022USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash equivalents maturity period	90 days
Time period to capture relevant loan loss data	48 months
Number of PPP Loan Funded | Loan	385
Total PPP Loan Funded	$ 26,400,000
Outstanding PPP Loan	$ 3,600,000
Obligation to repurchase mortgage loans prescribed time period	4 months
Description of tax benefit	A tax position is recognized as a benefit if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded.
Uncertain tax positions	$ 0	$ 0
Interest or penalties	$ 0	$ 0
Number of business segments | Segment	2
Supplemental Retirement Plan [Member] | Scenario Forecast [Member]
Summary Of Significant Accounting Policies [Line Items]
Prior service credits			$ 45,000
Net actuarial losses			$ 55,000
Consumer Loans or Second Mortgages and HELOCs [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment disclosure requirement	unless such loans are 90 days past due or are classified as a TDR.
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
FDIC insurance coverage limit	$ 250,000
Certificates of deposit maturity period	5 years
Maximum [Member] | Residential One-to-Four Family Real Estate Portfolio Segment [Member]
Summary Of Significant Accounting Policies [Line Items]
Loan-to-value ratio	80.00%
Maximum [Member] | Second Mortgages and Home Equity Lines of Credit Property Segment [Member]
Summary Of Significant Accounting Policies [Line Items]
Loan-to-value ratio	80.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Certificates of deposit maturity period	1 year
Percentage of tax benefit that likely of being realized on examination with taxing authority	50.00%

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Components of Accumulated Other Comprehensive Loss (AOCI) and Related Tax Effects (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Total other comprehensive income (loss)	$ (1,076)	$ 1,429
Accumulated other comprehensive income (loss), net of tax	(181)	895
Accumulated Net Investment Gain Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	249	1,713
Other comprehensive Loss, Tax effect	(64)	(313)
Total other comprehensive income (loss)	185	1,400
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	(646)	(712)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	222	254
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	(424)	(458)
Other comprehensive Loss, Tax effect	58	(47)
Total other comprehensive income (loss)	$ (366)	$ (505)

Securities Available for Sale -

Securities Available for Sale - Schedule of Amortized Cost and Fair Value of Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 51,417	$ 53,654
Gross Unrealized Gains	635	1,712
Gross Unrealized Losses	(386)
Fair Value	51,666	55,366
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,939
Gross Unrealized Losses	(168)
Fair Value	10,771
US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,995	1,993
Gross Unrealized Gains		3
Gross Unrealized Losses	(17)
Fair Value	1,978	1,996
Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,510	4,300
Gross Unrealized Gains	33	56
Gross Unrealized Losses	(7)
Fair Value	2,536	4,356
Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	351	595
Gross Unrealized Gains	2	5
Fair Value	353	600
Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,349	32,538
Gross Unrealized Gains	324	919
Gross Unrealized Losses	(194)
Fair Value	23,479	33,457
Commercial Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,733	8,857
Gross Unrealized Gains	223	525
Fair Value	8,956	9,382
Commercial Mortgage Backed Securities, U.S. Government-guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	103	977
Gross Unrealized Gains		24
Fair Value	103	1,001
Collateralized Mortgage Obligations, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	796	996
Gross Unrealized Gains	14	52
Fair Value	810	1,048
Collateralized Mortgage Obligations, US Government Guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,641	3,398
Gross Unrealized Gains	39	128
Fair Value	$ 2,680	$ 3,526

Securities Available for Sale_2

Securities Available for Sale - Investments Classified by Contractual Maturity Date (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Available-for-sale Securities, Debt Maturities, Amortized Cost
After 1 year through 5 years	$ 10,073
After 5 years through 10 years	5,722
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Total	15,795
Mortgage-backed securities and collateralized mortgage obligations	35,622
Amortized Cost	51,417	$ 53,654
Available-for-sale Securities, Debt Maturities, Fair Value
After 1 year through 5 years	9,974
After 5 years through 10 years	5,664
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair Value Total	15,638
Mortgage-backed securities and collateralized mortgage obligations	36,028
Available-for-sale Securities, Debt Securities, Fair Value Total	$ 51,666	$ 55,366

Securities Available for Sale_3

Securities Available for Sale - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)Debt_Security	Dec. 31, 2020USD ($)Debt_Security
Schedule of Available-for-sale Securities [Line Items]
Fair value of investment securities pledged as collateral	$ 1,979,000	$ 1,958,000
Number of debt securities with unrealized losses | Debt_Security	17	0
Proceeds from sales of available-for-sale securities	$ 0	$ 0
Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Investment securities on equity	$ 0	$ 0

Securities Available for Sale_4

Securities Available for Sale - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Detail) $ in Thousands	Dec. 31, 2021USD ($)
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	$ (386)
Less Than Twelve Months, Fair Value	24,949
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(168)
Less Than Twelve Months, Fair Value	10,771
US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(17)
Less Than Twelve Months, Fair Value	1,978
Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(7)
Less Than Twelve Months, Fair Value	723
Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(194)
Less Than Twelve Months, Fair Value	$ 11,477

Loans - Summary of Loan Portfol

Loans - Summary of Loan Portfolio (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 549,837	$ 489,305
Allowance for loan losses		(6,289)	(6,784)
Net deferred loan costs and fees, and purchase premiums		1,073	1,123
Total loans, net		544,621	483,644
Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		525,043	458,757
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		197,423	143,893
Commercial Real Estate Loans [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		197,423	143,893
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	17,242	20,259
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		7,552	10,289
One-to-Four Family [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		236,364	235,648
One-to-Four Family [Member] | Residential Real Estate [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		236,364	235,648
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		57,295	48,166
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		33,961	31,050
Construction [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 33,961	$ 31,050
[1]	Non-impaired loan balance includes $3.6 million and $10.9 million of PPP loans as of December 31, 2021 and 2020, respectively, for which no allowance is provided due to the full guarantee from the SBA.

Loans - Additional Information

Loans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)ContractTDR	Dec. 31, 2020USD ($)ContractTDR
Accounts, Notes, Loans and Financing Receivable [Line Items]
Servicing loans for participants	$ 6,222,000	$ 2,410,000
Impaired loans, additional funds committed	$ 0
Loans subject to troubled debt restructurings | TDR	1	1
Allowances related to troubled debt restructurings	$ 100,000	$ 133,000
Number of Contracts | Contract	15	18
TDRs Listed as Accrual	$ 2,228,000	$ 2,915,000
Minimum past due days for loan rating	90 days
30 - 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings defaulted over 30 days past due	$ 0	$ 0
Residential Real Estate [Member] | Payment Deferral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of Contracts | TDR	1
Residential Real Estate [Member] | Nonperforming Financial Instruments [Member] | Payment Deferral [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs Listed as Accrual	$ 213,000
Residential Real Estate [Member] | Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	3 months
Residential Real Estate [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	30 years
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	1 year
Number of Contracts | Contract		1
TDRs Listed as Accrual		$ 40,000

Loans - Summary of Activity in

Loans - Summary of Activity in the Allowance for Loan Losses by Loan Category (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		$ 6,784		$ 4,280
Provision (credit) for loan losses		(438)		2,553
Loans charged-off		(67)		(71)
Recoveries		10		22
Ending balance		6,289		6,784
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		3,402		1,840
Provision (credit) for loan losses		49		1,562
Ending balance		3,451		3,402
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		416	[1]	235
Provision (credit) for loan losses		81		179
Recoveries		2		2
Ending balance	[1]	499		416
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		127		128
Provision (credit) for loan losses		24		54
Loans charged-off		(67)		(68)
Recoveries		3		13
Ending balance		87		127
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		1,646		1,096
Provision (credit) for loan losses		(558)		543
Recoveries		5		7
Ending balance		1,093		1,646
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		442		289
Provision (credit) for loan losses		20		156
Loans charged-off				(3)
Ending balance		462		442
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		751		692
Provision (credit) for loan losses		(54)		59
Ending balance		$ 697		$ 751
[1]	Non-impaired loan balance includes $3.6 million and $10.9 million of PPP loans as of December 31, 2021 and 2020, respectively, for which no allowance is provided due to the full guarantee from the SBA.

Loans - Summary of Additional I

Loans - Summary of Additional Information Pertaining to the Allowance for Loan Losses (Detail) - USD ($) $ in Thousands		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans		$ 100		$ 133
Allowance for non-impaired loans		6,189		6,651
Total allowance for loan losses		6,289		6,784		$ 4,280
Impaired loans		3,858		8,949
Non-impaired loans		545,979		480,356
Total loans		549,837		489,305
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans		3,451		3,402
Total allowance for loan losses		3,451		3,402		1,840
Impaired loans				4,751
Non-impaired loans		197,423		139,142
Total loans		197,423		143,893
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	[1]	499		416
Total allowance for loan losses		499	[1]	416	[1]	235
Non-impaired loans	[1]	17,242		20,259
Total loans	[1]	17,242		20,259
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans		87		127
Total allowance for loan losses		87		127		128
Non-impaired loans		7,552		10,289
Total loans		7,552		10,289
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans		81		133
Allowance for non-impaired loans		1,012		1,513
Total allowance for loan losses		1,093		1,646		1,096
Impaired loans		3,255		3,575
Non-impaired loans		233,109		232,073
Total loans		236,364		235,648
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans		19
Allowance for non-impaired loans		443		442
Total allowance for loan losses		462		442		289
Impaired loans		603		623
Non-impaired loans		56,692		47,543
Total loans		57,295		48,166
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans		697		751
Total allowance for loan losses		697		751		$ 692
Non-impaired loans		33,961		31,050
Total loans		$ 33,961		$ 31,050
[1]	Non-impaired loan balance includes $3.6 million and $10.9 million of PPP loans as of December 31, 2021 and 2020, respectively, for which no allowance is provided due to the full guarantee from the SBA.

Loans - Summary of Additional_2

Loans - Summary of Additional Information Pertaining to the Allowance for Loan Losses (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Non-impaired loans	$ 545,979	$ 480,356
PPP Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Non-impaired loans	$ 3,600	$ 10,900

Loans - Schedule of Past Due an

Loans - Schedule of Past Due and Non-Accrual Loans by Loan Category (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	[1]	$ 1,380	$ 540
Non-accrual Loans		2,624	7,173
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	[1]	85	102
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	[1]	894
Non-accrual Loans		2,133	1,876
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	[1]	401	412
Non-accrual Loans		491	584
Commercial Real Estate Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	[1]		26
Non-accrual Loans			4,713
30 - 59 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		963	133
30 - 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		76	38
30 - 59 Days Past Due [Member] | One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		701
30 - 59 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		186	95
60 - 89 Days Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		417	64
60 - 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		9	64
60 - 89 Days Past Due [Member] | One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		193
60 - 89 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		$ 215
90 Days or More Past Due [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due			343
90 Days or More Past Due [Member] | Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due			317
90 Days or More Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due			$ 26
[1]	Excludes non-accrual loans which are separately presented.

Loans - Summary of Impaired Loa

Loans - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	$ 2,843	$ 7,539
Unpaid Principal Balance without a valuation allowance	2,862	7,555
Recorded Investment with a valuation allowance	982	1,382
Unpaid Principal Balance with a valuation allowance	996	1,394
Related Allowance, Total impaired loans	100	133
Recorded Investment, Total impaired loans	3,825	8,921
Unpaid Principal Balance, Total impaired loans	3,858	8,949
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance		4,753
Unpaid Principal Balance without a valuation allowance		4,751
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	2,364	2,160
Unpaid Principal Balance without a valuation allowance	2,377	2,181
Recorded Investment with a valuation allowance	874	1,382
Unpaid Principal Balance with a valuation allowance	878	1,394
Related Allowance, Total impaired loans	81	133
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	479	626
Unpaid Principal Balance without a valuation allowance	485	$ 623
Recorded Investment with a valuation allowance	108
Unpaid Principal Balance with a valuation allowance	118
Related Allowance, Total impaired loans	$ 19

Loans - Summary of Information

Loans - Summary of Information Related to Average Balances of Impaired Loans and Interest Income Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 6,148	$ 6,976
Interest Income Recognized	232	467
Cash Basis Interest Recognized	129	159
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	3,132	3,550
Interest Income Recognized	202	399
Cash Basis Interest Recognized	125	159
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	525	588
Interest Income Recognized	30	60
Cash Basis Interest Recognized	4
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 2,491	2,838
Interest Income Recognized		$ 8

Loans - Schedule of Troubled De

Loans - Schedule of Troubled Debt Restructuring (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)OfficeLeaseContract	Dec. 31, 2020USD ($)OfficeLeaseContract
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	15	18
TDRs Listed as Accrual	$ 2,228	$ 2,915
Trouble Debt Restructurings Listed As Accrual
Financing Receivable Modifications [Line Items]
Number of Contracts | Office	11	14
TDRs Listed as Accrual	$ 1,200	$ 1,748
Trouble Debt Restructurings Listed As Non Accrual
Financing Receivable Modifications [Line Items]
Number of Contracts | Lease	4	4
TDRs Listed as Accrual	$ 1,028	$ 1,167
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	12	16
TDRs Listed as Accrual	$ 2,022	$ 2,833
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	3	1
TDRs Listed as Accrual	$ 206	$ 42
Residential Real Estate [Member] | Trouble Debt Restructurings Listed As Accrual | One-to-Four Family [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Office	9	12
TDRs Listed as Accrual	$ 1,103	$ 1,666
Residential Real Estate [Member] | Trouble Debt Restructurings Listed As Accrual | Home Equity Loans and Lines of Credit [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Office	2	1
TDRs Listed as Accrual	$ 97	$ 42
Residential Real Estate [Member] | Trouble Debt Restructurings Listed As Non Accrual | One-to-Four Family [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Lease	3	4
TDRs Listed as Accrual	$ 919	$ 1,167
Residential Real Estate [Member] | Trouble Debt Restructurings Listed As Non Accrual | Home Equity Loans and Lines of Credit [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Lease	1
TDRs Listed as Accrual	$ 109
Commercial Real Estate Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract		1
TDRs Listed as Accrual		$ 40
Commercial Real Estate Loans [Member] | Trouble Debt Restructurings Listed As Accrual
Financing Receivable Modifications [Line Items]
Number of Contracts | Office		1
TDRs Listed as Accrual		$ 40

Loans - Summary of Company's Lo

Loans - Summary of Company's Loans by Risk Rating (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 549,837	$ 489,305
Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	298,574	291,644
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	237,645	180,803
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	8,180	11,075
Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	5,438	5,783
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	197,423	143,893
Commercial Real Estate Loans [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	186,774	129,925
Commercial Real Estate Loans [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,106	9,257
Commercial Real Estate Loans [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	3,543	4,711
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	17,242	20,259
Commercial and Industrial [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	16,910	19,828
Commercial and Industrial [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	332	431
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,552	10,289
Consumer [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	7,552	10,289
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	236,364	235,648
One-to-Four Family [Member] | Residential Real Estate [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	234,225	233,773
One-to-Four Family [Member] | Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	361	803
One-to-Four Family [Member] | Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	1,778	1,072
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	57,295	48,166
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Note Rated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	56,797	47,582
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	381	584
Second Mortgages and HELOC [Member] | Residential Real Estate [Member] | Substandard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	117
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	33,961	31,050
Construction [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 33,961	$ 31,050

Loan Servicing - Additional Inf

Loan Servicing - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Servicing Assets At Amortized Value [Line Items]
Unpaid principal balances of residential mortgage loans serviced for others	$ 1,975,876,000	$ 1,760,306,000
Custodial Escrow balances	16,600,000	14,200,000
Increase (decrease) in valuation allowance of mortgage servicing rights	(438,000)	2,067,000
Contractually specified servicing fees, net	$ 5,012,000	$ 3,458,000
Measurement Input, Discount Rate [Member]
Servicing Assets At Amortized Value [Line Items]
Discount rate	0.12	0.12
Measurement Input, Constant Prepayment Rate [Member] | Minimum [Member]
Servicing Assets At Amortized Value [Line Items]
Discount rate	0.15	0.19
Measurement Input, Constant Prepayment Rate [Member] | Maximum [Member]
Servicing Assets At Amortized Value [Line Items]
Discount rate	0.18	0.27

Loan Servicing - Summary of Act

Loan Servicing - Summary of Activity Relating to Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Mortgage servicing rights:
Balance at beginning of year	$ 15,372	$ 9,484
Additions through originations	5,998	8,432
Amortization	(3,197)	(2,544)
Balance at end of year	18,173	15,372
Valuation allowance:
Balance at beginning of year	2,995	928
Provision (credit)	(438)	2,067
Balance at end of year	2,557	2,995
Mortgage servicing rights, amortized cost	15,616	12,377
Mortgage servicing rights, fair value	$ 16,355	$ 12,490

Premises and Equipment - Summar

Premises and Equipment - Summary of Cost and Accumulated Depreciation and Amortization of Premises and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Land and improvements	$ 953	$ 953
Buildings and improvements	6,325	3,343
Leasehold improvements	1,097	2,236
Furniture and equipment	4,295	5,558
Construction-in-progress		145
Property plant and equipment, gross	12,670	12,235
Less accumulated depreciation and amortization	(4,986)	(7,454)
Property plant and equipment, net	$ 7,684	$ 4,781
Buildings and Improvements [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	5 years
Buildings and Improvements [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	50 years
Leasehold Improvements [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Leasehold Improvements [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	10 years
Furniture and Equipment [Member] | Minimum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	3 years
Furniture and Equipment [Member] | Maximum [Member]
Property Plant And Equipment [Line Items]
Estimated Useful Life	10 years

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 707,000	$ 1,508,000

Deposits - Summary of Deposit B

Deposits - Summary of Deposit Balances by Type (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deposits [Abstract]
Demand deposits	$ 145,666	$ 96,731
NOW accounts	53,996	53,530
Money market deposits	90,544	77,393
Regular and other savings accounts	191,712	185,481
Brokered deposits	10,061	10,056
Total non-certificate accounts	491,979	423,191
Term certificates less than $250,000	85,877	60,026
Term certificates of $250,000 or more	20,235	23,418
Term certificates - brokered	40,056	21,672
Total certificate accounts	146,168	105,116
Total deposits	$ 638,147	$ 528,307

Deposits - Summary of Term Cert

Deposits - Summary of Term Certificates, Including Brokered Deposits, by Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Amount
2021		$ 81,320
2022	$ 95,232	20,122
2023	31,966	2,269
2024	17,464	781
2025	755	624
2026	751
Total certificate accounts	$ 146,168	$ 105,116
Weighted Average Rate
2021		0.95%
2022	0.53%	1.46%
2023	0.30%	1.06%
2024	0.30%	1.15%
2025	0.53%	0.64%
2026	0.27%
Total	0.45%	1.05%

Borrowings - Summary of Borrowi

Borrowings - Summary of Borrowings from FHLBB (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fixed-rate advances maturing:
2021		$ 21,895
2022	$ 5,000	10,000
2023	5,000
2025	40,000	30,000
Advances From Federal Home Loan Banks	$ 50,000	$ 61,895
Weighted Average Rate
2021		1.27%
2022	0.30%	2.20%
2023	0.46%
2025	1.39%	1.35%
Advances from FHLBB, Weighted Average Rate	1.18%	1.46%

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Overnight advances of FHLBB borrowings	$ 0	$ 0
Federal Home Loan Bank advances	50,000,000	61,895,000
Paycheck Protection Program [Member]
Debt Instrument [Line Items]
Outstanding advances	$ 11,400,000	0
Correspondent Bank [Member]
Debt Instrument [Line Items]
Available borrowing capacity			$ 12,500,000
Federal Home Loan Bank advances		0	$ 0
FHLBB [Member]
Debt Instrument [Line Items]
Percentage on carrying value of first mortgage loans pledged as collateral	75.00%
Available borrowing capacity	$ 111,500,000
FHLBB [Member] | Commercial Real Estate Loans [Member]
Debt Instrument [Line Items]
Percentage on carrying value of first mortgage loans pledged as collateral	65.00%
FHLBB With Interest Rate Adjusts Daily [Member]
Debt Instrument [Line Items]
Available borrowing capacity	$ 4,195,000
Federal Home Loan Bank advances	$ 0	0
FHLBB With Interest Rate Adjusts Daily [Member] | Maximum [Member]
Debt Instrument [Line Items]
Percentage on total assets for borrowings under line of credit	2.00%
Federal Reserve Bank of Boston [Member]
Debt Instrument [Line Items]
Available borrowing capacity	$ 2,000,000
Federal Home Loan Bank advances	$ 0	$ 0

Borrowings - Summary of Outstan

Borrowings - Summary of Outstanding Balances of Short Term Borrowings from FHLBB (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Federal Home Loan Bank Advances Activity For Year [Abstract]
Average daily balance	$ 4,357,000	$ 2,265,000
Maximum outstanding at any month end	$ 28,032,000	$ 16,181,000

Income Taxes - Allocation of Fe

Income Taxes - Allocation of Federal and State Income Taxes Between Current and Deferred Portions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Current tax expense:
Federal	$ 2,797	$ 789
State	1,384	1,393
Total current tax expense	4,181	2,182
Deferred tax expense (benefit):
Federal	(301)	4,174
State	(287)	887
Total deferred federal and state tax expense (benefit)	(588)	5,061
Change in valuation allowance	(531)	(1,766)
Total deferred tax expense (benefit)	(1,119)	3,295
Total tax expense	$ 3,062	$ 5,477

Income Taxes - Summary of Diffe

Income Taxes - Summary of Differences Between Statutory Federal Income Tax Expense (Benefit) and Actual Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Statutory federal tax rate of 21%	$ 2,659	$ 5,341
Increase (decrease) resulting from:
State taxes, net of federal tax effect	867	1,801
Bank-owned life insurance	(34)	(38)
Tax-exempt income	(4)	(6)
Change in valuation allowance	(531)	(1,766)
Other, net	105	145
Total tax expense	$ 3,062	$ 5,477

Income Taxes - Summary of Dif_2

Income Taxes - Summary of Differences Between Statutory Federal Income Tax Expense (Benefit) and Actual Tax Expense (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Statutory federal tax rate	21.00%	21.00%

Income Taxes - Summary of Compo

Income Taxes - Summary of Components of Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Deferred tax assets, gross	$ 5,844	$ 4,248
Valuation allowance		(531)
Deferred tax assets, net	5,844	3,717
Deferred tax liabilities:
Deferred tax liabilities, gross	(7,583)	(7,012)
Net deferred tax liability	(1,739)	(3,295)
Federal [Member]
Deferred tax assets:
Deferred tax assets, gross	3,977	2,962
Deferred tax liabilities:
Deferred tax liabilities, gross	(5,160)	(4,837)
State [Member]
Deferred tax assets:
Deferred tax assets, gross	1,867	1,286
Deferred tax liabilities:
Deferred tax liabilities, gross	$ (2,423)	$ (2,175)

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Employee benefit plans	$ 729	$ 785
Allowance for loan losses	1,938	2,071
Funded status of post-retirement benefits	143	(47)
Securities available for sale	(64)	(313)
Depreciation and amortization	62	144
Net deferred loan origination costs	(276)	(281)
Mortgage servicing rights	(4,390)	(3,479)
Charitable contribution carryforward		531
Derivatives	(374)	(2,722)
Right-of-use asset	(508)
Lease liability	508
Stock-based compensation	390	290
Other, net	103	257
Deferred tax assets (liabilities) before valuation allowances	(1,739)	(2,764)
Valuation allowance on net deferred tax assets		(531)
Net deferred tax liability	$ (1,739)	$ (3,295)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Valuation allowance for deferred tax assets	100.00%
Charitable contribution carryforward	$ 0	$ 531,000
Federal income tax reserve for loan losses	$ 2,033,000
Percentage of tax reserve for loan losses used for purpose other than to absorb losses subject to taxation	150.00%
Deferred income tax liability not been provided	$ 571,000

On-Balance Sheet Derivative I_2

On-Balance Sheet Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional amount	$ 85,887,000	$ 396,551,000
Derivative Loan Commitments [Member] | Net Gain on Sales of Mortgage Loans [Member]
Derivative [Line Items]
Increase (reductions) in aggregate fair value on derivatives, interest rate lock commitments	(10,457,000)	10,349,000
Undesignated Forward Loan Sale Commitments and TBA Securities [Member]
Derivative [Line Items]
Derivative, Notional amount	80,407,000	390,248,000
Undesignated Forward Loan Sale Commitments and TBA Securities [Member] | Net Gain on Sales of Mortgage Loans [Member]
Derivative [Line Items]
Increase (reductions) in aggregate fair value on derivatives, interest rate lock commitments	(2,102,000)	2,007,000
Other Assets [Member] | Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative fair value, Asset	1,364,000	11,821,000
Other Assets [Member] | Undesignated Forward Loan Sale Commitments and TBA Securities [Member]
Derivative [Line Items]
Derivative fair value, Asset	50,000	44,000
Other Liabilities [Member] | Undesignated Forward Loan Sale Commitments and TBA Securities [Member]
Derivative [Line Items]
Derivative fair value, Liability	$ 84,000	$ 2,180,000

Minimum Regulatory Capital Re_3

Minimum Regulatory Capital Requirements - Additional Information (Detail)	Dec. 31, 2021
Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer of common equity tier 1 capital to risk weighted assets ratio (as a percent)	0.025

Minimum Regulatory Capital Re_4

Minimum Regulatory Capital Requirements - Summary of Actual and Minimum Capital Amounts and Ratios Exclusive of Capital Conservation Buffer (Detail) - Bank [Member] $ in Thousands	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total capital (to risk weighted assets), actual amount	$ 100,180	$ 97,406
Tier 1 capital (to risk weighted assets), actual amount	93,288	90,037
Common equity Tier 1 capital (to risk weighted assets), actual amount	93,288	90,037
Tier 1 capital (to average assets), actual amount	$ 93,288	$ 90,037
Total capital (to risk weighted assets), actual ratio	0.174	0.157
Tier 1 capital (to risk weighted assets), actual ratio	0.162	0.145
Common equity Tier 1 capital (to risk weighted assets), actual ratio	16.20%	14.50%
Tier 1 capital (to average assets), actual ratio	0.123	0.127
Total capital (to risk weighted assets), for minimum capital adequacy purposes amount	$ 45,956	$ 49,682
Tier 1 capital (to risk weighted assets), for minimum capital adequacy purposes amount	34,467	37,261
Common equity Tier 1 capital (to risk weighted assets), for minimum capital adequacy amount	25,850	27,946
Common equity Tier 1 capital (to risk weighted assets), for minimum capital adequacy amount	$ 30,355	$ 28,466
Total capital (to risk weighted assets), for minimum capital adequacy purposes ratio	0.080	0.080
Tier 1 capital (to risk weighted assets), for minimum capital adequacy purposes ratio	0.060	0.060
Common equity Tier 1 capital (to risk weighted assets), for minimum capital adequacy purposes ratio	4.50%	4.50%
Tier 1 capital (to average assets), for minimum capital adequacy purposes ratio	0.040	0.040
Total capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions amount	$ 57,445	$ 62,102
Tier 1 capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions amount	45,956	49,682
Common equity Tier 1 capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions amount	37,339	40,366
Tier 1 capital (to average assets), minimum to be well capitalized under prompt corrective action provisions amount	$ 37,943	$ 35,582
Total capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions ratio	0.100	0.100
Tier 1 capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions ratio	0.080	0.080
Common equity Tier 1 capital (to risk weighted assets), minimum to be well capitalized under prompt corrective action provisions ratio	6.50%	6.50%
Tier 1 capital (to average assets), minimum to be well capitalized under prompt corrective action provisions ratio	0.050	0.050

Post-Retirement Plans - Additio

Post-Retirement Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Other non-interest expense	$ 6,821,000	$ 6,514,000
Supplemental Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued benefits	391,000	453,000
Other non-interest expense	152,000	65,000
Endorsement Split-Dollar Life Insurance Arrangements [Member]
Defined Benefit Plan Disclosure [Line Items]
Accrued benefits	486,000	472,000
Post-retirement benefit expense	$ 14,000	20,000
401(k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Description of employees eligibility	The Company maintains a 401(k) Plan whereby each employee reaching the age of 21 automatically becomes a participant in the plan.  Employees may contribute up to 15% of their compensation subject to certain limits based on federal tax laws. All employees who have worked for one year or 1,000 hours are eligible for an automatic employer contribution of 3% of employees’ compensation, which requires no vesting period.
Minimum age of employee to become participant	21 years
Maximum annual contributions per employee, percent	15.00%
Minimum number of year worked by employees	1 year
Minimum number of hours worked by employees	1000 hours
Employer contribution percentage on employees compensation	3.00%
Automatic employer matching contributions vesting period	0 years
Employer matching contribution, percent	50.00%
Employer match of eligible employees contributions percentage	2.00%
Employer matching contributions vesting period	4 years
Contribution expense	$ 898,000	$ 852,000
401(k) Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contribution percentage on employees compensation	4.00%

Post-Retirement Plans - Summary

Post-Retirement Plans - Summary of Information Pertaining to Activity in Plan (Details) - Supplemental Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Change in plan assets:
Employer contributions	$ 201	$ 201
Benefits paid	(201)	(201)
Change in benefit obligation:
Benefit obligation at beginning of year	1,457	1,506
Service cost	13	11
Interest cost	17	36
Actuarial (gain) loss	(19)	105
Benefits paid	(201)	(201)
Benefit obligation at end of year	1,267	1,457
Unfunded status and accrued supplemental pension cost at year end	(1,267)	(1,457)
Accumulated benefit obligation at year end	$ 1,267	$ 1,457

Post-Retirement Plans - Summa_2

Post-Retirement Plans - Summary of Assumptions Used to Determine Benefit Obligation (Details) - Supplemental Retirement Plan [Member]	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.90%	1.25%
Annual inflation factor	1.00%	1.00%

Post-Retirement Plans - Summa_3

Post-Retirement Plans - Summary of Net Periodic Benefit Cost Included in Other Non-Interest Expenses Attributable to Plan (Details) - Supplemental Retirement Plan [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13	$ 11
Interest cost	17	36
Amortization of net actuarial loss	62	45
Amortization of prior service credit	(45)	(57)
Net periodic benefit cost	$ 47	$ 35

Post-Retirement Plans - Summa_4

Post-Retirement Plans - Summary of Assumptions Used to Determine Net Periodic Benefit Cost (Details) - Supplemental Retirement Plan [Member]	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.25%	2.50%
Annual inflation factor	1.00%	1.00%

Post-Retirement Plans - Summa_5

Post-Retirement Plans - Summary of Estimated Future Benefit Payments Expected Future Services (Details) - Supplemental Retirement Plan [Member] $ in Thousands	Dec. 31, 2021USD ($)
Defined Benefit Plan Disclosure [Line Items]
2022	$ 209
2023	345
2024	204
2025	200
2026	90
2027-2031	$ 187

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted	40,491	333,118
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option term	10 years	10 years
Options and awards vesting period	5 years
Stock-based compensation expense	$ 591,000	$ 703,000
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted	19,750
Grant date fair value per share	$ 20.15
Stock-based compensation expense	$ 641,000	$ 891,000
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted	18,000
Grant date fair value per share	$ 20.15
Minimum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period		3 years
Maximum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period		5 years
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	586,872
Stock option term	10 years
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	234,749
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period	3 years
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period	5 years
2020 Inducement Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period	5 years
2020 Inducement Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted	44,118
2020 Inducement Plan [Member] | Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted	15,000
2021 Equity Plan [Member] | Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period	3 years
Awards granted	19,750
Grant date fair value per share	$ 20.15
2021 Equity Plan [Member] | Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Awards granted	18,000
Grant date fair value per share	$ 20.15
2021 Equity Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	100,000

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Grants of Options to Purchase Shares of Common Stock (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted	40,491	333,118
Option fair value	$ 6.20
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period (years)	5 years
Expiration period (years)	10 years	10 years
Expected volatility	30.98%
Expected volatility, minimum		24.94%
Expected volatility, maximum		29.87%
Expected life (years)	6 years 2 months 12 days
Risk free interest rate	0.64%
Risk free interest rate, minimum		0.44%
Risk free interest rate, maximum		1.47%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option fair value		$ 2.69
Minimum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period (years)		3 years
Expected life (years)		6 years
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option fair value		$ 4.87
Maximum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period (years)		5 years
Expected life (years)		6 years 6 months

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity and Certain Other Information Related to Stock Options Grants Under 2017 Equity Plan and 2020 Inducement Plan (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Stock Option Grants
Beginning Balance	587,168
Granted	40,491	333,118
Exercised	(19,276)
Forfeited	(9,000)
Ending Balance	599,383	587,168
Exercisable at December 31, 2021	261,733
Unrecognized compensation cost (inclusive of directors' options)	$ 1,072,768
Weighted Average Exercise Price
Beginning Balance	$ 13.32
Granted	20.06
Exercised	13.48
Forfeited	11.48
Ending Balance	13.80	$ 13.32
Exercisable at December 31, 2021	$ 14.26
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted Average Remaining Contractual Term	8 years 6 months	8 years 4 months 24 days
Weighted Average Remaining Contractual Term, Exercisable	7 years 7 months 9 days
Aggregate Intrinsic Value, Outstanding	$ 6,115,920
Aggregate Intrinsic Value, Exercisable	$ 2,548,314
Stock Options [Member]
Stock Option Grants
Weighted average remaining recognition period (years)	2 years 29 days

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Activity and Certain Other Information Related to Restricted Stock Awards Under Equity Plan (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)$ / sharesshares
Restricted Stock Awards [Member]
Restricted Stock Awards
Beginning Balance | shares	122,012
Granted | shares	19,750
Vested | shares	(40,165)
Forfeited | shares	(2,112)
Ending Balance | shares	99,485
Unrecognized compensation cost | $	$ 1,124,787
Weighted average remaining recognition period (years)	2 years 7 months 6 days
Weighted Average Grant Price
Beginning Balance | $ / shares	$ 12.72
Granted | $ / shares	20.15
Vested | $ / shares	13.44
Forfeited | $ / shares	11.48
Ending Balance | $ / shares	$ 13.93
Performance-Based Restricted Stock Units [Member]
Restricted Stock Awards
Granted | shares	18,000
Ending Balance | shares	18,000
Unrecognized compensation cost | $	$ 310,355
Weighted average remaining recognition period (years)	2 years 3 months 14 days
Weighted Average Grant Price
Granted | $ / shares	$ 20.15
Ending Balance | $ / shares	$ 20.15
Total Restricted Stock Awards and Performance-Based Restricted Stock Units [Member]
Restricted Stock Awards
Beginning Balance | shares	122,012
Granted | shares	37,750
Vested | shares	(40,165)
Forfeited | shares	(2,112)
Ending Balance | shares	117,485
Unrecognized compensation cost | $	$ 1,435,142
Weighted average remaining recognition period (years)	2 years 6 months 18 days
Weighted Average Grant Price
Beginning Balance | $ / shares	$ 12.72
Granted | $ / shares	20.15
Vested | $ / shares	13.44
Forfeited | $ / shares	11.48
Ending Balance | $ / shares	$ 14.89

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Activity and Certain Other Information Related to Restricted Stock Awards Under Equity Plan (Parenthetical) (Detail)	Dec. 31, 2021shares
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum number of shares that could vest	27,000

Employee Stock Ownership Plan -

Employee Stock Ownership Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Loan repaid term	25 years
Interest rate	3.25%	4.75%
Number of allocated shares	18,780
Annual allocation of shares, expiration year	2040
ESOP expense	$ 339,000	$ 256,000
Unallocated shares	356,818
Unallocated shares, value	$ 8,564,000
Common Stock [Member]
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Sale of stock, price per share	$ 10
The Randolph Savings Charitable Foundation, Inc. [Member]
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Sale of share in employee stock ownership plan	469,498

Share Repurchase Program - Addi

Share Repurchase Program - Additional Information (Detail) - USD ($)	Jan. 25, 2022	Sep. 14, 2020	Oct. 31, 2021	Oct. 31, 2020	Sep. 30, 2017	Dec. 31, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Cost of shares repurchased						$ 8,529,000	$ 1,749,000
September 2017 Share Repurchase Program [Member]
Class Of Stock [Line Items]
Stock repurchase program percentage of outstanding shares repurchased					10.00%
Number of shares authorized to repurchase					586,854
Number of shares repurchased		568,403
Cost of shares repurchased		$ 8,452,000
October 2020 Share Repurchase Program [Member]
Class Of Stock [Line Items]
Stock repurchase program percentage of outstanding shares repurchased				10.00%
Number of shares authorized to repurchase				552,000
Number of shares repurchased							435,601
Cost of shares repurchased							$ 8,819,000
October 2021 Share Repurchase Program [Member]
Class Of Stock [Line Items]
Stock repurchase program percentage of outstanding shares repurchased			10.00%
Number of shares authorized to repurchase			510,000
Number of shares repurchased						4,337
Cost of shares repurchased						$ 100,000
October 2021 Share Repurchase Program [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Stock repurchase program percentage of outstanding shares repurchased	1.00%
Number of shares authorized to repurchase	62,000

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Calculation of Average Number of Shares Outstanding Used to Calculate Basic and Diluted Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Earnings Per Share [Abstract]
Average number of common shares outstanding	5,262,824	5,511,524
Less: Average unallocated ESOP shares	(366,183)	(384,963)
Average number of common shares outstanding used to calculate basic earnings per share	4,896,641	5,126,561
Effect of dilutive stock options	212,097	36,481
Average number of common shares outstanding used to calculate dilutive earnings per share	5,108,738	5,163,042

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments Outstanding Contract Amounts Represent Credit Risk (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments to Originate Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 107,889	$ 411,401
Unused Lines and Letters of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	79,012	71,458
Unadvanced Funds on Construction Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	13,879	9,110
Overdraft Lines of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 7,967	$ 7,969

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021Member
Commitments And Contingencies [Line Items]
Salary continuation term of employment arrangement	3 years
Five Members of Senior Management [Member]
Commitments And Contingencies [Line Items]
Number of members with change in control agreements	5
Change in control agreement description of terms	The company provide that if, within two years of a change of control of the Company or the Bank, the executive in involuntarily terminated other than for cause, disability or death, or voluntarily resigns for good reason, the executive will be entitled to a lump-sum payment equal to two times salary plus bonus, except for one executive where the payment is equal to one times salary plus bonus.
Four Members of Senior Management [Member]
Commitments And Contingencies [Line Items]
Number of members with change in control agreements	4
Change in control agreement description of terms	The company provide that if, within one year of a change of control of the Company or the Bank, the executive is involuntarily terminated other than for cause, disability or death, or voluntarily resigns for good reason, the executive will be entitled to a lump-sum payment equal to one times salary plus bonus.

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Recorded at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 51,666	$ 55,366
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	51,666	55,366
Fair value, Loans held for sale	44,766	119,112
Derivative assets	1,414	11,865
Derivative liabilities	84	2,180
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	51,666
Fair value, Portfolio loans	13,780	13,780
Fair value, Loans held for sale	44,766	119,112
Fair Value, Measurements, Recurring [Member] | Derivative Loan Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,364	11,821
Fair Value, Measurements, Recurring [Member] | Forward Loan Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	50	44
Fair Value, Measurements, Recurring [Member] | Forward Loan Sale Commitments, including TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	84	2,180
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		55,366
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	51,666
Fair value, Portfolio loans	13,780	13,780
Fair value, Loans held for sale	44,766	119,112
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Derivative Loan Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,364	11,821
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Forward Loan Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	50	44
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Forward Loan Sale Commitments, including TBAs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities	$ 84	2,180
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		$ 55,366

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Additional information (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, assets, level 1 to level 2 transfers, amount	$ 0	$ 0
Fair value, assets, level 2 to level 1 transfers, amount	0	0
Fair value, liabilities, level 1 to level 2 transfers, amount	0	0
Fair value, liabilities, level 2 to level 1 transfers, amount	0	0
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on nonrecurring basis	$ 0	$ 0

Fair Value of Assets and Liab_5

Fair Value of Assets and Liabilities - Schedule of Assets Recorded at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	$ 16,355	$ 12,490
Gains (Losses) on assets held	(5)
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains (losses) on assets held, mortgage servicing rights	438	(2,067)
Gains (Losses) on assets held	438
Gains (Losses) on assets held		(2,067)
Fair Value, Nonrecurring | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	15,616	12,377
Assets, fair value	15,616	12,377
Fair Value, Nonrecurring | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans, fair value	2,551	6,318
Fair value, Foreclosed real estate		132
Assets, fair value	$ 2,551	$ 6,450

Fair Value of Assets and Liab_6

Fair Value of Assets and Liabilities - Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Financial assets:
Securities available for sale	$ 51,666	$ 55,366
Level 2 [Member]
Financial assets:
Securities available for sale	51,666	55,366
Loans held for sale	44,766	119,112
Derivative assets	1,414	11,865
Financial liabilities:
Deposits	637,538	528,786
FRB advances		11,431
FHLBB advances	50,001	63,071
Derivative liabilities	84	2,180
Level 3 [Member]
Financial assets:
Loans, net	549,674	490,914
Carrying Amount [Member]
Financial assets:
Securities available for sale	51,666	55,366
Loans held for sale	44,766	119,112
Loans, net	544,621	483,644
Derivative assets	1,414	11,865
Financial liabilities:
Deposits	638,147	528,307
FRB advances		11,431
FHLBB advances	50,000	61,895
Derivative liabilities	84	2,180
Fair Value [Member]
Financial assets:
Securities available for sale	51,666	55,366
Loans held for sale	44,766	119,112
Loans, net	549,674	490,914
Derivative assets	1,414	11,865
Financial liabilities:
Deposits	637,538	528,786
FRB advances		11,431
FHLBB advances	50,001	63,071
Derivative liabilities	$ 84	$ 2,180

Segment Information - Additiona

Segment Information - Additional Information (Detail)	6 Months Ended		12 Months Ended
	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2021USD ($)SegmentOffice	Dec. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Number of business segments | Segment			2
Number of branch offices | Office			5
Percentage of loan servicing fees	0.25%
Servicing fees amount			$ (1,691,000)	$ 1,153,000
Envision Mortgage [Member]
Segment Reporting Information [Line Items]
Premium percentage for new loans			1.50%	1.50%
Premium income			$ 2,662,000	$ 1,493,000
Percentage of fees for HELOC			1.00%	1.00%
Servicing fees amount			$ (2,313,000)	$ 772,000
Envision Bank [Member]
Segment Reporting Information [Line Items]
Percentage of loan servicing fees		0.14%		0.14%
Servicing fees amount			$ 622,000	$ 381,000

Segment Information - Summary o

Segment Information - Summary of Segment Information (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net interest income		$ 21,960,000	$ 18,867,000
Provision (credit) for loan losses		(438,000)	2,553,000
Net interest income after provision (credit) for loan losses		22,398,000	16,314,000
Non-interest income:
Customer service fees		1,618,000	1,283,000
Gain on loan origination and sale activities, net	[1]	30,347,000	55,729,000
Mortgage servicing fees, net		1,691,000	(1,153,000)
Other		929,000	1,045,000
Total non-interest income		34,585,000	56,904,000
Non-interest expenses:
Salaries and employee benefits		28,212,000	33,161,000
Occupancy and equipment		2,792,000	3,545,000
Other non-interest expenses		10,654,000	9,610,000
Total non-interest expenses		41,658,000	46,316,000
Income before income taxes and elimination of inter-segment profit		15,325,000	26,902,000
Elimination of inter-segment profit		(2,662,000)	(1,493,000)
Income before income taxes		12,663,000	25,409,000
Income tax expense		3,062,000	5,477,000
Net income		9,601,000	19,932,000
Total assets		803,278,000	721,072,000
Envision Bank [Member]
Segment Reporting Information [Line Items]
Net interest income		18,894,000	16,235,000
Provision (credit) for loan losses		(438,000)	2,553,000
Net interest income after provision (credit) for loan losses		19,332,000	13,682,000
Non-interest income:
Customer service fees		1,538,000	1,180,000
Mortgage servicing fees, net		(622,000)	(381,000)
Other		428,000	465,000
Total non-interest income		1,344,000	1,264,000
Non-interest expenses:
Salaries and employee benefits		7,031,000	9,161,000
Occupancy and equipment		1,825,000	1,770,000
Other non-interest expenses		4,435,000	5,228,000
Total non-interest expenses		13,291,000	16,159,000
Income before income taxes and elimination of inter-segment profit		7,385,000	(1,213,000)
Total assets		708,631,000	537,722,000
Envision Mortgage [Member]
Segment Reporting Information [Line Items]
Net interest income		3,066,000	2,632,000
Net interest income after provision (credit) for loan losses		3,066,000	2,632,000
Non-interest income:
Customer service fees		80,000	103,000
Gain on loan origination and sale activities, net	[1]	30,347,000	55,729,000
Mortgage servicing fees, net		2,313,000	(772,000)
Other		501,000	580,000
Total non-interest income		33,241,000	55,640,000
Non-interest expenses:
Salaries and employee benefits		21,181,000	24,000,000
Occupancy and equipment		967,000	1,775,000
Other non-interest expenses		6,219,000	4,382,000
Total non-interest expenses		28,367,000	30,157,000
Income before income taxes and elimination of inter-segment profit		7,940,000	28,115,000
Total assets		$ 94,647,000	$ 183,350,000
[1]	Before elimination of inter-segment profit

Other Non-Interest Expenses - A

Other Non-Interest Expenses - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Income And Expenses [Abstract]
Percentage of certain items exceeding interest and non interest income	1.00%	1.00%

Other Non-Interest Expenses - S

Other Non-Interest Expenses - Schedule of Company's Total Interest and Non-Interest Income Included in Other Non-Interest Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Income And Expenses [Abstract]
Software amortization, licenses and maintenance	$ 1,667	$ 1,303
Credit reports	769	820
Card related expenses	468	429
Data communication and telephone	397	391
Directors' fees, including stock-based compensation	$ 777	$ 579

Global Pandemic Affecting Ran_3

Global Pandemic Affecting Randolph Bancorp, Inc.- Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Unusual Risk Or Uncertainty [Line Items]
Disaster Response Plan Costs	$ 229,000
Commercial Loan [Member] | Payment Deferral [Member]
Unusual Risk Or Uncertainty [Line Items]
Loan, amount		$ 37,500,000
Residential Real Estate Loans in Portfolio [Member] | Payment Deferral [Member]
Unusual Risk Or Uncertainty [Line Items]
Loan, amount		19,100,000
Residential Real Estate Loan Serviced for Other [Member] | Payment Deferral [Member]
Unusual Risk Or Uncertainty [Line Items]
Loan, amount		$ 68,400,000

Global Pandemic Affecting Ran_4

Global Pandemic Affecting Randolph Bancorp, Inc.- Summary of Lending Activity and Outstanding Balances of PPP Loans and The Associated Pledges (Detail) $ in Thousands	Dec. 31, 2021USD ($)
Financing Receivable Recorded Investment Past Due [Line Items]
PPP Loans Originated	$ 26,354
PPP Loan Balance Outstanding	3,585
Amount Pledged To PPLF	15,387
2020 PPP Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
PPP Loans Originated	15,387
PPP Loan Balance Outstanding	16
Amount Pledged To PPLF	15,387
2021 PPP Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
PPP Loans Originated	10,967
PPP Loan Balance Outstanding	$ 3,569

Global Pandemic Affecting Ran_5

Global Pandemic Affecting Randolph Bancorp, Inc. - Summary of Loan Portfolio (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	$ 56,644	$ 57,510
Suspended/Reduction Payment	[2]	1,991	20,562
Resumed Payment	[2]	37,735	30,437
Full Payoff	[3]	16,918	6,511
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	53,224	53,797
Suspended/Reduction Payment	[2]	1,991	20,494
Resumed Payment	[2]	36,325	28,802
Full Payoff	[3]	14,908	4,501
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	15,771	15,514
Suspended/Reduction Payment	[2]	1,949	12,974
Resumed Payment	[2]	8,063	2,109
Full Payoff	[3]	5,759	431
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	2,936	3,179
Suspended/Reduction Payment	[2]	42	626
Resumed Payment	[2]	1,458	1,287
Full Payoff	[3]	1,436	1,266
Residential Real Estate [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	341	350
Suspended/Reduction Payment	[2]		350
Resumed Payment	[2]	341
Residential Real Estate [Member] | Commercial Real Estate Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	34,176	34,754
Suspended/Reduction Payment	[2]		6,544
Resumed Payment	[2]	26,463	25,406
Full Payoff	[3]	7,713	2,804
Commercial and Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	3,362	3,645
Resumed Payment	[2]	1,352	1,635
Full Payoff	[3]	2,010	2,010
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Deferrals Granted	[1]	58	68
Suspended/Reduction Payment	[2]		$ 68
Resumed Payment	[2]	$ 58
[1]
[2]
[3]

Global Pandemic Affecting Ran_6

Global Pandemic Affecting Randolph Bancorp, Inc. - Schedule of Past Due and Non-Accrual Loans (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		$ 27,601	$ 37,442
Special Mention		7,460	9,375
Sub-standard	[1]	4,665	4,182
Non-accrual	[1],[2]	1,334	4,378
Residential Real Estate [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		26,523	36,170
Special Mention		7,128	8,944
Sub-standard	[1]	4,665	4,182
Non-accrual	[1],[2]	1,334	4,378
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		8,678	14,887
Special Mention		212	196
Sub-standard	[1]	1,122
Non-accrual	[1],[2]	1,334	196
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		1,500	1,913
Residential Real Estate [Member] | Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		341	350
Residential Real Estate [Member] | Commercial Real Estate Loans [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		16,004	19,020
Special Mention		6,916	8,748
Sub-standard	[1]	3,543	4,182
Non-accrual	[1],[2]		4,182
Commercial and Industrial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		1,020	1,204
Special Mention		332	431
Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
Pass Rated / Not Rated		$ 58	$ 68
[1]	These three columns indicate the risk rating and subsequent outstanding balance of loans that have received a deferral. The Pass Rated/Not Rated, Special Mention and Substandard columns reconcile to the Suspended Payment/Reduced Payment columns in the preceding table.
[2]	Nonaccrual loans are risk rated as either special mention or substandard and are included as a balance in those columns.

Parent Company Condensed Fina_3

Parent Company Condensed Financial Statements - Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and due from banks	$ 3,501	$ 4,206
Total assets	803,278	721,072
Liabilities
Other liabilities	9,878	14,900
Total liabilities	702,375	621,253
Stockholders' Equity:
Common stock	50	54
Additional paid-in capital	44,078	50,937
Retained earnings	60,524	51,689
ESOP-Unearned compensation	(3,568)	(3,756)
Accumulated other comprehensive income (loss), net of tax	(181)	895
Total stockholders' equity	100,903	99,819	$ 78,462
Total liabilities and stockholders' equity	803,278	721,072
Randolph Bancorp, Inc. and Predecessor Randolph Bancorp [Member]
Assets
Cash and due from banks	3,240	4,829
Investment in Envision Bank	93,126	90,959
Income taxes receivable	661
ESOP loan	3,895	4,042
Total assets	100,922	99,830
Liabilities
Income taxes payable		8
Due to Envision Bank	4	3
Other liabilities	15
Total liabilities	19	11
Stockholders' Equity:
Common stock	50	54
Additional paid-in capital	44,078	50,937
Retained earnings	60,524	51,689
ESOP-Unearned compensation	(3,568)	(3,756)
Accumulated other comprehensive income (loss), net of tax	(181)	895
Total stockholders' equity	100,903	99,819
Total liabilities and stockholders' equity	$ 100,922	$ 99,830

Parent Company Condensed Fina_4

Parent Company Condensed Financial Statements - Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Condensed Income Statements Captions [Line Items]
Interest income	$ 24,113	$ 23,588
Applicable income tax (credit)	3,062	5,477
Net income	9,601	19,932
Randolph Bancorp, Inc. and Predecessor Randolph Bancorp [Member]
Condensed Income Statements Captions [Line Items]
Interest income	131	198
Dividend income	8,000	5,000
Operating expenses	191	171
Income before incomes taxes and equity in undistributed net income of Envision Bank	7,940	5,027
Applicable income tax (credit)	(12)	7
Income before equity in undistributed net income of Envision Bank	7,952	5,020
Equity in undistributed net income of Envision Bank	1,649	14,912
Net income	$ 9,601	$ 19,932

Parent Company Condensed Fina_5

Parent Company Condensed Financial Statements - Statements of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 9,601	$ 19,932
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Net cash provided by (used in) operating activities	125,117	(43,293)
Cash flows from investing activities:
Net cash provided by (used in) investing activities	(100,712)	(9,910)
Cash flows from financing activities:
Stock repurchases	(8,529)	(1,749)
Proceeds from exercise of stock options	261
Common stock dividends paid	(766)
Net cash provided by financing activities	77,270	58,725
Net change in cash and cash equivalents	101,675	5,522
Cash and cash equivalents at beginning of year	13,774	8,252
Cash and cash equivalents at end of year	115,449	13,774
Randolph Bancorp, Inc. and Predecessor Randolph Bancorp [Member]
Cash flows from operating activities:
Net income	9,601	19,932
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in undistributed net income of Envision Bank	(1,649)	(14,912)
Dividends received from Envision Bank	(8,000)	(5,000)
Increase (decrease) in income taxes payable (receivable)	(669)	8
Increase in other liabilities	15
Change in intercompany receivable/payable		(15)
Net cash provided by (used in) operating activities	(702)	13
Cash flows from investing activities:
Principal payments received on ESOP loan	147	120
Dividends received from Envision Bank	8,000	5,000
Net cash provided by (used in) investing activities	8,147	5,120
Cash flows from financing activities:
Stock repurchases	(8,529)	(1,749)
Proceeds from exercise of stock options	261
Common stock dividends paid	(766)
Net cash provided by financing activities	(9,034)	(1,749)
Net change in cash and cash equivalents	(1,589)	3,384
Cash and cash equivalents at beginning of year	4,829	1,445
Cash and cash equivalents at end of year	$ 3,240	$ 4,829

Leases - Additional Information

Leases - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021USD ($)LeaseAgreement
Lessee Lease Description [Line Items]
Number of operating lease agreement | LeaseAgreement	10
Lessee, Operating Lease, Existence of Option to Extend [true false]	true
Right-of-use asset related to operating leases	$ 1,800,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets
Operating lease cost	$ 834,000
Weighted average remaining lease term for operating leases	4 years 6 months
Weighted average discount rate	1.99%
Minimum [Member]
Lessee Lease Description [Line Items]
Lease renewal term	1 year
Maximum [Member]
Lessee Lease Description [Line Items]
Lease renewal term	10 years

Leases - Undiscounted Cash Flow

Leases - Undiscounted Cash Flows of Base Rent Related to Operating Leases with Payments (Detail) $ in Thousands	Dec. 31, 2021USD ($)
Leases [Abstract]
2022	$ 619
2023	396
2024	309
2025	245
2026	226
Thereafter	95
Total minimum lease payments	1,890
Less: amount representing interest	(84)
Present value of future minimum lease payments	$ 1,806
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	us-gaap:OtherLiabilities

Mortgage Banking Income - Compo

Mortgage Banking Income - Components of Gain on Loan Origination and Sale Activities and Mortgage Servicing Fees (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Gain on loan origination and sale activities, net
Gain on sale of mortgage loans and realized gain from derivative financial instruments, net	$ 33,578	$ 34,203
Net change in fair value of loans held for sale and portfolio loans accounted for at fair value	(3,536)	3,263
Capitalized residential mortgage loan servicing rights	5,998	8,428
Net change in fair value of derivative loan commitments and forward loan sale commitments	(8,355)	8,342
Gain on loan origination and sales activities, net	27,685	54,236
Mortgage servicing fees, net
Residential mortgage loan servicing fees	5,012	3,458
Amortization of residential mortgage loan servicing rights	(3,197)	(2,543)
Release (provision) to the valuation allowance of mortgage loan servicing rights	438	(2,068)
Sub-servicer expenses (1)	(562)
Mortgage servicing fees, net	1,691	(1,153)
Total gain on loan origination and sales activities and mortgage servicing fees, net	$ 29,376	$ 53,083