BSB Bancorp 10-K 15 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 06, 2019	Jun. 30, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Entity Registrant Name	BSB BANCORP, INC.
Entity Central Index Key	0001522420
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 276,496,828
Entity Common Stock, Shares Outstanding		9,851,708
Trading Symbol	BLMT
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 1,901	$ 1,771
Interest-bearing deposits in other banks	141,477	109,117
Cash and cash equivalents	143,378	110,888
Interest-bearing time deposits with other banks	4,229	2,440
Investments in available-for-sale securities	4,040	16,921
Investments in held-to-maturity securities (fair value of $145,369 as of December 31, 2018 and $158,385 as of December 31, 2017)	148,025	160,090
Federal Home Loan Bank stock, at cost	38,658	32,382
Loans held for sale	2,902
Loans, net of allowance for loan losses of $17,939 as of December 31, 2018 and $16,312 as of December 31, 2017	2,624,372	2,296,958
Premises and equipment, net	2,177	2,254
Accrued interest receivable	7,290	6,344
Deferred tax asset, net	6,793	5,794
Income taxes receivable	49	53
Bank-owned life insurance	36,540	36,967
Other assets	11,648	5,474
Total assets	3,030,101	2,676,565
Deposits:
Noninterest-bearing	203,373	221,462
Interest-bearing	1,757,539	1,529,789
Total deposits	1,960,912	1,751,251
Federal Home Loan Bank advances	838,250	723,150
Securities sold under agreements to repurchase	2,883	3,268
Accrued interest payable	2,050	1,594
Deferred compensation liability	8,384	7,919
Other liabilities	15,828	11,354
Total liabilities	2,828,307	2,498,536
Stockholders' equity:
Common stock; $0.01 par value, 100,000,000 shares authorized; 9,776,429 and 9,707,665 shares issued and outstanding at December 31, 2018 and 2017, respectively	98	97
Additional paid-in capital	96,590	94,590
Retained earnings	109,774	86,884
Accumulated other comprehensive (loss) income	(1,188)	89
Unearned compensation - ESOP	(3,480)	(3,631)
Total stockholders' equity	201,794	178,029
Total liabilities and stockholders' equity	$ 3,030,101	$ 2,676,565

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Investments in held-to-maturity securities, fair value	$ 145,369	$ 158,385
Loans, allowance for loan losses	$ 17,939	$ 16,312
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	9,776,429	9,707,665
Common stock, shares outstanding	9,776,429	9,707,665

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest and dividend income:
Interest and fees on loans	$ 91,337	$ 72,011	$ 57,513
Interest on taxable debt securities	3,494	3,356	3,159
Dividends	1,923	1,193	760
Other interest income	1,497	583	189
Total interest and dividend income	98,251	77,143	61,621
Interest expense:
Interest on deposits	23,761	12,900	9,434
Interest on Federal Home Loan Bank advances	13,391	8,150	4,788
Interest on securities sold under agreements to repurchase	5	4	4
Interest on other borrowed funds			5
Total interest expense	37,157	21,054	14,231
Net interest and dividend income	61,094	56,089	47,390
Provision for loan losses	1,657	2,762	2,385
Net interest and dividend income after provision for loan losses	59,437	53,327	45,005
Noninterest income:
Income from bank-owned life insurance	1,478	1,120	1,050
Net gain on sales of securities		38
Net gain on sales of loans	756	936	271
Loan level derivative income	1,417
Net (loss) gain on investments held in Rabbi Trust	(65)	158	36
Other income	182	192	140
Total noninterest income	5,020	3,627	2,750
Noninterest expense:
Salaries and employee benefits	20,327	19,533	17,757
Director compensation	775	1,355	971
Occupancy expense	986	964	991
Equipment expense	383	422	452
Deposit insurance	1,972	1,733	1,285
Data processing	2,782	2,793	3,120
Professional fees	1,064	1,044	964
Marketing	982	912	872
Merger expense	1,700
Other expense	2,045	1,930	1,937
Total noninterest expense	33,016	30,686	28,349
Income before income tax expense	31,441	26,268	19,406
Income tax expense	8,532	11,882	7,425
Net income	22,909	14,386	11,981
Net income available to common stockholders	$ 22,906	$ 14,278	$ 11,791
Earnings per share
Basic	$ 2.56	$ 1.63	$ 1.38
Diluted	$ 2.44	$ 1.55	$ 1.33
Customer Service Fees
Noninterest income:
Income from Customer service and loan servicing	$ 896	$ 785	$ 903
Loan Servicing Fee
Noninterest income:
Income from Customer service and loan servicing	$ 356	$ 398	$ 350

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 22,909	$ 14,386	$ 11,981
Other comprehensive (loss) income, net of tax:
Net change in fair value of securities available for sale	(49)	(31)	149
Net change in other comprehensive (loss) income for defined-benefit postretirement plan	29	17	70
Net change in fair value of cash flow hedges	(1,276)
Total other comprehensive (loss) income	(1,296)	(14)	219
Total comprehensive income	$ 21,613	$ 14,372	$ 12,200

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Unearned Compensation - ESOP
Balance (in shares) at Dec. 31, 2015		9,086,639
Balance at Dec. 31, 2015	$ 146,203	$ 91	$ 89,648	$ 60,517	$ (116)	$ (3,937)
Net income	11,981			11,981
Other comprehensive income (loss)	219				219
ESOP shares committed to be released	360		207			153
Stock based compensation-restricted stock awards	869		869
Stock based compensation-stock options	780		780
Proceeds from exercises of stock options, net of cash paid for income taxes	298		298
Proceeds from exercises of stock options, net of cash paid for income taxes (in shares)		27,964
Restricted stock awards granted (in shares)		(4,526)
Restricted stock awards granted	(118)		(118)
Tax benefit from stock compensation	329		329
Balance (in shares) at Dec. 31, 2016		9,110,077
Balance at Dec. 31, 2016	160,921	$ 91	92,013	72,498	103	(3,784)
Net income	14,386			14,386
Other comprehensive income (loss)	(14)				(14)
ESOP shares committed to be released	444		291			153
Stock based compensation-restricted stock awards	1,835		1,835
Stock based compensation-stock options	724		724
Proceeds from exercises of stock options, net of cash paid for income taxes	56	$ 1	55
Proceeds from exercises of stock options, net of cash paid for income taxes (in shares)		120,749
Restricted stock awards granted (in shares)		476,839
Restricted stock awards granted	$ (323)	$ 5	(328)
Balance (in shares) at Dec. 31, 2017	9,707,665	9,707,665
Balance at Dec. 31, 2017	$ 178,029	$ 97	94,590	86,884	89	(3,631)
Net income	22,909			22,909
Other comprehensive income (loss)	(1,296)				(1,296)
Reclassification of income tax effects related to items stranded within accumulated other comprehensive income from the Tax Cuts and Jobs Act				(19)	19
ESOP shares committed to be released	484		333			151
Stock based compensation-restricted stock awards	1,332		1,332
Stock based compensation-stock options	73		73
Proceeds from exercises of stock options, net of cash paid for income taxes	$ 537	$ 1	536
Proceeds from exercises of stock options, net of cash paid for income taxes (in shares)	99,199	77,735
Restricted stock awards granted (in shares)		(8,971)
Restricted stock awards granted	$ (274)		(274)
Balance (in shares) at Dec. 31, 2018	9,776,429	9,776,429
Balance at Dec. 31, 2018	$ 201,794	$ 98	$ 96,590	$ 109,774	$ (1,188)	$ (3,480)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 22,909	$ 14,386	$ 11,981
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of securities, net	784	843	833
Gain on sales of securities		(38)
Gain on sales of loans, net	(756)	(936)	(271)
Loans originated for sale	(19,480)	(5,439)	(10,134)
Proceeds from sales of loans	54,502	71,473	11,649
Provision for loan losses	1,657	2,762	2,385
Change in unamortized mortgage premium	44	(2,388)	(1,928)
Change in net deferred loan costs	(59)	196	1,041
ESOP expense	484	444	360
Depreciation and amortization expense	590	595	621
Impairment of fixed assets	3	18	16
Deferred income tax (benefit) expense	(492)	2,535	(1,741)
Gain on sale of fixed assets	(11)		0
Increase in bank-owned life insurance	(1,478)	(1,120)	(1,050)
Stock based compensation expense	1,405	2,559	1,649
Excess tax benefit from stock-based compensation			(329)
Net change in:
Accrued interest receivable	(946)	(1,709)	(854)
Other assets	(3,864)	(807)	400
Income taxes receivable	4	370	(423)
Income taxes payable			145
Accrued interest payable	456	571	30
Deferred compensation liability	465	876	609
Other liabilities	2,866	574	(2,216)
Net cash provided by operating activities	59,083	85,765	12,773
Cash flows from investing activities:
Maturities of interest-bearing time deposits with other banks	3,340	234	131
Purchases of interest-bearing time deposits with other banks	(5,129)	(2,440)	(234)
Proceeds from sales of available-for-sale securities	0	5,038	0
Proceeds from maturities of available-for-sale securities	12,750
Proceeds from maturities, payments, and calls of held-to-maturity securities	38,558	28,362	25,976
Purchases of held-to-maturity securities	(27,214)	(59,022)	(19,812)
Redemption of Federal Home Loan Bank stock	22,020	3,767	3,014
Purchases of Federal Home Loan Bank stock	(28,296)	(11,078)	(9,776)
Recoveries of loans previously charged off	17	24	61
Loan originations and principal collections, net	(91,532)	(57,732)	16,997
Purchases of loans	(274,709)	(438,883)	(350,653)
Proceeds from sales of fixed assets	25
Capital expenditures	(530)	(512)	(335)
Proceeds from death benefit of bank-owned life insurance	1,905
Premiums paid on bank-owned life insurance		(5)	(5,005)
Net cash used in investing activities	(348,795)	(532,247)	(339,636)
Cash flows from financing activities:
Net (decrease) increase in demand deposits, interest-bearing checking and savings accounts	(44,892)	112,716	122,737
Net increase in time deposits	254,553	169,113	77,166
Proceeds from long-term Federal Home Loan Bank advances	105,000	125,000	211,250
Principal payments on long-term Federal Home Loan Bank advances	(67,000)	(85,000)	(7,000)
Net change in short-term Federal Home Loan Bank advances	77,100	174,300	(69,400)
Payment to counterparty for interest rate cap contracts	(4,085)
Net (decrease) increase in securities sold under agreements to repurchase	(385)	1,283	(1,710)
Proceeds from exercise of stock options, net of cash paid	537	56	298
Payment of income taxes for shares withheld in stock based award activity	(274)	(323)	(118)
Net increase in mortgagors' escrow accounts	1,648	1,349	926
Excess tax benefit from stock-based compensation			329
Net cash provided by financing activities	322,202	498,494	334,478
Net increase (decrease) in cash and cash equivalents	32,490	52,012	7,615
Cash and cash equivalents at beginning of period	110,888	58,876	51,261
Cash and cash equivalents at end of period	143,378	110,888	58,876
Supplemental disclosures:
Interest paid	36,701	20,483	14,201
Income taxes paid	9,020	8,977	9,446
Transfer of loans receivable to loans held for sale	$ 37,168	$ 63,913
Derecognition of loans and related recourse obligation in other borrowings			$ 1,020

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	NOTE 1 – SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations BSB Bancorp, Inc. (the “Company”) was incorporated in Maryland in June, 2011 to become the holding company of Belmont Savings Bank (the “Bank”), a state-chartered Massachusetts savings bank. The Company is supervised by the Board of Governors of the Federal Reserve System (“FRB”), while the Bank is subject to the regulations of, and periodic examination by, the Federal Deposit Insurance Corporation (“FDIC”) and the Massachusetts Division of Banks (the “Division”). The Bank’s deposits are insured by the Bank Insurance Fund of the FDIC up to $250,000 per account. For balances in excess of the FDIC deposit insurance limits, coverage is provided by the Massachusetts Depositors Insurance Fund, Inc. In connection with the Company’s conversion from a mutual holding company to stock holding company form of organization (the “conversion”), on October 4, 2011 we completed our initial public offering of common stock, selling 8,993,000 shares of common stock at $10.00 per share for approximately $89.9 million in gross proceeds, including 458,643 shares sold to the Bank’s employee stock ownership plan. In addition, in connection with the conversion, we issued 179,860 shares of our common stock and contributed $200,000 in cash to the Belmont Savings Bank Foundation. The Bank is a state chartered savings bank which was incorporated in 1885 and is headquartered in Belmont, Massachusetts. The Bank is engaged principally in the business of attracting deposits from the general public and investing those deposits in residential, commercial real estate loans, multifamily real estate loans, consumer loans, including indirect auto loans, commercial loans and construction loans, as well as investment securities. Merger On November 26, 2018, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with People’s United Financial, Inc. (“People’s United”). The Merger Agreement provides that upon the terms and subject to the conditions set forth therein, the Company will merge with and into People’s United, with People’s United as the surviving corporation (the “ Merger Completion of the Merger remains subject to customary closing conditions. The Merger is expected to close in the second quarter of 2019. Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Belmont Savings Bank and BSB Funding Corporation and the Bank’s wholly owned subsidiary, BSB Investment Corporation. All significant intercompany balances and transactions have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles and general practices within the financial services industry. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management 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. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of the allowance for loan losses, valuation and potential other-than-temporary impairment (“OTTI”) of investment securities and the valuation of deferred tax assets. Reclassification Certain previously reported amounts have been reclassified to conform to the current year’s presentation. Significant Group Concentrations of Credit Risk Most of the Company’s business activity is with customers located within the Commonwealth of Massachusetts. There are no concentrations of credit to borrowers that have similar economic characteristics. The majority of the Company’s loan portfolio is comprised of loans collateralized by real estate located in the Commonwealth of Massachusetts. Cash and Cash Equivalents For purposes of the consolidated statements of cash flows, cash and cash equivalents include cash, balances due from banks and interest-bearing deposits in other banks. Investment Securities Debt securities that management has the positive intent and ability to hold to maturity are classified as “held-to-maturity” and recorded at amortized cost. Debt securities not classified as held-to-maturity or trading are classified as “available-for-sale” and recorded at fair value, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Equity securities are carried at fair value with changes in fair value recognized in current earnings. Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the investment securities, adjusted for the effect of actual prepayments in the case of mortgage-backed securities. Gains and losses on the sale of investment securities are recorded on the trade date and are determined using the specific identification method. Each reporting period, the Company evaluates all investment securities classified as available-for-sale or held-to-maturity, with a decline in fair value below the amortized cost of the investment to determine whether or not the impairment is deemed to be OTTI. Consideration is given to the obligor of the security, whether the security is guaranteed, whether there is a projected adverse change in cash flows, the liquidity of the security, the type of security, the capital position of security issuers, and payment history of the security, amongst other factors when evaluating these individual investment securities. OTTI is required to be recognized if (1) the Company intends to sell the security; (2) 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, the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the depreciation 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. Federal Home Loan Bank Stock As a member of the FHLB, the Company is required to invest in stock of the FHLB. Based on redemption provisions, the stock has no quoted market value and is carried at cost. Management evaluates the Company’s investment in the FHLB stock for OTTI at least on a quarterly basis and more frequently when economic or market conditions warrant such evaluation. Based on its most recent analysis of the FHLB as of December 31, 2018, management deems its investment in FHLB stock to not be other-than-temporarily impaired. Loans Held For Sale Loans purchased or transferred from held for investment, (if intent or ability to hold existing loans changes), and loans originated and intended for sale in the secondary market are carried at the lower of cost or estimated fair value, in the aggregate. Net unrealized losses, if any, are recognized through a valuation allowance by charges to income. Direct loan origination costs and fees are deferred upon origination and are recognized on the date of sale. Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off generally are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, any deferred fees or costs on originated loans and unamortized premiums on purchased loans. Interest income is accrued on the unpaid principal balance. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the expected term as an adjustment of the related loan yield using the interest method. The accrual of interest on all loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of collection. Past due status is based on contractual terms of the loan. In all cases, loans are placed on nonaccrual if collection of principal or interest is considered doubtful. All interest accrued but not collected for loans that are placed on nonaccrual is reversed against interest income. The interest on these loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual status. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Cash receipts of interest income on impaired loans are credited to principal to the extent necessary to eliminate doubt as to the collectability of the net carrying amount of the loan. Some or all of the cash receipts of interest income on impaired loans is recognized as interest income if the remaining net carrying amount of the loan is deemed to be fully collectible. When recognition of interest income on an impaired loan on a cash basis is appropriate, the amount of income that is recognized is limited to that which would have been accrued on the net carrying amount of the loan at the contractual interest rate. Any cash interest payments received in excess of the limit and not applied to reduce the net carrying amount of the loan are recorded as recoveries of charge-offs until the charge-offs are fully recovered. Allowance for Loan Losses The allowance for loan losses is established as losses are estimated to have occurred through a provision for loan losses charged to earnings. Loan losses are charged against the allowance for loan losses when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance for loan losses. The allowance for loan losses is evaluated on a regular basis by management. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance for loan losses consists of general, allocated and unallocated components, as further described below. General Component: The general component of the allowance for loan losses is based on historical loss experience adjusted for qualitative factors stratified by the following loan segments: residential real estate, home equity lines of credit, commercial real estate, multi-family real estate, construction, commercial, indirect auto and other consumer. Management uses a rolling average of historical losses based on a time frame appropriate to capture relevant loss data for each loan segment. This historical loss factor is adjusted for the following qualitative factors: levels/trends in delinquencies; trends in volume and terms of loans; effects of changes in risk selection and underwriting standards and other changes in lending policies, procedures and practices; experience/ability/depth of lending management and staff; and national and local economic trends and conditions. There were no changes in the Company’s policies or methodology pertaining to the general component of the allowance for loan losses during 2018 or 2017. However, during the year ended December 31, 2018, the Company determined that multi-family real estate loans should be evaluated separately from other commercial real estate loans as its own homogenous loan segment. Accordingly, the related prior year amounts have been reclassified to reflect this change. 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 real estate loans and home equity lines of credit – The Company generally does not originate or purchase loans with a loan-to-value ratio greater than 80 percent and does not grant subprime loans. Loans in this segment are generally collateralized by owner-occupied residential real estate and repayment is primarily dependent on the credit quality of the individual borrower and secondarily, liquidation of the collateral. 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 – Loans in this segment are primarily income-producing properties in eastern Massachusetts. The underlying cash flows generated by the properties are adversely impacted by a downturn in the economy as evidenced by increased vacancy rates, which in turn, will have an effect on the credit quality in this segment. Management generally performs on-site inspections, obtains rent rolls and leases annually and continually monitors the cash flows of these borrowers. Multi-family real estate loans - These loans are primarily secured by five or more unit residential properties. The underlying cash flows generated by the properties may be adversely impacted by a downturn in the economy and increased vacancy rates, which in turn, will have an effect on the credit quality in this segment. Management generally performs on-site inspections, obtains rent rolls annually and continually monitors the cash flows of these borrowers. Construction loans – Loans in this segment primarily include speculative real estate development loans for which payment is derived from sale and/or lease up of the property. Credit risk is affected by cost overruns, time to sell or lease at adequate prices, and market conditions. Commercial loans – Loans in this segment are made to businesses and are primarily secured by real estate and in some cases, other assets of the business. Repayment is expected from the cash flows of the business. A weakened economy, and resultant decreased consumer and business spending, will have an effect on the credit quality in this segment. Indirect auto loans – Loans in this segment are secured installment loans that are originated through a network of select regional automobile dealerships. The Company’s interest in the vehicle is secured with a recorded lien on the state title of each automobile. Collections are sensitive to changes in borrower financial circumstances, and the collateral can depreciate or be damaged in the event of repossession. Repayment is primarily dependent on the credit worthiness and the cash flow of the individual borrower and secondarily, liquidation of collateral. Consumer loans – Loans in this segment include secured and unsecured consumer loans including passbook loans, consumer lines of credit, overdraft protection and other consumer unsecured loans. Repayment is dependent on the credit quality and the cash flow of the individual borrower. Allocated Component: The allocated component relates to loans that are classified as impaired. 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. 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 troubled debt restructuring (“TDR”). All TDRs are classified as impaired and therefore are subject to a specific review for impairment. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate at the time of impairment or, as a practical expedient, at the loan’s observable market price or the fair value of the collateral if the loan is collateral-dependent. Generally, TDRs are measured for impairment using the discounted cash flow method except in instances where foreclosure is probable in which case the fair value of collateral method is used. Loans that have been classified as TDRs and which subsequently default are reviewed to determine if the loan should be deemed collateral dependent. In such an instance, any shortfall between the value of the collateral and the book value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. Generally, all other impaired loans are collateral dependent and impairment is measured through the collateral method. All loans on non-accrual status, with the exception of indirect auto and consumer loans, are considered to be impaired. When the measurement of the impaired loan is less than the recorded investment in the loan, the impairment is recorded through the allowance for loan losses. However, for collateral dependent loans, the amount of the recorded investment in a loan that exceeds the fair value of the collateral is charged-off against the allowance for loan losses in lieu of an allocation of a specific allowance amount when such an amount has been identified definitively as uncollectable. Unallocated Component: An unallocated component is maintained to cover uncertainties that could affect management’s estimate of incurred losses. The unallocated component of the allowance for loan losses reflects the margin of imprecision inherent in the underlying assumptions used in the methodologies for estimating allocated and general reserves in the portfolio. In the ordinary course of business, the Bank enters into commitments to extend credit, commercial letters of credit and standby letters of credit. Such financial instruments are recorded in the consolidated financial statements when they are funded or become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for loan losses. The reserve for off-balance sheet commitments is included in other liabilities in the consolidated balance sheet. At December 31, 2018 and 2017, the reserve for unfunded loan commitments was $16,000 and $36,000, respectively. The related provision for off-balance sheet credit losses is included in non-interest expense in the consolidated statement of operations. Premises and Equipment Land is carried at cost. Buildings and equipment are stated at cost, less accumulated depreciation, computed on the straight-line method over the estimated useful lives of the assets. It is general practice to charge the cost of maintenance and repairs to earnings when incurred; major expenditures for betterments are capitalized and depreciated over the shorter of the lease term for leasehold improvements or their estimated useful lives. The cost and related accumulated depreciation of assets sold, or otherwise disposed of, are removed from the related accounts and any gain or loss is included in earnings. Bank-owned Life Insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at cash surrender value. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income on the consolidated statements of operations and are generally not subject to income taxes. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. A life insurance policy with any individual carrier is limited to 15% of tier one capital and the total cash surrender value of life insurance policies is limited to 25% of tier one capital. Transfers and Servicing of Financial Assets Transfers of an entire financial asset, a group of entire financial assets, or a participating interest in an entire financial asset 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. During the normal course of business, the Company may transfer whole loans or a portion of a financial asset, such as a participation loan or the government guaranteed portion of a loan. In order to be eligible for sales treatment, the transfer of the portion of the loan must meet the criteria of a participating interest. If it does not meet the criteria of a participating interest, the transfer will be accounted for as a secured borrowing. In order to meet the criteria for a participating interest, 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 has the right to pledge or exchange the entire loan. The Company services mortgage and indirect auto loans for others. Loan servicing fee income is reported in the consolidated statements of operations as fees are earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal and are recorded as income when earned. Late fees and ancillary fees related to loan servicing are not material. Mortgage servicing rights (“MSR”) are initially recorded as an asset and measured at fair value when loans are sold to third parties with servicing rights retained. MSR assets are amortized in proportion to, and over the period of, estimated net servicing revenues. The carrying value of the MSR assets is periodically reviewed for impairment using the lower of amortized cost or fair value methodology. The fair value of the servicing rights is determined by estimating the present value of future net cash flows, taking into consideration market loan prepayment speeds, discount rates, servicing costs and other economic factors. For purposes of measuring impairment, the underlying loans are stratified into relatively homogeneous pools based on predominant risk characteristics which include product type (i.e., fixed or adjustable) and interest rate bands. If the aggregate carrying value of the capitalized MSR for a stratum exceeds its fair value, MSR impairment is recognized in earnings through a valuation allowance for the difference. As the loans are repaid and net servicing revenue is earned, the MSR asset is amortized as an offset to loan servicing income. Servicing revenues are expected to exceed this amortization expense. However, if actual prepayment experience or defaults exceed what was originally anticipated, net servicing revenues may be less than expected and MSR may be impaired. No servicing assets or liabilities related to auto loans were recorded, as the contractual servicing fees are adequate to compensate the Company for its servicing responsibilities. Other Real Estate Owned and Other Foreclosed Assets Assets acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value, less estimated costs to sell, at the date of foreclosure or when control is established, creating 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 cost to sell. Revenue and expenses from operations, changes in the valuation allowance and any direct write downs are included in other non-interest expense. The Company classifies commercial loans as in-substance repossessed or foreclosed if the Company receives physical possession of the debtor’s assets regardless of whether formal foreclosure proceedings take place. The Company classifies residential real estate loans as in-substance repossessed or foreclosed upon either obtaining legal title to the residential real estate property upon completion of a foreclosure or when the borrower conveys all interest in the property to the Company to satisfy the loan through a completion of a deed in lieu of foreclosure or through a similar legal agreement. Derivative Financial Instruments Derivative financial instruments (“Derivatives”) are carried at fair value in the Company’s consolidated financial statements. The accounting for changes in the fair value of derivatives is determined by whether each derivative has been designated and qualifies as part of a hedging relationship, and further, by the type of hedging relationship. At the inception of a hedge, the Company documents certain items, including but not limited to the following: the relationship between hedging instruments and hedged items, the Company’s risk management objectives, hedging strategies, and the evaluation of hedge transaction effectiveness. Documentation includes linking all derivatives designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific forecasted transactions. For those derivatives that are designated and qualify for special hedge accounting, the Company designates the hedging instrument, based upon the exposure being hedged, as either a fair value hedge or a cash flow hedge. For derivatives that are designated and qualify as a cash flow hedge (i.e., hedging the exposure to variability in expected future cash flows that is attributable to a particular risk), the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive income (loss), net of related tax, and reclassified into earnings in the same period or periods during which the hedged transactions affect earnings. The remaining gain or loss on the derivative in excess of the cumulative change in the present value of future cash flows of the hedged item (i.e., the ineffective portion), if any, is recognized in current earnings during the period. For derivatives designated and qualifying as a fair value hedge (i.e., hedging the exposure to changes in the fair value of an asset or liability or an identified portion thereof that is attributable to the hedged risk), the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item attributable to the hedged risk, are recognized in current earnings during the period of the change in fair values. Hedge accounting is discontinued prospectively when (1) a derivative is no longer highly effective in offsetting changes in the fair value or cash flow of a hedged item, (2) a derivative expires or is settled, (3) it is no longer likely that a forecasted transaction associated with the hedge will occur, or (4) it is determined that designation of a derivative as a hedge is no longer appropriate. For derivatives not designated as hedging instruments, such as loan level derivatives and risk participation agreements, changes in fair value are recognized in other noninterest income during the period of change. Advertising Costs Advertising costs are expensed as incurred and recorded within marketing expense. Belmont Savings Bank Supplemental Executive Retirement Plan The compensation cost of an employee’s retirement benefit is recognized on the projected unit credit method over the employee’s approximate service period. The aggregate cost method is utilized for funding purposes. The Company accounts for its supplemental executive retirement plan using an actuarial model that allocates benefit costs over the service period of employees 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 or loss. Other Supplemental Executive Retirement Plans The compensation cost of an employee’s retirement benefit is accrued over the estimated period of the employee’s service. At each measurement date, the aggregate amount accrued equals the then present value of the benefits expected to be provided to the employee in exchange for the employee’s service to that date. Employee Stock Ownership Plan Compensation expense for the Employee Stock Ownership Plan (“ESOP”) is recorded at an amount equal to the shares allocated by the ESOP multiplied by the average fair value of the shares during the period. The Company recognizes compensation expense ratably over the year based upon the Company’s estimate of the number of shares expected to be allocated by the ESOP. Unearned compensation applicable to the ESOP is reflected as a reduction of stockholders’ equity in the consolidated balance sheets. The difference between the average fair value and the cost of the shares allocated by the ESOP is recorded as an adjustment to additional paid-in capital. Stock Based Compensation The Company recognizes stock-based compensation based on the grant-date fair value of the award adjusted for expected forfeitures. The Company values share-based stock option awards granted using the Black-Scholes option-pricing model. The Company recognizes compensation expense for its awards on a straight-line basis over the requisite service period for the entire award (straight-line attribution method), ensuring that the amount of compensation cost recognized at any date at least equals the portion of the grant-date fair value of the award that is vested at that time. 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 bases 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 all available evidence, both positive and negative, it is determined that it is more likely than not that some or all of the deferred tax assets will not be realized. Fair Value Hierarchy The Company measures the fair values of its financial instruments in accordance with accounting guidance that requires an entity to base fair value on exit price, and maximize the use of observable inputs and minimize the use of unobservable inputs to determine the exit price. Under applicable accounting guidance, the Company categorizes its financial instruments, based on the priority of inputs to the valuation technique, into a three-level hierarchy, as described below. Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 - Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 - Inputs are unobservable inputs for the asset or liability. Transfers between levels are recognized at the end of a reporting period, if applicable. Earnings per Share (“EPS”) Basic earnings per share is calculated using the two-class method. The two-class method is an earnings allocation formula under which earnings per share is calculated from common stock and participating securities considering both dividends declared (or accumulated) and participation rights in undistributed earnings as if all such earnings had been distributed during the period. Under this method, all earnings distributed and undistributed, are allocated to participating securities and common shares based on their respective rights to receive dividends. Unvested share-based payment awards that contain nonforfeitable rights to dividends are considered participating securities (i.e. unvested restricted stock), not subject to performance based measures. Basic earnings per share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. Diluted earnings per s

RESTRICTIONS ON CASH AND AMOUNT

RESTRICTIONS ON CASH AND AMOUNTS DUE FROM BANKS	12 Months Ended
	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
RESTRICTIONS ON CASH AND AMOUNTS DUE FROM BANKS	NOTE 2 – RESTRICTIONS ON CASH AND AMOUNTS DUE FROM BANKS The Bank is required to maintain certain reserve requirements with the Federal Reserve Bank of Boston. The amount of this reserve requirement was $25.5 million and $25.2 million at December 31, 2018 and 2017, respectively.

INVESTMENT SECURITIES

INVESTMENT SECURITIES	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
INVESTMENT SECURITIES	NOTE 3 – INVESTMENT SECURITIES Debt securities have been classified in the consolidated balance sheets according to management’s intent. The following table presents a summary of the amortized cost, gross unrealized holding gains and losses and fair value of available-for-sale and held-to-maturity debt securities for the periods indicated. Gross unrealized holding gains and losses on available-for-sale securities are included in accumulated other comprehensive income (loss). December 31, 2018 December 31, 2017 Amortized Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: Corporate debt securities $ 4,162 $ — $ (122 ) $ 4,040 $ 16,975 $ 24 $ (78 ) $ 16,921 $ 4,162 $ — $ (122 ) $ 4,040 $ 16,975 $ 24 $ (78 ) $ 16,921 Held-to-maturity securities: U.S. government sponsored mortgage-backed securities $ 137,261 $ 227 $ (2,863 ) $ 134,625 $ 142,383 $ 145 $ (2,089 ) $ 140,439 Corporate debt securities 10,764 12 (32 ) 10,744 17,707 239 — 17,946 $ 148,025 $ 239 $ (2,895 ) $ 145,369 $ 160,090 $ 384 $ (2,089 ) $ 158,385 The amortized cost and estimated fair value of debt securities by contractual maturity at December 31, 2018 is as follows. 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. Available-for-Sale Held-to-Maturity Amortized Cost Basis Fair Value Amortized Cost Basis Fair Value Due within one year $ — $ — $ — $ — Due after one year through five years 4,162 4,040 23,073 22,719 Due after five years through ten years — — 18,803 18,246 Due after ten years — — 106,149 104,404 $ 4,162 $ 4,040 $ 148,025 $ 145,369 At December 31, 2018 and 2017, investment securities with a carrying value of $5.6 million were pledged to secure securities sold under agreements to repurchase. Investment securities with a carrying value of $40.5 million and $47.7 million were pledged to secure borrowings with the FHLB at December 31, 2018 and 2017, respectively, and investment securities with a carrying value of $8.8 million and $15.8 million were pledged to an available line of credit with the Federal Reserve Bank of Boston at December 31, 2018 and 2017, respectively. During the year ended December 31, 2017 proceeds from the sale of investment securities available for sale amounted to $5,038,000, resulting in realized gains of $38,000. There were no sales of investment securities available for sale during the years ending December 31, 2018 and 2016. In addition to the investment securities listed above, the Company holds investments in a Rabbi Trust that are used to fund the executive and director non-qualified deferred compensation plan. These investment securities are available to satisfy the claims of general creditors of the Company in the event of bankruptcy and are included in the consolidated balance sheets in other assets. These investment securities consisted primarily of cash and cash equivalents and mutual funds and recorded at fair value. The fair value of these investment securities at December 31, 2018 and 2017 was $2.8 million. For the years ended December 31, 2018 and 2017, the net (loss) gain on these investments still held at the reporting date was ($65,000) and $158,000, respectively. Refer to Note 15 – Employee Benefit Plans, for more information on the non-qualified deferred compensation plan. Information pertaining to investment securities with gross unrealized losses at December 31, 2018 and 2017, aggregated by investment category and length of time that individual investment securities have been in a continuous loss position, follows: Less than 12 Months 12 Months and Over # of Holdings Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2018: Available-for-sale Corporate debt securities 1 $ — $ — $ 4,040 $ (122 ) Held-to-maturity Corporate debt securities 4 7,820 (32 ) — — U.S. government sponsored mortgage-backed securities 97 11,421 (84 ) 103,597 (2,779 ) Total temporarily impaired securities 102 $ 19,241 $ (116 ) $ 107,637 $ (2,901 ) December 31, 2017: Available-for-sale Corporate debt securities 1 $ — $ — $ 4,144 $ (78 ) Held-to-maturity U.S. government sponsored mortgage-backed securities 81 64,056 (718 ) 62,798 (1,371 ) Total temporarily impaired securities 82 $ 64,056 $ (718 ) $ 66,942 $ (1,449 ) Management evaluates investment securities for other-than-temporary impairment at least on a quarterly basis, and more frequently when economic or market concerns warrant such evaluation. When there are investment securities in an unrealized loss position, consideration is given to (1) the length of time and the extent to which the fair value has been less than cost, (2) the financial condition and near-term prospects of the issuer, and (3) the intent and ability of the Company to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value. At December 31, 2018, 102 debt securities had unrealized losses with aggregate depreciation of 2.56% from the Company’s amortized cost basis. The Company’s unrealized losses on investments in corporate bonds and mortgage-backed securities are primarily caused by changes in market interest rates. The contractual terms of these investments do not permit the companies to settle the security at a price less than the par value of the investment. 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 the investments. Therefore, it is expected that the investment securities would not be settled at a price less than the par value of the investment. Because the Company does not intend to sell the investments and it is more likely than not that the Company will not be required to sell the investments before recovery of their amortized cost basis, it does not consider these investments to be other-than-temporarily impaired at December 31, 2018.

LOANS, ALLOWANCE FOR LOAN LOSSE

LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY	NOTE 4 – LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY A summary of the balances of loans follows: December 31, 2018 2017 Mortgage loans on real estate: Residential one-to-four family loans $ 1,583,000 $ 1,333,058 Commercial real estate loans 555,028 486,392 Multi-family real estate loans 203,657 155,680 Home equity lines of credit 163,199 178,624 Construction loans 50,480 53,045 Total real estate loans 2,555,364 2,206,799 Other loans: Commercial loans 62,462 63,722 Indirect auto loans 11,965 30,227 Consumer loans 418 435 74,845 94,384 Total loans 2,630,209 2,301,183 Net deferred loan costs 3,485 3,426 Net unamortized mortgage premiums 8,617 8,661 Allowance for loan losses (17,939 ) (16,312 ) Total loans, net $ 2,624,372 $ 2,296,958 The following tables present the activity in the allowance for loan losses for the years ended December 31, 2018, 2017 and 2016 and the balances of the allowance for loan losses and recorded investment in loans by portfolio class based on impairment method at December 31, 2018 and 2017. The recorded investment in loans in any of the following tables does not include accrued and unpaid interest or any deferred loan fees or costs, as amounts are not significant. Year Ended December 31, 2018 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 6,400 $ 1,034 $ — $ — $ 7,434 Commercial real estate 4,979 819 — — 5,798 Multi-family real estate 1,604 107 — — 1,711 Home equity lines of credit 947 (131 ) — — 816 Construction 764 (42 ) — — 722 Commercial 758 (75 ) (4 ) — 679 Indirect auto 230 (127 ) (32 ) 13 84 Other consumer 9 4 (11 ) 4 6 Unallocated 621 68 — — 689 Total $ 16,312 $ 1,657 $ (47 ) $ 17 $ 17,939 Year Ended December 31, 2017 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 4,828 $ 1,572 $ — $ — $ 6,400 Commercial real estate 3,676 1,303 — — 4,979 Multi-family real estate 1,209 395 — — 1,604 Home equity lines of credit 1,037 (90 ) — — 947 Construction 1,219 (455 ) — — 764 Commercial 728 30 — — 758 Indirect auto 362 (109 ) (45 ) 22 230 Other consumer 9 12 (14 ) 2 9 Unallocated 517 104 — — 621 Total $ 13,585 $ 2,762 $ (59 ) $ 24 $ 16,312 Year Ended December 31, 2016 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 3,574 $ 1,254 $ — $ — $ 4,828 Commercial real estate 3,495 181 — — 3,676 Multi-family real estate 983 226 — — 1,209 Home equity lines of credit 928 109 — — 1,037 Construction 801 418 — — 1,219 Commercial 613 115 — — 728 Indirect auto 623 (232 ) (85 ) 56 362 Other consumer 10 10 (16 ) 5 9 Unallocated 213 304 — — 517 Total $ 11,240 $ 2,385 $ (101 ) $ 61 $ 13,585 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Total Loan Balance Allowance Loan Balance Allowance Loan Balance Allowance Residential one-to-four family $ 2,545 $ 5 $ 1,580,455 $ 7,429 $ 1,583,000 $ 7,434 Commercial real estate 2,820 — 552,208 5,798 555,028 5,798 Multi-family real estate — — 203,657 1,711 203,657 1,711 Home equity lines of credit — — 163,199 816 163,199 816 Construction — — 50,480 722 50,480 722 Commercial — — 62,462 679 62,462 679 Indirect auto 11 — 11,954 84 11,965 84 Other consumer — — 418 6 418 6 Unallocated — — — 689 — 689 Total $ 5,376 $ 5 $ 2,624,833 $ 17,934 $ 2,630,209 $ 17,939 December 31, 2017 Individually evaluated for impairment Collectively evaluated for impairment Total Loan Balance Allowance Loan Balance Allowance Loan Balance Allowance Residential one-to-four family $ 2,688 $ 147 $ 1,330,370 $ 6,253 $ 1,333,058 $ 6,400 Commercial real estate 2,877 — 483,515 4,979 486,392 4,979 Multi-family real estate — — 155,680 1,604 155,680 1,604 Home equity lines of credit — — 178,624 947 178,624 947 Construction — — 53,045 764 53,045 764 Commercial — — 63,722 758 63,722 758 Indirect auto 4 — 30,223 230 30,227 230 Other consumer — — 435 9 435 9 Unallocated — — — 621 — 621 Total $ 5,569 $ 147 $ 2,295,614 $ 16,165 $ 2,301,183 $ 16,312 Information about loans that meet the definition of an impaired loan in ASC 310-10-35 is as follows as of December 31, 2018 and 2017: Impaired loans with a related allowance for credit losses at December 31, 2018 Unpaid Related Recorded Principal Allowance For Investment Balance Credit Losses Residential one-to-four family $ 192 $ 192 $ 5 Totals $ 192 $ 192 $ 5 Impaired loans with no related allowance for credit losses at December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 2,353 $ 2,476 $ — Commercial real estate 2,820 2,820 — Indirect auto 11 11 — Totals $ 5,184 $ 5,307 $ — Impaired loans with a related allowance for credit losses at December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 725 $ 725 $ 147 Totals $ 725 $ 725 $ 147 Impaired loans with no related allowance for credit losses at December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 1,963 $ 2,052 $ — Commercial real estate 2,877 2,877 — Indirect auto 4 4 — Totals $ 4,844 $ 4,933 $ — The following tables set forth information regarding interest income recognized on impaired loans, by portfolio, for the periods indicated. Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016 With an allowance recorded Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Residential one-to-four family $ 238 $ 11 $ 897 $ 32 $ 1,273 $ 33 Commercial real estate — — — — 3,124 136 Totals $ 238 $ 11 $ 897 $ 32 $ 4,397 $ 169 Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016 Without an allowance recorded Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Residential one-to-four family $ 2,074 $ 50 $ 1,986 $ 94 $ 2,977 $ 78 Commercial real estate 2,848 123 3,159 140 784 34 Home equity lines of credit 8 — 106 13 200 8 Indirect auto 7 — 6 — 12 — Totals $ 4,937 $ 173 $ 5,257 $ 247 $ 3,973 $ 120 At December 31, 2018, there were no additional funds committed to be advanced in connection with loans to borrowers with impaired loans. The following is a summary of past due and non-accrual loans at December 31, 2018 and 2017: December 31, 2018 30–59 Days 60–89 Days 90 Days or More Total Past Due 90 days or more and accruing Loans on Non-accrual Real estate loans: Residential one-to-four family $ 438 $ 239 $ 721 $ 1,398 $ — $ 1,159 Home equity lines of credit 214 — — 214 — — Other loans: Indirect auto 189 33 11 233 — 11 $ 841 $ 272 $ 732 $ 1,845 $ — $ 1,170 December 31, 2017 30–59 Days 60–89 Days 90 Days or More Total Past Due 90 days or more and accruing Loans on Non-accrual Real estate loans: Residential one-to-four family $ 711 $ — $ 260 $ 971 $ — $ 1,372 Home equity lines of credit 716 — — 716 — — Other loans: Indirect auto 347 30 4 381 — 4 $ 1,774 $ 30 $ 264 $ 2,068 $ — $ 1,376 Credit Quality Information The Company utilizes a nine grade internal loan rating system for commercial real estate, multi-family, construction and commercial loans, and a five grade internal loan rating system for certain residential real estate, home equity and consumer loans that are rated if the loans become delinquent, impaired or are restructured as a TDR. Loans rated 1, 2, 2.5, 3 and 3.5: Loans in these categories are considered “pass” rated loans with low to average risk. Loans rated 4: Loans in this category are considered “special mention.” These loans are starting to show signs of potential weakness and are being closely monitored by management. Loans rated 5: Loans in this category are considered “substandard.” Generally, a loan is considered substandard if it is 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: Loans in this category are considered “doubtful.” Loans classified as doubtful 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: Loans in this category are considered “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, multi-family, construction and commercial loans. On an annual basis, the Company engages an independent third party to review a significant portion of loans within these segments and to assess the credit risk management practices of the Company’s commercial lending department. Management uses the results of these reviews as part of its annual review process and overall credit risk administration. On a quarterly basis, the Company formally reviews the ratings on all residential real estate and home equity loans if they have become delinquent. Criteria used to determine ratings consist of loan-to-value ratios and days delinquent. The following table presents the Company’s loans by risk rating at December 31, 2018 and 2017. There were no loans rated as 6 (“doubtful”) or 7 (“loss”) at the dates indicated. December 31, 2018 Loans rated 1-3.5 Loans rated 4 Loans rated 5 Loans not rated (A) Total Residential one-to-four family $ — $ 335 $ 1,832 $ 1,580,833 $ 1,583,000 Commercial real estate 551,327 — 3,701 — 555,028 Multi-family real estate 203,657 — — — 203,657 Construction 50,480 — — — 50,480 Commercial 62,462 — — — 62,462 Home equity lines of credit — — — 163,199 163,199 Indirect auto — — — 11,965 11,965 Other consumer — — — 418 418 Total $ 867,926 $ 335 $ 5,533 $ 1,756,415 $ 2,630,209 December 31, 2017 Loans rated 1-3.5 Loans rated 4 Loans rated 5 Loans not rated (A) Total Residential one-to-four family $ — $ 344 $ 2,060 $ 1,330,654 $ 1,333,058 Commercial real estate 482,574 — 3,818 — 486,392 Multi-family real estate 155,680 — — — 155,680 Construction 53,045 — — — 53,045 Commercial 63,682 40 — — 63,722 Home equity lines of credit — — 772 177,852 178,624 Indirect auto — — — 30,227 30,227 Other consumer — — — 435 435 Total $ 754,981 $ 384 $ 6,650 $ 1,539,168 $ 2,301,183 (A) Residential one-to-four family real estate and home equity lines of credit are not formally risk rated by the Company unless the loans become delinquent, impaired or are restructured as a TDR. Indirect auto loans and other consumer loans are not formally risk rated by the Company. The Company periodically modifies loans to extend the term, reduce the interest rate or make other concessions to help a borrower stay current on their loan and to avoid foreclosure. The Company generally does not forgive principal or interest on loans or modify the interest rates on loans to those not otherwise available in the market. Any loans that are modified are reviewed by the Company to determine if a TDR has occurred, which is when, for economic or legal reasons related to a borrower’s financial difficulties, the Company grants a concession to the borrower that it would not otherwise consider. During the year ended December 31, 2018, no loans were modified and determined to be TDRs. During the year ended December 31, 2017, no loans were modified and determined to be TDRs and one existing TDR was modified again to extend the maturity. The following table shows the Company’s total TDRs and other pertinent information as of the dates indicated: December 31, 2018 December 31, 2017 TDRs on Accrual Status $ 4,206 $ 4,194 TDRs on Non-accrual Status — 645 Total TDRs $ 4,206 $ 4,839 Amount of specific allocation included in the allowance for loan losses associated with TDRs $ 5 $ 147 Additional commitments to lend to a borrower who has been a party to a TDR $ — $ — The following table shows the TDR modifications which occurred during the years ended December 31, 2017 and 2016 and the outstanding recorded investment subsequent to the modifications occurring: Year Ended December 31, 2017 # of Contracts Pre-modification outstanding recorded investment Post-modification outstanding recorded investment (a) Real estate loans: Commercial real estate 1 $ 273 $ 273 1 $ 273 $ 273 Year Ended December 31, 2016 # of Contracts Pre-modification outstanding recorded investment Post-modification outstanding recorded investment (a) Real estate loans: Residential one-to-four family 1 $ 621 $ 699 Commercial real estate 3 3,394 3,394 4 $ 4,015 $ 4,093 (a) The post-modification balances represent the balance of the loan on the date of the modifications. These amounts may show an increase when the modifications include a capitalization of interest or taxes. The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the years indicated: For the Years Ended December 31, 2017 December 31, 2016 Capitalization of interest, taxes and extended maturity $ — $ 699 Extended maturity 273 3,394 Total $ 273 $ 4,093 For purposes of the following table the Company generally considers a loan to have defaulted when it reaches 90 days past due. The following table shows the loans that have been modified during the past twelve months which have subsequently defaulted during the periods indicated: For the years ended December 31, 2018 2017 2016 Number of Contracts Recorded Investment Number of Contracts Recorded Investment Number of Contracts Recorded Investment TDRs that subsequently defaulted Residential one-to-four family — $ — — $ — 1 $ 497 Totals — $ — — $ — 1 $ 497 Foreclosure Proceedings Consumer mortgage loans collateralized by residential real estate property that are in the process of foreclosure totaled $253,000 and $0 as of December 31, 2018 and December 31, 2017, respectively. The Company did not have any foreclosed residential real estate property held as of December 31, 2018 or December 31, 2017. Pledged Loans At December 31, 2018 and 2017, $1.9 billion and $1.4 billion in loans, respectively, were pledged to secure FHLB advances.

TRANSFERS AND SERVICING

TRANSFERS AND SERVICING	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
TRANSFERS AND SERVICING	NOTE 5 – TRANSFERS AND SERVICING Certain residential mortgage loans are periodically sold by the Company to the secondary market. Generally, these loans are sold without recourse or other credit enhancements. The Company sells loans and both releases and retains the servicing rights. For loans sold with servicing rights retained, the Company provides the servicing for the loans on a per-loan fee basis. The Company has also periodically sold auto loans to other financial institutions without recourse or other credit enhancements, and the Company generally provides servicing for these loans. Mortgage loans sold for cash during the years ended December 31, 2018, 2017 and 2016 were $53.7 million, $70.5 million and $11.4 million, respectively, with net gains recognized in non-interest income of $756,000, $936,000 and $271,000, respectively. No auto loans were sold for cash during the years ended December 31, 2018, 2017 and 2016. At December 31, 2018 and 2017, residential mortgage loans previously sold and serviced by the Company were $142.8 million and $114.5 million, respectively. At December 31, 2018 and 2017, auto loans previously sold and serviced by the Company were $2.9 million and $10.5 million, respectively. There were no liabilities incurred during the years ended December 31, 2018 and 2017 in connection with these loan sales. Changes in mortgage servicing rights, which are included in other assets, were as follows, during the periods indicated: Years Ended December 31, 2018 2017 2016 Balance at beginning of period $ 855 $ 403 $ 479 Capitalization 402 508 85 Amortization (205 ) (130 ) (101 ) Valuation allowance adjustment 50 74 (60 ) Balance at end of period $ 1,102 $ 855 $ 403 As of December 31, 2018 and 2017, the fair value of mortgage servicing rights approximated carrying value.

PREMISES AND EQUIPMENT

PREMISES AND EQUIPMENT	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
PREMISES AND EQUIPMENT	NOTE 6 – PREMISES AND EQUIPMENT A summary of the cost and accumulated depreciation of premises and equipment follows: December 31, 2018 2017 Land $ 161 $ 161 Buildings 3,516 3,516 Leasehold improvements 1,414 1,414 Furniture and equipment 4,736 4,350 9,827 9,441 Accumulated depreciation (7,650 ) (7,187 ) $ 2,177 $ 2,254 Depreciation and amortization expense for the years ended December 31, 2018, 2017 and 2016 amounted to $590,000, $595,000 and $621,000, respectively. During the year ended December 31, 2018, the Company sold equipment with a net book value of $14,000 and recognized a gain on sale of $11,000. During the years ended December 31, 2018, 2017 and 2016, the Company determined that certain assets had no future economic benefit to the Company and recorded impairment charges of $3,000, $18,000, and $16,000, respectively, within equipment expense on the consolidated statements of operations. During the year ended December 31, 2016, the Company disposed of assets with an original cost of $3.5 million that were fully depreciated and no longer in use. No gain or loss was recognized as a result of this disposal.

DEPOSITS

DEPOSITS	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
DEPOSITS	NOTE 7 – DEPOSITS The aggregate amount of time deposits in denominations that meet or exceed the FDIC insurance limit of $250,000 at December 31, 2018 and 2017 was $216.1 million and $128.7 million, respectively. At December 31, 2018, the scheduled maturities of time deposits are as follows: 2019 $ 418,035 2020 165,487 2021 63,731 2022 38,984 2023 73,030 $ 759,267 Included in time deposits are brokered deposits of $288.6 million and $247.2 million at December 31, 2018 and 2017, respectively. The amounts of overdraft deposits that were reclassified to loans at December 31, 2018 and 2017 were $43,000 and $48,000, respectively. Related Party Deposits Deposit accounts of directors, executive officers and their affiliates totaled $17.7 million and $8.5 million at December 31, 2018 and 2017, respectively. Secured Deposits The Bank has an Irrevocable Letter of Credit Reimbursement Agreement with the FHLB, whereby upon the Bank’s request, an irrevocable letter of credit is issued to secure public unit deposit accounts. These letters of credit are secured by a blanket security agreement on qualified collateral, principally mortgage loans, home equity lines of credit, commercial loans and U.S. government sponsored mortgage-backed securities in an aggregate amount equal to outstanding letters of credit. The amount of funds available to the Bank through the FHLB is reduced by any letters of credit outstanding. At December 31, 2018 and 2017, there were $194.5 million and $5.0 million of letters of credit outstanding, respectively.

SHORT-TERM BORROWINGS

SHORT-TERM BORROWINGS	12 Months Ended
	Dec. 31, 2018
Disclosure Text Block [Abstract]
SHORT-TERM BORROWINGS	NOTE 8 – SHORT-TERM BORROWINGS Federal Home Loan Bank Advances Fixed rate FHLB advances with an original maturity of less than one year, amounted to $383.0 million and $305.9 million at December 31, 2018 and 2017, respectively, at a weighted average rate of 2.64% and 1.52%, respectively. The Bank also has an available line of credit with the FHLB in the amount of $5.6 million at December 31, 2018 and 2017 at an interest rate that adjusts daily. All borrowings from the FHLB are secured by a blanket security agreement on qualified collateral, principally mortgage loans, home equity lines of credit, commercial loans and U.S. government sponsored mortgage-backed securities in an aggregate amount equal to outstanding advances. The Bank’s unused remaining available borrowing capacity at the FHLB was approximately $270.6 million and $279.2 million at December 31, 2018 and 2017, respectively. At December 31, 2018 and 2017, the Bank had sufficient collateral at the FHLB to support its obligations and was in compliance with the FHLB’s collateral pledging program. Securities Sold Under Agreements to Repurchase Securities sold under agreements to repurchase amounted to $2.9 million and $3.3 million at December 31, 2018 and 2017, respectively, mature on a daily basis and are secured by U.S. government sponsored mortgage-backed securities. The weighted average interest rate on these agreements was 0.15% at December 31, 2018 and 2017. The obligations to repurchase the securities sold are reflected as a liability in the consolidated balance sheets. The dollar amounts of the securities underlying the agreements remain in the asset accounts. The repurchase agreements stipulate that the securities are not delivered to the customer and instead are held in segregated safekeeping accounts maintained by the Company’s safekeeping agent.

LONG-TERM BORROWINGS

LONG-TERM BORROWINGS	12 Months Ended
	Dec. 31, 2018
Disclosure Text Block [Abstract]
LONG-TERM BORROWINGS	NOTE 9 – LONG-TERM BORROWINGS Long-term debt at December 31, 2018 and 2017 consists of the following fixed rate FHLB advances: Amount Weighted Average Rate 2018 2017 2018 2017 Fixed rate advances maturing: 2018 $ — $ 47,000 — % 1.63 % 2019 225,250 225,250 1.49 % 1.49 % 2020 35,000 35,000 1.76 % 1.76 % 2021 15,000 15,000 2.03 % 2.03 % 2022 110,000 95,000 2.27 % 2.17 % 2023 70,000 — 3.04 % — % $ 455,250 $ 417,250 1.96 % 1.70 %

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	NOTE 10 – INCOME TAXES Allocation of federal and state income taxes between current and deferred portions is as follows: Years Ended December 31, 2018 2017 2016 Current tax provision: Federal $ 6,215 $ 7,386 $ 7,212 State 2,809 1,961 1,954 9,024 9,347 9,166 Deferred tax expense (benefit): Federal (335 ) (71 ) (1,391 ) State (157 ) (20 ) (350 ) Effect of change in statutory federal tax rate — 2,626 — (492 ) 2,535 (1,741 ) Total provision for income taxes $ 8,532 $ 11,882 $ 7,425 The reasons for the differences between the statutory federal income tax rate and the effective tax rates are summarized as follows: Years Ended December 31, 2018 2017 2016 Statutory federal tax rate 21.0 % 35.0 % 35.0 % Increase (decrease) resulting from: State taxes, net of federal tax benefit 6.7 4.8 5.4 Bank-owned life insurance (1.0 ) (1.5 ) (1.9 ) Tax exempt income (0.3 ) (0.6 ) (0.8 ) Change in statutory federal tax rate — 10.0 — Share based compensation (0.5 ) (3.5 ) 1.2 Non-deductible merger expenses 1.1 — — Other, net 0.1 1.0 (0.6 ) Effective tax rates 27.1 % 45.2 % 38.3 % The components of the net deferred tax asset are as follows: December 31, 2018 2017 Deferred tax assets: Employee benefit and deferred compensation plans $ 2,428 $ 2,375 Allowance for loan losses 5,047 4,596 Accrued rent 7 8 Interest on non-performing loans 35 34 Stock options 313 356 Unrealized loss on securities available for sale 34 15 Cash flow hedge 499 — ESOP 104 92 Gross deferred tax assets 8,467 7,476 Deferred tax liabilities: Mortgage servicing rights (310 ) (240 ) Deferred loan origination costs (948 ) (860 ) Restricted stock awards (203 ) (280 ) Depreciation (142 ) (201 ) Unrecognized retirement benefit (69 ) (58 ) Other (2 ) (43 ) Gross deferred tax liabilities (1,674 ) (1,682 ) Net deferred tax asset $ 6,793 $ 5,794 The Company does not have any uncertain tax positions at December 31, 2018 or 2017 which require accrual or disclosure. The Company records interest and penalties as part of income tax expense. No interest or penalties were recorded for the years ended December 31, 2018, 2017 and 2016. 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, 2015 through 2018. The years open to examination by state taxing authorities vary by jurisdiction; no years prior to 2015 are open. In prior years, the Company was allowed a special tax-basis bad debt deduction under certain provisions of the Internal Revenue Code. As a result, retained earnings of the Company as of December 31, 2018 and 2017 includes approximately $3.6 million for which federal and state income taxes have not been provided. If the Company no longer qualifies as a bank as defined in certain provisions of the Internal Revenue Code, this amount will be subject to recapture in taxable income ratably over four (4) years, subject to a combined federal and state tax rate of approximately 28%. The Tax Cuts and Jobs Act. The Tax Cuts and Jobs Act was enacted on December 22, 2017. Among other things, the new law (i) establishes a new, flat corporate federal statutory income tax rate of 21%, (ii) eliminates the corporate alternative minimum tax and allows the use of any such carryforwards to offset regular tax liability for any taxable year, (iii) limits the deduction for net interest expense incurred by U.S. corporations, (iv) allows businesses to immediately expense, for tax purposes, the cost of new investments in certain qualified depreciable assets, (v) eliminates or reduces certain deductions related to meals and entertainment expenses, (vi) modifies the limitation on excessive employee remuneration to eliminate the exception for performance-based compensation and clarifies the definition of a covered employee and (vii) limits the deductibility of deposit insurance premiums. The Tax Cuts and Jobs Act also significantly changes U.S. tax law related to foreign operations, however, such changes do not currently impact the Company. As stated above, as a result of the enactment of the Tax Cuts and Jobs Act on December 22, 2017, the Company remeasured its deferred tax assets and liabilities based upon the newly enacted U.S. statutory federal income tax rate of 21%, which is the tax rate at which these assets and liabilities are expected to reverse in the future. As a result, the Company recorded a one-time charge of $2.63 million, recorded within income tax expense, during the year ended December 31, 2017.

OFF-BALANCE SHEET ARRANGEMENTS

OFF-BALANCE SHEET ARRANGEMENTS	12 Months Ended
	Dec. 31, 2018
Off Balance Sheet Arrangements [Abstract]
OFF-BALANCE SHEET ARRANGEMENTS	NOTE 11 – OFF-BALANCE SHEET ARRANGEMENTS Credit-Related Financial Instruments The Company is a party to credit related 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 grant and purchase loans, commitments under lines of credit, commitments under construction loans and standby letters of credit. Such commitments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The Company minimizes its exposure to loss under these commitments by subjecting them to credit approval and monitoring procedures. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. The Company follows the same credit policies in making commitments as it does for on-balance sheet financial instruments. At December 31, 2018 and 2017, the following financial instruments were outstanding whose contract amounts represent credit risk: Contract Amount 2018 2017 Commitments to grant loans $ 10,189 $ 23,702 Unfunded commitments under lines of credit 339,360 325,768 Unadvanced portion of construction loans 72,375 11,486 Standby letters of credit 869 561 Commitments to purchase loans 31,494 65,692 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 home equity and commercial lines of credit may expire without being drawn upon. Therefore, the total commitment amounts do not necessarily represent future cash requirements. The amount of collateral obtained, if it is deemed necessary by the Company, is based on management’s credit evaluation of the customer. Unfunded commitments under revolving credit lines and overdraft protection agreements are commitments for possible future extensions of credit to existing customers. These lines of credit are uncollateralized and usually do not contain a specified maturity date and ultimately may not be drawn upon to the total extent to which the Company is committed. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. Those letters of credit are primarily issued to support public and private borrowing arrangements. Essentially all letters of credit issued have expiration dates within one year. The credit risk involved in issuing letters of credit is essentially the same as that involved in extending loan facilities to customers. The Company generally holds collateral supporting those commitments. Commitments to purchase loans are conditional commitments issued by the Company to purchase loans through select correspondent mortgage companies who originate and sell loans as part of their operations. Typically the commitment to purchase is valid as long as there is no violation of any condition established in the correspondent contract. Commitments generally have fixed expiration dates or other termination clauses and generally do not require payment of a fee.

COMMITMENTS AND CONTINGENT LIAB

COMMITMENTS AND CONTINGENT LIABILITIES	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	NOTE 12 – COMMITMENTS AND CONTINGENT LIABILITIES Pursuant to the terms of noncancelable lease agreements in effect at December 31, 2018, pertaining to banking premises and equipment, future minimum rent commitments under various operating leases are as follows: 2019 $ 360 2020 266 2021 122 2022 122 2023 78 Thereafter 44 $ 992 Certain leases contain provisions for escalation of minimum lease payments contingent upon increases in real estate taxes and percentage increases in the consumer price index. Also, certain leases contain options to extend for periods from one to ten years. The cost of such rentals is not included above. Total rent expense for the years ended December 31, 2018, 2017 and 2016 amounted to $362,000, $363,000 and $348,000, respectively. If the merger agreement with People’s United is terminated under certain circumstances, the Company may be required to pay to People’s United a termination fee equal to $12.5 million.

LEGAL CONTINGENCIES

LEGAL CONTINGENCIES	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Legal Matters and Contingencies [Text Block]	NOTE 13 – LEGAL CONTINGENCIES In the normal course of business, there are various outstanding legal proceedings. In the opinion of management, after consulting with legal counsel, the consolidated financial position and results of operations of the Company are not expected to be affected materially by the outcome of such proceedings. Subsequent to December 31, 2018, the Company was notified about two complaints that were filed with respect to the proposed merger with Peoples United one of which filed for voluntary dismissal without prejudice on March 6, 2019. However, while these complaints have been filed with the courts, as of the time of filing of this Annual Report on Form 10-K none of the defendants named in the complaints, including the Company, had been served with either complaint. The Company’s stockholders approved the proposed merger at the February 27, 2019 special meeting. The Company believes that the allegations in the above complaints are without merit and, if served, intends to defend against them vigorously. Currently, however, it is not possible to predict the outcome of the litigation, if any, or the impact the litigation may have on the Company, People’s United, or the Proposed Merger.

MINIMUM REGULATORY CAPITAL REQU

MINIMUM REGULATORY CAPITAL REQUIREMENTS	12 Months Ended
	Dec. 31, 2018
MINIMUM REGULATORY CAPITAL REQUIREMENTS	NOTE 14 – MINIMUM REGULATORY CAPITAL REQUIREMENTS The Company’s primary source of cash is dividends from the Bank. The Bank is subject to certain restrictions on the amount of dividends that it may declare without prior regulatory approval. In addition, the dividends declared cannot be in excess of the amount which would cause the Bank to fall below the minimum required for capital adequacy purposes. The Company (on a consolidated basis) and the Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s and Bank’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and the Bank must meet specific capital guidelines that involve quantitative measures of their assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. The capital amounts and classifications are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Prompt corrective action provisions are not applicable to bank holding companies. On July 2, 2013, the Federal Reserve Bank (“FRB”) approved the final rules implementing the Basel Committee on Banking Supervision’s capital guidelines for U.S. banks (“Basel III Capital Rules”). On July 9, 2013, the FDIC also approved, as an interim final rule, the regulatory capital requirements for U.S. banks, following the actions of the FRB. On April 8, 2014, the FDIC adopted as final its interim final rule, which is identical in substance to the final rules issued by the FRB in July 2013. Under the final rules, minimum requirements increased for both the quantity and quality of capital held by the Bank. The rules include a new Common Equity Tier 1 capital risk-weighted assets minimum ratio of 4.5%, raise the minimum ratio of Tier 1 capital to risk-weighted assets from 4.0% to 6.0%, require a minimum ratio of Total capital to risk-weighted assets of 8.0%, and require a minimum Tier 1 leverage ratio of 4.0%. The Basel III Capital Rules became effective for the Company and the Bank on January 1, 2015 (subject to a phase-in period for the capital conservation buffer discussed below). Quantitative measures established by the Basel III Capital Rules to ensure capital adequacy require the maintenance of minimum amounts and ratios (set forth in the table below) of Common Equity Tier 1 capital, Tier 1 capital and Total capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital to adjusted quarterly average assets (as defined). Effective January 1, 2019, the Basel III Capital Rules require the Company and the Bank to maintain (i) a minimum ratio of Common Equity Tier 1 capital to risk-weighted assets of at least 4.5%, plus a 2.5% “capital conservation buffer” (which is added to the 4.5% Common Equity Tier 1 capital ratio as that buffer is phased in, effectively resulting in a minimum ratio of Common Equity Tier 1 capital to risk-weighted assets of at least 7.0% upon full implementation), (ii) a minimum ratio of Tier 1 capital to risk-weighted assets of at least 6.0%, plus the capital conservation buffer (which is added to the 6.0% Tier 1 capital ratio as that buffer is phased in, effectively resulting in a minimum Tier 1 capital ratio of 8.5% upon full implementation), (iii) a minimum ratio of Total capital (that is, Tier 1 plus Tier 2) to risk-weighted assets of at least 8.0%, plus the capital conservation buffer (which is added to the 8.0% total capital ratio as that buffer is phased in, effectively resulting in a minimum total capital ratio of 10.5% upon full implementation) and (iv) a minimum leverage ratio of 4.0%, calculated as the ratio of Tier 1 capital to average quarterly assets. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and will be phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reached 2.5% on January 1, 2019). The capital conservation buffer is designed to absorb losses during periods of economic stress and, as detailed above, effectively increases the minimum required risk-weighted capital ratios. Banking institutions with a ratio of Common Equity Tier 1 capital to risk-weighted assets below the effective minimum (4.5% plus the capital conservation buffer) will face constraints on dividends, equity repurchases and compensation based on the amount of the shortfall. Management believes, as of December 31, 2018 and 2017, that the Company and the Bank meet all capital adequacy requirements to which they are subject. As of December 31, 2018, 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, an institution must maintain minimum Total risk-based, Tier 1 risk-based, Common Equity Tier 1 risk-based 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 following table presents actual and required capital ratios as of December 31, 2018 and December 31, 2017 for the Company and the Bank under the Basel III Capital Rules. The minimum required capital amounts presented include the minimum required capital levels as of December 31, 2018 and December 31, 2017 based on the phase-in provisions of the Basel III Capital Rules and the minimum required capital levels as of January 1, 2019 when the Basel III Capital Rules become fully phased-in. Capital levels required to be considered well-capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. Minimum Capital Required Minimum Capital Required Minimum To Be Well Minimum Capital For Capital Adequacy Plus For Capital Adequacy Plus Capitalized Under Required For Capital Conservation Buffer Capital Conservation Buffer Prompt Corrective Actual Capital Adequacy Basel III Phase-In Schedule Basel III Fully Phased In Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio As of December 31, 2018: Total Capital (to Risk Weighted Assets) Consolidated $ 220,938 11.75 % $ 150,424 8.00 % $ 185,680 9.875 % $ 197,431 10.50 % N/A N/A Belmont Savings Bank 215,460 11.46 % 150,436 8.00 % 185,695 9.875 % 197,448 10.50 % $ 188,045 10.00 % Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 202,983 10.80 % $ 112,818 6.00 % $ 148,074 7.875 % $ 159,825 8.50 % N/A N/A Belmont Savings Bank 197,505 10.50 % 112,827 6.00 % 148,086 7.875 % 159,839 8.50 % $ 150,436 8.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 202,983 10.80 % $ 84,613 4.50 % $ 119,869 6.375 % $ 131,621 7.00 % N/A N/A Belmont Savings Bank 197,505 10.50 % 84,620 4.50 % 119,879 6.375 % 131,632 7.00 % $ 122,229 6.50 % Tier 1 Capital (to Average Assets) Consolidated $ 202,983 6.97 % $ 116,553 4.00 % $ 116,553 4.00 % $ 116,553 4.00 % N/A N/A Belmont Savings Bank 197,505 6.78 % 116,553 4.00 % 116,553 4.00 % 116,553 4.00 % $ 145,692 5.00 % Minimum Capital Required Minimum Capital Required Minimum To Be Well Minimum Capital For Capital Adequacy Plus For Capital Adequacy Plus Capitalized Under Required For Capital Conservation Buffer Capital Conservation Buffer Prompt Corrective Actual Capital Adequacy Basel III Phase-In Schedule Basel III Fully Phased In Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio As of December 31, 2017: Total Capital (to Risk Weighted Assets) Consolidated $ 194,287 11.30 % $ 137,498 8.00 % $ 158,982 9.25 % $ 180,466 10.50 % N/A N/A Belmont Savings Bank 189,311 11.01 % 137,497 8.00 % 158,981 9.25 % 180,465 10.50 % $ 171,871 10.00 % Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 177,939 10.35 % $ 103,123 6.00 % $ 124,607 7.25 % $ 146,092 8.50 % N/A N/A Belmont Savings Bank 172,963 10.06 % 103,123 6.00 % 124,607 7.25 % 146,091 8.50 % $ 137,497 8.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 177,939 10.35 % $ 77,343 4.50 % $ 98,827 5.75 % $ 120,311 7.00 % N/A N/A Belmont Savings Bank 172,963 10.06 % 77,342 4.50 % 98,826 5.75 % 120,310 7.00 % $ 111,716 6.50 % Tier 1 Capital (to Average Assets) Consolidated $ 177,939 6.97 % $ 102,148 4.00 % $ 102,148 4.00 % $ 102,148 4.00 % N/A N/A Belmont Savings Bank 172,963 6.77 % 102,147 4.00 % 102,147 4.00 % 102,147 4.00 % $ 127,683 5.00 % Stock Repurchase Plans. From time to time, the Company’s Board of Directors has authorized stock repurchase plans. In general, stock repurchase plans allow the Company to proactively manage its capital position and return excess capital to shareholders. As of December 31, 2018 and December 31, 2017, the Company had an active stock repurchase plan to repurchase up to 500,000 shares of the Company’s common stock. During the years ended December 31, 2018, 2017 and 2016 no shares were repurchased under the repurchase plan.

EMPLOYEE BENEFIT PLANS

EMPLOYEE BENEFIT PLANS	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
EMPLOYEE BENEFIT PLANS	NOTE 15 – EMPLOYEE BENEFIT PLANS Belmont Savings Bank Supplemental Executive Retirement Plan Effective October 1, 2010, the Company established the Belmont Savings Bank Supplemental Executive Retirement Plan (the “Plan”). The purpose of the Plan is to remain competitive with our peers in our compensation arrangements and to help us retain certain executive officers of the Company. At December 31, 2018 and 2017, there were four participants in the Plan. Participants are fully vested after the completion of between five and ten years of service. The plan is unfunded. Information pertaining to the activity in the plan is as follows: Years Ended December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 1,798 $ 1,521 Service cost 258 253 Interest cost 68 66 Actuarial gain (53 ) (42 ) Benefit obligation at end of year 2,071 1,798 Funded status at end of year $ (2,071 ) $ (1,798 ) Accrued pension benefit $ (2,317 ) $ (2,003 ) Accumulated benefit obligation $ 1,397 $ 1,175 The assumptions used to determine the benefit obligation are as follows: December 31, 2018 2017 Discount rate 4.25 % 3.80 % Rate of compensation increase 3.00 % 3.00 % The components of net periodic pension cost are as follows: December 31, 2018 2017 Service cost $ 258 $ 253 Interest cost 68 66 Amortization of gain (18 ) (19 ) Amortization of prior service cost 6 6 Net periodic cost $ 314 $ 306 Other changes in benefit obligations recognized in other comprehensive loss are as follows: December 31, 2018 2017 Amortization of prior service cost $ (6 ) $ (6 ) Amortization of unrecognized gain 19 19 Net actuarial gain (53 ) (42 ) Total recognized in other comprehensive loss $ (40 ) $ (29 ) The assumptions used to determine net periodic pension cost are as follows: December 31, 2018 2017 Discount rate 3.80 % 4.35 % Rate of compensation increase 3.00 % 3.00 % Amounts recognized in accumulated other comprehensive loss, before tax effects, consist of the following: December 31, 2018 2017 Unrecognized prior service cost $ 34 $ 40 Unrecognized net gain (279 ) (245 ) Total recognized in other comprehensive loss $ (245 ) $ (205 ) The estimated prior service cost that will be amortized from accumulated other comprehensive income into net periodic pension expense during the year ending December 31, 2019 is $6,000. The estimated unrecognized net gain that will be accreted from accumulated other comprehensive income into net periodic pension expense during the year ending December 31, 2019 is $29,000. The Company does not expect to contribute to the Plan in 2019. Estimated future benefit payments, which reflect expected future service, as appropriate, are as follows: Year Ending December 31, Amount 2019 $ 58 2020 192 2021 267 2022 267 2023 267 Years 2024-2028 1,628 Other Supplemental Retirement Plans The Company has supplemental retirement plans for certain eligible executive officers that do not participate in the Belmont Savings Bank Supplemental Executive Retirement Plan which provide for a lump sum benefit upon termination of employment at or after age 55 and completing 10 or more years of service (certain reduced benefits are available prior to attaining age 55 or fewer than 10 years of service), subject to certain limitations as set forth in the agreements. The present value of these future payments is being accrued over the service period. The estimated liability at December 31, 2018 and 2017 relating to these plans was $2.8 million and $2.6 million, respectively. The discount rate used to determine the Company’s obligation was 4.25% and 3.8% during the years ended December 31, 2018 and 2017, respectively. The projected rate of salary increase was 3% during the years ended December 31, 2018 and 2017. Total supplemental retirement plan expense amounted to $252,000, $331,000 and $233,000 for the years ended December 31, 2018, 2017 and 2016, respectively. The Company has a supplemental retirement plan for eligible directors that provides for monthly benefits based upon years of service to the Company, subject to certain limitations as set forth in the agreements. The present value of these future payments is being accrued over the estimated period of service. The estimated liability at December 31, 2018 and 2017 relating to this plan was $689,000 and $697,000, respectively. The discount rate used to determine the Company’s obligation was 4.25% and 3.8% during the years ended December 31, 2018 and 2017, respectively. Total supplemental retirement plan expense amounted to $21,000, $64,000 and $55,000 for the years ended December 31, 2018, 2017 and 2016, respectively. Incentive Compensation Plan The Incentive Compensation Plan is a discretionary annual cash-based incentive plan that is an integral part of the participant’s total compensation package and supports the continued growth and profitability of the Bank. Each year participants are awarded for the achievement of certain performance objectives on a company-wide and individual basis. Compensation expense recognized was $2.4 million, $2.3 million and $2.0 million for the years ended December 31, 2018, 2017 and 2016, respectively. Defined Contribution Plan The Bank sponsors a 401(k) plan covering substantially all employees meeting certain eligibility requirements. Under the provisions of the plan, employees are able to contribute up to an annual limit of the lesser of 75% of eligible compensation or the maximum allowed by the Internal Revenue Service. The Company’s contributions for the years ended December 31, 2018, 2017 and 2016 totaled $950,000, $891,000 and $839,000, respectively. Deferred Compensation Plan The Company has a deferred compensation plan by which selected employees and directors of the Company are entitled to elect, prior to the beginning of each year, to defer the receipt of an amount of their compensation for the forthcoming year to an individual deferred compensation account established by the Bank. Compensation that is deferred is held in a Rabbi Trust, or grantor trust. The Rabbi Trust is maintained by the Bank primarily for purposes of providing a vehicle for deferred compensation for certain Directors and employees of the Company. The plan is administered by a third party and permits participants to select from a number of investment options for the investment of their account balances. Each participant is always 100% vested in his or her deferred compensation account balance. As of December 31, 2018 and 2017, the recorded liability relating to the Rabbi Trust was $2.8 million and $2.8 million, respectively. Employee Stock Ownership Plan The Company maintains an Employee Stock Ownership Plan (“ESOP”) to provide eligible employees the opportunity to own Company stock. This plan is a tax-qualified retirement plan for the benefit of all Company employees. Contributions are allocated to eligible participants on the basis of compensation, subject to federal tax law limits. The Company contributed funds to a subsidiary to enable it to grant a loan to the ESOP for the purchase of 458,643 shares of the Company’s common stock at a price of $10.00 per share. The loan obtained by the ESOP from the Company’s subsidiary to purchase Company common stock is payable annually over 30 years at a rate per annum equal to the Prime Rate on the first business day of each calendar year, or 4.5% for 2018. Loan payments are principally funded by cash contributions from the Bank. The loan is secured by the shares purchased, which are held in a suspense account for allocation among participants as the loan is repaid. Cash dividends paid on allocated shares are distributed to participants and cash dividends paid on unallocated shares are used to repay the outstanding debt of the ESOP. Shares used as collateral to secure the loan are released and available for allocation to eligible employees as the principal and interest on the loan is paid. At December 31, 2018, the remaining principal balance on the ESOP debt is payable as follows: Years Ending December 31, Amount 2019 $ 88 2020 93 2021 98 2022 104 2023 110 Thereafter 3,380 $ 3,873 Shares held by the ESOP include the following: December 31, 2018 2017 Unallocated 347,803 363,091 Allocated 96,799 84,813 444,602 447,904 The fair value of unallocated shares was approximately $9.8 million and $10.6 million at December 31, 2018 and 2017, respectively. Total compensation expense recognized in connection with the ESOP for the years ended December 31, 2018, 2017 and 2016 was $484,000, $444,000 and $360,000, respectively. Severance Agreements The Company has entered into employment agreements and change in control agreements with certain executive officers which would provide the executive officers with severance payments based on salary, and the continuation of other benefits, upon a change in control as defined in the agreements.

STOCK BASED COMPENSATION

STOCK BASED COMPENSATION	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK BASED COMPENSATION	NOTE 16 – STOCK BASED COMPENSATION On November 14, 2012, the stockholders of the Company approved the BSB Bancorp, Inc. 2012 Equity Incentive Plan. The table below presents the amount of cumulatively granted stock options and restricted stock awards, net of forfeitures, through December 31, 2018 under the BSB Bancorp, Inc. 2012 Equity Incentive Plan. On February 8, 2017, the stockholders of the Company approved the BSB Bancorp, Inc. 2017 Equity Incentive Plan. The BSB Bancorp, Inc. 2017 Equity Incentive Plan authorized the issuance or delivery to participants of up to 487,200 shares of BSB Bancorp, Inc. common stock pursuant to grants of restricted stock awards and/or restricted stock unit awards. On March 15, 2017, 487,200 restricted stock awards were granted under the Plan at $27.10, the grant date fair value per share, with a ten year vesting period and an estimated 2.64% forfeiture rate. The awards are not deemed to be participating securities. Upon the approval of this new plan, the Company canceled the existing 2012 Equity Incentive Plan and no further awards will be granted out of that plan. The following table presents the amount of cumulatively granted restricted stock awards, net of forfeitures, through December 31, 2018 under the BSB Bancorp, Inc. 2017 Equity Incentive Plan: Cumulative Granted Authorized Authorized Net of Forfeitures Stock Restricted Authorized Stock Restricted Outstanding Option Awards Stock Awards Total Option Awards Stock Awards Total 2012 Equity Incentive Plan 917,286 366,914 1,284,200 889,092 363,570 1,252,662 2017 Equity Incentive Plan — 487,200 487,200 — 487,200 487,200 The following table presents the pre-tax expense associated with stock option and restricted stock awards and the related tax benefits recognized: For the year ended December 31, 2018 2017 2016 Stock based compensation expense Stock options $ 73 $ 724 $ 780 Restricted stock awards 1,332 1,835 869 Total stock based award expense $ 1,405 $ 2,559 $ 1,649 Related tax benefits recognized in earnings $ 376 $ 874 $ 492 The adoption of ASU 2016-09 required that the excess tax benefit associated with stock compensation transactions be recorded through earnings while the previous guidance required the recognition of the excess tax benefit through additional paid-in capital. Excess tax benefits recognized from stock-based compensation for the periods indicated below are as follows: For the year ended December 31, 2018 2017 Excess tax benefits recognized in net income $ 324 $ 1,348 The following table presents relevant information relating to the Company’s stock options for the periods indicated: For the year ended December 31, 2018 2017 2016 Weighted average grant date fair value of options granted $ — $ — $ 4.63 Intrinsic value of stock options exercised 1,829 3,299 368 Cash paid to settle equity instruments granted under stock based compensation arrangements — — — Total compensation cost related to non-vested awards not yet recognized and the weighted average period (in years) over which it is expected to be recognized is as follows: As of December 31, 2018 Weighted Amount average period Stock options $ 69 1.85 Restricted stock 9,637 8.21 Total $ 9,706 The Company granted the awards presented in the table below. The fair value of the stock options granted was estimated on the date of the grant using the Black-Scholes option pricing model with the following assumptions used: • Expected volatility is based on the standard deviation of the historical volatility of the daily adjusted closing price of the Company’s shares. • Expected term represents the period of time that the option is expected to be outstanding. The Company determined the expected life using the “Simplified Method.” • Expected dividend yield is determined based on management’s expectations regarding issuing dividends in the foreseeable future. • The risk-free interest 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 stock-based compensation expense recognized in earnings is based on the amount of awards ultimately expected to vest, therefore a forfeiture assumption is estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Date of grant 3/1/2016 Options granted 27,500 Exercise price $ 22.31 Vesting period (1) 5 years Expiration date 3/1/2026 Expected volatility 16.13 % Expected term 6.5 years Expected dividend yield 0 % Risk free interest rate 1.54 % Fair value $ 4.63 (1)- Vesting is ratably and the period begins on the date of grant. The option exercise price is derived from trading value on the date of grant. A summary of the status of the Company’s Stock Option and Restricted Stock Awards for the year ended December 31, 2018 is presented in the tables below: Outstanding Stock option awards Weighted average exercise price Weighted average remaining contractual term (in years) Aggregate intrinsic value Balance at January 1, 2018 590,522 $ 12.86 Granted — — Exercised (99,199 ) 12.10 Forfeited — — Balance at December 31, 2018 491,323 $ 13.02 4.22 $ 7,390 Exercisable 464,428 $ 12.58 4.08 $ 7,189 Non-vested restricted stock awards Weighted average grant price Balance at January 1, 2018 484,902 $ 27.07 Granted 3,898 32.30 Vested (49,137 ) 26.94 Forfeited — — Balance at December 31, 2018 439,663 $ 27.13 For the years ended December 31, 2018, 2017 and 2016, the fair value of shares vested during the year amounted to $1.5 million, $2.2 million and $1.9 million, respectively.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER SHARE	NOTE 17 – EARNINGS PER SHARE Earnings per share consisted of the following components for the years ended December 31, 2018, 2017 and 2016: December 31, December 31, December 31, 2018 2017 2016 Net income $ 22,909 $ 14,386 $ 11,981 Undistributed earnings attributable to participating securities (3 ) (108 ) (190 ) Net income available to common stockholders $ 22,906 $ 14,278 $ 11,791 Weighted average shares outstanding, basic 8,941,394 8,754,393 8,571,861 Effect of dilutive shares 445,297 429,400 286,030 Weighted average shares outstanding, assuming dilution 9,386,691 9,183,793 8,857,891 Basic EPS $ 2.56 $ 1.63 $ 1.38 Effect of dilutive shares (0.12 ) (0.08 ) (0.05 ) Diluted EPS $ 2.44 $ 1.55 $ 1.33 During the years ended December 31, 2018 and 2017 no shares of common stock were outstanding but not included in the computation of EPS because they were antidilutive under the treasury stock method During the year ended December 31, 2016, average options to purchase 22,992 shares of common stock were outstanding but not included in the computation of EPS because they were antidilutive under the treasury stock method.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	NOTE 18 – RELATED PARTY TRANSACTIONS In the ordinary course of business, the Bank has granted loans to principal officers and directors and their affiliates. As of December 31, 2018 and 2017, related party loans were not significant.

RESTRICTIONS ON DIVIDENDS, LOAN

RESTRICTIONS ON DIVIDENDS, LOANS AND ADVANCES	12 Months Ended
	Dec. 31, 2018
Disclosure of Restrictions on Dividends, Loans and Advances Disclosure [Abstract]
Restrictions on Dividends, Loans and Advances [Text Block]	NOTE 19 – RESTRICTIONS ON DIVIDENDS, LOANS AND ADVANCES Federal and state banking regulations place certain restrictions on dividends paid and loans or advances made by the Bank to the Company. The total amount for dividends which may be paid in any calendar year cannot exceed the Bank’s net income for the current year, plus the Bank’s net income retained for the two previous years, without regulatory approval. Loans or advances are limited to 10 percent of the Bank’s capital stock and surplus on a secured basis. In addition, dividends paid by the Bank to the Company would be prohibited if the effect thereof would cause the Bank’s capital to be reduced below applicable minimum capital requirements.

FAIR VALUES OF ASSETS AND LIABI

FAIR VALUES OF ASSETS AND LIABILITIES	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	NOTE 20 – FAIR VALUES OF ASSETS AND LIABILITIES Determination of Fair Value The fair value of an asset or liability 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. The Company uses prices and inputs that are current as of the measurement date, including during periods of market dislocation. In periods of market dislocation, the observability of prices and inputs may be reduced for many instruments. This condition could cause an instrument to be reclassified from one level to another. 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 of cash flows or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. Accordingly, the fair value estimates may not be realized in an immediate settlement of the instrument. The Company groups its assets and liabilities measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the observability and reliability of the assumptions used to determine fair value. Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 - Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 - Inputs are unobservable inputs for the asset or liability. For assets and liabilities, fair value is based upon the lowest level of observable input that is significant to the fair value measurement. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon models that primarily use, as inputs, observable market based parameters. The Company’s valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes the Company’s valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the reported fair value amounts have not been comprehensively revalued since the presentation dates, and therefore, estimates of fair value after the consolidated balance sheet date may differ significantly from the amounts presented herein. A more detailed description of the valuation methodologies used for assets and liabilities measured at fair value is set forth below. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. These valuation methodologies were applied to all of the Company’s financial assets and financial liabilities carried at fair value for December 31, 2018 and 2017. There were no significant transfers between levels of the fair value hierarchy during the years ended December 31, 2018 and 2017. Financial Assets and Financial Liabilities: Financial assets and financial liabilities measured at fair value on a recurring basis include the following: Investment Securities Available for Sale : The Company’s investment in corporate debt securities is generally classified within Level 2 of the fair value hierarchy. For these securities, the Company obtains fair value measurements from independent pricing services. The fair value measurements consider observable data that may include reported trades, dealer quotes, market spreads, cash flows, the U.S. treasury yield curve, trading levels, market consensus prepayment speeds, credit information and the instrument’s terms and conditions. Investments held in the Rabbi Trust : Investments held in the Rabbi Trust consist primarily of exchange-traded mutual funds and are recorded at fair value and included in other assets. The purpose of these investments is to fund certain director and executive non-qualified retirement benefits and deferred compensation. The exchange-traded mutual funds were valued based on quoted market prices and are categorized as Level 1. Derivatives : Currently, the Company uses interest rate caps and loan level derivatives, including interest rate swap agreements and risk participation-out agreements, to manage its interest rate risk. The valuations of these derivative instruments are determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative instrument. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair value of the interest rate caps is determined using the market standard methodology of discounting the future expected cash receipts that would occur if variable interest rates rise above the strike rate of the contracts. The variable interest rates used in the calculation of projected receipts on the interest rate caps are based on an expectation of future interest rates derived from observable market interest rate curves and volatilities. The fair values for the loan level derivatives are based on settlement values adjusted for credit risks associated with the counterparties and the Company and observable market interest rate curves. Credit risk adjustments consider factors such as the likelihood of default by the Company and its counterparties, its net exposures and remaining contractual life. To date, the Company has not realized any losses due to a counterparty’s inability to pay any net uncollateralized position. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative instruments for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. The Company had no derivative assets or liabilities as of December 31, 2017. A majority of the inputs used to value the Company’s derivatives fall within Level 2 of the fair value hierarchy. Any related credit value adjustments generally utilize Level 3 inputs such as estimates of credit spreads. However, as of December 31, 2018, the Company has assessed the valuation methodology of these derivative instruments and determined that the credit valuation adjustments do not materially impact the overall valuation of the derivative positions; accordingly, the Company classifies these derivative instruments entirely within Level 2 of the fair value hierarchy. The following table summarizes financial assets measured at fair value on a recurring basis as of December 31, 2018 and 2017, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Level 2 Level 3 Total Fair Value At December 31, 2018 Assets: Securities available-for-sale Corporate debt securities $ — $ 4,040 $ — $ 4,040 Rabbi trust investments 2,787 — — 2,787 Derivatives: Interest rate caps — 2,303 — 2,303 Interest rate swaps — 2,967 — 2,967 Risk participation-out agreements — 22 — 22 Totals $ 2,787 $ 9,332 $ — $ 12,119 Liabilities: Derivatives: Interest rate swaps $ — $ 3,144 $ — $ 3,144 Totals $ — $ 3,144 $ — $ 3,144 Level 1 Level 2 Level 3 Total Fair Value At December 31, 2017 Securities available-for-sale Corporate debt securities $ — $ 16,921 $ — $ 16,921 Rabbi trust investments 2,808 — — 2,808 Totals $ 2,808 $ 16,921 $ — $ 19,729 Certain financial assets and financial liabilities are measured at fair value on a non-recurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Financial assets measured at fair value on a non-recurring basis during the reported periods include certain impaired loans reported at the fair value of the underlying collateral. Fair value is measured using appraised values of collateral and adjusted as necessary by management based on unobservable inputs for specific properties. However, the choice of observable data is subject to significant judgment, and there are often adjustments based on judgment in order to make observable data comparable and to consider the impact of time, the condition of properties, interest rates, and other market factors on current values. Additionally, commercial real estate appraisals frequently involve discounting of projected cash flows, which relies inherently on unobservable data. Therefore, real estate collateral related nonrecurring fair value measurement adjustments have generally been classified as Level 3. Estimates of fair value used for other collateral supporting commercial loans generally are based on assumptions not observable in the marketplace and therefore such valuations have been classified as Level 3. Financial assets measured at fair value on a non-recurring basis during the reported periods also include loans held for sale. Residential mortgage loans held for sale are recorded at the lower of cost or fair value and are therefore measured at fair value on a non-recurring basis. The fair values for loans held for sale are estimated based on commitments in effect from investors or prevailing market prices for loans with similar terms to borrowers of similar credit quality and are included in Level 3. There were no impaired loans that were re-measured and reported at fair value through either a charge off or a specific valuation allowance based upon the fair value of the underlying collateral at December 31, 2018 and 2017. The following table presents loans held for sale at December 31, 2018 and 2017. December 31, 2018 Level 1 Level 2 Level 3 Loans held for sale $ — $ — $ 2,902 Totals $ — $ — $ 2,902 December 31, 2017 Level 1 Level 2 Level 3 Loans held for sale $ — $ — $ — Totals $ — $ — $ — Non-Financial Assets and Non-Financial Liabilities: The Company has no non-financial assets or non-financial liabilities measured at fair value on a recurring basis. Non-financial assets measured at fair value on a non-recurring basis generally include certain foreclosed assets which, upon initial recognition, were re-measured and reported at fair value through a charge-off to the allowance for loan losses and certain foreclosed assets which, subsequent to their initial recognition, are remeasured at fair value through a write-down included in other non-interest expense. Non-financial assets measured at fair value on a non-recurring basis also include mortgage servicing right assets that are re-measured and reported at the lower of amortized cost or fair value. The following table presents the non-financial assets that were re-measured and reported at the lower of cost or fair value at the periods indicated: December 31, 2018 Level 1 Level 2 Level 3 Mortgage servicing rights $ — $ — $ 1,102 Totals $ — $ — $ 1,102 December 31, 2017 Level 1 Level 2 Level 3 Mortgage servicing rights $ — $ — $ 855 Totals $ — $ — $ 855 There were no foreclosed assets at December 31, 2018 or 2017. ASC Topic 825, “Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The methodologies for estimating the fair value of financial assets and financial liabilities that are measured at fair value on a recurring or non-recurring basis are discussed above. The estimated fair value approximates carrying value for cash and cash equivalents, interest bearing time deposits with other banks, Federal Home Loan Bank stock, bank owned life insurance, accrued interest receivable and payable, securities sold under agreements to repurchase, and mortgagors’ escrow accounts. ASU 2016-01 requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. The exit price notion is a market-based measurement of fair value that is represented by the price to sell an asset or transfer a liability in the principal market (or most advantageous market in the absence of a principal market) on the measurement date. For December 31, 2018, the fair values of loans are estimated on an exit price basis incorporating discounts for credit, liquidity and marketability factors. This is not comparable with the fair values disclosed for December 31, 2017, which were based on an entrance price basis. Summary of Fair Values of Financial Instruments not Carried at Fair Value The estimated fair values, and related carrying or notional amounts, of the Company’s financial instruments are as follows for the periods indicated: December 31, 2018 Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 143,378 $ 143,378 $ 143,378 $ — $ — Interest-bearing time deposits with other banks 4,229 4,229 — 4,229 — Held-to-maturity securities 148,025 145,369 — 145,369 — Federal Home Loan Bank stock 38,658 38,658 — 38,658 — Loans, net 2,624,372 2,537,595 — — 2,537,595 Accrued interest receivable 7,290 7,290 7,290 — — Bank owned life insurance 36,540 36,540 — 36,540 Financial liabilities: Deposits 1,960,912 1,956,139 1,201,644 754,495 — Federal Home Loan Bank advances 838,250 834,495 — 834,495 — Securities sold under agreements to repurchase 2,883 2,883 — 2,883 — Accrued interest payable 2,050 2,050 2,050 — — Mortgagors’ escrow accounts 6,338 6,338 — 6,338 — December 31, 2017 Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 110,888 $ 110,888 $ 110,888 $ — $ — Interest-bearing time deposits with other banks 2,440 2,440 — 2,440 — Held-to-maturity securities 160,090 158,385 — 158,385 — Federal Home Loan Bank stock 32,382 32,382 — 32,382 — Bank owned life insurance 36,967 36,967 — 36,967 Loans, net 2,296,958 2,251,971 — — 2,251,971 Accrued interest receivable 6,344 6,344 6,344 — — Financial liabilities: Deposits 1,751,251 1,748,995 1,246,537 502,458 — Federal Home Loan Bank advances 723,150 719,430 — 719,430 — Securities sold under agreements to repurchase 3,268 3,268 — 3,268 — Accrued interest payable 1,594 1,594 1,594 — — Mortgagors’ escrow accounts 4,690 4,690 — 4,690 —

OTHER COMPREHENSIVE (LOSS) INCO

OTHER COMPREHENSIVE (LOSS) INCOME	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
OTHER COMPREHENSIVE (LOSS) INCOME	NOTE 21 – OTHER COMPREHENSIVE (LOSS) INCOME The following table presents a reconciliation of the changes in the components of other comprehensive (loss) income for the dates indicated, including the amount of income tax benefit (expense) allocated to each component of other comprehensive (loss) income: Year Ended December 31, 2018 Pre Tax Amount Tax Benefit (Expense) After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ (68 ) $ 19 $ (49 ) Net change in fair value of securities available for sale (68 ) 19 (49 ) Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 53 (15 ) 38 Reclassification adjustment included in net income 1 (13 ) 4 (9 ) Net change defined-benefit post-retirement benefit plans 40 (11 ) 29 Cash flow hedges: Change in fair value of cash flow hedges (1,782 ) 501 (1,281 ) Reclassification adjustment included in net income 2 7 (2 ) 5 Net change in fair value of cash flow hedges (1,775 ) 499 (1,276 ) Total other comprehensive loss $ (1,803 ) $ 507 $ (1,296 ) Year Ended December 31, 2017 Pre Tax Amount Tax Benefit (Expense) After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ (13 ) $ 5 $ (8 ) Reclassification adjustment for net gains included in net income 3 (38 ) 15 (23 ) Net change in fair value of securities available for sale (51 ) 20 (31 ) Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 42 (17 ) 25 Reclassification adjustment included in net income 1 (13 ) 5 (8 ) Net change defined-benefit post-retirement benefit plans 29 (12 ) 17 Total other comprehensive loss $ (22 ) $ 8 $ (14 ) Year Ended December 31, 2016 Pre Tax Amount Tax Expense After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ 247 $ (98 ) $ 149 Net change in fair value of securities available for sale 247 (98 ) 149 Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 112 (46 ) 66 Reclassification adjustment included in net income 1 6 (2 ) 4 Net change defined-benefit post-retirement benefit plans 118 (48 ) 70 Total other comprehensive income $ 365 $ (146 ) $ 219 1- Reclassification adjustments are comprised of amortization of prior service cost and unrecognized gain (loss) and have been reclassified out of accumulated 2- Reclassification adjustments are comprised of amortization of the interest rate cap premiums paid upon execution under the Caplet method. The deferred premium has been reclassified out of accumulated o 3- Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated The components of accumulated o (loss) i December 31, 2018 December 31, 2017 Net unrealized holding loss on available-for-sale securities, net of tax $ (88 ) $ (32 ) Unrecognized benefit pertaining to defined benefit plan, net of tax 176 121 Unrealized holding loss on cash flow hedges, net of tax (1,276 ) — Accumulated $ (1,188 ) $ 89 Accumulated accumulated accumulated

DERIVATIVES AND HEDGING

DERIVATIVES AND HEDGING	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND HEDGING	NOTE 22 – DERIVATIVES AND HEDGING Risk Management Objective of Using Derivatives The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk, primarily by managing the amount, sources, and duration of its assets and liabilities and through the use of derivative financial instruments when deemed appropriate. The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company has purchased interest rate caps and entered into certain interest rate swap contracts and risk participation-out agreements. Interest rate caps designated as cash flow hedges involve the receipt of variable amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an up-front premium payment. Interest rate caps can minimize significant unplanned fluctuations in earnings and cash flows caused by interest rate volatility. Derivatives not designated as hedges are not speculative and result from a service the Company provides to certain customers. The Company executes interest rate swaps with commercial banking customers to facilitate such customers’ respective risk management strategies. Those interest rate swaps are simultaneously hedged by offsetting derivatives that the Company executes with a third party, such that the Company minimizes its net risk exposure resulting from such transactions. As the interest rate derivatives associated with this program do not meet the hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings. Additionally, the Company has risk participation agreements with other banks. Risk participation agreements occur when the Company participates out a portion of the loan and the related swap to another bank or participates in a loan and related swap where another bank is the lead. With a risk participation out, the Company pays another bank to take on the risk associated with the participant bank’s pro-rata swap portion should the borrower default. With a risk participation in, the Company gets paid a fee to take on the risk associated with having to make the lead bank whole on the Company’s portion of the pro-rata swap should the borrower default. Changes in the fair value of risk participation agreements are recorded in current period earnings. The Company recognizes its derivative instruments on the consolidated balance sheet at fair value. On the date the derivative instrument is entered into, the Company designates whether the derivative is part of a hedging relationship (i.e. cash flow or fair value hedge). The Company formally documents relationships between hedging instruments and hedged items, as well as its risk management objective and strategy for undertaking hedging transactions. The Company also assesses, both at the hedge’s inception and on an ongoing basis, whether the derivative instruments used in hedging transactions are highly effective in offsetting the changes in cash flows or fair values of hedged items. Changes in the fair value of derivative instruments that are highly effective and qualify as cash flow hedges are recorded in other comprehensive income (loss), net of tax. Any ineffective portion is recorded in earnings. The Company discontinues hedge accounting when it is determined that the derivative instrument is no longer effective in offsetting changes of the hedged risk on the hedged item, or management determines that the designation of the derivative instrument as a hedging instrument is no longer appropriate. Included in loan level derivative income within the consolidated statements of operations is interest rate swap fee income received from dealer counterparties net of fees paid to third party advisors as well as the change in the fair values of interest rate swaps and risk participation agreements. Cash Flow Hedges of Interest Rate Risk In September of 2018, two $50 million notional interest rate cap agreements were purchased to limit the Company’s exposure to rising interest rates related to $50 million of rolling, one-month FHLB advances and brokered deposits. Under the terms of the agreements, the Company paid premiums of $2.6 million for the right to receive cash flow payments if the 1-month LIBOR rate rises above the caps’ strike price of 3.00%, thus effectively ensuring interest expense is capped at a maximum rate of 3.00% for the duration of the agreements. The maturity date of the agreements is September 12, 2024 and the unamortized cap premium was $2.6 million as of December 31, 2018. In March of 2018, a $100 million notional interest rate cap agreement was purchased to limit the Company’s exposure to rising interest rates related to $100 million of rolling, three-month FHLB advances. Under the terms of the agreement, the Company paid a premium of $1.5 million for the right to receive cash flow payments if the 3-month LIBOR rate rises above the cap’s strike price of 3.00%, thus effectively ensuring interest expense is capped at a maximum rate of 3.00% for the duration of the agreement. The maturity date of the agreement is March 21, 2023 and the unamortized cap premium was $1.5 million as of December 31, 2018. The interest rate cap agreements are designated as cash flow hedges. The fair value of the interest rate cap agreements are included in other assets on the Company’s consolidated balance sheets. Changes in the fair value, representing unrealized gains or losses, are recorded in accumulated Amounts reported in accumulated The notional amounts of the financial derivative instruments do not represent exposure to credit loss. The Company is exposed to credit loss only to the extent the counterparty defaults in its responsibility to pay interest under the terms of the agreements. The credit risk in derivative instruments is mitigated by entering into transactions with highly-rated counterparties that management believes to be creditworthy and by limiting the amount of exposure to each counterparty. The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the consolidated balance sheets as of the periods presented: Fair Value of Derivative Instruments Asset Derivatives December 31, 2018 December 31, 2017 Number of Transactions Notional Amount Balance Sheet Location Fair Value Number of Transactions Notional Amount Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Interest rate caps 3 $ 200,000 Other Assets $ 2,303 — $ — Other Assets $ — Total derivatives designated as hedging instruments $ 2,303 $ — Derivatives not designated as hedging instruments: Interest Rate Swaps - Commercial Loan Customers 9 $ 76,792 Other Assets $ 2,967 — $ — Other Assets $ — Risk Participation-Out Agreements - Third Party Financial Institution 3 $ 6,340 Other Assets 22 — $ — Other Assets — Total derivatives not designated as hedging instruments $ 2,989 $ — Fair Value of Derivative Instruments Liability Derivatives December 31, 2018 December 31, 2017 Number of Transactions Notional Amount Balance Sheet Location Fair Value Number of Transactions Notional Amount Balance Sheet Location Fair Value Derivatives not designated as hedging instruments: Interest Rate Swaps - Third Party Financial Institution 9 $ 76,792 Other Liabilities $ 3,144 — $ — Other Liabilities $ — Total derivatives not designated as hedging instruments $ 3,144 $ — The following table presents the effect of the Company’s derivative financial instruments included in other comprehensive (loss) income and reclassifications into earnings for the periods indicated: Amount of Pre-Tax Gain (Loss) Recognized in Other Comprehensive Income on Derivatives Location of Pre-Tax Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income Amount of Pre-Tax Gain (Loss) Reclassified from Accumulated Income Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2018 Year Ended December 31, 2017 Derivatives in Cash Flow Hedging Relationships Interest Rate Products $ (1,782 ) $ — Interest expense $ (7 ) $ — Total $ (1,782 ) $ — $ (7 ) $ — The following table presents the effect of the Company’s derivative financial instruments included in current earnings for the periods indicated: Location of Gain (Loss) Recognized in Income on Derivative Instruments Amount of Gain (Loss) Recognized in Income on Derivative Instruments Year Ended December 31, 2018 Year Ended December 31, 2017 Interest Rate Swaps Loan level derivative income $ (177 ) $ — Risk Participation-Out Agreements Loan level derivative income 7 — Total $ (170 ) $ — Certain derivative agreements contain provisions that require the Company or the third party financial institution to post collateral if the derivative exposure exceeds a certain threshold. The Company has posted cash collateral of $240,000 to one third party financial institution in connection with these arrangements as of December 31, 2018. The Company has agreements with certain of its derivative counterparties that contain credit-risk-related contingent provisions. These provisions provide the counterparty with the right to terminate its derivative positions and require the Company to settle its obligations under the agreements if the Company defaults on certain of its indebtedness or if the Company fails to maintain its status as a well-capitalized institution. Counterparty Credit Risk. By utilizing derivative instruments, the Company is exposed to credit risk to the extent that counterparties to the derivative instruments do not perform as required. Should a counterparty fail to perform under the terms of a derivative instrument, the Company’s credit exposure is limited to the net positive fair value and accrued interest of all derivative instruments with each counterparty. The Company seeks to minimize counterparty credit risk through credit approvals, limits, monitoring procedures, and obtaining collateral, where appropriate. Institutional counterparties must have an investment grade credit rating and be approved by the Company’s Board of Directors. As such, management believes the risk of incurring credit losses on derivative instruments with institutional counterparties is remote. The Company’s exposure relating to institutional counterparties was $0 at December 31, 2018. Credit exposure is mitigated by the value of collateral pledged by the counterparty.

BALANCE SHEET OFFSETTING

BALANCE SHEET OFFSETTING	12 Months Ended
	Dec. 31, 2018
Text Block [Abstract]
BALANCE SHEET OFFSETTING	NOTE 23 – BALANCE SHEET OFFSETTING Certain financial instruments, including derivatives, may be eligible for offset in the consolidated balance sheets and/or subject to master netting arrangements or similar agreements. Our derivative transactions with upstream financial institution counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts and there may be an intention to settle such amounts on a net basis. The Company does not offset fair value amounts recognized for derivative instruments or repurchase agreements. The Company does net the amount recognized for the right to reclaim cash collateral against the obligation to return cash collateral arising from derivative instruments executed with the same counterparty under a master netting arrangement. Collateral legally required to be maintained at dealer banks by the Company is monitored and adjusted as necessary. The following tables present the Company’s asset and liability derivative positions and repurchase agreements and the potential effect of netting arrangements on its financial position, as of the periods indicated: December 31, 2018 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Assets Gross Amounts Offset in the Statement of Financial Position Net Amounts of Assets Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Derivative Assets $ 5,292 $ — $ 5,292 $ 2,304 $ — $ 2,988 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Derivative Liabilities $ 3,144 $ — $ 3,144 $ 2,304 $ 240 $ 600 Securities sold under agreements to repurchase $ 2,883 $ — $ 2,883 $ — $ 2,883 $ — December 31, 2017 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Securities sold under agreements to repurchase $ 3,268 $ — $ 3,268 $ — $ 3,268 $ —

CONDENSED FINANCIAL STATEMENTS

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	NOTE 24 – CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY The following condensed financial statements are for the Parent Company only and should be read in conjunction with the consolidated financial statements of the Company. Condensed Balance Sheets December 31, 2018 2017 Assets Cash and cash equivalents held at Belmont Savings Bank $ 1,440 $ 919 Investment in Belmont Savings Bank 196,318 173,054 Investment in BSB Funding Corp. 4,192 4,065 Other assets 25 45 Total assets $ 201,975 $ 178,083 Liabilities and Stockholders’ Equity Accrued expenses $ 16 $ 38 Other liabilities 165 16 Total liabilities 181 54 Stockholders’ equity 201,794 178,029 Total liabilities and stockholders’ equity $ 201,975 $ 178,083 Condensed Statements of Operations Years Ended December 31, 2018 2017 2016 Interest and dividend income: Interest on cash equivalents $ 9 $ — $ — Dividends from subsidiaries — — — Total interest and dividend income 9 — — Interest expense — — — Net interest and dividend income 9 — — Non-interest income — — — Non-interest expense 232 230 219 Loss before income taxes and equity in undistributed earnings of subsidiaries (223 ) (230 ) (219 ) Income tax benefit (63 ) (94 ) (89 ) Loss before equity in income of subsidiaries (160 ) (136 ) (130 ) Equity in undistributed earnings of Belmont Savings Bank 22,942 14,432 12,025 Equity in undistributed earnings of BSB Funding Corp 127 90 86 Net income $ 22,909 $ 14,386 $ 11,981 Condensed Statements of Cash Flows Years Ended December 31, 2018 2017 2016 Cash flows from operating activities: Net income $ 22,909 $ 14,386 $ 11,981 Adjustments to reconcile net income to net cash used in operating activities: Equity in undistributed earnings of Belmont Savings Bank (22,942 ) (14,432 ) (12,025 ) Equity in undistributed earnings of BSB Funding Corp. (127 ) (90 ) (86 ) Deferred income tax expense — — — Other, net — 26 (27 ) Net cash used in operating activities (160 ) (110 ) (157 ) Cash flows from investing activities: Return of capital from BSB Funding Corp. — 460 — Investment in Belmont Savings Bank — — — Net cash provided by investing activities — 460 — Cash flows from financing activities: Proceeds from exercise of stock options, net of cash paid 681 50 298 Restricted stock awards issued, net of awards surrendered — — (118 ) Net cash provided by financing activities 681 50 180 Net increase in cash and cash equivalents 521 400 23 Cash and cash equivalents at beginning of period 919 519 496 Cash and cash equivalents at end of period $ 1,440 $ 919 $ 519

QUARTERLY DATA (UNAUDITED)

QUARTERLY DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	NOTE 25 – QUARTERLY DATA (UNAUDITED) Quarterly results of operations are as follows for the periods indicated: Years Ended December 31, 2018 2017 Fourth Quarter Third Quarter Second Quarter First Quarter Fourth Quarter Third Quarter Second Quarter First Quarter Interest and dividend income $ 26,306 $ 25,644 $ 23,882 $ 22,419 $ 21,114 $ 19,758 $ 18,764 $ 17,506 Interest expense 10,862 10,235 8,779 7,281 6,414 5,579 4,816 4,245 Net interest income 15,444 15,409 15,103 15,138 14,700 14,179 13,948 13,261 Provision for loan losses 465 191 726 274 691 535 707 829 Net interest income, after provision for loan losses 14,979 15,218 14,377 14,864 14,009 13,644 13,241 12,432 Non-interest income 1,279 1,136 1,711 895 1,117 885 995 630 Non-interest expense 9,712 7,826 7,796 7,685 7,636 7,929 7,645 7,476 Income before taxes 6,546 8,528 8,292 8,074 7,490 6,600 6,591 5,586 Income tax expense 1,943 2,300 2,224 2,064 5,382 2,001 2,579 1,920 Net income $ 4,603 $ 6,228 $ 6,068 $ 6,010 $ 2,108 $ 4,599 $ 4,012 $ 3,666 Earnings per common share Basic $ 0.51 $ 0.70 $ 0.68 $ 0.68 $ 0.24 $ 0.52 $ 0.45 $ 0.42 Diluted $ 0.49 $ 0.66 $ 0.65 $ 0.64 $ 0.23 $ 0.50 $ 0.43 $ 0.40

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events [Text Block]	NOTE 26 – SUBSEQUENT EVENTS The Company has evaluated subsequent events for potential recognition and/or disclosure through the date these consolidated financial statements were issued.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations BSB Bancorp, Inc. (the “Company”) was incorporated in Maryland in June, 2011 to become the holding company of Belmont Savings Bank (the “Bank”), a state-chartered Massachusetts savings bank. The Company is supervised by the Board of Governors of the Federal Reserve System (“FRB”), while the Bank is subject to the regulations of, and periodic examination by, the Federal Deposit Insurance Corporation (“FDIC”) and the Massachusetts Division of Banks (the “Division”). The Bank’s deposits are insured by the Bank Insurance Fund of the FDIC up to $250,000 per account. For balances in excess of the FDIC deposit insurance limits, coverage is provided by the Massachusetts Depositors Insurance Fund, Inc. In connection with the Company’s conversion from a mutual holding company to stock holding company form of organization (the “conversion”), on October 4, 2011 we completed our initial public offering of common stock, selling 8,993,000 shares of common stock at $10.00 per share for approximately $89.9 million in gross proceeds, including 458,643 shares sold to the Bank’s employee stock ownership plan. In addition, in connection with the conversion, we issued 179,860 shares of our common stock and contributed $200,000 in cash to the Belmont Savings Bank Foundation. The Bank is a state chartered savings bank which was incorporated in 1885 and is headquartered in Belmont, Massachusetts. The Bank is engaged principally in the business of attracting deposits from the general public and investing those deposits in residential, commercial real estate loans, multifamily real estate loans, consumer loans, including indirect auto loans, commercial loans and construction loans, as well as investment securities.
Merger	Merger On November 26, 2018, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with People’s United Financial, Inc. (“People’s United”). The Merger Agreement provides that upon the terms and subject to the conditions set forth therein, the Company will merge with and into People’s United, with People’s United as the surviving corporation (the “ Merger Completion of the Merger remains subject to customary closing conditions. The Merger is expected to close in the second quarter of 2019.
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Belmont Savings Bank and BSB Funding Corporation and the Bank’s wholly owned subsidiary, BSB Investment Corporation. All significant intercompany balances and transactions have been eliminated in consolidation. The Company’s consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles and general practices within the financial services industry.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management 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. Material estimates that are particularly susceptible to significant changes in the near-term relate to the determination of the allowance for loan losses, valuation and potential other-than-temporary impairment (“OTTI”) of investment securities and the valuation of deferred tax assets.
Reclassification	Reclassification Certain previously reported amounts have been reclassified to conform to the current year’s presentation.
Significant Group Concentrations of Credit Risk	Significant Group Concentrations of Credit Risk Most of the Company’s business activity is with customers located within the Commonwealth of Massachusetts. There are no concentrations of credit to borrowers that have similar economic characteristics. The majority of the Company’s loan portfolio is comprised of loans collateralized by real estate located in the Commonwealth of Massachusetts.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the consolidated statements of cash flows, cash and cash equivalents include cash, balances due from banks and interest-bearing deposits in other banks.
Investment Securities	Investment Securities Debt securities that management has the positive intent and ability to hold to maturity are classified as “held-to-maturity” and recorded at amortized cost. Debt securities not classified as held-to-maturity or trading are classified as “available-for-sale” and recorded at fair value, with unrealized gains and losses excluded from earnings and reported in other comprehensive income (loss). Equity securities are carried at fair value with changes in fair value recognized in current earnings. Purchase premiums and discounts are recognized in interest income using the interest method over the terms of the investment securities, adjusted for the effect of actual prepayments in the case of mortgage-backed securities. Gains and losses on the sale of investment securities are recorded on the trade date and are determined using the specific identification method. Each reporting period, the Company evaluates all investment securities classified as available-for-sale or held-to-maturity, with a decline in fair value below the amortized cost of the investment to determine whether or not the impairment is deemed to be OTTI. Consideration is given to the obligor of the security, whether the security is guaranteed, whether there is a projected adverse change in cash flows, the liquidity of the security, the type of security, the capital position of security issuers, and payment history of the security, amongst other factors when evaluating these individual investment securities. OTTI is required to be recognized if (1) the Company intends to sell the security; (2) 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, the present value of expected cash flows is not sufficient to recover the entire amortized cost basis. For impaired debt securities that the Company intends to sell, or more likely than not will be required to sell, the full amount of the depreciation 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.
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock As a member of the FHLB, the Company is required to invest in stock of the FHLB. Based on redemption provisions, the stock has no quoted market value and is carried at cost. Management evaluates the Company’s investment in the FHLB stock for OTTI at least on a quarterly basis and more frequently when economic or market conditions warrant such evaluation. Based on its most recent analysis of the FHLB as of December 31, 2018, management deems its investment in FHLB stock to not be other-than-temporarily impaired.
Loans Held For Sale	Loans Held For Sale Loans purchased or transferred from held for investment, (if intent or ability to hold existing loans changes), and loans originated and intended for sale in the secondary market are carried at the lower of cost or estimated fair value, in the aggregate. Net unrealized losses, if any, are recognized through a valuation allowance by charges to income. Direct loan origination costs and fees are deferred upon origination and are recognized on the date of sale.
Loans	Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or pay-off generally are reported at their outstanding unpaid principal balances adjusted for charge-offs, the allowance for loan losses, any deferred fees or costs on originated loans and unamortized premiums on purchased loans. Interest income is accrued on the unpaid principal balance. Loan origination fees, net of certain direct origination costs, are deferred and recognized over the expected term as an adjustment of the related loan yield using the interest method. The accrual of interest on all loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of collection. Past due status is based on contractual terms of the loan. In all cases, loans are placed on nonaccrual if collection of principal or interest is considered doubtful. All interest accrued but not collected for loans that are placed on nonaccrual is reversed against interest income. The interest on these loans is accounted for on the cash-basis or cost-recovery method, until qualifying for return to accrual status. Loans are returned to accrual status when all the principal and interest amounts contractually due are brought current and future payments are reasonably assured. Cash receipts of interest income on impaired loans are credited to principal to the extent necessary to eliminate doubt as to the collectability of the net carrying amount of the loan. Some or all of the cash receipts of interest income on impaired loans is recognized as interest income if the remaining net carrying amount of the loan is deemed to be fully collectible. When recognition of interest income on an impaired loan on a cash basis is appropriate, the amount of income that is recognized is limited to that which would have been accrued on the net carrying amount of the loan at the contractual interest rate. Any cash interest payments received in excess of the limit and not applied to reduce the net carrying amount of the loan are recorded as recoveries of charge-offs until the charge-offs are fully recovered.
Allowance for Loan Losses	Allowance for Loan Losses The allowance for loan losses is established as losses are estimated to have occurred through a provision for loan losses charged to earnings. Loan losses are charged against the allowance for loan losses when management believes the uncollectibility of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance for loan losses. The allowance for loan losses is evaluated on a regular basis by management. This evaluation is inherently subjective as it requires estimates that are susceptible to significant revision as more information becomes available. The allowance for loan losses consists of general, allocated and unallocated components, as further described below. General Component: The general component of the allowance for loan losses is based on historical loss experience adjusted for qualitative factors stratified by the following loan segments: residential real estate, home equity lines of credit, commercial real estate, multi-family real estate, construction, commercial, indirect auto and other consumer. Management uses a rolling average of historical losses based on a time frame appropriate to capture relevant loss data for each loan segment. This historical loss factor is adjusted for the following qualitative factors: levels/trends in delinquencies; trends in volume and terms of loans; effects of changes in risk selection and underwriting standards and other changes in lending policies, procedures and practices; experience/ability/depth of lending management and staff; and national and local economic trends and conditions. There were no changes in the Company’s policies or methodology pertaining to the general component of the allowance for loan losses during 2018 or 2017. However, during the year ended December 31, 2018, the Company determined that multi-family real estate loans should be evaluated separately from other commercial real estate loans as its own homogenous loan segment. Accordingly, the related prior year amounts have been reclassified to reflect this change. 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 real estate loans and home equity lines of credit – The Company generally does not originate or purchase loans with a loan-to-value ratio greater than 80 percent and does not grant subprime loans. Loans in this segment are generally collateralized by owner-occupied residential real estate and repayment is primarily dependent on the credit quality of the individual borrower and secondarily, liquidation of the collateral. 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 – Loans in this segment are primarily income-producing properties in eastern Massachusetts. The underlying cash flows generated by the properties are adversely impacted by a downturn in the economy as evidenced by increased vacancy rates, which in turn, will have an effect on the credit quality in this segment. Management generally performs on-site inspections, obtains rent rolls and leases annually and continually monitors the cash flows of these borrowers. Multi-family real estate loans - These loans are primarily secured by five or more unit residential properties. The underlying cash flows generated by the properties may be adversely impacted by a downturn in the economy and increased vacancy rates, which in turn, will have an effect on the credit quality in this segment. Management generally performs on-site inspections, obtains rent rolls annually and continually monitors the cash flows of these borrowers. Construction loans – Loans in this segment primarily include speculative real estate development loans for which payment is derived from sale and/or lease up of the property. Credit risk is affected by cost overruns, time to sell or lease at adequate prices, and market conditions. Commercial loans – Loans in this segment are made to businesses and are primarily secured by real estate and in some cases, other assets of the business. Repayment is expected from the cash flows of the business. A weakened economy, and resultant decreased consumer and business spending, will have an effect on the credit quality in this segment. Indirect auto loans – Loans in this segment are secured installment loans that are originated through a network of select regional automobile dealerships. The Company’s interest in the vehicle is secured with a recorded lien on the state title of each automobile. Collections are sensitive to changes in borrower financial circumstances, and the collateral can depreciate or be damaged in the event of repossession. Repayment is primarily dependent on the credit worthiness and the cash flow of the individual borrower and secondarily, liquidation of collateral. Consumer loans – Loans in this segment include secured and unsecured consumer loans including passbook loans, consumer lines of credit, overdraft protection and other consumer unsecured loans. Repayment is dependent on the credit quality and the cash flow of the individual borrower. Allocated Component: The allocated component relates to loans that are classified as impaired. 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. 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 troubled debt restructuring (“TDR”). All TDRs are classified as impaired and therefore are subject to a specific review for impairment. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate at the time of impairment or, as a practical expedient, at the loan’s observable market price or the fair value of the collateral if the loan is collateral-dependent. Generally, TDRs are measured for impairment using the discounted cash flow method except in instances where foreclosure is probable in which case the fair value of collateral method is used. Loans that have been classified as TDRs and which subsequently default are reviewed to determine if the loan should be deemed collateral dependent. In such an instance, any shortfall between the value of the collateral and the book value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. Generally, all other impaired loans are collateral dependent and impairment is measured through the collateral method. All loans on non-accrual status, with the exception of indirect auto and consumer loans, are considered to be impaired. When the measurement of the impaired loan is less than the recorded investment in the loan, the impairment is recorded through the allowance for loan losses. However, for collateral dependent loans, the amount of the recorded investment in a loan that exceeds the fair value of the collateral is charged-off against the allowance for loan losses in lieu of an allocation of a specific allowance amount when such an amount has been identified definitively as uncollectable. Unallocated Component: An unallocated component is maintained to cover uncertainties that could affect management’s estimate of incurred losses. The unallocated component of the allowance for loan losses reflects the margin of imprecision inherent in the underlying assumptions used in the methodologies for estimating allocated and general reserves in the portfolio. In the ordinary course of business, the Bank enters into commitments to extend credit, commercial letters of credit and standby letters of credit. Such financial instruments are recorded in the consolidated financial statements when they are funded or become payable. The credit risk associated with these commitments is evaluated in a manner similar to the allowance for loan losses. The reserve for off-balance sheet commitments is included in other liabilities in the consolidated balance sheet. At December 31, 2018 and 2017, the reserve for unfunded loan commitments was $16,000 and $36,000, respectively. The related provision for off-balance sheet credit losses is included in non-interest expense in the consolidated statement of operations.
Premises and Equipment	Premises and Equipment Land is carried at cost. Buildings and equipment are stated at cost, less accumulated depreciation, computed on the straight-line method over the estimated useful lives of the assets. It is general practice to charge the cost of maintenance and repairs to earnings when incurred; major expenditures for betterments are capitalized and depreciated over the shorter of the lease term for leasehold improvements or their estimated useful lives. The cost and related accumulated depreciation of assets sold, or otherwise disposed of, are removed from the related accounts and any gain or loss is included in earnings.
Bank-owned Life Insurance	Bank-owned Life Insurance Bank-owned life insurance policies are reflected on the consolidated balance sheets at cash surrender value. Changes in the net cash surrender value of the policies, as well as insurance proceeds received, are reflected in non-interest income on the consolidated statements of operations and are generally not subject to income taxes. The Company reviews the financial strength of the insurance carriers prior to the purchase of life insurance policies and no less than annually thereafter. A life insurance policy with any individual carrier is limited to 15% of tier one capital and the total cash surrender value of life insurance policies is limited to 25% of tier one capital.
Transfers and Servicing of Financial Assets	Transfers and Servicing of Financial Assets Transfers of an entire financial asset, a group of entire financial assets, or a participating interest in an entire financial asset 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. During the normal course of business, the Company may transfer whole loans or a portion of a financial asset, such as a participation loan or the government guaranteed portion of a loan. In order to be eligible for sales treatment, the transfer of the portion of the loan must meet the criteria of a participating interest. If it does not meet the criteria of a participating interest, the transfer will be accounted for as a secured borrowing. In order to meet the criteria for a participating interest, 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 has the right to pledge or exchange the entire loan. The Company services mortgage and indirect auto loans for others. Loan servicing fee income is reported in the consolidated statements of operations as fees are earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal and are recorded as income when earned. Late fees and ancillary fees related to loan servicing are not material. Mortgage servicing rights (“MSR”) are initially recorded as an asset and measured at fair value when loans are sold to third parties with servicing rights retained. MSR assets are amortized in proportion to, and over the period of, estimated net servicing revenues. The carrying value of the MSR assets is periodically reviewed for impairment using the lower of amortized cost or fair value methodology. The fair value of the servicing rights is determined by estimating the present value of future net cash flows, taking into consideration market loan prepayment speeds, discount rates, servicing costs and other economic factors. For purposes of measuring impairment, the underlying loans are stratified into relatively homogeneous pools based on predominant risk characteristics which include product type (i.e., fixed or adjustable) and interest rate bands. If the aggregate carrying value of the capitalized MSR for a stratum exceeds its fair value, MSR impairment is recognized in earnings through a valuation allowance for the difference. As the loans are repaid and net servicing revenue is earned, the MSR asset is amortized as an offset to loan servicing income. Servicing revenues are expected to exceed this amortization expense. However, if actual prepayment experience or defaults exceed what was originally anticipated, net servicing revenues may be less than expected and MSR may be impaired. No servicing assets or liabilities related to auto loans were recorded, as the contractual servicing fees are adequate to compensate the Company for its servicing responsibilities.
Other Real Estate Owned and Other Foreclosed Assets	Other Real Estate Owned and Other Foreclosed Assets Assets acquired through, or in lieu of, loan foreclosure are held for sale and are initially recorded at fair value, less estimated costs to sell, at the date of foreclosure or when control is established, creating 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 cost to sell. Revenue and expenses from operations, changes in the valuation allowance and any direct write downs are included in other non-interest expense. The Company classifies commercial loans as in-substance repossessed or foreclosed if the Company receives physical possession of the debtor’s assets regardless of whether formal foreclosure proceedings take place. The Company classifies residential real estate loans as in-substance repossessed or foreclosed upon either obtaining legal title to the residential real estate property upon completion of a foreclosure or when the borrower conveys all interest in the property to the Company to satisfy the loan through a completion of a deed in lieu of foreclosure or through a similar legal agreement.
Derivative Financial Instruments	Derivative Financial Instruments Derivative financial instruments (“Derivatives”) are carried at fair value in the Company’s consolidated financial statements. The accounting for changes in the fair value of derivatives is determined by whether each derivative has been designated and qualifies as part of a hedging relationship, and further, by the type of hedging relationship. At the inception of a hedge, the Company documents certain items, including but not limited to the following: the relationship between hedging instruments and hedged items, the Company’s risk management objectives, hedging strategies, and the evaluation of hedge transaction effectiveness. Documentation includes linking all derivatives designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific forecasted transactions. For those derivatives that are designated and qualify for special hedge accounting, the Company designates the hedging instrument, based upon the exposure being hedged, as either a fair value hedge or a cash flow hedge. For derivatives that are designated and qualify as a cash flow hedge (i.e., hedging the exposure to variability in expected future cash flows that is attributable to a particular risk), the effective portion of the gain or loss on the derivative is reported as a component of other comprehensive income (loss), net of related tax, and reclassified into earnings in the same period or periods during which the hedged transactions affect earnings. The remaining gain or loss on the derivative in excess of the cumulative change in the present value of future cash flows of the hedged item (i.e., the ineffective portion), if any, is recognized in current earnings during the period. For derivatives designated and qualifying as a fair value hedge (i.e., hedging the exposure to changes in the fair value of an asset or liability or an identified portion thereof that is attributable to the hedged risk), the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item attributable to the hedged risk, are recognized in current earnings during the period of the change in fair values. Hedge accounting is discontinued prospectively when (1) a derivative is no longer highly effective in offsetting changes in the fair value or cash flow of a hedged item, (2) a derivative expires or is settled, (3) it is no longer likely that a forecasted transaction associated with the hedge will occur, or (4) it is determined that designation of a derivative as a hedge is no longer appropriate. For derivatives not designated as hedging instruments, such as loan level derivatives and risk participation agreements, changes in fair value are recognized in other noninterest income during the period of change.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and recorded within marketing expense.
Belmont Savings Bank and Other Supplemental Executive Retirement Plans	Belmont Savings Bank Supplemental Executive Retirement Plan The compensation cost of an employee’s retirement benefit is recognized on the projected unit credit method over the employee’s approximate service period. The aggregate cost method is utilized for funding purposes. The Company accounts for its supplemental executive retirement plan using an actuarial model that allocates benefit costs over the service period of employees 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 or loss. Other Supplemental Executive Retirement Plans The compensation cost of an employee’s retirement benefit is accrued over the estimated period of the employee’s service. At each measurement date, the aggregate amount accrued equals the then present value of the benefits expected to be provided to the employee in exchange for the employee’s service to that date.
Employee Stock Ownership Plan	Employee Stock Ownership Plan Compensation expense for the Employee Stock Ownership Plan (“ESOP”) is recorded at an amount equal to the shares allocated by the ESOP multiplied by the average fair value of the shares during the period. The Company recognizes compensation expense ratably over the year based upon the Company’s estimate of the number of shares expected to be allocated by the ESOP. Unearned compensation applicable to the ESOP is reflected as a reduction of stockholders’ equity in the consolidated balance sheets. The difference between the average fair value and the 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 Company recognizes stock-based compensation based on the grant-date fair value of the award adjusted for expected forfeitures. The Company values share-based stock option awards granted using the Black-Scholes option-pricing model. The Company recognizes compensation expense for its awards on a straight-line basis over the requisite service period for the entire award (straight-line attribution method), ensuring that the amount of compensation cost recognized at any date at least equals the portion of the grant-date fair value of the award that is vested at that time.
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 bases 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 all available evidence, both positive and negative, it is determined that it is more likely than not that some or all of the deferred tax assets will not be realized.
Fair Value Hierarchy	Fair Value Hierarchy The Company measures the fair values of its financial instruments in accordance with accounting guidance that requires an entity to base fair value on exit price, and maximize the use of observable inputs and minimize the use of unobservable inputs to determine the exit price. Under applicable accounting guidance, the Company categorizes its financial instruments, based on the priority of inputs to the valuation technique, into a three-level hierarchy, as described below. Level 1 - Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 - Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 - Inputs are unobservable inputs for the asset or liability. Transfers between levels are recognized at the end of a reporting period, if applicable.
Earnings per Share (EPS)	Earnings per Share (“EPS”) Basic earnings per share is calculated using the two-class method. The two-class method is an earnings allocation formula under which earnings per share is calculated from common stock and participating securities considering both dividends declared (or accumulated) and participation rights in undistributed earnings as if all such earnings had been distributed during the period. Under this method, all earnings distributed and undistributed, are allocated to participating securities and common shares based on their respective rights to receive dividends. Unvested share-based payment awards that contain nonforfeitable rights to dividends are considered participating securities (i.e. unvested restricted stock), not subject to performance based measures. Basic earnings per share is calculated by dividing net income available to common shareholders by the weighted average number of common shares outstanding. Diluted earnings per share have been calculated in a manner similar to that of basic earnings per share except that the weighted average number of common shares outstanding is increased to include the number of additional common shares that would have been outstanding if all potentially dilutive common shares (such as those resulting from the exercise of stock options or the attainment of performance measures) were issued during the period, computed using the treasury stock method.
Comprehensive Income	Comprehensive Income Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income. Although certain changes in assets and liabilities are reported as a separate component of the stockholders’ equity section of the consolidated balance sheets, such items, along with net income, are components of comprehensive income. Other comprehensive income includes unrealized gains and losses on securities available for sale, changes in the value of cash flow hedges and changes in the funded status of the Belmont Savings Bank Supplemental Executive Retirement Plan.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued amendments to ASC section 606 “Revenue from Contracts with Customers” through issuance of ASU 2014-09, “Revenue from Contracts with Customers.” ASU 2014-09 affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides steps to follow to achieve the core principle. An entity should disclose sufficient information to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Qualitative and quantitative information is required about contracts with customers, including significant judgments and changes in judgments made in applying the requirements to those contracts, and assets recognized from the costs to obtain or fulfill a contract. In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606).” The amendments in ASU 2015-14 defer the effective date of ASU 2014-09 for all entities by one year to interim and annual reporting periods beginning after December 15, 2017. Our revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income. The Company adopted this standard as of January 1, 2018 utilizing the modified retrospective approach. As a result, we did not identify any significant changes to our methodology of recognizing revenue and as such, no cumulative effect adjustment to opening retained earnings was deemed necessary. The majority of our revenue-generating transactions are not subject to ASC 606, including revenue generated from financial instruments, such as our loans, letters of credit, derivatives and investment securities, as well as revenue related to our mortgage servicing activities, as these activities are subject to other GAAP discussed elsewhere within our disclosures. Descriptions of our revenue-generating activities that are within the scope of ASC 606, which are presented in our consolidated statements of operations as components of non-interest income are as follows: • Customer service fees - these represent general service fees for monthly account maintenance and activity- or transaction-based fees and consist of transaction-based revenue, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when our performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed (such as a wire transfer, debit card transaction or ATM withdrawal). Payment for such performance obligations is generally received at the time the performance obligations are satisfied. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities.” ASU 2016-01, among other things, (i) requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet, (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, (v) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments, (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and (vii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. The amendments in ASU 2016-01 were effective for the Company on January 1, 2018 with a change to the exit price notion methodology for the Company’s fair value disclosures of financial instruments. The adoption of this guidance was not material to the Company’s consolidated financial statements. Refer to Note 20 – Fair Values of Assets and Liabilities. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” Under ASU 2016-02, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. Consistent with current GAAP, the recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee primarily will depend on its classification as a finance or operating lease. However, unlike current GAAP, which requires only capital leases to be recognized on the balance sheet, ASU 2016-02 will require both types of leases to be recognized on the balance sheet. In July 2018, the FASB issued ASU 2018-11, “Leases (Topic 842) – Targeted Improvements”, which provided an additional, optional transition method to adopt ASU 2016-02 and providing lessors with a practical expedient to not separate lease and nonlease components. In December 2018, the FASB issued ASU 2018-20, “Leases (Topic 842) – Narrow-Scope Improvements for Lessors”, which provided clarification on sales and other taxes collected from lessees, certain lessor costs and recognition of variable payments for contracts with lease and nonlease components. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods therein. Early adoption is permitted. In June 2016, the FASB issued ASU 2016-13, “Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 changes the impairment model for most financial assets and sets forth a “current expected credit loss” model which will require the Company to measure all expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. This method is forward-looking and will generally result in earlier recognition of allowances for losses. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets measured at amortized cost and also applies to some off-balance sheet credit exposures. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. In November 2018, the FASB issued ASU 2018-19, “Codification Improvements to Topic 326, Financial Instruments-Credit Losses”. ASU 2018-19 clarifies that receivables arising from operating leases are not within the scope of ASU 2016-13. The effective date and transition requirements for the amendments in ASU 2018-19 are the same for public business entities as those disclosed in ASU 2016-13 above, while ASU 2018-19 changes the effective date for non public business entities to fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. We are currently evaluating the impact of adopting ASU 2016-13 on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments.” ASU 2016-15 provides guidance on the classification of certain cash receipts and cash payments for presentation in the statement of cash flows. The amendments in ASU 2016-15 were effective for the Company on January 1, 2018 and did not have a material impact on its consolidated financial statements. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash.” ASU 2016-18 requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash or restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in ASU 2016-18 were effective for the Company on January 1, 2018 and did not have a material impact on its consolidated financial statements. In February 2017, the FASB issued ASU 2017-05, “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets.” ASU 2017-05 is meant to clarify the scope of ASC Subtopic 610-20, “Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets.” The amendments in ASU 2017-05 were effective for the Company on January 1, 2018 and did not have a material impact on its consolidated financial statements. In March 2017, the FASB issued ASU 2017-07, “Compensation-Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” ASU 2017-07 is meant to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The amendments in ASU 2017-07 require that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately. The amendments in ASU 2017-07 were effective for the Company on January 1, 2018 and did not have a material impact on its consolidated financial statements. In March 2017, the FASB issued ASU 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities.” The amendments in ASU 2017-08 shorten the amortization period for certain callable debt securities held at a premium. Specifically, the amendments require the premium to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. For public business entities, the amendments in ASU 2017-08 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. The adoption of ASU 2017-08 is not expected to have a material impact on the Company’s consolidated financial statements. In July 2017, the FASB issued ASU 2017-11, “Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception.” The amendments in Part I of ASU 2017-11 change the classification analysis of certain equity-linked financial instruments (or embedded features) with down round features. The amendments in Part II of ASU 2017-11 recharacterize the indefinite deferral of certain provisions of Topic 480 that now are presented as pending content in the Codification, to a scope exception. Those amendments do not have an accounting effect. When determining whether certain financial instruments should be classified as liabilities or equity instruments, a down round feature no longer precludes equity classification when assessing whether the instrument is indexed to an entity’s own stock. The amendments also clarify existing disclosure requirements for equity-classified instruments. For public business entities, the amendments in Part I of ASU 2017-11 are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period for which financial statements (interim or annual) have not been issued or have not been made available for issuance. The amendments in Part II of ASU 2017-11 do not require any transition approach because those amendments do not have an accounting effect. The adoption of ASU 2017-11 is not expected to have a material impact on the Company’s consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities”. The purpose of ASU 2017-12 is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. The amendments in ASU 2017-12 are effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. ASU 2017-12 requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the consolidated statement of financial position as of the date of adoption. The Company adopted this ASU as of January 1, 2018. The adoption of this guidance did not have a material impact on the Company’s consolidated financial statements. Refer to Note 22 – Derivatives and Hedging. In February 2018, the FASB issued ASU 2018-02, “Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income”. The purpose of ASU 2018-02 is to eliminate the stranded tax effects resulting from the Tax Reform Act. The underlying guidance that requires the effect of a change in tax laws or rates be included in income from continuing operations is not affected. The amendments in ASU 2018-02 are effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. The Company early adopted ASU 2018-02 on January 1, 2018 with a reclassification adjustment of $19,000 from accumulated other comprehensive income to retained earnings. In June 2018, the FASB issued ASU 2018-07, “Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting.” The purpose of ASU 2018-07 is to expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The amendments in ASU 2018-07 apply the requirements of Topic 718 to nonemployee awards except for specific guidance on inputs to an option pricing model and the attribution of cost (that is, the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). The amendments in ASU 2018-07 are effective for public business entities for fiscal years beginning after December 15, 2018 including interim periods within that fiscal year. Early adoption is permitted, but no earlier than the adoption of Topic 606. The adoption of this guidance is not expected to have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement”. The purpose of ASU 2018-13 is to improve the effectiveness of disclosures in the notes to financial statements by facilitating clear communication of the information required by GAAP that is most important to users of each entity’s financial statements. The amendments in ASU 2018-13 are effective for public business entities for fiscal years beginning after December 15, 2019. Early adoption is permitted. An entity is permitted to early adopt any removed or modified disclosures upon issuance of ASU 2018-13 and delay adoption of the additional disclosures until their effective date. The amendments removed the disclosure requirements for transfers between Levels 1 and 2 of the fair value hierarchy, the policy for timing of transfers between levels of the fair value hierarchy and the valuation processes for Level 3 fair value measurements. Additionally, the amendments modified the disclosure requirements for investments in certain entities that calculate net asset value and measurement uncertainty. Finally, the amendments added disclosure requirements for the changes in unrealized gains and losses included in other comprehensive income for recurring Level 3 fair value measurements and the range and weighted average of significant unobservable inputs used to develop Level 3 measurements. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. The adoption of ASU 2018-13 is not expected to have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation - Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20).” The purpose of ASU 2018-14 is to improve the effectiveness of disclosures in the notes to financial statements by facilitating clear communication of the information required by GAAP that is most important to users of each entity’s financial statements. The amendments in ASU 2018-14 are effective for public business entities for fiscal years ending after December 15, 2020. Early adoption is permitted. The amendments modified the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The amendments in ASU 2018-14 should be applied retrospectively to all periods presented. The adoption of ASU 2018-14 is not expected to have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, “Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40).” ASU 2018-15 is meant to address the diversity in practice in accounting for the costs of implementation activities performed in a cloud computing arrangement that is a service contract that resulted from the issuance of ASU 2015-05 “Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement.” The amendments in ASU 2018-15 align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The amendments in ASU 2018-15 are effective for public business entities for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. The amendments in ASU 2018-15 should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The adoption of ASU 2018-15 is not expected to have a material impact on the Company’s consolidated financial statements. In October 2018, the FASB issued ASU 2018-16, “Derivatives and Hedging (Topic 815) – Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedging Accounting Purposes” The purpose of ASU 2018-16 is to permit the use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815. The amendments in ASU 2018-16 are effective for public business entities for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, if ASU 2017-12 has already been adopted. The Company has already adopted ASU 2017-12. Early adoption is permitted in any interim period upon issuance of ASU 2018-16 if a public business entity has adopted ASU 2017-12. The amendments in ASU 2018-16 should be applied prospectively for qualifying new or redesignated hedging relationships entered into on or after the date of adoption. The adoption of ASU 2018-16 is not expected to have a material impact on the Company’s consolidated financial statements. In November 2018, the FASB issued ASU 2018-17, “Consolidation (Topic 810) – Targeted Improvements to Related Party Guidance for Variable Interest Entities” The purpose of ASU 2018-17 is to require reporting entities to consider indirect interests held through related parties under common control on a proportional basis rather than as the equivalent of a direct interest in its entirety when determining whether a decision-making fee is a variable interest. The amendments in ASU 2018-17 are effective for public business entities for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted. The amendments in ASU 2018-17 should be applied retrospectively with a cumulative-effect adjustment to retained earnings at the beginning of the earliest period presented. The adoption of ASU 2018-17 is not expected to have a material impact on the Company’s consolidated financial statements. In November 2018, the FASB issued ASU 2018-18, “Collaborative Arrangements (Topic 808) – Clarifying the Interaction Between Topic 808 and Topic 606” The purpose of ASU 2018-18 is to make targeted improvements to generally accepted accounting principles for collaborative arrangements including clarification that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606; adding unit-of-account guidance in Topic 808 to align with the guidance in Topic 606; and precluding presentation of collaborative arrangement transactions together with revenue recognized under Topic 606 if the transaction is not directly related to sales to third parties and the collaborative arrangement participant is not a customer. The amendments in ASU 2018-18 are effective for public business entities for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period, provided the amendments in ASU 2018-18 are not adopted earlier than the adoption of Topic 606. The amendments in ASU 2018-18 should be applied retrospectively to the date of initial application of Topic 606 through a cumulative effect adjustment to the opening balance of retained earnings as of the later of the earliest annual period presented and the annual period that includes the date of initial application of Topic 606. The adoption of ASU 2018-18 is not expected to have a material impact on the Company’s consolidated financial statements.

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Amortized Cost Basis and Fair Value of Available for Sale and Held-to-Maturity Securities	The following table presents a summary of the amortized cost, gross unrealized holding gains and losses and fair value of available-for-sale and held-to-maturity debt securities for the periods indicated. Gross unrealized holding gains and losses on available-for-sale securities are included in accumulated other comprehensive income (loss). December 31, 2018 December 31, 2017 Amortized Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Basis Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities: Corporate debt securities $ 4,162 $ — $ (122 ) $ 4,040 $ 16,975 $ 24 $ (78 ) $ 16,921 $ 4,162 $ — $ (122 ) $ 4,040 $ 16,975 $ 24 $ (78 ) $ 16,921 Held-to-maturity securities: U.S. government sponsored mortgage-backed securities $ 137,261 $ 227 $ (2,863 ) $ 134,625 $ 142,383 $ 145 $ (2,089 ) $ 140,439 Corporate debt securities 10,764 12 (32 ) 10,744 17,707 239 — 17,946 $ 148,025 $ 239 $ (2,895 ) $ 145,369 $ 160,090 $ 384 $ (2,089 ) $ 158,385
Amortized Cost Basis and Estimated Fair Value of Debt Securities by Contractual Maturity	The amortized cost and estimated fair value of debt securities by contractual maturity at December 31, 2018 is as follows. 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. Available-for-Sale Held-to-Maturity Amortized Cost Basis Fair Value Amortized Cost Basis Fair Value Due within one year $ — $ — $ — $ — Due after one year through five years 4,162 4,040 23,073 22,719 Due after five years through ten years — — 18,803 18,246 Due after ten years — — 106,149 104,404 $ 4,162 $ 4,040 $ 148,025 $ 145,369
Securities with Gross Unrealized Losses Aggregated by Investment Category and Length of Time	Information pertaining to investment securities with gross unrealized losses at December 31, 2018 and 2017, aggregated by investment category and length of time that individual investment securities have been in a continuous loss position, follows: Less than 12 Months 12 Months and Over # of Holdings Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2018: Available-for-sale Corporate debt securities 1 $ — $ — $ 4,040 $ (122 ) Held-to-maturity Corporate debt securities 4 7,820 (32 ) — — U.S. government sponsored mortgage-backed securities 97 11,421 (84 ) 103,597 (2,779 ) Total temporarily impaired securities 102 $ 19,241 $ (116 ) $ 107,637 $ (2,901 ) December 31, 2017: Available-for-sale Corporate debt securities 1 $ — $ — $ 4,144 $ (78 ) Held-to-maturity U.S. government sponsored mortgage-backed securities 81 64,056 (718 ) 62,798 (1,371 ) Total temporarily impaired securities 82 $ 64,056 $ (718 ) $ 66,942 $ (1,449 )

LOANS, ALLOWANCE FOR LOAN LOS_2

LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY (Tables)	12 Months Ended
	Dec. 31, 2018
LOANS ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY [Line Items]
Summary of Loans	A summary of the balances of loans follows: December 31, 2018 2017 Mortgage loans on real estate: Residential one-to-four family loans $ 1,583,000 $ 1,333,058 Commercial real estate loans 555,028 486,392 Multi-family real estate loans 203,657 155,680 Home equity lines of credit 163,199 178,624 Construction loans 50,480 53,045 Total real estate loans 2,555,364 2,206,799 Other loans: Commercial loans 62,462 63,722 Indirect auto loans 11,965 30,227 Consumer loans 418 435 74,845 94,384 Total loans 2,630,209 2,301,183 Net deferred loan costs 3,485 3,426 Net unamortized mortgage premiums 8,617 8,661 Allowance for loan losses (17,939 ) (16,312 ) Total loans, net $ 2,624,372 $ 2,296,958
Activity in Allowance for Loan Losses by Portfolio Class and Balances of Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Class	The following tables present the activity in the allowance for loan losses for the years ended December 31, 2018, 2017 and 2016 and the balances of the allowance for loan losses and recorded investment in loans by portfolio class based on impairment method at December 31, 2018 and 2017. The recorded investment in loans in any of the following tables does not include accrued and unpaid interest or any deferred loan fees or costs, as amounts are not significant. Year Ended December 31, 2018 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 6,400 $ 1,034 $ — $ — $ 7,434 Commercial real estate 4,979 819 — — 5,798 Multi-family real estate 1,604 107 — — 1,711 Home equity lines of credit 947 (131 ) — — 816 Construction 764 (42 ) — — 722 Commercial 758 (75 ) (4 ) — 679 Indirect auto 230 (127 ) (32 ) 13 84 Other consumer 9 4 (11 ) 4 6 Unallocated 621 68 — — 689 Total $ 16,312 $ 1,657 $ (47 ) $ 17 $ 17,939 Year Ended December 31, 2017 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 4,828 $ 1,572 $ — $ — $ 6,400 Commercial real estate 3,676 1,303 — — 4,979 Multi-family real estate 1,209 395 — — 1,604 Home equity lines of credit 1,037 (90 ) — — 947 Construction 1,219 (455 ) — — 764 Commercial 728 30 — — 758 Indirect auto 362 (109 ) (45 ) 22 230 Other consumer 9 12 (14 ) 2 9 Unallocated 517 104 — — 621 Total $ 13,585 $ 2,762 $ (59 ) $ 24 $ 16,312 Year Ended December 31, 2016 Beginning Balance Provision (Benefit) Charge-offs Recoveries Ending Balance Residential one-to-four family $ 3,574 $ 1,254 $ — $ — $ 4,828 Commercial real estate 3,495 181 — — 3,676 Multi-family real estate 983 226 — — 1,209 Home equity lines of credit 928 109 — — 1,037 Construction 801 418 — — 1,219 Commercial 613 115 — — 728 Indirect auto 623 (232 ) (85 ) 56 362 Other consumer 10 10 (16 ) 5 9 Unallocated 213 304 — — 517 Total $ 11,240 $ 2,385 $ (101 ) $ 61 $ 13,585 December 31, 2018 Individually evaluated for impairment Collectively evaluated for impairment Total Loan Balance Allowance Loan Balance Allowance Loan Balance Allowance Residential one-to-four family $ 2,545 $ 5 $ 1,580,455 $ 7,429 $ 1,583,000 $ 7,434 Commercial real estate 2,820 — 552,208 5,798 555,028 5,798 Multi-family real estate — — 203,657 1,711 203,657 1,711 Home equity lines of credit — — 163,199 816 163,199 816 Construction — — 50,480 722 50,480 722 Commercial — — 62,462 679 62,462 679 Indirect auto 11 — 11,954 84 11,965 84 Other consumer — — 418 6 418 6 Unallocated — — — 689 — 689 Total $ 5,376 $ 5 $ 2,624,833 $ 17,934 $ 2,630,209 $ 17,939 December 31, 2017 Individually evaluated for impairment Collectively evaluated for impairment Total Loan Balance Allowance Loan Balance Allowance Loan Balance Allowance Residential one-to-four family $ 2,688 $ 147 $ 1,330,370 $ 6,253 $ 1,333,058 $ 6,400 Commercial real estate 2,877 — 483,515 4,979 486,392 4,979 Multi-family real estate — — 155,680 1,604 155,680 1,604 Home equity lines of credit — — 178,624 947 178,624 947 Construction — — 53,045 764 53,045 764 Commercial — — 63,722 758 63,722 758 Indirect auto 4 — 30,223 230 30,227 230 Other consumer — — 435 9 435 9 Unallocated — — — 621 — 621 Total $ 5,569 $ 147 $ 2,295,614 $ 16,165 $ 2,301,183 $ 16,312
Information about Loans that Meet Definition of Impaired Loan	Information about loans that meet the definition of an impaired loan in ASC 310-10-35 is as follows as of December 31, 2018 and 2017: Impaired loans with a related allowance for credit losses at December 31, 2018 Unpaid Related Recorded Principal Allowance For Investment Balance Credit Losses Residential one-to-four family $ 192 $ 192 $ 5 Totals $ 192 $ 192 $ 5 Impaired loans with no related allowance for credit losses at December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 2,353 $ 2,476 $ — Commercial real estate 2,820 2,820 — Indirect auto 11 11 — Totals $ 5,184 $ 5,307 $ — Impaired loans with a related allowance for credit losses at December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 725 $ 725 $ 147 Totals $ 725 $ 725 $ 147 Impaired loans with no related allowance for credit losses at December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance For Credit Losses Residential one-to-four family $ 1,963 $ 2,052 $ — Commercial real estate 2,877 2,877 — Indirect auto 4 4 — Totals $ 4,844 $ 4,933 $ —
Information regarding Interest Income Recognized on Impaired Loans	The following tables set forth information regarding interest income recognized on impaired loans, by portfolio, for the periods indicated. Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016 With an allowance recorded Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Residential one-to-four family $ 238 $ 11 $ 897 $ 32 $ 1,273 $ 33 Commercial real estate — — — — 3,124 136 Totals $ 238 $ 11 $ 897 $ 32 $ 4,397 $ 169 Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016 Without an allowance recorded Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Residential one-to-four family $ 2,074 $ 50 $ 1,986 $ 94 $ 2,977 $ 78 Commercial real estate 2,848 123 3,159 140 784 34 Home equity lines of credit 8 — 106 13 200 8 Indirect auto 7 — 6 — 12 — Totals $ 4,937 $ 173 $ 5,257 $ 247 $ 3,973 $ 120
Summary of Past Due and Non-Accrual Loans	The following is a summary of past due and non-accrual loans at December 31, 2018 and 2017: December 31, 2018 30–59 Days 60–89 Days 90 Days or More Total Past Due 90 days or more and accruing Loans on Non-accrual Real estate loans: Residential one-to-four family $ 438 $ 239 $ 721 $ 1,398 $ — $ 1,159 Home equity lines of credit 214 — — 214 — — Other loans: Indirect auto 189 33 11 233 — 11 $ 841 $ 272 $ 732 $ 1,845 $ — $ 1,170 December 31, 2017 30–59 Days 60–89 Days 90 Days or More Total Past Due 90 days or more and accruing Loans on Non-accrual Real estate loans: Residential one-to-four family $ 711 $ — $ 260 $ 971 $ — $ 1,372 Home equity lines of credit 716 — — 716 — — Other loans: Indirect auto 347 30 4 381 — 4 $ 1,774 $ 30 $ 264 $ 2,068 $ — $ 1,376
Company's Loans by Risk Rating	The following table presents the Company’s loans by risk rating at December 31, 2018 and 2017. There were no loans rated as 6 (“doubtful”) or 7 (“loss”) at the dates indicated. December 31, 2018 Loans rated 1-3.5 Loans rated 4 Loans rated 5 Loans not rated (A) Total Residential one-to-four family $ — $ 335 $ 1,832 $ 1,580,833 $ 1,583,000 Commercial real estate 551,327 — 3,701 — 555,028 Multi-family real estate 203,657 — — — 203,657 Construction 50,480 — — — 50,480 Commercial 62,462 — — — 62,462 Home equity lines of credit — — — 163,199 163,199 Indirect auto — — — 11,965 11,965 Other consumer — — — 418 418 Total $ 867,926 $ 335 $ 5,533 $ 1,756,415 $ 2,630,209 December 31, 2017 Loans rated 1-3.5 Loans rated 4 Loans rated 5 Loans not rated (A) Total Residential one-to-four family $ — $ 344 $ 2,060 $ 1,330,654 $ 1,333,058 Commercial real estate 482,574 — 3,818 — 486,392 Multi-family real estate 155,680 — — — 155,680 Construction 53,045 — — — 53,045 Commercial 63,682 40 — — 63,722 Home equity lines of credit — — 772 177,852 178,624 Indirect auto — — — 30,227 30,227 Other consumer — — — 435 435 Total $ 754,981 $ 384 $ 6,650 $ 1,539,168 $ 2,301,183
Trouble Debt Restructuring Accrual Status	The following table shows the Company’s total TDRs and other pertinent information as of the dates indicated: December 31, 2018 December 31, 2017 TDRs on Accrual Status $ 4,206 $ 4,194 TDRs on Non-accrual Status — 645 Total TDRs $ 4,206 $ 4,839 Amount of specific allocation included in the allowance for loan losses associated with TDRs $ 5 $ 147 Additional commitments to lend to a borrower who has been a party to a TDR $ — $ —
Troubled Debt Restructurings on Financing Receivables	The following table shows the TDR modifications which occurred during the years ended December 31, 2017 and 2016 and the outstanding recorded investment subsequent to the modifications occurring: Year Ended December 31, 2017 # of Contracts Pre-modification outstanding recorded investment Post-modification outstanding recorded investment (a) Real estate loans: Commercial real estate 1 $ 273 $ 273 1 $ 273 $ 273 Year Ended December 31, 2016 # of Contracts Pre-modification outstanding recorded investment Post-modification outstanding recorded investment (a) Real estate loans: Residential one-to-four family 1 $ 621 $ 699 Commercial real estate 3 3,394 3,394 4 $ 4,015 $ 4,093
Post Modification of Trouble Debt Restructuring Balance	The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the years indicated: For the Years Ended December 31, 2017 December 31, 2016 Capitalization of interest, taxes and extended maturity $ — $ 699 Extended maturity 273 3,394 Total $ 273 $ 4,093
Modified and subsequently defaulted
LOANS ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY [Line Items]
Troubled Debt Restructurings On Financing Receivables That Subsequently Defaulted [Table Text Block]	The following table shows the loans that have been modified during the past twelve months which have subsequently defaulted during the periods indicated: For the years ended December 31, 2018 2017 2016 Number of Contracts Recorded Investment Number of Contracts Recorded Investment Number of Contracts Recorded Investment TDRs that subsequently defaulted Residential one-to-four family — $ — — $ — 1 $ 497 Totals — $ — — $ — 1 $ 497

TRANSFERS AND SERVICING (Tables

TRANSFERS AND SERVICING (Tables)	12 Months Ended
	Dec. 31, 2018
Transfers and Servicing [Abstract]
Changes in Mortgage Servicing Rights	Changes in mortgage servicing rights, which are included in other assets, were as follows, during the periods indicated: Years Ended December 31, 2018 2017 2016 Balance at beginning of period $ 855 $ 403 $ 479 Capitalization 402 508 85 Amortization (205 ) (130 ) (101 ) Valuation allowance adjustment 50 74 (60 ) Balance at end of period $ 1,102 $ 855 $ 403

PREMISES AND EQUIPMENT (Tables)

PREMISES AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Cost and Accumulated Depreciation of Premises and Equipment	A summary of the cost and accumulated depreciation of premises and equipment follows: December 31, 2018 2017 Land $ 161 $ 161 Buildings 3,516 3,516 Leasehold improvements 1,414 1,414 Furniture and equipment 4,736 4,350 9,827 9,441 Accumulated depreciation (7,650 ) (7,187 ) $ 2,177 $ 2,254

DEPOSITS (Tables)

DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Scheduled Maturities of Time Deposits	At December 31, 2018, the scheduled maturities of time deposits are as follows: 2019 $ 418,035 2020 165,487 2021 63,731 2022 38,984 2023 73,030 $ 759,267

LONG-TERM BORROWINGS (Tables)

LONG-TERM BORROWINGS (Tables)	12 Months Ended
	Dec. 31, 2018
Federal Home Loan Bank Advances
Schedule of Maturities of Long-Term Debt	Long-term debt at December 31, 2018 and 2017 consists of the following fixed rate FHLB advances: Amount Weighted Average Rate 2018 2017 2018 2017 Fixed rate advances maturing: 2018 $ — $ 47,000 — % 1.63 % 2019 225,250 225,250 1.49 % 1.49 % 2020 35,000 35,000 1.76 % 1.76 % 2021 15,000 15,000 2.03 % 2.03 % 2022 110,000 95,000 2.27 % 2.17 % 2023 70,000 — 3.04 % — % $ 455,250 $ 417,250 1.96 % 1.70 %

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2018
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: Years Ended December 31, 2018 2017 2016 Current tax provision: Federal $ 6,215 $ 7,386 $ 7,212 State 2,809 1,961 1,954 9,024 9,347 9,166 Deferred tax expense (benefit): Federal (335 ) (71 ) (1,391 ) State (157 ) (20 ) (350 ) Effect of change in statutory federal tax rate — 2,626 — (492 ) 2,535 (1,741 ) Total provision for income taxes $ 8,532 $ 11,882 $ 7,425
Summary of Reasons for Differences between Statutory Income Tax Rate and Effective Tax Rate	The reasons for the differences between the statutory federal income tax rate and the effective tax rates are summarized as follows: Years Ended December 31, 2018 2017 2016 Statutory federal tax rate 21.0 % 35.0 % 35.0 % Increase (decrease) resulting from: State taxes, net of federal tax benefit 6.7 4.8 5.4 Bank-owned life insurance (1.0 ) (1.5 ) (1.9 ) Tax exempt income (0.3 ) (0.6 ) (0.8 ) Change in statutory federal tax rate — 10.0 — Share based compensation (0.5 ) (3.5 ) 1.2 Non-deductible merger expenses 1.1 — — Other, net 0.1 1.0 (0.6 ) Effective tax rates 27.1 % 45.2 % 38.3 %
Components of Net Deferred Tax Assets	The components of the net deferred tax asset are as follows: December 31, 2018 2017 Deferred tax assets: Employee benefit and deferred compensation plans $ 2,428 $ 2,375 Allowance for loan losses 5,047 4,596 Accrued rent 7 8 Interest on non-performing loans 35 34 Stock options 313 356 Unrealized loss on securities available for sale 34 15 Cash flow hedge 499 — ESOP 104 92 Gross deferred tax assets 8,467 7,476 Deferred tax liabilities: Mortgage servicing rights (310 ) (240 ) Deferred loan origination costs (948 ) (860 ) Restricted stock awards (203 ) (280 ) Depreciation (142 ) (201 ) Unrecognized retirement benefit (69 ) (58 ) Other (2 ) (43 ) Gross deferred tax liabilities (1,674 ) (1,682 ) Net deferred tax asset $ 6,793 $ 5,794

OFF-BALANCE SHEET ARRANGEMENTS

OFF-BALANCE SHEET ARRANGEMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Off Balance Sheet Arrangements [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]	At December 31, 2018 and 2017, the following financial instruments were outstanding whose contract amounts represent credit risk: Contract Amount 2018 2017 Commitments to grant loans $ 10,189 $ 23,702 Unfunded commitments under lines of credit 339,360 325,768 Unadvanced portion of construction loans 72,375 11,486 Standby letters of credit 869 561 Commitments to purchase loans 31,494 65,692

COMMITMENTS AND CONTINGENT LI_2

COMMITMENTS AND CONTINGENT LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Pursuant to the terms of noncancelable lease agreements in effect at December 31, 2018, pertaining to banking premises and equipment, future minimum rent commitments under various operating leases are as follows: 2019 $ 360 2020 266 2021 122 2022 122 2023 78 Thereafter 44 $ 992

MINIMUM REGULATORY CAPITAL RE_2

MINIMUM REGULATORY CAPITAL REQUIREMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Actual Capital Amounts and Ratio	The following table presents actual and required capital ratios as of December 31, 2018 and December 31, 2017 for the Company and the Bank under the Basel III Capital Rules. The minimum required capital amounts presented include the minimum required capital levels as of December 31, 2018 and December 31, 2017 based on the phase-in provisions of the Basel III Capital Rules and the minimum required capital levels as of January 1, 2019 when the Basel III Capital Rules become fully phased-in. Capital levels required to be considered well-capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. Minimum Capital Required Minimum Capital Required Minimum To Be Well Minimum Capital For Capital Adequacy Plus For Capital Adequacy Plus Capitalized Under Required For Capital Conservation Buffer Capital Conservation Buffer Prompt Corrective Actual Capital Adequacy Basel III Phase-In Schedule Basel III Fully Phased In Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio As of December 31, 2018: Total Capital (to Risk Weighted Assets) Consolidated $ 220,938 11.75 % $ 150,424 8.00 % $ 185,680 9.875 % $ 197,431 10.50 % N/A N/A Belmont Savings Bank 215,460 11.46 % 150,436 8.00 % 185,695 9.875 % 197,448 10.50 % $ 188,045 10.00 % Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 202,983 10.80 % $ 112,818 6.00 % $ 148,074 7.875 % $ 159,825 8.50 % N/A N/A Belmont Savings Bank 197,505 10.50 % 112,827 6.00 % 148,086 7.875 % 159,839 8.50 % $ 150,436 8.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 202,983 10.80 % $ 84,613 4.50 % $ 119,869 6.375 % $ 131,621 7.00 % N/A N/A Belmont Savings Bank 197,505 10.50 % 84,620 4.50 % 119,879 6.375 % 131,632 7.00 % $ 122,229 6.50 % Tier 1 Capital (to Average Assets) Consolidated $ 202,983 6.97 % $ 116,553 4.00 % $ 116,553 4.00 % $ 116,553 4.00 % N/A N/A Belmont Savings Bank 197,505 6.78 % 116,553 4.00 % 116,553 4.00 % 116,553 4.00 % $ 145,692 5.00 % Minimum Capital Required Minimum Capital Required Minimum To Be Well Minimum Capital For Capital Adequacy Plus For Capital Adequacy Plus Capitalized Under Required For Capital Conservation Buffer Capital Conservation Buffer Prompt Corrective Actual Capital Adequacy Basel III Phase-In Schedule Basel III Fully Phased In Action Provisions Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio As of December 31, 2017: Total Capital (to Risk Weighted Assets) Consolidated $ 194,287 11.30 % $ 137,498 8.00 % $ 158,982 9.25 % $ 180,466 10.50 % N/A N/A Belmont Savings Bank 189,311 11.01 % 137,497 8.00 % 158,981 9.25 % 180,465 10.50 % $ 171,871 10.00 % Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 177,939 10.35 % $ 103,123 6.00 % $ 124,607 7.25 % $ 146,092 8.50 % N/A N/A Belmont Savings Bank 172,963 10.06 % 103,123 6.00 % 124,607 7.25 % 146,091 8.50 % $ 137,497 8.00 % Common Equity Tier 1 Capital (to Risk Weighted Assets) Consolidated $ 177,939 10.35 % $ 77,343 4.50 % $ 98,827 5.75 % $ 120,311 7.00 % N/A N/A Belmont Savings Bank 172,963 10.06 % 77,342 4.50 % 98,826 5.75 % 120,310 7.00 % $ 111,716 6.50 % Tier 1 Capital (to Average Assets) Consolidated $ 177,939 6.97 % $ 102,148 4.00 % $ 102,148 4.00 % $ 102,148 4.00 % N/A N/A Belmont Savings Bank 172,963 6.77 % 102,147 4.00 % 102,147 4.00 % 102,147 4.00 % $ 127,683 5.00 %

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2018
Information Pertaining to Activity in Plan	Information pertaining to the activity in the plan is as follows: Years Ended December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 1,798 $ 1,521 Service cost 258 253 Interest cost 68 66 Actuarial gain (53 ) (42 ) Benefit obligation at end of year 2,071 1,798 Funded status at end of year $ (2,071 ) $ (1,798 ) Accrued pension benefit $ (2,317 ) $ (2,003 ) Accumulated benefit obligation $ 1,397 $ 1,175
Components of Net Periodic Pension Cost	The components of net periodic pension cost are as follows: December 31, 2018 2017 Service cost $ 258 $ 253 Interest cost 68 66 Amortization of gain (18 ) (19 ) Amortization of prior service cost 6 6 Net periodic cost $ 314 $ 306
Other Changes in Benefit Obligations Recognized in Other Comprehensive Loss	Other changes in benefit obligations recognized in other comprehensive loss are as follows: December 31, 2018 2017 Amortization of prior service cost $ (6 ) $ (6 ) Amortization of unrecognized gain 19 19 Net actuarial gain (53 ) (42 ) Total recognized in other comprehensive loss $ (40 ) $ (29 )
Amounts Recognized in Accumulated Other Comprehensive Income, before Tax Effects	Amounts recognized in accumulated other comprehensive loss, before tax effects, consist of the following: December 31, 2018 2017 Unrecognized prior service cost $ 34 $ 40 Unrecognized net gain (279 ) (245 ) Total recognized in other comprehensive loss $ (245 ) $ (205 )
Estimated Future Benefit Payments	Estimated future benefit payments, which reflect expected future service, as appropriate, are as follows: Year Ending December 31, Amount 2019 $ 58 2020 192 2021 267 2022 267 2023 267 Years 2024-2028 1,628
Schedule of Employee Stock Ownership Plan (ESOP) Disclosures	At December 31, 2018, the remaining principal balance on the ESOP debt is payable as follows: Years Ending December 31, Amount 2019 $ 88 2020 93 2021 98 2022 104 2023 110 Thereafter 3,380 $ 3,873 Shares held by the ESOP include the following: December 31, 2018 2017 Unallocated 347,803 363,091 Allocated 96,799 84,813 444,602 447,904
Defined Benefit Obligations [Member]
Schedule of Assumptions Used	The assumptions used to determine the benefit obligation are as follows: December 31, 2018 2017 Discount rate 4.25 % 3.80 % Rate of compensation increase 3.00 % 3.00 %
Net Periodic Benefit Costs [Member]
Schedule of Assumptions Used	The assumptions used to determine net periodic pension cost are as follows: December 31, 2018 2017 Discount rate 3.80 % 4.35 % Rate of compensation increase 3.00 % 3.00 %

STOCK BASED COMPENSATION (Table

STOCK BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2018
Cumulatively Granted Restricted Stock Awards Net of Forfeitures	The following table presents the amount of cumulatively granted restricted stock awards, net of forfeitures, through December 31, 2018 under the BSB Bancorp, Inc. 2017 Equity Incentive Plan: Cumulative Granted Authorized Authorized Net of Forfeitures Stock Restricted Authorized Stock Restricted Outstanding Option Awards Stock Awards Total Option Awards Stock Awards Total 2012 Equity Incentive Plan 917,286 366,914 1,284,200 889,092 363,570 1,252,662 2017 Equity Incentive Plan — 487,200 487,200 — 487,200 487,200
Pre-Tax Expense Associated with Stock Option and Restricted Stock Awards and Related Tax Benefits Recognized	The following table presents the pre-tax expense associated with stock option and restricted stock awards and the related tax benefits recognized: For the year ended December 31, 2018 2017 2016 Stock based compensation expense Stock options $ 73 $ 724 $ 780 Restricted stock awards 1,332 1,835 869 Total stock based award expense $ 1,405 $ 2,559 $ 1,649 Related tax benefits recognized in earnings $ 376 $ 874 $ 492
Unrecognized Compensation Cost Related to Non-Vested Awards and Weighted Average Recognition Period	Total compensation cost related to non-vested awards not yet recognized and the weighted average period (in years) over which it is expected to be recognized is as follows: As of December 31, 2018 Weighted Amount average period Stock options $ 69 1.85 Restricted stock 9,637 8.21 Total $ 9,706
Summary of Stock Option	The following table presents relevant information relating to the Company’s stock options for the periods indicated: For the year ended December 31, 2018 2017 2016 Weighted average grant date fair value of options granted $ — $ — $ 4.63 Intrinsic value of stock options exercised 1,829 3,299 368 Cash paid to settle equity instruments granted under stock based compensation arrangements — — —
Fair Value of Stock Options Granted Estimate on Date of Grant Using Black-Scholes Option-Pricing Model	Date of grant 3/1/2016 Options granted 27,500 Exercise price $ 22.31 Vesting period (1) 5 years Expiration date 3/1/2026 Expected volatility 16.13 % Expected term 6.5 years Expected dividend yield 0 % Risk free interest rate 1.54 % Fair value $ 4.63 (1)- Vesting is ratably and the period begins on the date of grant.
Summary of Stock Option and Restricted Stock Awards	A summary of the status of the Company’s Stock Option and Restricted Stock Awards for the year ended December 31, 2018 is presented in the tables below: Outstanding Stock option awards Weighted average exercise price Weighted average remaining contractual term (in years) Aggregate intrinsic value Balance at January 1, 2018 590,522 $ 12.86 Granted — — Exercised (99,199 ) 12.10 Forfeited — — Balance at December 31, 2018 491,323 $ 13.02 4.22 $ 7,390 Exercisable 464,428 $ 12.58 4.08 $ 7,189 Non-vested restricted stock awards Weighted average grant price Balance at January 1, 2018 484,902 $ 27.07 Granted 3,898 32.30 Vested (49,137 ) 26.94 Forfeited — — Balance at December 31, 2018 439,663 $ 27.13
Adoption of ASU 2016-09
Excess Tax Benefits Recognized from Stock Based Compensation	Excess tax benefits recognized from stock-based compensation for the periods indicated below are as follows: For the year ended December 31, 2018 2017 Excess tax benefits recognized in net income $ 324 $ 1,348

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Components of Earning Per Share	Earnings per share consisted of the following components for the years ended December 31, 2018, 2017 and 2016: December 31, December 31, December 31, 2018 2017 2016 Net income $ 22,909 $ 14,386 $ 11,981 Undistributed earnings attributable to participating securities (3 ) (108 ) (190 ) Net income available to common stockholders $ 22,906 $ 14,278 $ 11,791 Weighted average shares outstanding, basic 8,941,394 8,754,393 8,571,861 Effect of dilutive shares 445,297 429,400 286,030 Weighted average shares outstanding, assuming dilution 9,386,691 9,183,793 8,857,891 Basic EPS $ 2.56 $ 1.63 $ 1.38 Effect of dilutive shares (0.12 ) (0.08 ) (0.05 ) Diluted EPS $ 2.44 $ 1.55 $ 1.33

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes financial assets measured at fair value on a recurring basis as of December 31, 2018 and 2017, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value: Level 1 Level 2 Level 3 Total Fair Value At December 31, 2018 Assets: Securities available-for-sale Corporate debt securities $ — $ 4,040 $ — $ 4,040 Rabbi trust investments 2,787 — — 2,787 Derivatives: Interest rate caps — 2,303 — 2,303 Interest rate swaps — 2,967 — 2,967 Risk participation-out agreements — 22 — 22 Totals $ 2,787 $ 9,332 $ — $ 12,119 Liabilities: Derivatives: Interest rate swaps $ — $ 3,144 $ — $ 3,144 Totals $ — $ 3,144 $ — $ 3,144 Level 1 Level 2 Level 3 Total Fair Value At December 31, 2017 Securities available-for-sale Corporate debt securities $ — $ 16,921 $ — $ 16,921 Rabbi trust investments 2,808 — — 2,808 Totals $ 2,808 $ 16,921 $ — $ 19,729
Schedule of Estimated Fair Values and Related Carrying or Notional Amounts of Financial Instruments	The estimated fair values, and related carrying or notional amounts, of the Company’s financial instruments are as follows for the periods indicated: December 31, 2018 Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 143,378 $ 143,378 $ 143,378 $ — $ — Interest-bearing time deposits with other banks 4,229 4,229 — 4,229 — Held-to-maturity securities 148,025 145,369 — 145,369 — Federal Home Loan Bank stock 38,658 38,658 — 38,658 — Loans, net 2,624,372 2,537,595 — — 2,537,595 Accrued interest receivable 7,290 7,290 7,290 — — Bank owned life insurance 36,540 36,540 — 36,540 Financial liabilities: Deposits 1,960,912 1,956,139 1,201,644 754,495 — Federal Home Loan Bank advances 838,250 834,495 — 834,495 — Securities sold under agreements to repurchase 2,883 2,883 — 2,883 — Accrued interest payable 2,050 2,050 2,050 — — Mortgagors’ escrow accounts 6,338 6,338 — 6,338 — December 31, 2017 Carrying Amount Fair Value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 110,888 $ 110,888 $ 110,888 $ — $ — Interest-bearing time deposits with other banks 2,440 2,440 — 2,440 — Held-to-maturity securities 160,090 158,385 — 158,385 — Federal Home Loan Bank stock 32,382 32,382 — 32,382 — Bank owned life insurance 36,967 36,967 — 36,967 Loans, net 2,296,958 2,251,971 — — 2,251,971 Accrued interest receivable 6,344 6,344 6,344 — — Financial liabilities: Deposits 1,751,251 1,748,995 1,246,537 502,458 — Federal Home Loan Bank advances 723,150 719,430 — 719,430 — Securities sold under agreements to repurchase 3,268 3,268 — 3,268 — Accrued interest payable 1,594 1,594 1,594 — — Mortgagors’ escrow accounts 4,690 4,690 — 4,690 —
Asset Held For Sale
Assets Measured on Non-recurring Basis	The following table presents loans held for sale at December 31, 2018 and 2017. December 31, 2018 Level 1 Level 2 Level 3 Loans held for sale $ — $ — $ 2,902 Totals $ — $ — $ 2,902 December 31, 2017 Level 1 Level 2 Level 3 Loans held for sale $ — $ — $ — Totals $ — $ — $ —
Non-financial Assets
Assets Measured on Non-recurring Basis	The following table presents the non-financial assets that were re-measured and reported at the lower of cost or fair value at the periods indicated: December 31, 2018 Level 1 Level 2 Level 3 Mortgage servicing rights $ — $ — $ 1,102 Totals $ — $ — $ 1,102 December 31, 2017 Level 1 Level 2 Level 3 Mortgage servicing rights $ — $ — $ 855 Totals $ — $ — $ 855

OTHER COMPREHENSIVE (LOSS) IN_2

OTHER COMPREHENSIVE (LOSS) INCOME (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Schedules of Other Comprehensive (Loss) Income	The following table presents a reconciliation of the changes in the components of other comprehensive (loss) income for the dates indicated, including the amount of income tax benefit (expense) allocated to each component of other comprehensive (loss) income: Year Ended December 31, 2018 Pre Tax Amount Tax Benefit (Expense) After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ (68 ) $ 19 $ (49 ) Net change in fair value of securities available for sale (68 ) 19 (49 ) Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 53 (15 ) 38 Reclassification adjustment included in net income 1 (13 ) 4 (9 ) Net change defined-benefit post-retirement benefit plans 40 (11 ) 29 Cash flow hedges: Change in fair value of cash flow hedges (1,782 ) 501 (1,281 ) Reclassification adjustment included in net income 2 7 (2 ) 5 Net change in fair value of cash flow hedges (1,775 ) 499 (1,276 ) Total other comprehensive loss $ (1,803 ) $ 507 $ (1,296 ) Year Ended December 31, 2017 Pre Tax Amount Tax Benefit (Expense) After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ (13 ) $ 5 $ (8 ) Reclassification adjustment for net gains included in net income 3 (38 ) 15 (23 ) Net change in fair value of securities available for sale (51 ) 20 (31 ) Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 42 (17 ) 25 Reclassification adjustment included in net income 1 (13 ) 5 (8 ) Net change defined-benefit post-retirement benefit plans 29 (12 ) 17 Total other comprehensive loss $ (22 ) $ 8 $ (14 ) Year Ended December 31, 2016 Pre Tax Amount Tax Expense After Tax Amount Securities available-for-sale: Change in fair value of securities available for sale $ 247 $ (98 ) $ 149 Net change in fair value of securities available for sale 247 (98 ) 149 Defined benefit post-retirement benefit plans: Change in the actuarial gain/loss 112 (46 ) 66 Reclassification adjustment included in net income 1 6 (2 ) 4 Net change defined-benefit post-retirement benefit plans 118 (48 ) 70 Total other comprehensive income $ 365 $ (146 ) $ 219 1- Reclassification adjustments are comprised of amortization of prior service cost and unrecognized gain (loss) and have been reclassified out of accumulated 2- Reclassification adjustments are comprised of amortization of the interest rate cap premiums paid upon execution under the Caplet method. The deferred premium has been reclassified out of accumulated o 3- Reclassification adjustments are comprised of realized security gains. The gains have been reclassified out of accumulated
Components of Accumulated Other Comprehensive (Loss) Income, included in Stockholders' Equity	The components of accumulated o (loss) i December 31, 2018 December 31, 2017 Net unrealized holding loss on available-for-sale securities, net of tax $ (88 ) $ (32 ) Unrecognized benefit pertaining to defined benefit plan, net of tax 176 121 Unrealized holding loss on cash flow hedges, net of tax (1,276 ) — Accumulated $ (1,188 ) $ 89

DERIVATIVES AND HEDGING (Tables

DERIVATIVES AND HEDGING (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Financial Instruments	The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the consolidated balance sheets as of the periods presented: Fair Value of Derivative Instruments Asset Derivatives December 31, 2018 December 31, 2017 Number of Transactions Notional Amount Balance Sheet Location Fair Value Number of Transactions Notional Amount Balance Sheet Location Fair Value Derivatives designated as hedging instruments: Interest rate caps 3 $ 200,000 Other Assets $ 2,303 — $ — Other Assets $ — Total derivatives designated as hedging instruments $ 2,303 $ — Derivatives not designated as hedging instruments: Interest Rate Swaps - Commercial Loan Customers 9 $ 76,792 Other Assets $ 2,967 — $ — Other Assets $ — Risk Participation-Out Agreements - Third Party Financial Institution 3 $ 6,340 Other Assets 22 — $ — Other Assets — Total derivatives not designated as hedging instruments $ 2,989 $ — Fair Value of Derivative Instruments Liability Derivatives December 31, 2018 December 31, 2017 Number of Transactions Notional Amount Balance Sheet Location Fair Value Number of Transactions Notional Amount Balance Sheet Location Fair Value Derivatives not designated as hedging instruments: Interest Rate Swaps - Third Party Financial Institution 9 $ 76,792 Other Liabilities $ 3,144 — $ — Other Liabilities $ — Total derivatives not designated as hedging instruments $ 3,144 $ —
Derivative Financial Instruments Included in Other Comprehensive (Loss) Income and Reclassifications into Earnings	The following table presents the effect of the Company’s derivative financial instruments included in other comprehensive (loss) income and reclassifications into earnings for the periods indicated: Amount of Pre-Tax Gain (Loss) Recognized in Other Comprehensive Income on Derivatives Location of Pre-Tax Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income Amount of Pre-Tax Gain (Loss) Reclassified from Accumulated Income Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2018 Year Ended December 31, 2017 Derivatives in Cash Flow Hedging Relationships Interest Rate Products $ (1,782 ) $ — Interest expense $ (7 ) $ — Total $ (1,782 ) $ — $ (7 ) $ —
Effect of Derivative Financial Instruments included in Current Earnings	The following table presents the effect of the Company’s derivative financial instruments included in current earnings for the periods indicated: Location of Gain (Loss) Recognized in Income on Derivative Instruments Amount of Gain (Loss) Recognized in Income on Derivative Instruments Year Ended December 31, 2018 Year Ended December 31, 2017 Interest Rate Swaps Loan level derivative income $ (177 ) $ — Risk Participation-Out Agreements Loan level derivative income 7 — Total $ (170 ) $ —

BALANCE SHEET OFFSETTING (Table

BALANCE SHEET OFFSETTING (Tables)	12 Months Ended
	Dec. 31, 2018
Offsetting [Abstract]
Asset and Liability Derivative Positions and Repurchase Agreements	The following tables present the Company’s asset and liability derivative positions and repurchase agreements and the potential effect of netting arrangements on its financial position, as of the periods indicated: December 31, 2018 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Assets Gross Amounts Offset in the Statement of Financial Position Net Amounts of Assets Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Derivative Assets $ 5,292 $ — $ 5,292 $ 2,304 $ — $ 2,988 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Derivative Liabilities $ 3,144 $ — $ 3,144 $ 2,304 $ 240 $ 600 Securities sold under agreements to repurchase $ 2,883 $ — $ 2,883 $ — $ 2,883 $ — December 31, 2017 Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts of Recognized Liabilities Gross Amounts Offset in the Statement of Financial Position Net Amounts of Liabilities Presented in the Statement of Financial Position Financial Instruments Collateral Pledged (Received) Net Amount Securities sold under agreements to repurchase $ 3,268 $ — $ 3,268 $ — $ 3,268 $ —

CONDENSED FINANCIAL STATEMENT_2

CONDENSED FINANCIAL STATEMENTS OF PARENT COMPANY (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheets	The following condensed financial statements are for the Parent Company only and should be read in conjunction with the consolidated financial statements of the Company. Condensed Balance Sheets December 31, 2018 2017 Assets Cash and cash equivalents held at Belmont Savings Bank $ 1,440 $ 919 Investment in Belmont Savings Bank 196,318 173,054 Investment in BSB Funding Corp. 4,192 4,065 Other assets 25 45 Total assets $ 201,975 $ 178,083 Liabilities and Stockholders’ Equity Accrued expenses $ 16 $ 38 Other liabilities 165 16 Total liabilities 181 54 Stockholders’ equity 201,794 178,029 Total liabilities and stockholders’ equity $ 201,975 $ 178,083
Condensed Statements of Operations	Condensed Statements of Operations Years Ended December 31, 2018 2017 2016 Interest and dividend income: Interest on cash equivalents $ 9 $ — $ — Dividends from subsidiaries — — — Total interest and dividend income 9 — — Interest expense — — — Net interest and dividend income 9 — — Non-interest income — — — Non-interest expense 232 230 219 Loss before income taxes and equity in undistributed earnings of subsidiaries (223 ) (230 ) (219 ) Income tax benefit (63 ) (94 ) (89 ) Loss before equity in income of subsidiaries (160 ) (136 ) (130 ) Equity in undistributed earnings of Belmont Savings Bank 22,942 14,432 12,025 Equity in undistributed earnings of BSB Funding Corp 127 90 86 Net income $ 22,909 $ 14,386 $ 11,981
Condensed Statements of Cash Flows	Condensed Statements of Cash Flows Years Ended December 31, 2018 2017 2016 Cash flows from operating activities: Net income $ 22,909 $ 14,386 $ 11,981 Adjustments to reconcile net income to net cash used in operating activities: Equity in undistributed earnings of Belmont Savings Bank (22,942 ) (14,432 ) (12,025 ) Equity in undistributed earnings of BSB Funding Corp. (127 ) (90 ) (86 ) Deferred income tax expense — — — Other, net — 26 (27 ) Net cash used in operating activities (160 ) (110 ) (157 ) Cash flows from investing activities: Return of capital from BSB Funding Corp. — 460 — Investment in Belmont Savings Bank — — — Net cash provided by investing activities — 460 — Cash flows from financing activities: Proceeds from exercise of stock options, net of cash paid 681 50 298 Restricted stock awards issued, net of awards surrendered — — (118 ) Net cash provided by financing activities 681 50 180 Net increase in cash and cash equivalents 521 400 23 Cash and cash equivalents at beginning of period 919 519 496 Cash and cash equivalents at end of period $ 1,440 $ 919 $ 519

QUARTERLY DATA (UNAUDITED) (Tab

QUARTERLY DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Table Text Block]	Quarterly results of operations are as follows for the periods indicated: Years Ended December 31, 2018 2017 Fourth Quarter Third Quarter Second Quarter First Quarter Fourth Quarter Third Quarter Second Quarter First Quarter Interest and dividend income $ 26,306 $ 25,644 $ 23,882 $ 22,419 $ 21,114 $ 19,758 $ 18,764 $ 17,506 Interest expense 10,862 10,235 8,779 7,281 6,414 5,579 4,816 4,245 Net interest income 15,444 15,409 15,103 15,138 14,700 14,179 13,948 13,261 Provision for loan losses 465 191 726 274 691 535 707 829 Net interest income, after provision for loan losses 14,979 15,218 14,377 14,864 14,009 13,644 13,241 12,432 Non-interest income 1,279 1,136 1,711 895 1,117 885 995 630 Non-interest expense 9,712 7,826 7,796 7,685 7,636 7,929 7,645 7,476 Income before taxes 6,546 8,528 8,292 8,074 7,490 6,600 6,591 5,586 Income tax expense 1,943 2,300 2,224 2,064 5,382 2,001 2,579 1,920 Net income $ 4,603 $ 6,228 $ 6,068 $ 6,010 $ 2,108 $ 4,599 $ 4,012 $ 3,666 Earnings per common share Basic $ 0.51 $ 0.70 $ 0.68 $ 0.68 $ 0.24 $ 0.52 $ 0.45 $ 0.42 Diluted $ 0.49 $ 0.66 $ 0.65 $ 0.64 $ 0.23 $ 0.50 $ 0.43 $ 0.40

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2011	Nov. 26, 2018	Dec. 31, 2017
Stock issued, shares		8,993,000
Stock issued, price per share		$ 10
Gross proceeds		$ 89,900,000
Shares sold to the Bank's employee stock ownership plan		458,643
Due days of accrual of interest on all loans	90 days
Originate loans with a loan-to-value	80.00%
Common Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01	$ 0.01
Shares, Issued			2
Retained Earnings [Member]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings Tax Effect	$ (19,000)
Contract Termination [Member]
The company pay termination fee to people united	12,500,000
Belmont Savings Bank
Stock issued, shares		179,860
Cash contribution to charity		$ 200,000
Common Stock, Par or Stated Value Per Share			$ 0.01
Reserve for Off-balance Sheet Activities
Reserve for unfunded loan commitments	16,000			$ 36,000
Maximum
Insured amount for per account deposit by Bank Insurance Fund	$ 250,000
Life insurance policy with individual carrier as a percentage of tier one capital	15.00%
Total cash surrender value of life insurance policies as a percentage of tier one capital	25.00%

Restrictions on Cash and Amou_2

Restrictions on Cash and Amounts due From Banks - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents subject to withdrawals and usage restrictions	$ 25.5	$ 25.2

Available For Sale Securities (

Available For Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Available-for-sale [Abstract]
Available-for-sale Securities, Amortized Cost Basis	$ 4,162	$ 16,975
Available-for-sale Securities, Gross Unrealized Gains		24
Available-for-sale Securities, Gross Unrealized Losses	(122)	(78)
Available-for-sale Securities, Fair Value	4,040	16,921
Corporate debt securities
Available-for-sale [Abstract]
Available-for-sale Securities, Amortized Cost Basis	4,162	16,975
Available-for-sale Securities, Gross Unrealized Gains		24
Available-for-sale Securities, Gross Unrealized Losses	(122)	(78)
Available-for-sale Securities, Fair Value	$ 4,040	$ 16,921

Held For Sale Securities (Detai

Held For Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Held-to-maturity securities[Abstract]
Held-to-maturity securities, Amortized Cost Basis	$ 148,025	$ 160,090
Held-to-maturity securities, Fair Value	145,369	158,385
Held-to-maturity Securities
Held-to-maturity securities[Abstract]
Held-to-maturity securities, Amortized Cost Basis	148,025	160,090
Held-to-maturity securities, Gross Unrealized Gains	239	384
Held-to-maturity securities, Gross Unrealized Losses	(2,895)	(2,089)
Held-to-maturity securities, Fair Value	145,369	158,385
Held-to-maturity Securities | U.S. government sponsored mortgage-backed securities
Held-to-maturity securities[Abstract]
Held-to-maturity securities, Amortized Cost Basis	137,261	142,383
Held-to-maturity securities, Gross Unrealized Gains	227	145
Held-to-maturity securities, Gross Unrealized Losses	(2,863)	(2,089)
Held-to-maturity securities, Fair Value	134,625	140,439
Held-to-maturity Securities | Corporate debt securities
Held-to-maturity securities[Abstract]
Held-to-maturity securities, Amortized Cost Basis	10,764	17,707
Held-to-maturity securities, Gross Unrealized Gains	12	239
Held-to-maturity securities, Gross Unrealized Losses	(32)
Held-to-maturity securities, Fair Value	$ 10,744	$ 17,946

Amortized Cost Basis and Estima

Amortized Cost Basis and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Due within one year, Available-for-sale Securities, Amortized Cost Basis	$ 0
Due after one year through five years, Available-for-sale Securities, Amortized Cost Basis	4,162
Due after five years through ten years, Available-for-sale Securities, Amortized Cost Basis	0
Due after ten years, Available-for-sale Securities, Amortized Cost Basis	0
Available-for-sale Securities, Amortized Cost Basis	4,162	$ 16,975
Due within one year, Available-for-sale Securities, Fair Value	0
Due after one year through five years, Available-for-sale Securities, Fair Value	4,040
Due after five years through ten years, Available-for-sale Securities, Fair Value	0
Due after ten years, Available-for-sale Securities, Fair Value	0
Available-for-sale Securities, Fair Value	4,040	16,921
Due within one year, Held-to-Maturity, Amortized Cost Basis	0
Due after one year through five years, Held-to-Maturity, Amortized Cost Basis	23,073
Due after five years through ten years, Held-to-Maturity, Amortized Cost Basis	18,803
Due after ten years, Held-to-Maturity, Amortized Cost Basis	106,149
Held-to-Maturity, Amortized Cost Basis	148,025	160,090
Due within one year, Held-to-Maturity, Fair Value	0
Due after one year through five years, Held-to-Maturity, Fair Value	22,719
Due after five years through ten years, Held-to-Maturity, Fair Value	18,246
Due after ten years, Held-to-Maturity, Fair Value	104,404
Held-to-Maturity, Fair Value	$ 145,369	$ 158,385

Securities with Gross Unrealize

Securities with Gross Unrealized Losses Aggregated by Investment Category and Length of Time (Detail) $ in Thousands	Dec. 31, 2018USD ($)Entity	Dec. 31, 2017USD ($)Entity
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of Holdings | Entity	102	82
Less than 12 Months, Fair Value	$ 19,241	$ 64,056
Less than 12 Months, Unrealized Losses	(116)	(718)
Over 12 Months, Fair Value	107,637	66,942
Over 12 Months, Unrealized Losses	$ (2,901)	$ (1,449)
Corporate debt securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of Holdings | Entity	1	1
Available-for-sale, Less than 12 Months, Fair Value	$ 0	$ 0
Available-for-sale, Less than 12 Months, Unrealized Losses	0	0
Available-for-sale, Over 12 Months, Fair Value	4,040	4,144
Available-for-sale, Over 12 Months, Unrealized Losses	$ (122)	$ (78)
Number of Holdings | Entity	4
Held-to-maturity, Less than 12 Months, Fair Value	$ 7,820
Held-to-maturity, Less than 12 Months, Unrealized Losses	(32)
Held-to-maturity, Over 12 Months, Fair Value	0
Held-to-maturity, Over 12 Months, Unrealized Losses	$ 0
U.S. government sponsored mortgage-backed securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Number of Holdings | Entity	97	81
Held-to-maturity, Less than 12 Months, Fair Value	$ 11,421	$ 64,056
Held-to-maturity, Less than 12 Months, Unrealized Losses	(84)	(718)
Held-to-maturity, Over 12 Months, Fair Value	103,597	62,798
Held-to-maturity, Over 12 Months, Unrealized Losses	$ (2,779)	$ (1,371)

Investment Securities - Additio

Investment Securities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Entity	Dec. 31, 2017USD ($)Entity	Dec. 31, 2016USD ($)
Investment Securities [Line Items]
Proceeds from sales of available-for-sale securities	$ 0	$ 5,038	$ 0
Number of securities that had unrealized losses | Entity	102	82
Securities that had unrealized losses, aggregate depreciation percentage	2.56%
Securities pledged to secure securities sold under agreements to repurchase	$ 5,600	$ 5,600
Securities pledged to secure borrowings with Federal Home Loan Bank	40,500	47,700
Securities pledged to secure available line of credit with Federal Home Loan Bank	8,800	15,800
Realized gains of investments		38
Trading securities, unrealized holding gain (loss)	(65)	158	$ 36
Rabbi Trust
Investment Securities [Line Items]
Trading securities, fair value	2,800	2,800
Trading securities, unrealized holding gain (loss)	$ (65)	$ 158

Summary of Loans (Detail)

Summary of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	$ 2,630,209	$ 2,301,183
Net deferred loan costs	3,485	3,426
Net unamortized mortgage premiums	8,617	8,661
Allowance for loan losses	(17,939)	(16,312)	$ (13,585)	$ (11,240)
Total loans, net	2,624,372	2,296,958
Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	50,480	53,045
Allowance for loan losses	(722)	(764)	(1,219)	(801)
Mortgage Loan Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	2,555,364	2,206,799
Mortgage Loan Portfolio Segment | Multifamily Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	203,657	155,680
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	1,583,000	1,333,058
Allowance for loan losses	(7,434)	(6,400)	(4,828)	(3,574)
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	555,028	486,392
Allowance for loan losses	(5,798)	(4,979)	(3,676)	(3,495)
Mortgage Loan Portfolio Segment | Real Estate Loan | Multifamily Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	203,657	155,680
Allowance for loan losses	(1,711)	(1,604)	(1,209)	(983)
Mortgage Loan Portfolio Segment | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	163,199	178,624
Allowance for loan losses	(816)	(947)	(1,037)	(928)
Mortgage Loan Portfolio Segment | Construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	50,480	53,045
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	62,462	63,722
Allowance for loan losses	(679)	(758)	(728)	(613)
Consumer Portfolio Segment | Indirect auto loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	11,965	30,227
Allowance for loan losses	(84)	(230)	(362)	(623)
Consumer Portfolio Segment | Other Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	418	435
Allowance for loan losses	(6)	(9)	$ (9)	$ (10)
Commercial and Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans Balance	$ 74,845	$ 94,384

Allowance for Loan Losses by Po

Allowance for Loan Losses by Portfolio Class (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				$ 16,312				$ 13,585	$ 16,312	$ 13,585	$ 11,240
Provision (benefit)	$ 465	$ 191	$ 726	274	$ 691	$ 535	$ 707	829	1,657	2,762	2,385
Charge-offs									(47)	(59)	(101)
Recoveries									17	24	61
Ending Balance	17,939				16,312				17,939	16,312	13,585
Construction loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				764				1,219	764	1,219	801
Provision (benefit)									(42)	(455)	418
Ending Balance	722				764				722	764	1,219
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				6,400				4,828	6,400	4,828	3,574
Provision (benefit)									1,034	1,572	1,254
Ending Balance	7,434				6,400				7,434	6,400	4,828
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				4,979				3,676	4,979	3,676	3,495
Provision (benefit)									819	1,303	181
Ending Balance	5,798				4,979				5,798	4,979	3,676
Mortgage Loan Portfolio Segment | Real Estate Loan | Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				1,604				1,209	1,604	1,209	983
Provision (benefit)									107	395	226
Ending Balance	1,711				1,604				1,711	1,604	1,209
Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				947				1,037	947	1,037	928
Provision (benefit)									(131)	(90)	109
Ending Balance	816				947				816	947	1,037
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				758				728	758	728	613
Provision (benefit)									(75)	30	115
Charge-offs									(4)
Ending Balance	679				758				679	758	728
Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				230				362	230	362	623
Provision (benefit)									(127)	(109)	(232)
Charge-offs									(32)	(45)	(85)
Recoveries									13	22	56
Ending Balance	84				230				84	230	362
Consumer Portfolio Segment | Other Consumer Loan
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				9				9	9	9	10
Provision (benefit)									4	12	10
Charge-offs									(11)	(14)	(16)
Recoveries									4	2	5
Ending Balance	6				9				6	9	9
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance				$ 621				$ 517	621	517	213
Provision (benefit)									68	104	304
Ending Balance	$ 689				$ 621				$ 689	$ 621	$ 517

Individually Impaired Loans by

Individually Impaired Loans by Class of Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, Loan Balance	$ 5,376	$ 5,569
Individually evaluated for impairment, Loan allowance	5	147
Collectively evaluated for impairment, Loan Balance	2,624,833	2,295,614
Collectively evaluated for impairment, Loan allowance	17,934	16,165
Total Loan Balance	2,630,209	2,301,183
Total Loan, allowance	17,939	16,312	$ 13,585	$ 11,240
Construction loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan Balance	50,480	53,045
Collectively evaluated for impairment, Loan allowance	722	764
Total Loan Balance	50,480	53,045
Total Loan, allowance	722	764	1,219	801
Mortgage Loan Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loan Balance	2,555,364	2,206,799
Mortgage Loan Portfolio Segment | Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loan Balance	203,657	155,680
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, Loan Balance	2,545	2,688
Individually evaluated for impairment, Loan allowance	5	147
Collectively evaluated for impairment, Loan Balance	1,580,455	1,330,370
Collectively evaluated for impairment, Loan allowance	7,429	6,253
Total Loan Balance	1,583,000	1,333,058
Total Loan, allowance	7,434	6,400	4,828	3,574
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, Loan Balance	2,820	2,877
Collectively evaluated for impairment, Loan Balance	552,208	483,515
Collectively evaluated for impairment, Loan allowance	5,798	4,979
Total Loan Balance	555,028	486,392
Total Loan, allowance	5,798	4,979	3,676	3,495
Mortgage Loan Portfolio Segment | Real Estate Loan | Multifamily Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan Balance	203,657	155,680
Collectively evaluated for impairment, Loan allowance	1,711	1,604
Total Loan Balance	203,657	155,680
Total Loan, allowance	1,711	1,604	1,209	983
Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan Balance	163,199	178,624
Collectively evaluated for impairment, Loan allowance	816	947
Total Loan Balance	163,199	178,624
Total Loan, allowance	816	947	1,037	928
Mortgage Loan Portfolio Segment | Construction loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Total Loan Balance	50,480	53,045
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan Balance	62,462	63,722
Collectively evaluated for impairment, Loan allowance	679	758
Total Loan Balance	62,462	63,722
Total Loan, allowance	679	758	728	613
Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment, Loan Balance	11	4
Collectively evaluated for impairment, Loan Balance	11,954	30,223
Collectively evaluated for impairment, Loan allowance	84	230
Total Loan Balance	11,965	30,227
Total Loan, allowance	84	230	362	623
Consumer Portfolio Segment | Other Consumer Loan
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan Balance	418	435
Collectively evaluated for impairment, Loan allowance	6	9
Total Loan Balance	418	435
Total Loan, allowance	6	9	9	10
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Collectively evaluated for impairment, Loan allowance	689	621
Total Loan, allowance	$ 689	$ 621	$ 517	$ 213

Impaired Loans (Detail)

Impaired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired loans with a related allowance for credit losses, Recorded Investment	$ 192	$ 725
Impaired loans with a related allowance for credit losses at, Unpaid Principal Balance	192	725
Impaired loans with a related allowance for credit losses at, Specific Allowance	5	147
Impaired loans with no related allowance for credit losses, Recorded Investment	5,184	4,844
Impaired loans with no related allowance for credit losses, Unpaid Principal Balance	5,307	4,933
Impaired loans with a related allowance for credit losses, Average recorded Investment	238	897	$ 4,397
Impaired loans with a related allowance for credit losses, Interest income recognized	11	32	169
Impaired loans with no related allowance for credit losses, Average recorded Investment	4,937	5,257	3,973
Impaired loans with no related allowance for credit losses, Interest income recognized	173	247	120
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired loans with a related allowance for credit losses, Recorded Investment	192	725
Impaired loans with a related allowance for credit losses at, Unpaid Principal Balance	192	725
Impaired loans with a related allowance for credit losses at, Specific Allowance	5	147
Impaired loans with no related allowance for credit losses, Recorded Investment	2,353	1,963
Impaired loans with no related allowance for credit losses, Unpaid Principal Balance	2,476	2,052
Impaired loans with a related allowance for credit losses, Average recorded Investment	238	897	1,273
Impaired loans with a related allowance for credit losses, Interest income recognized	11	32	33
Impaired loans with no related allowance for credit losses, Average recorded Investment	2,074	1,986	2,977
Impaired loans with no related allowance for credit losses, Interest income recognized	50	94	78
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired loans with no related allowance for credit losses, Recorded Investment	2,820	2,877
Impaired loans with no related allowance for credit losses, Unpaid Principal Balance	2,820	2,877
Impaired loans with a related allowance for credit losses, Average recorded Investment			3,124
Impaired loans with a related allowance for credit losses, Interest income recognized			136
Impaired loans with no related allowance for credit losses, Average recorded Investment	2,848	3,159	784
Impaired loans with no related allowance for credit losses, Interest income recognized	123	140	34
Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired loans with no related allowance for credit losses, Average recorded Investment	8	106	200
Impaired loans with no related allowance for credit losses, Interest income recognized		13	8
Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Impaired loans with no related allowance for credit losses, Recorded Investment	11	4
Impaired loans with no related allowance for credit losses, Unpaid Principal Balance	11	4
Impaired loans with no related allowance for credit losses, Average recorded Investment	$ 7	$ 6	$ 12

Past Due and Non-Accrual Loans

Past Due and Non-Accrual Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	$ 1,845	$ 2,068
90 days or more and accruing	0	0
Loans on Non-accrual	1,170	1,376
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	1,398	971
90 days or more and accruing	0	0
Loans on Non-accrual	1,159	1,372
Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	214	716
90 days or more and accruing	0	0
Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	233	381
90 days or more and accruing	0	0
Loans on Non-accrual	11	4
30-59 Days
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	841	1,774
30-59 Days | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	438	711
30-59 Days | Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	214	716
30-59 Days | Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	189	347
60-89 Days
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	272	30
60-89 Days | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	239
60-89 Days | Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	33	30
Loans 90 Days Or More Past Due
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	732	264
Loans 90 Days Or More Past Due | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	721	260
Loans 90 Days Or More Past Due | Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Days Past Due	$ 11	$ 4

Loans Classified by Risk Rating

Loans Classified by Risk Rating (Detail) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		$ 2,630,209	$ 2,301,183
Construction loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		50,480	53,045
Mortgage Loan Portfolio Segment
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		2,555,364	2,206,799
Mortgage Loan Portfolio Segment | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		203,657	155,680
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		1,583,000	1,333,058
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		555,028	486,392
Mortgage Loan Portfolio Segment | Real Estate Loan | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		203,657	155,680
Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		163,199	178,624
Mortgage Loan Portfolio Segment | Construction loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		50,480	53,045
Commercial Portfolio Segment
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		62,462	63,722
Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		11,965	30,227
Consumer Portfolio Segment | Other Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		418	435
Loans rated 1-3.5
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		867,926	754,981
Loans rated 1-3.5 | Construction loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		50,480	53,045
Loans rated 1-3.5 | Mortgage Loan Portfolio Segment | Multifamily Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		203,657	155,680
Loans rated 1-3.5 | Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		551,327	482,574
Loans rated 1-3.5 | Commercial Portfolio Segment
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		62,462	63,682
Loans rated 4
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		335	384
Loans rated 4 | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		335	344
Loans rated 4 | Commercial Portfolio Segment
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance			40
Loans rated 5
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		5,533	6,650
Loans rated 5 | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		1,832	2,060
Loans rated 5 | Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance		3,701	3,818
Loans rated 5 | Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance			772
Loans not rated
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance	[1]	1,756,415	1,539,168
Loans not rated | Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance	[1]	1,580,833	1,330,654
Loans not rated | Mortgage Loan Portfolio Segment | Home equity lines of credit
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance	[1]	163,199	177,852
Loans not rated | Consumer Portfolio Segment | Indirect auto loans
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance	[1]	11,965	30,227
Loans not rated | Consumer Portfolio Segment | Other Consumer Loan
Financing Receivable, Recorded Investment [Line Items]
Total Loans Balance	[1]	$ 418	$ 435
[1]	Residential one-to-four family real estate and home equity lines of credit are not formally risk rated by the Company unless the loans become delinquent, impaired or are restructured as a TDR. Indirect auto loans and other consumer loans are not formally risk rated by the Company.

Loans, Allowance for Loan Los_3

Loans, Allowance for Loan Losses and Credit Quality - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans pledged to secure FHLB advances	$ 1,900,000	$ 1,400,000
Residential one-to-four family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Consumer mortgage loans in the process of foreclosure amount	$ 253,000	$ 0

Troubled Debt Restructuring Acc

Troubled Debt Restructuring Accrual Status (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total TDRs	$ 4,206	$ 4,839
Amount of specific allocation included in the allowance for loan losses associated with TDRs	5	147
Additional commitments to lend to a borrower who has been a party to a TDR	0	0
Accrual Loans
Financing Receivable, Recorded Investment [Line Items]
Total TDRs	$ 4,206	4,194
Non-accrual Loans
Financing Receivable, Recorded Investment [Line Items]
Total TDRs		$ 645

Troubled Debt Restructurings on

Troubled Debt Restructurings on Financing Receivables (Detail) $ in Thousands		12 Months Ended
		Dec. 31, 2017USD ($)Contract	Dec. 31, 2016USD ($)Contract
Financing Receivable, Modifications [Line Items]
Post-modification outstanding recorded investment		$ 273	$ 4,093
Mortgage Loan Portfolio Segment | Real Estate Loan
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract		1	4
Pre-modification outstanding recorded investment		$ 273	$ 4,015
Post-modification outstanding recorded investment	[1]	$ 273	$ 4,093
Mortgage Loan Portfolio Segment | Real Estate Loan | Residential one-to-four family
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract			1
Pre-modification outstanding recorded investment			$ 621
Post-modification outstanding recorded investment	[1]		$ 699
Mortgage Loan Portfolio Segment | Real Estate Loan | Commercial real estate loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract		1	3
Pre-modification outstanding recorded investment		$ 273	$ 3,394
Post-modification outstanding recorded investment	[1]	$ 273	$ 3,394
[1]	The post-modification balances represent the balance of the loan on the date of the modifications. These amounts may show an increase when the modifications include a capitalization of interest or taxes.

Post Modification of Troubled D

Post Modification of Troubled Debt Restructuring Balance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Post-modification outstanding recorded investment	$ 273	$ 4,093
Capitalization of interest, taxes and extended maturity
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Post-modification outstanding recorded investment		699
Extended Maturity
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Post-modification outstanding recorded investment	$ 273	$ 3,394

Summary of Loans Modified and S

Summary of Loans Modified and Subsequently Defaulted (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)Contract	Dec. 31, 2017USD ($)Contract	Dec. 31, 2016USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	0	0	1
Recorded Investment | $	$ 0	$ 0	$ 497
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	0	0	1
Recorded Investment | $	$ 0	$ 0	$ 497

Transfers and Servicing - Addit

Transfers and Servicing - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transferred Loans [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Total principal balance of loans	$ 0	$ 0	$ 0
Residential Mortgage
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Loans previously sold and serviced	142,800,000	114,500,000
Proceed from sale of loans	53,700,000	70,500,000	11,400,000
Gains from sale of loans	756,000	936,000	271,000
Indirect auto loans
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Loans previously sold and serviced	2,900,000	10,500,000
Proceed from sale of loans	$ 0	$ 0	$ 0

Changes in MSR (Detail)

Changes in MSR (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transfers and Servicing [Abstract]
Balance at beginning of period	$ 855	$ 403	$ 479
Capitalization	402	508	85
Amortization	(205)	(130)	(101)
Valuation allowance adjustment	50	74	(60)
Balance at end of period	$ 1,102	$ 855	$ 403

Summary of Cost and Accumulated

Summary of Cost and Accumulated Depreciation of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Land	$ 161	$ 161
Buildings	3,516	3,516
Leasehold improvements	1,414	1,414
Furniture and equipment	4,736	4,350
Property, Plant and Equipment, Gross, Total	9,827	9,441
Accumulated depreciation	(7,650)	(7,187)
Premises and equipment, net	$ 2,177	$ 2,254

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 590,000	$ 595,000	$ 621,000
Assets impairment charges	3,000	$ 18,000	16,000
Assets cost	14,000		3,500,000
Gain loss on disposal of assets	$ 11,000		$ 0

Scheduled Maturities of Time De

Scheduled Maturities of Time Deposits (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Time Deposit [Line Items]
2019	$ 418,035
2020	165,487
2021	63,731
2022	38,984
2023	73,030
Time Deposits Total	$ 759,267

Deposits - Additional Informati

Deposits - Additional Information (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Time Deposit [Line Items]
Aggregate amount of time deposits	$ 216,100,000	$ 128,700,000
Brokered deposits included in time deposits	288,600,000	247,200,000
Overdraft deposits reclassified to loans	43,000	48,000
Letter of credit outstanding	194,500,000	5,000,000
Directors, Executive Officers and Affiliates
Time Deposit [Line Items]
Deposit accounts	$ 17,700,000	$ 8,500,000

Short-Term Borrowings - Additio

Short-Term Borrowings - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Federal Home Loan Bank advances, short-term	$ 383,000	$ 305,900
Federal Home Loan Bank advances weighted average interest rate, short term	2.64%	1.52%
Federal Home Loan Bank advances, available line of credit	$ 5,600	$ 5,600
Federal Home Loan Bank advances, unused remaining available borrowing capacity	270,600	279,200
Securities sold under agreements to repurchase	$ 2,883	$ 3,268
Securities sold under agreements to repurchase, weighted average interest rate	0.15%	0.15%

Long-Term Debt Consisting FHLB

Long-Term Debt Consisting FHLB Advances (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
2018	$ 0	$ 47,000
2019	225,250	225,250
2020	35,000	35,000
2021	15,000	15,000
2022	110,000	95,000
2023	70,000	0
Long-term Federal Home Loan Bank Advances, Total	$ 455,250	$ 417,250
2018	0.00%	1.63%
2019	1.49%	1.49%
2020	1.76%	1.76%
2021	2.03%	2.03%
2022	2.27%	2.17%
2023	3.04%	0.00%
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate	1.96%	1.70%

Allocation of Federal and State

Allocation of Federal and State Income Taxes Between Current and Deferred Portions (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components Of Income Tax Expense Benefit [Line Items]
Federal									$ 6,215	$ 7,386	$ 7,212
State									2,809	1,961	1,954
Total current tax provision									9,024	9,347	9,166
Federal									(335)	(71)	(1,391)
State									(157)	(20)	(350)
Effect of change in statutory federal tax rate										2,626
Total deferred tax benefit									(492)	2,535	(1,741)
Total provision for income taxes	$ 1,943	$ 2,300	$ 2,224	$ 2,064	$ 5,382	$ 2,001	$ 2,579	$ 1,920	$ 8,532	$ 11,882	$ 7,425

Summary of Reasons for differen

Summary of Reasons for differences Between Statutory Income Tax Rate and Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory federal tax rate	21.00%	35.00%	35.00%
State taxes, net of federal tax benefit	6.70%	4.80%	5.40%
Bank-owned life insurance	(1.00%)	(1.50%)	(1.90%)
Tax exempt income	(0.30%)	(0.60%)	(0.80%)
Change in statutory federal tax rate		10.00%
Share based compensation	(0.50%)	(3.50%)	1.20%
Non-deductible merger expenses	1.10%
Other, net	0.10%	1.00%	(0.60%)
Effective tax rates	27.10%	45.20%	38.30%

Components of Net Deferred Tax

Components of Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Employee benefit and deferred compensation plans	$ 2,428	$ 2,375
Allowance for loan losses	5,047	4,596
Accrued rent	7	8
Interest on non-performing loans	35	34
Stock options	313	356
Unrealized loss on securities available for sale	34	15
Cash flow hedge	499
ESOP	104	92
Gross deferred tax assets	8,467	7,476
Deferred tax liabilities:
Mortgage servicing rights	(310)	(240)
Deferred loan origination costs	(948)	(860)
Restricted stock awards	(203)	(280)
Depreciation	(142)	(201)
Unrecognized retirement benefit	(69)	(58)
Other	(2)	(43)
Gross deferred tax liabilities	(1,674)	(1,682)
Net deferred tax asset	$ 6,793	$ 5,794

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax [Line Items]
Retained earnings which federal and state income taxes have not been provided	$ 3,600	$ 3,600
Period for recapture in taxable income if no longer qualifies as a bank	4 years
Federal and state tax rate applicable if no longer qualifies as a bank	28.00%
Statutory federal tax rate	21.00%	35.00%	35.00%
Charge recorded within income tax expense		$ 2,626

Financial Instruments Outstandi

Financial Instruments Outstanding whose Contract Amounts Represent Credit Risk (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Commitments to grant loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 10,189	$ 23,702
Unfunded commitments under lines of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	339,360	325,768
Unadvanced portion of construction loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	72,375	11,486
Standby Letters of Credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	869	561
Commitments to purchase loans
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 31,494	$ 65,692

Off-Balance Sheet Arrangement_2

Off-Balance Sheet Arrangements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Letters of credit issued expiration period	1 year

Future Minimum Rent Commitments

Future Minimum Rent Commitments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019	$ 360
2020	266
2021	122
2022	122
2023	78
Thereafter	44
Total	$ 992

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments And Contingencies Disclosure [Line Items]
Total rent expense	$ 362	$ 363	$ 348
Contract Termination [Member]
Commitments And Contingencies Disclosure [Line Items]
Potential Termination Fee	$ 12,500
Maximum [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease, optional renewal period	10 years
Minimum [Member]
Commitments And Contingencies Disclosure [Line Items]
Operating lease, optional renewal period	1 year

Minimum Regulatory Capital Re_3

Minimum Regulatory Capital Requirements - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, phased period	4 years
Stock repurchase plan, number of shares repurchased	0	0	0
Basel III
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 capital risk-weighted assets	4.50%
Total capital to risk weighted assets	8.00%
Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Active stock repurchase plan to repurchase	500,000	500,000
Maximum | Basel III
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital to risk weighted assets	6.00%
Minimum | Basel III
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum leverage ratio	4.00%
Tier 1 capital to risk weighted assets	4.00%
January 1, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, risk-weighted assets ratio	0.625%
January 1, 2019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, risk-weighted assets ratio	2.50%
Two Thousand Nineteen | Scenario, Forecast
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer, risk-weighted assets ratio				2.50%
Common Equity Tier 1 capital risk-weighted assets				4.50%
Minimum leverage ratio				4.00%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio				6.00%
Total Capital to Risk Weighted Assets, Minimum For Capital Adequacy Purposes Ratio				8.00%
Two Thousand Nineteen | Fully Phased In | Scenario, Forecast
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 capital risk-weighted assets				7.00%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio				8.50%
Total Capital to Risk Weighted Assets, Minimum For Capital Adequacy Purposes Ratio				10.50%

Actual Capital Amounts and Rati

Actual Capital Amounts and Ratios (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Actual Amount	$ 202,983	$ 177,939
Tier 1 Capital to Average Assets, Actual Ratio	6.97%	6.97%
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,148
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Actual Amount	$ 197,505	$ 172,963
Tier 1 Capital to Average Assets, Actual Ratio	6.78%	6.77%
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,147
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Tier 1 Capital to Average Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 145,692	$ 127,683
Tier 1 Capital to Average Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%
Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Actual Amount	$ 220,938	$ 194,287
Total Capital to Risk Weighted Assets, Actual Ratio	11.75%	11.30%
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 150,424	$ 137,498
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	8.00%	8.00%
Tier 1 Capital to Risk Weighted Assets, Actual Amount	$ 202,983	$ 177,939
Tier 1 Capital to Risk Weighted Assets, Actual Ratio	10.80%	10.35%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 112,818	$ 103,123
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	6.00%	6.00%
Common Equity Tier 1 Capital to Risk Weighted Assets, Actual Amount	$ 202,983	$ 177,939
Common Equity Tier 1 Capital to Risk Weighted Assets, Actual Ratio	10.80%	10.35%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 84,613	$ 77,343
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	4.50%	4.50%
Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Actual Amount	$ 215,460	$ 189,311
Total Capital to Risk Weighted Assets, Actual Ratio	11.46%	11.01%
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 150,436	$ 137,497
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	8.00%	8.00%
Total Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 188,045	$ 171,871
Total Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%
Tier 1 Capital to Risk Weighted Assets, Actual Amount	$ 197,505	$ 172,963
Tier 1 Capital to Risk Weighted Assets, Actual Ratio	10.50%	10.06%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 112,827	$ 103,123
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	6.00%	6.00%
Tier 1 Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 150,436	$ 137,497
Tier 1 Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	8.00%
Common Equity Tier 1 Capital to Risk Weighted Assets, Actual Amount	$ 197,505	$ 172,963
Common Equity Tier 1 Capital to Risk Weighted Assets, Actual Ratio	10.50%	10.06%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 84,620	$ 77,342
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	4.50%	4.50%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 122,229	$ 111,716
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%	6.50%
Basel III Phase-In Schedule | Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,148
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Basel III Phase-In Schedule | Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,147
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Basel III Phase-In Schedule | Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 185,680	$ 158,982
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	9.875%	9.25%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 148,074	$ 124,607
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	7.875%	7.25%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 119,869	$ 98,827
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	6.375%	5.75%
Basel III Phase-In Schedule | Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 185,695	$ 158,981
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	9.875%	9.25%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 148,086	$ 124,607
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	7.875%	7.25%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 119,879	$ 98,826
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	6.375%	5.75%
Basel III Fully Phased In | Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,148
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Basel III Fully Phased In | Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Amount	$ 116,553	$ 102,147
Tier 1 Capital to Average Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	4.00%	4.00%
Basel III Fully Phased In | Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 197,431	$ 180,466
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	10.50%	10.50%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 159,825	$ 146,092
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	8.50%	8.50%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 131,621	$ 120,311
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	7.00%	7.00%
Basel III Fully Phased In | Belmont Savings Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 197,448	$ 180,465
Total Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	10.50%	10.50%
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 159,839	$ 146,091
Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Plus Capital Conservation Buffer Ratio	8.50%	8.50%
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Amount	$ 131,632	$ 120,310
Common Equity Tier 1 Capital to Risk Weighted Assets, Minimum Capital Required For Capital Adequacy Ratio	7.00%	7.00%

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Mar. 15, 2017	Feb. 08, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted			3,898	487,200
Restricted stock grant date price			$ 32.30
Fair value of shares vested			$ 1.5	$ 2.2	$ 1.9
2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		487,200	487,200	487,200
2017 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock grant date price	$ 27.10
Vesting period of awards granted	10 years
Estimated forfeiture rate of awards granted	2.64%
Authorized Stock Awards			487,200	487,200
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards			1,284,200
2012 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted	0
Authorized Stock Awards			366,914

Cumulatively Granted Restricted

Cumulatively Granted Restricted Stock Awards Net of Forfeitures (Detail) - shares	Feb. 08, 2017	Dec. 31, 2018	Dec. 31, 2017
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		1,284,200
Cumulative Granted Net of Forfeitures		1,252,662
2012 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		917,286
Cumulative Granted Net of Forfeitures		889,092
2012 Equity Incentive Plan | RestrictedStock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		366,914
Cumulative Granted Net of Forfeitures		363,570
2017 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards	487,200	487,200	487,200
Cumulative Granted Net of Forfeitures		487,200
2017 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		0
Cumulative Granted Net of Forfeitures		0
2017 Equity Incentive Plan | RestrictedStock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Stock Awards		487,200	487,200
Cumulative Granted Net of Forfeitures		487,200

Pre-Tax Expense Associated with

Pre-Tax Expense Associated with Stock Option and Restricted Stock Awards and Related Tax Benefits Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock options	$ 73	$ 724	$ 780
Restricted stock awards	1,332	1,835	869
Total stock based compensation expense	1,405	2,559	1,649
Related tax benefits recognized in earnings	$ 376	$ 874	$ 492

Excess Tax Benefits Recognized

Excess Tax Benefits Recognized from Stock Based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits recognized in net income			$ 329
Adoption of ASU 2016-09
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefits recognized in net income	$ 324	$ 1,348

Summary of Stock Option (Detail

Summary of Stock Option (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value of options granted			$ 4.63
Intrinsic value of stock options exercised	$ 1,829	$ 3,299	$ 368
Cash paid to settle equity instruments granted under stock based compensation arrangements	$ 0	$ 0	$ 0

Compensation Cost Related to No

Compensation Cost Related to Non-Vested Awards not Yet Recognized and Weighted Average Recognition Period (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total	$ 9,706
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, amount	$ 69
Restricted stock, weighted average period	1 year 10 months 6 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, amount	$ 9,637
Restricted stock, weighted average period	8 years 2 months 16 days

Fair Value of Stock Options Gra

Fair Value of Stock Options Granted Estimate on Date of Grant Using Black-Scholes Option-Pricing Model (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted | shares	0
Date of grant 2016-03-01
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Date of grant	Mar. 1, 2016
Options granted | shares	27,500
Exercise price | $ / shares	$ 22.31
Vesting period	5 years	[1]
Expiration date	Mar. 1, 2026
Expected volatility	16.13%
Expected term	6 years 6 months
Expected dividend yield	0.00%
Risk free interest rate	1.54%
Fair value | $ / shares	$ 4.63
[1]	Vesting is ratably and the period begins on the date of grant.

Summary of Stock Option and Res

Summary of Stock Option and Restricted Stock Grants (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Stock option awards
Stock option awards, Beginning balance	590,522
Stock option awards, Granted	0
Stock option awards, Exercised	(99,199)
Stock option awards, Forfeited	0
Stock option awards, Ending balance	491,323	590,522
Stock option awards, Exercisable	464,428
Weighted Average Exercise Price
Weighted average exercise price, Beginning Balance	$ 12.86
Weighted average exercise price, Granted	0
Weighted average Exercise price, Exercised	12.10
Weighted average exercise price, Forfeited	0
Weighted average exercise price, Ending balance	13.02	$ 12.86
Weighted average exercise price, Exercisable	$ 12.58
Weighted average remaining contractual term
Weighted remaining contractual term, Ending balance	4 years 2 months 19 days
Weighted remaining contractual term, Exercisable	4 years 29 days
Aggregate intrinsic value
Aggregate intrinsic value, ending balance	$ 7,390
Aggregate intrinsic value, Exercisable	$ 7,189
Non-vested restricted stock awards
Non-vested restricted stock awards, Beginning balance	484,902
Restricted stock awards granted	3,898	487,200
Non-vested restricted stock awards, Vested	(49,137)
Non-vested restricted stock awards, Forfeited	0
Non-vested restricted stock awards, Ending balance	439,663	484,902
Weighted Average Grant Price
Weighted Average Grant Price, Beginning balance	$ 27.07
Weighted Average Grant Price, Granted	32.30
Weighted Average Grant Price, Vested	26.94
Weighted Average Grant Price, Forfeited	0
Weighted Average Grant Price, Ending balance	$ 27.13	$ 27.07

Earning Per Share (Detail)

Earning Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Net income	$ 4,603	$ 6,228	$ 6,068	$ 6,010	$ 2,108	$ 4,599	$ 4,012	$ 3,666	$ 22,909	$ 14,386	$ 11,981
Undistributed earnings attributable to participating securities									(3)	(108)	(190)
Net income available to common stockholders									$ 22,906	$ 14,278	$ 11,791
Weighted average shares outstanding, basic									8,941,394	8,754,393	8,571,861
Effect of dilutive shares									445,297	429,400	286,030
Weighted average shares outstanding, assuming dilution									9,386,691	9,183,793	8,857,891
Basic EPS	$ 0.51	$ 0.70	$ 0.68	$ 0.68	$ 0.24	$ 0.52	$ 0.45	$ 0.42	$ 2.56	$ 1.63	$ 1.38
Effect of dilutive shares									(0.12)	(0.08)	(0.05)
Diluted EPS	$ 0.49	$ 0.66	$ 0.65	$ 0.64	$ 0.23	$ 0.50	$ 0.43	$ 0.40	$ 2.44	$ 1.55	$ 1.33

Earnings Per Share - Additional

Earnings Per Share - Additional information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Antidilutive securities excluded from computation of earnings per share	0	0	22,992

Restrictions on Dividends Loans

Restrictions on Dividends Loans and Advances - Additional Information (Detail)	Dec. 31, 2018
Disclosure of Restrictions on Dividends, Loans and Advances Disclosure [Abstract]
Percentage Of Capital Stock And Surplus Maximum For Loans And Advances To Parent Company	10.00%

Summary of Financial Assets and

Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale	$ 4,040	$ 16,921
Asset Derivatives	5,292	0
Liability derivatives	3,144	0
Rabbi Trust
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2,800	2,800
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Totals	12,119	19,729
Totals	3,144
Fair Value, Measurements, Recurring | Interest Rate Caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2,303
Fair Value, Measurements, Recurring | Interest Rate Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2,967
Liability derivatives	3,144
Fair Value, Measurements, Recurring | Risk Participation-Out Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	22
Fair Value, Measurements, Recurring | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale	4,040	16,921
Fair Value, Measurements, Recurring | Rabbi Trust
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2,787	2,808
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Totals	2,787	2,808
Fair Value, Measurements, Recurring | Level 1 | Rabbi Trust
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	2,787	2,808
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Totals	9,332	16,921
Totals	3,144
Fair Value, Measurements, Recurring | Level 2 | Interest Rate Caps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2,303
Fair Value, Measurements, Recurring | Level 2 | Interest Rate Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2,967
Liability derivatives	3,144
Fair Value, Measurements, Recurring | Level 2 | Risk Participation-Out Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	22
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available-for-sale	$ 4,040	$ 16,921

Schedule of Loans Held-for-Sale

Schedule of Loans Held-for-Sale (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	$ 2,902
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	2,902
Totals	$ 2,902

Assets Remeasured and Reported

Assets Remeasured and Reported at Lower Amortized of Cost or Fair Value (Detail) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on a nonrecurring basis	$ 1,102	$ 855
Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on a nonrecurring basis	$ 1,102	$ 855

Fair Values of Assets and Lia_2

Fair Values of Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 143,378	$ 110,888	$ 58,876	$ 51,261
Interest-bearing time deposits with other banks	4,229	2,440
Held-to-maturity securities	148,025	160,090
Federal Home Loan Bank stock	38,658	32,382
Loans, net	2,624,372	2,296,958
Accrued interest receivable	7,290	6,344
Bank-owned life insurance	36,540	36,967
Liabilities
Deposits	1,960,912	1,751,251
Federal Home Loan Bank advances	838,250	723,150
Securities sold under agreements to repurchase	2,883	3,268
Accrued interest payable	2,050	1,594
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents	143,378	110,888
Interest-bearing time deposits with other banks	4,229	2,440
Held-to-maturity securities	145,369	158,385
Federal Home Loan Bank stock	38,658	32,382
Loans, net	2,537,595	2,251,971
Accrued interest receivable	7,290	6,344
Bank-owned life insurance	36,540	36,967
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Deposits	1,956,139	1,748,995
Federal Home Loan Bank advances	834,495	719,430
Securities sold under agreements to repurchase	2,883	3,268
Accrued interest payable	2,050	1,594
Mortgagors' escrow accounts	6,338	4,690
Carrying Amount
ASSETS
Cash and cash equivalents	143,378	110,888
Interest-bearing time deposits with other banks	4,229	2,440
Held-to-maturity securities	148,025	160,090
Federal Home Loan Bank stock	38,658	32,382
Loans, net	2,624,372	2,296,958
Accrued interest receivable	7,290	6,344
Bank-owned life insurance	36,540	36,967
Liabilities
Deposits	1,960,912	1,751,251
Federal Home Loan Bank advances	838,250	723,150
Securities sold under agreements to repurchase	2,883	3,268
Accrued interest payable	2,050	1,594
Mortgagors' escrow accounts	6,338	4,690
Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash and cash equivalents	143,378	110,888
Accrued interest receivable	7,290	6,344
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Deposits	1,201,644	1,246,537
Accrued interest payable	2,050	1,594
Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Interest-bearing time deposits with other banks	4,229	2,440
Held-to-maturity securities	145,369	158,385
Federal Home Loan Bank stock	38,658	32,382
Bank-owned life insurance	36,540	36,967
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Deposits	754,495	502,458
Federal Home Loan Bank advances	834,495	719,430
Securities sold under agreements to repurchase	2,883	3,268
Mortgagors' escrow accounts	6,338	4,690
Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Loans, net	$ 2,537,595	$ 2,251,971

Fair Values Of Assets and Lia_3

Fair Values Of Assets and Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Derivative Assets	$ 5,292	$ 0
Derivative Liabilities	$ 3,144	$ 0

Other Comprehensive (Loss) In_3

Other Comprehensive (Loss) Income - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax cut and job act 2017 AOCI re-measurement of deferred tax assets and liabilities		$ 19,000
Accounting Standards Update 2018-02
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of income tax effects related to items stranded within accumulated other comprehensive income from the Tax Cuts and Jobs Act	$ 19,000

Other Comprehensive (Loss) In_4

Other Comprehensive (Loss) Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Other Comprehensive Income (Loss) [Line Items]
Net change in fair value of securities available for sale, After Tax Amount	$ (49)	$ (31)	$ 149
Change in the net actuarial gain/loss, After Tax Amount	(53)	(42)
Net change defined-benefit post-retirement benefit plans, After Tax Amount	(29)	(17)	(70)
Net change in fair value of cash flow hedges, After Tax Amount	(1,276)
Net change defined-benefit post-retirement benefit plans, Pre-Tax Amount	(245)	(205)
Total other comprehensive (loss) income	(1,296)	(14)	219
Change in fair value of cash flow hedges	(1,782)
After Tax
Schedule of Other Comprehensive Income (Loss) [Line Items]
Change in fair value of securities available-for-sale, After Tax Amount	(49)	(8)	149
Net change in fair value of securities available for sale, After Tax Amount	(49)	(31)	149
Change in the net actuarial gain/loss, After Tax Amount	38	25	66
Reclassification adjustment included in net income, After Tax Amount	(9)	(8)	4
Net change defined-benefit post-retirement benefit plans, After Tax Amount	29	17	70
Net change in fair value of cash flow hedges, After Tax Amount	(1,276)
Reclassification adjustment included in net income	5
Reclassification adjustment included in net income, After Tax Amount		(23)
Total other comprehensive (loss) income	(1,296)	(14)	219
Change in fair value of cash flow hedges	(1,281)
Tax Benefit (Expense)
Schedule of Other Comprehensive Income (Loss) [Line Items]
Change in fair value of securities available-for-sale, Tax Benefit (Expense)	19	5	(98)
Net change in fair value of securities available for sale, Tax (Expense) Benefit	19	20	(98)
Change in the net actuarial gain/loss, Tax (Expense) Benefit	(15)	(17)	(46)
Reclassification adjustment included in net income, Tax (Expense) Benefit		15
Net change defined-benefit post-retirement benefit plans, Tax (Expense) Benefit	(11)	(12)	(48)
Reclassification adjustment included in net income, Tax Benefit (Expense)	(2)
Change in fair value of cash flow hedges	501
Total other comprehensive (loss) income, Tax	507	8	(146)
Reclassification adjustment included in net income	4	5	(2)
Net change in fair value of cash flow hedges, Tax Benefit (Expense)	499
Pre Tax
Schedule of Other Comprehensive Income (Loss) [Line Items]
Change in fair value of securities available-for-sale, Pre-Tax Amount	(68)	(13)	247
Net change in fair value of securities available for sale Pre-Tax Amount	(68)	(51)	247
Change in the net actuarial gain/loss, Pre-Tax Amount	53	42	112
Net change in fair value of cash flow hedges, Pre-Tax Amount	(1,775)
Reclassification adjustment included in net income, Pre-Tax Amount	(13)	(13)	6
Total other comprehensive (loss) income, Pre-Tax Amount	(1,803)	(22)	365
Reclassification adjustment included in net income, Pre-Tax Amount		(38)
Net change defined-benefit post-retirement benefit plans, Pre-Tax Amount	40	$ 29	$ 118
Reclassification adjustment included in net income, Pre-Tax Amount	7
Change in fair value of cash flow hedges	$ (1,782)

Components of Accumulated Other

Components of Accumulated Other Comprehensive (Loss) Income, included in Stockholders' Equity (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net unrealized holding loss on available-for-sale securities, net of tax	$ (88)	$ (32)
Unrecognized benefit pertaining to defined benefit plan, net of tax	176	121
Unrealized holding loss on cash flow hedges, net of tax	(1,276)	0
Accumulated other comprehensive (loss) income	$ (1,188)	$ 89

Employee and Director Benefit P

Employee and Director Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2011	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Compensation expense recognized	$ 2,400,000	$ 2,300,000	$ 2,000,000
Percentage of eligible compensation of employee	75.00%
Contributions by the Company	$ 950,000	$ 891,000	839,000
ESOP, purchase shares				458,643
Common stock price per share	$ 10
Loan obtained by the ESOP, payable annually over	30 years
Loan obtained by ESOP rate per annum equal to prime rate	4.50%
Discount rate used to determine obligation	4.25%	3.80%
Net periodic cost	$ 314,000	$ 306,000
Projected rate of salary increase	3.00%	3.00%
Percentage of deferred compensation vested	100.00%
Fair value of unallocated shares	$ 9,800,000	$ 10,600,000
Total compensation expense, Connection with ESOP	484,000	444,000	360,000
Scenario, Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated prior service benefit to be amortized from accumulated other comprehensive income					$ 6,000
Estimated unrecognized net gain to be amortized from accumulated other comprehensive income					$ 29,000
Rabbi Trust | Deferred Compensation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Recorded liability	2,800,000	2,800,000
Executive Officers | Other Supplemental Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated liability	$ 2,800,000	$ 2,600,000
Benefit upon termination of employment at or after age	55 years
Reduced benefits available prior to attaining age	55 years
Discount rate used to determine obligation	4.25%	3.80%
Net periodic cost	$ 252,000	$ 331,000	233,000
Projected rate of salary increase	3.00%	3.00%
Executive Officers | Maximum | Other Supplemental Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of years of service to complete	10 years
Executive Officers | Minimum | Other Supplemental Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of years of service to complete	10 years
Directors
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated liability	$ 689,000	$ 697,000
Discount rate used to determine obligation	4.25%	3.80%
Directors | Other Supplemental Retirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic cost	$ 21,000	$ 64,000	$ 55,000

Information Pertaining to Activ

Information Pertaining to Activity in Plan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$ 1,798	$ 1,521
Service cost	258	253
Interest cost	68	66
Actuarial gain	(53)	(42)
Benefit obligation at end of year	2,071	1,798
Funded status at end of year	(2,071)	(1,798)
Accrued pension benefit	(2,317)	(2,003)
Accumulated benefit obligation	$ 1,397	$ 1,175

Assumption used to Determine Be

Assumption used to Determine Benefit Obligation (Detail)	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.25%	3.80%
Rate of compensation increase	3.00%	3.00%

Components of Net Periodic Pens

Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 258	$ 253
Interest cost	68	66
Amortization of gain	(18)	(19)
Amortization of prior service cost	6	6
Net periodic cost	$ 314	$ 306

Changes in Benefit Obligations

Changes in Benefit Obligations Recognized in Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost	$ (6)	$ (6)
Amortization of unrecognized gain	19	19
Net actuarial gain	(53)	(42)
Total recognized in other comprehensive loss	$ (40)	$ (29)

Assumptions Used to Determine N

Assumptions Used to Determine Net Periodic Pension Cost (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.80%	4.35%
Rate of compensation increase	3.00%	3.00%

Amounts Recognized in Accumulat

Amounts Recognized in Accumulated Other Comprehensive Income, before Tax Effects (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost	$ 34	$ 40
Unrecognized net gain	(279)	(245)
Total recognized in accumulated other comprehensive loss	$ (245)	$ (205)

Estimated Future Benefit Paymen

Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Defined Benefit Plan Disclosure [Line Items]
2019	$ 58
2020	192
2021	267
2022	267
2023	267
Years 2024-2028	$ 1,628

Remaining Principal Balance on

Remaining Principal Balance on Employee Stock Ownership Plan Debt (Detail) - Employee Stock Ownership Plan [Member] $ in Thousands	Dec. 31, 2018USD ($)
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
2019	$ 88
2020	93
2021	98
2022	104
2023	110
Thereafter	3,380
Total	$ 3,873

Shares Held by Employee Stock O

Shares Held by Employee Stock Ownership Plan ESOP (Detail) - shares shares in Thousands	Dec. 31, 2018	Dec. 31, 2017
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Unallocated	347,803	363,091
Allocated	96,799	84,813
Total	444,602	447,904

Derivatives And Hedging - Addit

Derivatives And Hedging - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Collateral		$ 240,000
Designated as hedging instruments | Agreement One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Rolling FHLB advances		50,000,000
Premium paid		2,600,000
Designated as hedging instruments | Agreement Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Rolling FHLB advances	$ 100,000,000
Premium paid	1,500,000
Credit Risk
Derivative Instruments, Gain (Loss) [Line Items]
Credit derivative exposure net of collateral		0
Interest Rate Caps | Designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Debt instrument, face amount		200,000,000
Interest Rate Caps | Designated as hedging instruments | Agreement One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Debt instrument, face amount		50,000,000
Premium paid		$ 2,600,000
Agreement, maturity date		Sep. 12, 2024
Interest Rate Caps | Designated as hedging instruments | Agreement Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Debt instrument, face amount	100,000,000
Premium paid	$ 1,500,000
Agreement, maturity date		Mar. 21, 2023
Estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months		$ 207,000
Premium amortization		$ 7,000
Interest Rate Caps | Designated as hedging instruments | Maximum | Agreement One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest cap at maximum rate		3.00%
Interest Rate Caps | Designated as hedging instruments | Maximum | Agreement Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest cap at maximum rate	3.00%	3.00%
Interest Rate Caps | Designated as hedging instruments | London Interbank Offered Rate (LIBOR) | Minimum | Agreement One [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Libor cap strike price		3.00%
Interest Rate Caps | Designated as hedging instruments | London Interbank Offered Rate (LIBOR) | Minimum | Agreement Two [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Libor cap strike price	3.00%	3.00%

Derivatives And Hedging - Fair

Derivatives And Hedging - Fair Value of Derivative Financial Instruments (Detail) $ in Thousands	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Derivative Instruments And Hedging Activities [Line Items]
Liability derivatives	$ 3,144	$ 0
Asset Derivatives	5,292	$ 0
Designated as hedging instruments
Derivative Instruments And Hedging Activities [Line Items]
Asset Derivatives	2,303
Derivatives Not Designated as Hedging Instruments
Derivative Instruments And Hedging Activities [Line Items]
Liability derivatives	3,144
Asset Derivatives	$ 2,989
Interest Rate Caps | Designated as hedging instruments
Derivative Instruments And Hedging Activities [Line Items]
Number of Transactions	3
Notional Amount	$ 200,000
Asset Derivatives	$ 2,303
Interest Rate Swaps | Derivatives Not Designated as Hedging Instruments | Commercial loans
Derivative Instruments And Hedging Activities [Line Items]
Number of Transactions	9
Notional Amount	$ 76,792
Asset Derivatives	$ 2,967
Interest Rate Swaps | Derivatives Not Designated as Hedging Instruments | Third Party Financial Institution
Derivative Instruments And Hedging Activities [Line Items]
Number of Transactions	9
Notional Amount	$ 76,792
Liability derivatives	$ 3,144
Risk Participation-Out Agreements | Derivatives Not Designated as Hedging Instruments | Third Party Financial Institution
Derivative Instruments And Hedging Activities [Line Items]
Number of Transactions	3
Notional Amount	$ 6,340
Asset Derivatives	$ 22

Schedule of Derivative Financia

Schedule of Derivative Financial Instruments Included in Other Comprehensive (Loss) Income and Reclassifications into Earnings (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Other Comprehensive Income on Derivatives	$ (1,782)
Amount of Pre-Tax Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	(7)
Interest Rate Caps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pre-Tax Gain (Loss) Recognized in Other Comprehensive Income on Derivatives	(1,782)
Amount of Pre-Tax Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	$ (7)

Effect of Company's Derivative

Effect of Company's Derivative Financial Instruments (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative Instruments	$ (170)
Interest Rate Swaps
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative Instruments	(177)
Risk Participation-Out Agreements
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative Instruments	$ 7

Asset and Liability Derivative

Asset and Liability Derivative Positions and Repurchase Agreements (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Offsetting Derivative Assets [Abstract]
Gross Amounts of Recognized Assets, Derivative Assets	$ 5,292	$ 0
Gross Amounts Offset in the Statement of Financial Position, Derivative Assets	0
Net Amounts of Assets Presented in the Statement of Financial Position, Derivative Assets	5,292
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, Derivative Assets	2,304
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Pledged (Received), Derivative Assets	0
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount, Derivative Assets	2,988
Gross Amounts of Recognized Liabilities, Derivative Liabilities	3,144
Gross Amounts Offset in the Statement of Financial Position, Derivative Liabilities	0
Net Amounts of Liabilities Presented in the Statement of Financial Position, Derivative Liabilities	3,144
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, Derivative Liabilities	2,304
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Pledged (Received), Derivative Liabilities	240
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount, Derivative Liabilities	600
Gross Amounts of Recognized Liabilities , Securities sold under agreements to repurchase	2,883	3,268
Gross Amounts Offset in the Statement of Financial Position, Securities sold under agreements to repurchase	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position, Securities sold under agreements to repurchase	2,883	3,268
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments, Securities sold under agreements to repurchase	0	0
Gross Amounts Not Offset in the Statement of Financial Position, Collateral Pledged (Received) , Securities sold under agreements to repurchase	2,883	3,268
Gross Amounts Not Offset in the Statement of Financial Position, Net Amount, Securities sold under agreements to repurchase	$ 0	$ 0

Condensed Balance Sheets of Par

Condensed Balance Sheets of Parent Company (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents held at Belmont Savings Bank	$ 143,378	$ 110,888	$ 58,876	$ 51,261
Other assets	11,648	5,474
Total assets	3,030,101	2,676,565
Liabilities and Stockholders' Equity
Other liabilities	15,828	11,354
Total liabilities	2,828,307	2,498,536
Total stockholders' equity	201,794	178,029	160,921	146,203
Total liabilities and stockholders' equity	3,030,101	2,676,565
Parent Company
Assets
Cash and cash equivalents held at Belmont Savings Bank	1,440	919	$ 519	$ 496
Other assets	25	45
Total assets	201,975	178,083
Liabilities and Stockholders' Equity
Accrued expenses	16	38
Other liabilities	165	16
Total liabilities	181	54
Total stockholders' equity	201,794	178,029
Total liabilities and stockholders' equity	201,975	178,083
Parent Company | Belmont Savings Bank
Assets
Investment	196,318	173,054
Parent Company | Belmont Savings Bank Funding Corporation
Assets
Investment	$ 4,192	$ 4,065

Condensed Statements of Operati

Condensed Statements of Operations of Parent Company (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest and dividend income:
Dividends from subsidiaries									$ 1,923	$ 1,193	$ 760
Total interest and dividend income	$ 26,306	$ 25,644	$ 23,882	$ 22,419	$ 21,114	$ 19,758	$ 18,764	$ 17,506	98,251	77,143	61,621
Interest expense	10,862	10,235	8,779	7,281	6,414	5,579	4,816	4,245	37,157	21,054	14,231
Net interest and dividend income	15,444	15,409	15,103	15,138	14,700	14,179	13,948	13,261	61,094	56,089	47,390
Non-interest income	1,279	1,136	1,711	895	1,117	885	995	630	5,020	3,627	2,750
Non-interest expense	9,712	7,826	7,796	7,685	7,636	7,929	7,645	7,476	33,016	30,686	28,349
Income tax benefit	1,943	2,300	2,224	2,064	5,382	2,001	2,579	1,920	8,532	11,882	7,425
Net income	$ 4,603	$ 6,228	$ 6,068	$ 6,010	$ 2,108	$ 4,599	$ 4,012	$ 3,666	22,909	14,386	11,981
Parent Company
Interest and dividend income:
Interest on cash equivalents									9	0	0
Dividends from subsidiaries									0	0	0
Total interest and dividend income									9	0	0
Interest expense									0	0	0
Net interest and dividend income									9	0	0
Non-interest income									0	0	0
Non-interest expense									232	230	219
Loss before income taxes and equity in undistributed earnings of subsidiaries									(223)	(230)	(219)
Income tax benefit									(63)	(94)	(89)
Loss before equity in income of subsidiaries									(160)	(136)	(130)
Net income									22,909	14,386	11,981
Parent Company | Belmont Savings Bank
Interest and dividend income:
Equity in undistributed income									22,942	14,432	12,025
Parent Company | Belmont Savings Bank Funding Corporation
Interest and dividend income:
Equity in undistributed income									$ 127	$ 90	$ 86

Condensed Statement of Cash Flo

Condensed Statement of Cash Flows of Parent Company (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 4,603	$ 6,228	$ 6,068	$ 6,010	$ 2,108	$ 4,599	$ 4,012	$ 3,666	$ 22,909	$ 14,386	$ 11,981
Adjustments to reconcile net income to net cash used in operating activities:
Net cash provided by operating activities									59,083	85,765	12,773
Cash flows from financing activities:
Proceeds from exercise of stock options, net of cash paid									537	56	298
Net cash provided by financing activities									322,202	498,494	334,478
Net increase in cash and cash equivalents									32,490	52,012	7,615
Cash and cash equivalents at beginning of period				110,888				58,876	110,888	58,876	51,261
Cash and cash equivalents at end of period	143,378				110,888				143,378	110,888	58,876
Parent Company [Member]
Cash flows from operating activities:
Net income									22,909	14,386	11,981
Adjustments to reconcile net income to net cash used in operating activities:
Other, net										26	(27)
Net cash provided by operating activities									(160)	(110)	(157)
Cash flows from investing activities:
Net cash provided by investing activities										460
Cash flows from financing activities:
Proceeds from exercise of stock options, net of cash paid									681	50	298
Restricted stock awards issued, net of awards surrendered											(118)
Net cash provided by financing activities									681	50	180
Net increase in cash and cash equivalents									521	400	23
Cash and cash equivalents at beginning of period				$ 919				$ 519	919	519	496
Cash and cash equivalents at end of period	$ 1,440				$ 919				1,440	919	519
Parent Company [Member] | Belmont Savings Bank Foundation [Member]
Adjustments to reconcile net income to net cash used in operating activities:
Equity in undistributed earnings of Belmont Savings Bank									(22,942)	(14,432)	(12,025)
Parent Company [Member] | Belmont Savings Bank Funding Corporation [Member]
Adjustments to reconcile net income to net cash used in operating activities:
Equity in undistributed earnings of Belmont Savings Bank									$ (127)	(90)	$ (86)
Cash flows from investing activities:
Return of capital from BSB Funding Corp										$ 460

Quarterly Results of Operations

Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information [Line Items]
Interest and dividend income	$ 26,306	$ 25,644	$ 23,882	$ 22,419	$ 21,114	$ 19,758	$ 18,764	$ 17,506	$ 98,251	$ 77,143	$ 61,621
Interest expense	10,862	10,235	8,779	7,281	6,414	5,579	4,816	4,245	37,157	21,054	14,231
Net interest income	15,444	15,409	15,103	15,138	14,700	14,179	13,948	13,261	61,094	56,089	47,390
Provision for loan losses	465	191	726	274	691	535	707	829	1,657	2,762	2,385
Net interest income, after provision for loan losses	14,979	15,218	14,377	14,864	14,009	13,644	13,241	12,432	59,437	53,327	45,005
Non-interest income	1,279	1,136	1,711	895	1,117	885	995	630	5,020	3,627	2,750
Non-interest expense	9,712	7,826	7,796	7,685	7,636	7,929	7,645	7,476	33,016	30,686	28,349
Income before taxes	6,546	8,528	8,292	8,074	7,490	6,600	6,591	5,586	31,441	26,268	19,406
Income tax expense	1,943	2,300	2,224	2,064	5,382	2,001	2,579	1,920	8,532	11,882	7,425
Net income	$ 4,603	$ 6,228	$ 6,068	$ 6,010	$ 2,108	$ 4,599	$ 4,012	$ 3,666	$ 22,909	$ 14,386	$ 11,981
Earnings per common share
Basic	$ 0.51	$ 0.70	$ 0.68	$ 0.68	$ 0.24	$ 0.52	$ 0.45	$ 0.42	$ 2.56	$ 1.63	$ 1.38
Diluted	$ 0.49	$ 0.66	$ 0.65	$ 0.64	$ 0.23	$ 0.50	$ 0.43	$ 0.40	$ 2.44	$ 1.55	$ 1.33