Randolph Bancorp (RNDB) 10-Q 10 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 10, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	RNDB
Entity Registrant Name	Randolph Bancorp, Inc.
Entity Central Index Key	1,667,161
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		5,868,726

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 4,516	$ 4,370
Interest-bearing deposits	3,900	10,479
Total cash and cash equivalents	8,416	14,849
Certificates of deposit	3,185	3,675
Securities available for sale, at fair value	67,441	68,637
Loans held for sale, at fair value	19,923	30,452
Loans, net of allowance for loan losses of $3,437 in 2017 and $3,271 in 2016	352,962	332,991
Federal Home Loan Bank stock, at cost	2,201	2,478
Accrued interest receivable	1,144	1,163
Mortgage servicing rights, net	8,878	8,486
Premises and equipment, net	6,519	6,280
Bank-owned life insurance	7,922	7,884
Other assets	3,903	4,329
Total assets	482,494	481,224
Deposits:
Non-interest bearing	64,414	59,646
Interest bearing	297,683	291,533
Total deposits	362,097	351,179
Federal Home Loan Bank advances	30,487	38,667
Mortgagors' escrow accounts	1,704	1,572
Post-employment benefit obligations	2,751	2,886
Other liabilities	2,493	3,618
Total liabilities	399,532	397,922
Commitments and contingencies (Note 13)
Stockholders' Equity:
Preferred stock, no par value; authorized: 1,000,000 shares; issued: none
Common stock, $.01 par value; authorized: 15,000,000 shares; issued and outstanding: 5,868,726 shares at March 31, 2017 and December 31, 2016	59	59
Additional paid-in capital	56,398	56,373
Retained earnings	32,214	32,661
ESOP-Unearned compensation	(4,460)	(4,507)
Accumulated other comprehensive loss, net of tax	(1,249)	(1,284)
Total stockholders' equity	82,962	83,302
Total liabilities and stockholders' equity	$ 482,494	$ 481,224

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Loans, allowance for loan losses	$ 3,437	$ 3,271
Preferred stock, par value
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	5,868,726	5,868,726
Common stock, shares outstanding	5,868,726	5,868,726

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest and dividend income:
Loans	$ 3,416	$ 2,718
Securities-taxable	358	319
Securities-tax exempt	89	96
Interest-bearing deposits and certificates of deposit	21	22
Total interest and dividend income	3,884	3,155
Interest expense:
Deposits	336	314
Federal Home Loan Bank advances	64	61
Total interest expense	400	375
Net interest income	3,484	2,780
Provision for loan losses	235	62
Net interest income after provision for loan losses	3,249	2,718
Non-interest income:
Customer service fees	372	356
Net gain on sales of mortgage loans	2,038	681
Mortgage servicing fees, net	660	100
Gain on sales/calls of securities		62
Increase in cash surrender value of life insurance	38	56
Other	302	48
Total non-interest income	3,410	1,303
Non-interest expenses:
Salaries and employee benefits	4,676	2,202
Occupancy and equipment	656	394
Data processing	182	255
Professional fees	302	285
Marketing	148	69
Foreclosed real estate, net		4
FDIC insurance	43	83
Merger and integration costs	167	117
Other	955	607
Total non-interest expenses	7,129	4,016
Income (loss) before income taxes	(470)	5
Income tax expense (benefit)	(23)	3
Net income (loss)	$ (447)	$ 2
Weighted average common shares outstanding (basic and diluted)	5,420,356
Earnings (loss) per common share (basic and diluted)	$ (0.08)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net income (loss)	$ (447)	$ 2
Securities available for sale:
Unrealized holding gains	74	820
Reclassification adjustment for net gains realized in income		(62)
Net unrealized gains	74	758
Related tax effects	(26)
Net-of-tax amount	48	758
Related tax effects	0	0
Net-of-tax amount	(13)	3
Total other comprehensive income	35	761
Comprehensive income (loss)	(412)	763
Supplemental Retirement Plan [Member]
Securities available for sale:
Actuarial losses	9	(6)
Prior service (credits) costs recognized	(22)	9
Post-retirement benefit plans	$ (13)	$ 3

Consolidated Statements Changes

Consolidated Statements Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Unearned Compensation ESOP [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2015	$ 32,459			$ 32,198		$ 261
Net income (loss)	2			2
Other comprehensive income	761					761
Ending balance at Mar. 31, 2016	33,222			32,200		1,022
Beginning balance at Dec. 31, 2015	32,459			32,198		261
Ending balance at Dec. 31, 2016	83,302	$ 59	$ 56,373	32,661	$ (4,507)	(1,284)
Ending balance, shares at Dec. 31, 2016		5,868,726
Net income (loss)	(447)			(447)
Other comprehensive income	35					35
ESOP shares committed to be released	72		25		47
Ending balance at Mar. 31, 2017	$ 82,962	$ 59	$ 56,398	$ 32,214	$ (4,460)	$ (1,249)
Ending balance, shares at Mar. 31, 2017		5,868,726

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ (447,000)	$ 2,000
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Provision for loan losses	235,000	62,000
Loans originated for sale	(89,440,000)	(26,832,000)
Principal balance of loans sold	99,969,000	25,166,000
Net amortization of securities	70,000	40,000
Net change in deferred loan costs and fees	(38,000)	34,000
Gain on sales/calls of securities		(62,000)
Depreciation and amortization	135,000	143,000
ESOP expense	72,000
Increase in cash surrender value of life insurance	(38,000)	(56,000)
Net increase in mortgage servicing rights	(392,000)	(86,000)
Other, net	(827,000)	535,000
Net cash provided by (used in) operating activities	9,299,000	(1,054,000)
Cash flows from investing activities:
Redemption of certificates of deposit	490,000
Securities available for sale:
Calls/maturities	135,000	3,365,000
Purchases		(2,000,000)
Principal payments on mortgage-backed securities	1,039,000	947,000
Loan originations, net of principal repayments	(9,779,000)	(6,803,000)
Loans purchased, net of principal repayments	(10,390,000)	(836,000)
Redemption of Federal Home Loan Bank stock	277,000	427,000
Proceeds from sale of building		1,231,000
Purchases of premises and equipment	(374,000)	(510,000)
Net cash used in investing activities	(18,602,000)	(4,179,000)
Cash flows from financing activities:
Net increase in deposits	10,918,000	11,590,000
Net increase (decrease) in short-term Federal Home Loan Bank borrowings	(8,016,000)	4,179,000
Proceeds from long-term Federal Home Loan Bank advances		3,906,000
Repayments of long-term Federal Home Loan Bank advances	(164,000)	(13,555,000)
Net increase in mortgagors' escrow accounts	132,000	5,000
Stock offering costs		(223,000)
Net cash provided by financing activities	2,870,000	5,902,000
Net change in cash and cash equivalents	(6,433,000)	669,000
Cash and cash equivalents at beginning of period	14,849,000	4,646,000
Cash and cash equivalents at end of period	8,416,000	5,315,000
Supplemental cash flow information:
Interest paid on deposits and borrowed funds	404,000	$ 374,000
Income taxes paid	$ 3,000

Conversion and Basis of Present

Conversion and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Conversion and Basis of Presentation	1. CONVERSION AND BASIS OF PRESENTATION Conversion Randolph Bancorp, a Massachusetts-chartered mutual holding company and the parent company of Randolph Savings Bank (the “Bank”), adopted a plan of conversion (the “Plan of Conversion”) in January 2016 which was subsequently approved by Randolph Bancorp’s Corporators in May 2016. Under the Plan of Conversion, Randolph Bancorp converted from a mutual to a stock holding company in a series of transactions in which Randolph Bancorp, Inc. (“Bancorp”), a recently formed subsidiary of Randolph Bancorp, became the surviving entity. On July 1, 2016, the mutual-to-stock transaction was completed and Bancorp sold 5,686,750 shares of its common stock, representing the adjusted maximum of the offering range, at $10.00 per share, for gross proceeds of $56,867,500, including the sale of 469,498 shares to the Bank’s newly formed employee stock ownership plan (“ESOP”). The ESOP’s shares were funded by a loan from Bancorp to be repaid over 25 years with interest at the prime rate. The direct costs of stock offering were deducted from the proceeds of the offering and amounted to $2,325,000. In connection with the Plan of Conversion, Bancorp established The Randolph Savings Charitable Foundation, Inc. (the “Foundation”). The Foundation was funded with 181,976 shares of Bancorp’s common stock and $455,000 in cash. Bancorp recognized expense of $2,274,700 in the third quarter of 2016 for this contribution. The Bancorp and the Bank are required to restrict their net worth by establishing liquidation accounts (collectively, the “liquidation account”) for the benefit of eligible account holders who continue to maintain deposit accounts at the Bank after the conversion. The liquidation account will be reduced annually to the extent eligible depositors reduce their qualifying deposits and cannot be increased thereafter with additional deposits. In the event of a complete liquidation of the Bank, each eligible account holder would be entitled to receive a distribution from the liquidation account in an amount proportionate to the adjusted qualifying account balances then held. Neither the Bancorp nor the Bank may declare or pay a cash dividend on its common stock if such dividend would cause its regulatory capital to be reduced below the amount required to maintain the liquidation account. Basis of Financial Statement Presentation The consolidated financial statements include the accounts of Randolph Bancorp, Inc. and its wholly-owned subsidiary, Randolph Savings Bank (together, the “Company”). The Bank has subsidiaries involved in owning investment securities and foreclosed real estate properties and a subsidiary which provides loan closing services. All intercompany accounts and transactions have been eliminated in consolidation. These financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X issued by the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying interim financial statements do not include all information required under GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements, primarily consisting of normal recurring adjustments, have been included. The operating results for the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or any other interim period. For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the SEC.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2017
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	1. RECENT ACCOUNTING PRONOUNCEMENTS In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses

Acquisition

Acquisition	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Acquisition	1. ACQUISITION On July 1, 2016, the Company acquired all of the outstanding common stock of First Eastern Bankshares Corporation (“First Eastern”) for cash of $14.1 million. The results of operations of First Eastern are included in the Company’s consolidated statements of operations beginning on July 1, 2016. The following table presents selected unaudited pro forma financial information assuming the acquisition was completed on January 1, 2016. The pro forma amounts reflect adjustments related to reversal of non-recurring merger and integration costs and amortization and accretion of acquisition accounting fair value adjustments. No benefit for income taxes is included in the determination of the pro forma net loss due to the Company’s determination to establish a full valuation allowance for its deferred tax assets. The unaudited pro forma financial information does not reflect management’s estimate of any revenue enhancement opportunities or anticipated cost savings nor any adjustments related to the stock offering completed on July 1, 2016. The unaudited pro forma financial information is presented for illustrative purposes only and is not necessarily indicative of the combined financial results of the Company and First Eastern had the acquisition transaction actually been completed at the beginning of the period presented, nor does it indicate future results for any interim or annual period. Pro forma basic and diluted earnings (loss) per share are not presented as such information is not being presented as part of our historical financial statements for the three months ended March 31, 2016 due to the completion of the stock offering subsequent thereto. Unaudited pro forma financial information for the three months ended March 31, 2016 is as follows (in thousands): Net interest income $ 3,270 Non-interest income 3,230 Net loss (183 ) Direct acquisition and merger integration costs associated with the First Eastern business combination are being expensed as incurred and are presented separately in the accompanying statement of operations. Costs incurred during the three months ended March 31, 2016 consist principally of legal and consulting fees. Costs incurred during the three months ended March 31, 2017 consist principally of severance obligations and system conversion costs. Additional merger integration costs are expected to be incurred through the third quarter of 2017.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Accumulated Other Comprehensive Loss	1. ACCUMULATED OTHER COMPREHENSIVE LOSS Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income (loss). Although certain changes in assets and liabilities are reported as a separate component of stockholders’ equity, such items, along with net income (loss), are components of comprehensive income (loss). The components of accumulated other comprehensive loss, included in total stockholders’ equity, are as follows: March 31, December 31, 2017 2016 (In thousands) Securities available for sale: Net unrealized loss $ (624 ) $ (698 ) Tax effect (449 ) (423 ) Net-of-tax amount (1,073 ) (1,121 ) Supplemental retirement plan Unrecognized net actuarial loss (670 ) (679 ) Unrecognized net prior service credit 551 573 (119 ) (106 ) Tax effect (57 ) (57 ) Net-of-tax amount (176 ) (163 ) Accumulated other comprehensive loss $ (1,249 ) $ (1,284 )

Securities Available for Sale

Securities Available for Sale	3 Months Ended
	Mar. 31, 2017
Investments Debt And Equity Securities [Abstract]
Securities Available for Sale	1. SECURITIES AVAILABLE FOR SALE The amortized cost and fair value of securities available for sale, including gross unrealized gains and losses, are as follows: Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value (In thousands) March 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 85 $ (9 ) $ 4,075 Corporate 3,034 46 (10 ) 3,070 Municipal 13,708 281 (28 ) 13,961 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 20,564 155 (598 ) 20,121 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,619 49 (517 ) 14,151 U.S. Government-guaranteed 9,169 15 (112 ) 9,072 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 2,077 25 — 2,102 U.S. Government-guaranteed 349 4 — 353 Total debt securities 67,519 660 (1,274 ) 66,905 Mutual fund 545 — (9 ) 536 Total securities available for sale $ 68,064 $ 660 $ (1,283 ) $ 67,441 December 31, 2016 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 92 $ (10 ) $ 4,081 Corporate 3,044 54 (18 ) 3,080 Municipal 13,857 254 (56 ) 14,055 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 21,130 172 (580 ) 20,722 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,676 56 (554 ) 14,178 U.S. Government-guaranteed 9,589 12 (144 ) 9,457 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 2,127 28 — 2,155 U.S. Government-guaranteed 368 3 — 371 Total debt securities 68,790 671 (1,362 ) 68,099 Mutual fund 545 — (7 ) 538 Total securities available for sale $ 69,335 $ 671 $ (1,369 ) $ 68,637 The amortized cost and fair value of debt securities by contractual maturity at March 31, 2017 are presented below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Fair Cost Value (In thousands) Within 1 year $ 2,237 $ 2,259 After 1 year through 5 years 12,621 12,828 After 5 years through 10 years 5,883 6,019 20,741 21,106 Mortgage-backed securities 46,778 45,799 $ 67,519 $ 66,905 Information pertaining to securities with gross unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous loss position, follows: Less Over Twelve Months Gross Gross Unrealized Fair Unrealized Fair Losses Value Losses Value March 31, 2017 (In thousands) Debt securities: U.S. Government-sponsored enterprises $ (9 ) $ 1,991 Corporate (9 ) 522 (1 ) 477 Municipal (22 ) 2,204 (6 ) 480 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (598 ) 15,900 — — Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (517 ) 8,775 — — U.S. Government-guaranteed (112 ) 4,818 — — Total debt securities (1,267 ) 34,210 (7 ) 957 Mutual Fund (9 ) 536 — — $ (1,276 ) $ 34,746 $ (7 ) $ 957 December 31, 2016 Debt securities: U.S. Government-sponsored enterprises $ (10 ) $ 1,990 $ — $ — Corporate (14 ) 519 (4 ) 996 Municipal (46 ) 3,310 (10 ) 477 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (580 ) 16,261 — — Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (554 ) 8,766 — — U.S. Government-guaranteed (144 ) 5,927 — — Total debt securities (1,348 ) 36,773 (14 ) 1,473 Mutual Fund (7 ) 538 — — $ (1,355 ) $ 37,311 $ (14 ) $ 1,473 At March 31, 2017, 34 debt securities have unrealized losses with aggregate depreciation of 3.59% from the Company’s amortized cost basis. The unrealized losses at March 31, 2017, which related primarily to securities issued by U.S. government-sponsored enterprises, were primarily caused by an increase in long-term rates in the fourth quarter of 2016. 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 these investments. Therefore, it is expected that the bonds would not be settled at a price less than the par value of the investment. Because the Company does not intend to sell any debt securities and it is more likely than not that the Company will not be required to sell any debt securities before recovery of its amortized cost basis, it does not consider these investments to be other-than-temporarily impaired at March 31, 2017.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Loans and Allowance for Loan Losses	1. LOANS AND ALLOWANCE FOR LOAN LOSSES A summary of the loan portfolio at the dates indicated is as follows: March 31, 2017 December 31, 2016 (In thousands) Mortgage loans on real estate: Residential: One-to-four family $ 180,488 $ 179,025 Home equity loans and lines of credit 37,136 35,393 Commercial 91,828 88,394 Construction 26,538 23,629 335,990 326,441 Commercial and industrial 12,001 2,067 Consumer 7,194 6,578 Total loans 355,185 335,086 Allowance for loan losses (3,437 ) (3,271 ) Net deferred loan costs and fees, and purchase premiums 1,214 1,176 $ 352,962 $ 332,991 In March 2017, the Company purchased $9.8 million in loan participations originated through a super-regional bank. These loans are to local franchisees of a major international fast food retailer. The following table summarizes the changes in the allowance for loan losses by portfolio segment for the three months ended March 31, 2017 and 2016: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total (In thousands) Three Months Ended March 31, 2017 Allowance at December 31, 2016 $ 1,018 $ 436 $ 1,410 $ 225 $ 37 $ 145 $ 3,271 Provision (credit) for loan losses (61 ) (41 ) 109 (14 ) 157 85 235 Loans charged-off — — — — — (76 ) (76 ) Recoveries 4 — — — 1 2 7 Balance at March 31, 2017 $ 961 $ 395 $ 1,519 $ 211 $ 195 $ 156 $ 3,437 Three Months Ended March 31, 2016 Allowance at December 31, 2015 $ 1,076 $ 512 $ 1,402 $ 159 $ 37 $ 53 $ 3,239 Provision (credit) for loan losses (23 ) (81 ) 157 (38 ) (1 ) 48 62 Loans charged-off — — — — — (26 ) (26 ) Recoveries 1 — — — — 9 10 Balance at March 31, 2016 $ 1,054 $ 431 $ 1,559 $ 121 $ 36 $ 84 $ 3,285 Additional information pertaining to the allowance for loan losses at March 31, 2017 and December 31, 2016 is as follows: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total March 31, 2017 (In thousands) Allowance for impaired loans $ 184 $ 1 $ 9 $ — $ — $ — $ 194 Allowance for non-impaired loans 777 394 1,510 211 195 156 3,243 Total allowance for loan losses $ 961 $ 395 $ 1,519 $ 211 $ 195 $ 156 $ 3,437 Impaired loans $ 4,893 $ 276 $ 788 $ — $ — $ — $ 5,957 Non-impaired loans 175,595 36,860 91,040 26,538 12,001 7,194 349,228 Total loans $ 180,488 $ 37,136 $ 91,828 $ 26,538 $ 12,001 $ 7,194 $ 355,185 December 31, 2016 Allowance for impaired loans $ 190 $ 2 $ 8 $ — $ — $ — $ 200 Allowance for non-impaired loans 828 434 1,402 225 37 145 3,071 Total allowance for loan losses $ 1,018 $ 436 $ 1,410 $ 225 $ 37 $ 145 $ 3,271 Impaired loans $ 4,506 $ 276 $ 832 $ — $ - $ — $ 5,614 Non-impaired loans 174,519 35,117 87,562 23,629 2,067 6,578 329,472 Total loans $ 179,025 $ 35,393 $ 88,394 $ 23,629 $ 2,067 $ 6,578 $ 335,086 The following is a summary of past due and non-accrual loans at March 31, 2017 and December 31, 2016: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due Non-accrual Loans (In thousands) March 31, 2017 Residential one-to-four family $ 1,509 $ 155 $ — $ 1,664 $ 2,137 Home equity loans and lines of credit — — — — 276 Commercial real estate 400 — — 400 — Construction — — — — — Commercial and industrial — — — — — Consumer 3 11 — 14 — Total $ 1,912 $ 166 $ — $ 2,078 $ 2,413 December 31, 2016 Residential one-to-four family $ 1,168 $ 201 $ — $ 1,369 $ 1,945 Home equity loans and lines of credit 258 — — 258 276 Commercial real estate 400 — — 400 — Construction — — — — — Commercial and industrial — — — — — Consumer 59 — — 59 — Total $ 1,885 $ 201 $ — $ 2,086 $ 2,221 The following is a summary of impaired loans at March 31, 2017 and December 31, 2016: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) March 31, 2017 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,325 $ 2,281 $ — Home equity loans and lines of credit 247 247 — Commercial real estate 267 267 — Total 2,839 2,795 — Impaired loans with a valuation allowance: Residential one-to-four family 2,632 2,612 184 Home equity loans and lines of credit 30 29 1 Commercial real estate 521 521 9 Total 3,183 3,162 194 Total impaired loans $ 6,022 $ 5,957 $ 194 December 31, 2016 Impaired loans without a valuation allowance: Residential one-to-four family $ 1,922 $ 1,877 $ — Home equity loans and lines of credit 246 246 — Commercial real estate 270 270 — Total 2,438 2,393 — Impaired loans with a valuation allowance: Residential one-to-four family 2,648 2,629 190 Home equity loans and lines of credit 31 30 2 Commercial real estate 562 562 8 Total 3,241 3,221 200 Total impaired loans $ 5,679 $ 5,614 $ 200 Additional information pertaining to impaired loans follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Three Months Ended March 31, 2017 Residential one-to-four family $ 4,870 $ 41 $ 16 Home equity loans and lines of credit 276 — — Commercial real estate 807 9 — Total $ 5,953 $ 50 $ 16 Three Months Ended March 31, 2016 Residential one-to-four family $ 4,946 $ 41 $ 13 Home equity loans and lines of credit 277 — — Commercial real estate 1,441 16 — Commercial and industrial 16 — — Total $ 6,680 $ 57 $ 13 No additional funds are committed to be advanced in connection with impaired loans. Troubled Debt Restructurings The Company periodically grants concessions to borrowers experiencing financial difficulties. The Company’s troubled debt restructurings consist primarily of interest rate concessions for periods of three months to 30 years for residential real estate loans, and for periods up to one year for commercial real estate loans. At March 31, 2017, the Company had 18 residential real estate loans and three commercial real estate loans aggregating $4,479,000 and $589,000, respectively, which were subject to troubled debt restructuring agreements. At March 31, 2016, the Company had 19 residential real estate loans and five commercial real estate loans aggregating $4,870,000 and $1,052,000, respectively, which were subject to troubled debt restructuring agreements. As of March 31, 2017 and 2016, $5,067,000 and $5,644,000, respectively, in troubled debt restructurings were performing in accordance with the terms of the modified loan agreements. Included in such amounts are $1,756,000 and $1,740,000, respectively, that are being accounted for as non-accrual loans. For the three months ended March 31, 2017 and 2016 the Company did not enter into any loan modifications meeting the criteria of a troubled debt restructuring. Management performs a discounted cash flow calculation to determine the amount of impairment reserve required on each of the troubled debt restructurings. Any reserve required is recorded as part of the allowance for loan losses. During the three months ended March 31, 2017 and 2016, there were no material changes to the allowance for loan losses as a result of loan modifications made which were considered a troubled debt restructuring. During the three months ended March 31, 2017 and 2016, there were no troubled debt restructurings that defaulted (over 30 days past due) within twelve months of the restructure date. Credit Quality Information The Company utilizes an eight-grade internal loan rating system for commercial real estate, construction and commercial loans, as follows: Loans rated 1 – 3B are considered “pass” rated loans with low to average risk. Loans rated 4 are considered “special mention.” These loans are starting to show signs of potential weakness and are being closely monitored by management. Loans rated 5 are considered “substandard” and are inadequately protected by the current net worth and paying capacity of the obligors and/or the collateral pledged. There is a distinct possibility that the Company will sustain some loss if the weakness is not corrected. Loans rated 6 are considered “doubtful” and have all the weaknesses inherent in those classified substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, highly questionable and improbable. Loans rated 7 are considered uncollectible (“loss”) and of such little value that their continuance as loans is not warranted. On an annual basis, or more often if needed, the Company formally reviews the ratings on all commercial real estate, construction and commercial and industrial loans. Annually, the Company engages an independent third party to review a significant portion of loans within these segments. Management uses the results of these reviews as part of its annual review process. The following table presents the Company’s loans by risk rating at the dates indicated: March 31, 2017 December 31, 2016 Commercial Real Construction Commercial and Industrial Commercial Real Construction Commercial and Industrial (In thousands) Loans rated 1 - 3B $ 91,622 $ 26,188 $ 12,001 $ 88,186 $ 23,286 $ 2,067 Loans rated 4 — 350 — — 343 — Loans rated 5 206 — — 208 — — $ 91,828 $ 26,538 $ 12,001 $ 88,394 $ 23,629 $ 2,067 Residential mortgages, home equity loans and lines of credit, and consumer loans are monitored for credit quality based primarily on their payment status. When one of these of loans becomes more than 90 days delinquent, it is assigned an internal loan rating. At March 31, 2017, $884,000 in residential mortgages were rated as substandard and $1,294,000 in residential mortgages and $398,000 in home equity loans were rated as special mention. At December 31, 2016, $890,000 in residential mortgages were rated as substandard and $1,471,000 in residential mortgages and $400,000 in home equity loans were rated as special mention.

Loan Servicing

Loan Servicing	3 Months Ended
	Mar. 31, 2017
Transfers And Servicing [Abstract]
Loan Servicing	1. LOAN SERVICING Mortgage loans serviced for others are not included in the accompanying consolidated balance sheets. The unpaid principal balance of residential mortgage loans serviced for others was $1,074,511,000 and $1,046,551,000 at March 31, 2017 and December 31, 2016, respectively. The following table summarizes the activity relating to mortgage servicing rights for the three months ended March 31, 2017 and 2016 (in thousands): March 31, 2017 March 31, 2016 Mortgage servicing rights: Balance at beginning of year $ 8,910 $ 2,601 Additions through originations 451 206 Amortization (339 ) (120 ) Balance at end of period $ 9,022 $ 2,687 Valuation allowance: Balance at beginning of year $ 424 $ 34 Provision (credit) (280 ) — Balance at end of period $ 144 $ 34 Amortized cost, net $ 8,878 $ 2,653 Fair value $ 8,907 $ 2,898 During the three months ended March 31, 2017, the Company recorded a partial reversal of the valuation allowance for its mortgage servicing rights of $280,000 due to an increase in fair value caused by lower expected loan prepayments.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	1. INCOME TAXES During the three months ended March 31, 2017 and 2016, the Company recorded a federal tax benefit of $26,000 and $0, respectively, and state tax expense of $3,000 and $2,000, respectively. The federal tax benefit for the 2017 period resulted from, and was limited to, an offsetting tax provision attributable to other comprehensive income, specifically, appreciation in the fair value of available-for-sale securities. Since 2014, the Company has maintained a valuation allowance for all of its deferred tax assets based on a determination that it was more likely than not that such assets would not be realized. This determination was based on the Company’s net operating loss (“NOL”) carryforward position, its current period operating results exclusive of non-recurring items and its expectations for the upcoming year. In performing subsequent assessments, management has concluded that no significant changes in the key factors affecting the realizability of the deferred tax asset has occurred and that a valuation allowance for all deferred tax assets should be maintained.

On-Balance Sheet Derivative Ins

On-Balance Sheet Derivative Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
On-Balance Sheet Derivative Instruments and Hedging Activities	1. ON-BALANCE SHEET DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Derivative Loan Commitments Mortgage loan commitments qualify as derivative loan commitments if the loan that will result from exercise of the commitment will be held for sale upon funding. The Company enters into commitments to fund residential mortgage loans at specified rates and times in the future, with the intention that these loans will subsequently be sold in the secondary market. Outstanding derivative loan commitments expose the Company to the risk that the price of the loans arising from exercise of the loan commitment might decline from inception of the rate lock to funding of the loan due to an increase in mortgage interest rates. If interest rates increase, the value of these loan commitments decreases. Conversely, if interest rates decrease, the value of these loan commitments increases. The notional amount of derivative loan commitments was $43,620,000 and $32,904,000 at March 31, 2017 and December 31, 2016, respectively. The fair value of such commitments was an asset of $812,000 and $617,000 as of March 31, 2017 and December 31, 2016, respectively, and is included in other assets in the consolidated balance sheets. Forward Loan Sale Commitments The Company utilizes both “mandatory delivery” and “best efforts” forward loan sale commitments to mitigate the risk of potential decreases in the values of loans that would result from the exercise of the derivative loan commitments. With a “mandatory delivery” contract, the Company commits to deliver a certain principal amount of mortgage loans to an investor at a specified price on or before a specified date. If the Company fails to deliver the amount of mortgages necessary to fulfill the commitment by the specified date, it is obligated to pay a “pair-off” fee, based on then-current market prices, to the investor to compensate the investor for the shortfall. With a “best efforts” contract, the Company commits to deliver an individual mortgage loan of a specified principal amount and quality to an investor if the loan to the underlying borrower closes. Generally, the price the investor will pay the seller for an individual loan is specified prior to the loan being funded (e.g. on the same day the lender commits to lend funds to a potential borrower). The Company does not account for best efforts contracts as derivative instruments, as such contracts do not require payment of a pair-off fee if the underlying mortgage loan does not close. The Company expects that these forward loan sale commitments will experience inverse changes in fair value to the change in fair value of derivative loan commitments. The notional amount of forward loan sale commitments was $48,575,000 and $29,481,000 at March 31, 2017 and December 31, 2016, respectively. The fair value of certain of these commitments was an asset of $32,000 and $65,000 at March 31, 2017 and December 31, 2016, respectively, and is included in other assets in the consolidated balance sheets while the fair value of other such commitments was a liability of $104,000 and $47,000 at March 31, 2017 and December 31, 2016, respectively, and is included in other liabilities in the consolidated balance sheets.

Employee Stock Ownership Plan

Employee Stock Ownership Plan	3 Months Ended
	Mar. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee Stock Ownership Plan	1. EMPLOYEE STOCK OWNERSHIP PLAN In connection with our mutual-to-stock conversion and stock offering, the Company established an employee stock ownership plan (“ESOP) which acquired 469,498 shares of the Company’s common stock equaling 8% of the shares issued, including shares issued to the Foundation. The ESOP is a tax-qualified retirement plan providing employees the opportunity to own Company stock. Company contributions to the ESOP are allocated to eligible participants on the basis of compensation, subject to federal tax limits. The number of shares to be allocated annually is 18,780 through 2040. Shares are committed to be released on a monthly basis and allocated as of December 31 each year. During the three month period ended March 31, 2017, 4,695 shares were committed to be released resulting in compensation expense, based on the fair value of the Company’s stock, of $72,000. The fair value of the 446,023 unallocated and uncommitted shares at March 31, 2017 was $6,913,400.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	1. EARNINGS (LOSS) PER SHARE Basic earnings (loss) per share represents net income (loss) divided by the weighted average of common shares outstanding during the period. Unallocated ESOP shares are not considered to be outstanding for purposes of computing earnings per share. There were no potentially dilutive common stock equivalents outstanding at March 31, 2017. The cost of shares issued to the ESOP, but not yet allocated or committed to be released to participants, is shown as a reduction of stockholders’ equity. During the quarter ended March 31, 2017 there were 5,868,726 shares outstanding while the average of unallocated and uncommitted ESOP shares totaled 448,371 resulting in a total of 5,420,356 shares being used to compute basic and diluted earnings per share. As shares were not outstanding during the first quarter of 2016 earnings per share is not presented for this period.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	1. FAIR VALUE OF ASSETS AND LIABILITIES Determination of fair value The Company uses fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is best determined based upon quoted market prices. However, in many instances, there are no quoted market prices for the Company’s various assets and liabilities. In cases where quoted market prices are not available, fair values are based on estimates using present value or other valuation techniques. Those techniques are significantly affected by the assumptions used, including the discount rate and estimates of future cash flows. Accordingly, the fair value estimates may not be realized in an immediate settlement of the asset or liability. Effective July 1, 2016, the Company elected the fair value option pursuant to Accounting Standards Codification (“ASC”) 825, “Financial Instruments” for its residential mortgage loans being held for sale in the secondary market. ASC 825 allows for the irrevocable option to elect fair value accounting for the initial and subsequent measurement for certain financial assets and liabilities on a contract-by-contract basis that may otherwise not be required to be measured at fair value under other accounting standards. The Company elected the fair value option to better match changes in fair values of the loans with changes in the fair value of the forward loan sale commitments which are used to economically hedge them against changes in interest rates between the time an interest rate lock agreement is entered into with the borrower and the time the completed loan is sold. The aggregate fair value of the loans held for sale, the contractual balance of loans held for sale and the gain on loans held for sale totaled $19.9 million, $19.5 million and $427,000, respectively, at March 31, 2017. The gain on loans held for sale is reported as a component of net gains on sale of mortgage loans in the accompanying statement of operations for the three months ended March 31, 2017. The following methods and assumptions were used by the Company in estimating fair value disclosures: Cash and cash equivalents Certificates of deposit Securities Federal Home Loan Bank of Boston (“FHLBB”) stock Loans held for sale Loans Mortgage servicing rights Deposit liabilities FHLBB advances Accrued interest On-balance-sheet derivatives Off-balance sheet credit-related instruments Assets and liabilities measured at fair value on a recurring basis Assets and liabilities measured at fair value on a recurring basis are summarized below. . Total Level 1 Level 2 Level 3 Fair (In thousands) March 31, 2017 Assets: Securities available for sale: Debt securities $ — $ 66,905 $ — $ 66,905 Mutual fund — 536 — 536 Loans held for sale — 19,923 — 19,923 Derivative loan commitments — 812 — 812 Forward loan sale commitments — 32 — 32 Liabilities: Forward loan sale commitments — 104 — 104 December 31, 2016 Assets: Securities available for sale: Debt securities $ — $ 68,099 $ — $ 68,099 Mutual fund — 538 — 538 Loans held for sale — 30,452 — 30,452 Derivative loan commitments — 617 — 617 Forward loan sale commitments — 65 — 65 Liabilities: Forward loan sale commitments — 47 — 47 Assets measured at fair value on a non-recurring basis The Company may also be required, from time to time, to measure certain other assets at fair value on a non-recurring basis in accordance with U.S. generally accepted accounting principles. These adjustments to fair value usually result from application of lower-of-cost-or-market accounting or write-downs of individual assets. The following table summarizes the fair value hierarchy used to determine each adjustment and the carrying value of the related assets as of March 31, 2017 and December 31, 2016. March 31, 2017 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 1,585 Mortgage servicing rights — 8,878 — $ — $ 8,878 $ 1,585 December 31, 2016 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 518 Mortgage servicing rights — 8,486 — $ — $ 8,486 $ 518 The Company recorded a partial reversal of the valuation allowance for its mortgage servicing rights of $280,000 during the three months ended March 31, 2017, due to an increase in fair value caused by lower expected loan prepayments. There were no changes in the valuation allowance during the three months ended March 31, 2016. There were no liabilities measured at fair value on a non-recurring basis at March 31, 2017 and December 31, 2016. Summary of fair values of financial instruments The estimated fair values, and related carrying amounts, of the Company’s financial instruments are presented below. Certain financial instruments and all non-financial instruments are exempt from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein do not represent the underlying fair value of the Company. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents, and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include mortgagors’ escrow accounts and accrued interest payable. March 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 3,185 $ 3,200 $ — $ 3,200 $ — Securities available for sale 67,441 67,441 — 67,441 — Loans held for sale 19,923 19,923 — 19,923 — Loans, net 352,962 353,462 — — 353,462 Derivative assets 844 844 — 844 — Financial liabilities: Deposits $ 362,097 $ 361,798 $ — $ 361,798 $ — FHLBB advances 30,487 30,371 — 30,371 — Derivative liabilities 104 104 — 104 — December 31, 2016 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 3,675 $ 3,687 $ — $ 3,687 $ — Securities available for sale 68,637 68,637 — 68,637 — Loans held for sale 30,452 30,452 — 30,452 — Loans, net 332,991 331,132 — — 331,132 Derivative assets 682 682 — 682 — Financial liabilities: Deposits $ 351,179 $ 350,979 $ — $ 350,979 $ — FHLBB advances 38,667 38,531 — 38,531 — Derivative liabilities 47 47 — 47 —

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1. COMMITMENTS AND CONTINGENCIES Loan commitments The Company is a party to financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit. These instruments involve, to varying degrees, elements of market, credit and interest rate risk which are not recognized in the consolidated financial statements. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. The Company uses the same credit policies in making commitments and conditional obligations as it does for on-balance-sheet instruments. The following financial instruments were outstanding, at the dates indicated, whose contract amounts represent credit risk: March 31, 2017 December 31, 2016 (In thousands) Commitments to originate loans $ 28,500 $ 35,682 Unused lines and letters of credit 36,790 37,045 Unadvanced funds on construction loans 1,581 2,699 Overdraft lines of credit 9,119 9,189 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. The commitments for lines of credit may expire without being drawn upon. Therefore, the total commitment amounts do not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The majority of these financial instruments are collateralized by real estate. Other contingencies We are not currently a party to any pending legal proceedings that we believe would have a material adverse effect on our financial condition, results of operations or cash flows.

Conversion and Basis of Prese21

Conversion and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Financial Statement Presentation	Basis of Financial Statement Presentation The consolidated financial statements include the accounts of Randolph Bancorp, Inc. and its wholly-owned subsidiary, Randolph Savings Bank (together, the “Company”). The Bank has subsidiaries involved in owning investment securities and foreclosed real estate properties and a subsidiary which provides loan closing services. All intercompany accounts and transactions have been eliminated in consolidation. These financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X issued by the Securities and Exchange Commission (“SEC”). Accordingly, the accompanying interim financial statements do not include all information required under GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements, primarily consisting of normal recurring adjustments, have been included. The operating results for the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or any other interim period. For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the SEC.
Recent Accounting Pronouncements	In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses

Acquisition (Tables)

Acquisition (Tables)	3 Months Ended
	Mar. 31, 2017
Business Combinations [Abstract]
Summary of Unaudited Pro Forma Financial Information	Unaudited pro forma financial information for the three months ended March 31, 2016 is as follows (in thousands): Net interest income $ 3,270 Non-interest income 3,230 Net loss (183 )

Accumulated Other Comprehensi23

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss and Related Tax Effects	The components of accumulated other comprehensive loss, included in total stockholders’ equity, are as follows: March 31, December 31, 2017 2016 (In thousands) Securities available for sale: Net unrealized loss $ (624 ) $ (698 ) Tax effect (449 ) (423 ) Net-of-tax amount (1,073 ) (1,121 ) Supplemental retirement plan Unrecognized net actuarial loss (670 ) (679 ) Unrecognized net prior service credit 551 573 (119 ) (106 ) Tax effect (57 ) (57 ) Net-of-tax amount (176 ) (163 ) Accumulated other comprehensive loss $ (1,249 ) $ (1,284 )

Securities Available for Sale (

Securities Available for Sale (Tables)	3 Months Ended
	Mar. 31, 2017
Investments Debt And Equity Securities [Abstract]
Schedule of amortized cost and fair value of securities	The amortized cost and fair value of securities available for sale, including gross unrealized gains and losses, are as follows: Gross Gross Amortized Unrealized Unrealized Fair Cost Gains Losses Value (In thousands) March 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 85 $ (9 ) $ 4,075 Corporate 3,034 46 (10 ) 3,070 Municipal 13,708 281 (28 ) 13,961 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 20,564 155 (598 ) 20,121 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,619 49 (517 ) 14,151 U.S. Government-guaranteed 9,169 15 (112 ) 9,072 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 2,077 25 — 2,102 U.S. Government-guaranteed 349 4 — 353 Total debt securities 67,519 660 (1,274 ) 66,905 Mutual fund 545 — (9 ) 536 Total securities available for sale $ 68,064 $ 660 $ (1,283 ) $ 67,441 December 31, 2016 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 92 $ (10 ) $ 4,081 Corporate 3,044 54 (18 ) 3,080 Municipal 13,857 254 (56 ) 14,055 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 21,130 172 (580 ) 20,722 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,676 56 (554 ) 14,178 U.S. Government-guaranteed 9,589 12 (144 ) 9,457 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 2,127 28 — 2,155 U.S. Government-guaranteed 368 3 — 371 Total debt securities 68,790 671 (1,362 ) 68,099 Mutual fund 545 — (7 ) 538 Total securities available for sale $ 69,335 $ 671 $ (1,369 ) $ 68,637
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of debt securities by contractual maturity at March 31, 2017 are presented below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Amortized Fair Cost Value (In thousands) Within 1 year $ 2,237 $ 2,259 After 1 year through 5 years 12,621 12,828 After 5 years through 10 years 5,883 6,019 20,741 21,106 Mortgage-backed securities 46,778 45,799 $ 67,519 $ 66,905
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	Information pertaining to securities with gross unrealized losses, aggregated by investment category and length of time that individual securities have been in a continuous loss position, follows: Less Over Twelve Months Gross Gross Unrealized Fair Unrealized Fair Losses Value Losses Value March 31, 2017 (In thousands) Debt securities: U.S. Government-sponsored enterprises $ (9 ) $ 1,991 Corporate (9 ) 522 (1 ) 477 Municipal (22 ) 2,204 (6 ) 480 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (598 ) 15,900 — — Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (517 ) 8,775 — — U.S. Government-guaranteed (112 ) 4,818 — — Total debt securities (1,267 ) 34,210 (7 ) 957 Mutual Fund (9 ) 536 — — $ (1,276 ) $ 34,746 $ (7 ) $ 957 December 31, 2016 Debt securities: U.S. Government-sponsored enterprises $ (10 ) $ 1,990 $ — $ — Corporate (14 ) 519 (4 ) 996 Municipal (46 ) 3,310 (10 ) 477 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (580 ) 16,261 — — Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (554 ) 8,766 — — U.S. Government-guaranteed (144 ) 5,927 — — Total debt securities (1,348 ) 36,773 (14 ) 1,473 Mutual Fund (7 ) 538 — — $ (1,355 ) $ 37,311 $ (14 ) $ 1,473

Loans and Allowance for Loan 25

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2017
Receivables [Abstract]
Summary of Loan Portfolio	A summary of the loan portfolio at the dates indicated is as follows: March 31, 2017 December 31, 2016 (In thousands) Mortgage loans on real estate: Residential: One-to-four family $ 180,488 $ 179,025 Home equity loans and lines of credit 37,136 35,393 Commercial 91,828 88,394 Construction 26,538 23,629 335,990 326,441 Commercial and industrial 12,001 2,067 Consumer 7,194 6,578 Total loans 355,185 335,086 Allowance for loan losses (3,437 ) (3,271 ) Net deferred loan costs and fees, and purchase premiums 1,214 1,176 $ 352,962 $ 332,991
Summary of Changes in the Allowance for Loan Losses by Portfolio Segment	The following table summarizes the changes in the allowance for loan losses by portfolio segment for the three months ended March 31, 2017 and 2016: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total (In thousands) Three Months Ended March 31, 2017 Allowance at December 31, 2016 $ 1,018 $ 436 $ 1,410 $ 225 $ 37 $ 145 $ 3,271 Provision (credit) for loan losses (61 ) (41 ) 109 (14 ) 157 85 235 Loans charged-off — — — — — (76 ) (76 ) Recoveries 4 — — — 1 2 7 Balance at March 31, 2017 $ 961 $ 395 $ 1,519 $ 211 $ 195 $ 156 $ 3,437 Three Months Ended March 31, 2016 Allowance at December 31, 2015 $ 1,076 $ 512 $ 1,402 $ 159 $ 37 $ 53 $ 3,239 Provision (credit) for loan losses (23 ) (81 ) 157 (38 ) (1 ) 48 62 Loans charged-off — — — — — (26 ) (26 ) Recoveries 1 — — — — 9 10 Balance at March 31, 2016 $ 1,054 $ 431 $ 1,559 $ 121 $ 36 $ 84 $ 3,285
Summary of Additional Information Pertaining to the Allowance for Loan Losses	Additional information pertaining to the allowance for loan losses at March 31, 2017 and December 31, 2016 is as follows: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total March 31, 2017 (In thousands) Allowance for impaired loans $ 184 $ 1 $ 9 $ — $ — $ — $ 194 Allowance for non-impaired loans 777 394 1,510 211 195 156 3,243 Total allowance for loan losses $ 961 $ 395 $ 1,519 $ 211 $ 195 $ 156 $ 3,437 Impaired loans $ 4,893 $ 276 $ 788 $ — $ — $ — $ 5,957 Non-impaired loans 175,595 36,860 91,040 26,538 12,001 7,194 349,228 Total loans $ 180,488 $ 37,136 $ 91,828 $ 26,538 $ 12,001 $ 7,194 $ 355,185 December 31, 2016 Allowance for impaired loans $ 190 $ 2 $ 8 $ — $ — $ — $ 200 Allowance for non-impaired loans 828 434 1,402 225 37 145 3,071 Total allowance for loan losses $ 1,018 $ 436 $ 1,410 $ 225 $ 37 $ 145 $ 3,271 Impaired loans $ 4,506 $ 276 $ 832 $ — $ - $ — $ 5,614 Non-impaired loans 174,519 35,117 87,562 23,629 2,067 6,578 329,472 Total loans $ 179,025 $ 35,393 $ 88,394 $ 23,629 $ 2,067 $ 6,578 $ 335,086
Schedule of Past Due and Non-Accrual Loans	The following is a summary of past due and non-accrual loans at March 31, 2017 and December 31, 2016: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due Non-accrual Loans (In thousands) March 31, 2017 Residential one-to-four family $ 1,509 $ 155 $ — $ 1,664 $ 2,137 Home equity loans and lines of credit — — — — 276 Commercial real estate 400 — — 400 — Construction — — — — — Commercial and industrial — — — — — Consumer 3 11 — 14 — Total $ 1,912 $ 166 $ — $ 2,078 $ 2,413 December 31, 2016 Residential one-to-four family $ 1,168 $ 201 $ — $ 1,369 $ 1,945 Home equity loans and lines of credit 258 — — 258 276 Commercial real estate 400 — — 400 — Construction — — — — — Commercial and industrial — — — — — Consumer 59 — — 59 — Total $ 1,885 $ 201 $ — $ 2,086 $ 2,221
Summary of Impaired Loans and Additional Information Pertaining to Impaired Loans	The following is a summary of impaired loans at March 31, 2017 and December 31, 2016: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) March 31, 2017 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,325 $ 2,281 $ — Home equity loans and lines of credit 247 247 — Commercial real estate 267 267 — Total 2,839 2,795 — Impaired loans with a valuation allowance: Residential one-to-four family 2,632 2,612 184 Home equity loans and lines of credit 30 29 1 Commercial real estate 521 521 9 Total 3,183 3,162 194 Total impaired loans $ 6,022 $ 5,957 $ 194 December 31, 2016 Impaired loans without a valuation allowance: Residential one-to-four family $ 1,922 $ 1,877 $ — Home equity loans and lines of credit 246 246 — Commercial real estate 270 270 — Total 2,438 2,393 — Impaired loans with a valuation allowance: Residential one-to-four family 2,648 2,629 190 Home equity loans and lines of credit 31 30 2 Commercial real estate 562 562 8 Total 3,241 3,221 200 Total impaired loans $ 5,679 $ 5,614 $ 200 Additional information pertaining to impaired loans follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Three Months Ended March 31, 2017 Residential one-to-four family $ 4,870 $ 41 $ 16 Home equity loans and lines of credit 276 — — Commercial real estate 807 9 — Total $ 5,953 $ 50 $ 16 Three Months Ended March 31, 2016 Residential one-to-four family $ 4,946 $ 41 $ 13 Home equity loans and lines of credit 277 — — Commercial real estate 1,441 16 — Commercial and industrial 16 — — Total $ 6,680 $ 57 $ 13
Summary of Company's Loans by Risk Rating	The following table presents the Company’s loans by risk rating at the dates indicated: March 31, 2017 December 31, 2016 Commercial Real Construction Commercial and Industrial Commercial Real Construction Commercial and Industrial (In thousands) Loans rated 1 - 3B $ 91,622 $ 26,188 $ 12,001 $ 88,186 $ 23,286 $ 2,067 Loans rated 4 — 350 — — 343 — Loans rated 5 206 — — 208 — — $ 91,828 $ 26,538 $ 12,001 $ 88,394 $ 23,629 $ 2,067

Loan Servicing (Tables)

Loan Servicing (Tables)	3 Months Ended
	Mar. 31, 2017
Transfers And Servicing [Abstract]
Summary of Activity Relating to Mortgage Servicing Rights	The following table summarizes the activity relating to mortgage servicing rights for the three months ended March 31, 2017 and 2016 (in thousands): March 31, 2017 March 31, 2016 Mortgage servicing rights: Balance at beginning of year $ 8,910 $ 2,601 Additions through originations 451 206 Amortization (339 ) (120 ) Balance at end of period $ 9,022 $ 2,687 Valuation allowance: Balance at beginning of year $ 424 $ 34 Provision (credit) (280 ) — Balance at end of period $ 144 $ 34 Amortized cost, net $ 8,878 $ 2,653 Fair value $ 8,907 $ 2,898

Fair Value of Assets and Liab27

Fair Value of Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized below. . Total Level 1 Level 2 Level 3 Fair (In thousands) March 31, 2017 Assets: Securities available for sale: Debt securities $ — $ 66,905 $ — $ 66,905 Mutual fund — 536 — 536 Loans held for sale — 19,923 — 19,923 Derivative loan commitments — 812 — 812 Forward loan sale commitments — 32 — 32 Liabilities: Forward loan sale commitments — 104 — 104 December 31, 2016 Assets: Securities available for sale: Debt securities $ — $ 68,099 $ — $ 68,099 Mutual fund — 538 — 538 Loans held for sale — 30,452 — 30,452 Derivative loan commitments — 617 — 617 Forward loan sale commitments — 65 — 65 Liabilities: Forward loan sale commitments — 47 — 47
Schedule of Assets Measured at Fair Value on a Non-Recurring Basis	The following table summarizes the fair value hierarchy used to determine each adjustment and the carrying value of the related assets as of March 31, 2017 and December 31, 2016. March 31, 2017 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 1,585 Mortgage servicing rights — 8,878 — $ — $ 8,878 $ 1,585 December 31, 2016 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 518 Mortgage servicing rights — 8,486 — $ — $ 8,486 $ 518
Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments	The estimated fair values, and related carrying amounts, of the Company’s financial instruments are presented below. Certain financial instruments and all non-financial instruments are exempt from disclosure requirements. Accordingly, the aggregate fair value amounts presented herein do not represent the underlying fair value of the Company. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents, and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include mortgagors’ escrow accounts and accrued interest payable. March 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 3,185 $ 3,200 $ — $ 3,200 $ — Securities available for sale 67,441 67,441 — 67,441 — Loans held for sale 19,923 19,923 — 19,923 — Loans, net 352,962 353,462 — — 353,462 Derivative assets 844 844 — 844 — Financial liabilities: Deposits $ 362,097 $ 361,798 $ — $ 361,798 $ — FHLBB advances 30,487 30,371 — 30,371 — Derivative liabilities 104 104 — 104 — December 31, 2016 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 3,675 $ 3,687 $ — $ 3,687 $ — Securities available for sale 68,637 68,637 — 68,637 — Loans held for sale 30,452 30,452 — 30,452 — Loans, net 332,991 331,132 — — 331,132 Derivative assets 682 682 — 682 — Financial liabilities: Deposits $ 351,179 $ 350,979 $ — $ 350,979 $ — FHLBB advances 38,667 38,531 — 38,531 — Derivative liabilities 47 47 — 47 —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Summary of Financial Instruments Outstanding Contract Amounts Represent Credit Risk	The following financial instruments were outstanding, at the dates indicated, whose contract amounts represent credit risk: March 31, 2017 December 31, 2016 (In thousands) Commitments to originate loans $ 28,500 $ 35,682 Unused lines and letters of credit 36,790 37,045 Unadvanced funds on construction loans 1,581 2,699 Overdraft lines of credit 9,119 9,189

Conversion and Basis of Prese29

Conversion and Basis of Presentation - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 31, 2016	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Mar. 31, 2017	Jul. 01, 2016
Plan Of Conversion [Line Items]
Common stock, shares issued				5,868,726	5,868,726	5,686,750
Share issued, price per share						$ 10
Proceeds from issuance of common stock	$ 56,867,500
Direct cost of stock offering			$ 223,000	$ 2,325,000
Contribution to Randolph Charitable Foundation Inc, shares		181,976
Contribution to Randolph Charitable Foundation Inc, cash		$ 455,000
Contribution to Randolph Charitable Foundation Inc, expense recognized		$ 2,274,700,000
ESOP [Member]
Plan Of Conversion [Line Items]
Common stock, shares issued						469,498
Loan repayment period	25 years

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($)	Jul. 03, 2016	Mar. 31, 2017	Mar. 31, 2016
Business Acquisition [Line Items]
Business acquisition, date		Jul. 1, 2016
Income tax expense (benefit)		$ (23,000)	$ 3,000
Pro Forma [Member]
Business Acquisition [Line Items]
Income tax expense (benefit)		$ 0
First Eastern Bankshares Corporation [Member]
Business Acquisition [Line Items]
Cash payment to acquisition	$ 14,100,000

Acquisition - Summary of Unaudi

Acquisition - Summary of Unaudited Pro Forma Financial Information (Detail) - First Eastern Bankshares Corporation [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Business Acquisition [Line Items]
Net interest income	$ 3,270
Non-interest income	3,230
Net loss	$ (183)

Accumulated Other Comprehensi32

Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss and Related Tax Effects (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income	$ 35	$ 761
Accumulated other comprehensive loss, net of tax	(1,249)		$ (1,284)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(624)		(698)
Other comprehensive Loss, Tax effect	(449)		(423)
Total other comprehensive income	(1,073)		(1,121)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(670)		(679)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	551		573
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(119)		(106)
Other comprehensive Loss, Tax effect	(57)		(57)
Total other comprehensive income	$ (176)		$ (163)

Securities Available for Sale -

Securities Available for Sale - Schedule of Amortized Cost and Fair Value of Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 68,064	$ 69,335
Gross Unrealized Gains	660	671
Gross Unrealized Losses	(1,283)	(1,369)
Fair Value	67,441	68,637
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	67,519	68,790
Gross Unrealized Gains	660	671
Gross Unrealized Losses	(1,274)	(1,362)
Fair Value	66,905	68,099
Debt Securities [Member] | US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,999	3,999
Gross Unrealized Gains	85	92
Gross Unrealized Losses	(9)	(10)
Fair Value	4,075	4,081
Debt Securities [Member] | Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,034	3,044
Gross Unrealized Gains	46	54
Gross Unrealized Losses	(10)	(18)
Fair Value	3,070	3,080
Debt Securities [Member] | Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,708	13,857
Gross Unrealized Gains	281	254
Gross Unrealized Losses	(28)	(56)
Fair Value	13,961	14,055
Debt Securities [Member] | Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,564	21,130
Gross Unrealized Gains	155	172
Gross Unrealized Losses	(598)	(580)
Fair Value	20,121	20,722
Debt Securities [Member] | Commercial Mortgage Backed Securities, U.S. Government-guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,169	9,589
Gross Unrealized Gains	15	12
Gross Unrealized Losses	(112)	(144)
Fair Value	9,072	9,457
Debt Securities [Member] | Commercial Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,619	14,676
Gross Unrealized Gains	49	56
Gross Unrealized Losses	(517)	(554)
Fair Value	14,151	14,178
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	349	368
Gross Unrealized Gains	4	3
Fair Value	353	371
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,077	2,127
Gross Unrealized Gains	25	28
Fair Value	2,102	2,155
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	545	545
Gross Unrealized Losses	(9)	(7)
Fair Value	$ 536	$ 538

Securities Available for Sale34

Securities Available for Sale - Investments Classified by Contractual Maturity Date (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Available-for-sale Securities, Debt Maturities, Amortized Cost
Within 1 year	$ 2,237
After 1 year through 5 years	12,621
After 5 years through 10 years	5,883
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Total	20,741
Mortgage-backed securities	46,778
Available-for-sale Debt Securities, Amortized Cost Basis, Total	67,519
Available-for-sale Securities, Debt Maturities, Fair Value
Within 1 year	2,259
After 1 year through 5 years	12,828
After 5 years through 10 years	6,019
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair Value Total	21,106
Mortgage-backed securities	45,799
Available-for-sale Securities, Debt Securities, Fair Value Total	$ 66,905

Securities Available for Sale35

Securities Available for Sale - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	$ (1,276)	$ (1,355)
Less Than Twelve Months, Fair Value	34,746	37,311
Over Twelve Months, Gross Unrealized Losses	(7)	(14)
Over Twelve Months, Fair Value	957	1,473
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(1,267)	(1,348)
Less Than Twelve Months, Fair Value	34,210	36,773
Over Twelve Months, Gross Unrealized Losses	(7)	(14)
Over Twelve Months, Fair Value	957	1,473
Debt Securities [Member] | US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(9)	(10)
Less Than Twelve Months, Fair Value	1,991	1,990
Debt Securities [Member] | Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(9)	(14)
Less Than Twelve Months, Fair Value	522	519
Over Twelve Months, Gross Unrealized Losses	(1)	(4)
Over Twelve Months, Fair Value	477	996
Debt Securities [Member] | Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(22)	(46)
Less Than Twelve Months, Fair Value	2,204	3,310
Over Twelve Months, Gross Unrealized Losses	(6)	(10)
Over Twelve Months, Fair Value	480	477
Debt Securities [Member] | Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(598)	(580)
Less Than Twelve Months, Fair Value	15,900	16,261
Debt Securities [Member] | Commercial Mortgage Backed Securities, U.S. Government-guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(112)	(144)
Less Than Twelve Months, Fair Value	4,818	5,927
Debt Securities [Member] | Commercial Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(517)	(554)
Less Than Twelve Months, Fair Value	8,775	8,766
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(9)	(7)
Less Than Twelve Months, Fair Value	$ 536	$ 538

Securities Available for Sale36

Securities Available for Sale - Additional Information (Detail)	Mar. 31, 2017Debt_Security
Investments Debt And Equity Securities [Abstract]
Number of debt securities with unrealized losses	34
Unrealized losses debt securities aggregate depreciation percentage	3.59%

Loans and Allowance for Loan 37

Loans and Allowance for Loan Losses - Summary of Loan Portfolio (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 355,185	$ 335,086
Allowance for loan losses	(3,437)	(3,271)
Net deferred loan costs and fees, and purchase premiums	1,214	1,176
Net loans	352,962	332,991
Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	335,990	326,441
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	91,828	88,394
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	12,001	2,067
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,194	6,578
One-to-Four Family [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	180,488	179,025
One-to-Four Family [Member] | Residential Real Estate [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	180,488	179,025
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	37,136	35,393
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	26,538	23,629
Construction [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 26,538	$ 23,629

Loans and Allowance for Loan 38

Loans and Allowance for Loan Losses - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)TDR	Mar. 31, 2016USD ($)TDR	Dec. 31, 2016USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased loan participations originated through super-regional bank	$ 9,800,000
Impaired loans, additional funds committed	0
Troubled debt restructuring amount	5,067,000	$ 5,644,000
Changes to allowance for loan losses	$ 0	0
Minimum past due days for loan rating	90 days
Total loans	$ 355,185,000		$ 335,086,000
Residential Mortgage [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	884,000		890,000
Residential Mortgage [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,294,000		1,471,000
30 - 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings defaulted over 30 days past due	0	0
Non Accrual Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring amount	1,756,000	$ 1,740,000
Home Equity Loans and Lines of Credit [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 398,000		400,000
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans subject to troubled debt restructurings | TDR	18	19
Loans subject to troubled debt restructurings, amount	$ 4,479,000	$ 4,870,000
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans subject to troubled debt restructurings | TDR	3	5
Loans subject to troubled debt restructurings, amount	$ 589,000	$ 1,052,000
Total loans	91,828,000		88,394,000
Commercial Real Estate Loans [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 206,000		$ 208,000
Minimum [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	3 months
Maximum [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	30 years
Maximum [Member] | Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructuring, interest rate concession period	1 year

Loans and Allowance for Loan 39

Loans and Allowance for Loan Losses - Summary of Changes in the Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 3,271	$ 3,239
Provision (credit) for loan losses	235	62
Loans charged-off	(76)	(26)
Recoveries	7	10
Ending balance	3,437	3,285
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,410	1,402
Provision (credit) for loan losses	109	157
Ending balance	1,519	1,559
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	37	37
Provision (credit) for loan losses	157	(1)
Recoveries	1
Ending balance	195	36
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	145	53
Provision (credit) for loan losses	85	48
Loans charged-off	(76)	(26)
Recoveries	2	9
Ending balance	156	84
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,018	1,076
Provision (credit) for loan losses	(61)	(23)
Recoveries	4	1
Ending balance	961	1,054
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	436	512
Provision (credit) for loan losses	(41)	(81)
Ending balance	395	431
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	225	159
Provision (credit) for loan losses	(14)	(38)
Ending balance	$ 211	$ 121

Loans and Allowance for Loan 40

Loans and Allowance for Loan Losses - Summary of Additional Information Pertaining to the Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	$ 194	$ 200
Allowance for non-impaired loans	3,243	3,071
Total allowance for loan losses	3,437	3,271	$ 3,285	$ 3,239
Impaired loans	5,957	5,614
Non-impaired loans	349,228	329,472
Total loans	355,185	335,086
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	9	8
Allowance for non-impaired loans	1,510	1,402
Total allowance for loan losses	1,519	1,410	1,559	1,402
Impaired loans	788	832
Non-impaired loans	91,040	87,562
Total loans	91,828	88,394
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	195	37
Total allowance for loan losses	195	37	36	37
Non-impaired loans	12,001	2,067
Total loans	12,001	2,067
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	156	145
Total allowance for loan losses	156	145	84	53
Non-impaired loans	7,194	6,578
Total loans	7,194	6,578
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	184	190
Allowance for non-impaired loans	777	828
Total allowance for loan losses	961	1,018	1,054	1,076
Impaired loans	4,893	4,506
Non-impaired loans	175,595	174,519
Total loans	180,488	179,025
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	1	2
Allowance for non-impaired loans	394	434
Total allowance for loan losses	395	436	431	512
Impaired loans	276	276
Non-impaired loans	36,860	35,117
Total loans	37,136	35,393
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	211	225
Total allowance for loan losses	211	225	$ 121	$ 159
Non-impaired loans	26,538	23,629
Total loans	$ 26,538	$ 23,629

Loans and Allowance for Loan 41

Loans and Allowance for Loan Losses - Schedule of Past Due and Non-Accrual Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 2,078	$ 2,086
Non-accrual Loans	2,413	2,221
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14	59
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,664	1,369
Non-accrual Loans	2,137	1,945
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		258
Non-accrual Loans	276	276
Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	400	400
30 - 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,912	1,885
30 - 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3	59
30 - 59 Days Past Due [Member] | One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,509	1,168
30 - 59 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		258
30 - 59 Days Past Due [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	400	400
60 - 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	166	201
60 - 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11
60 - 89 Days Past Due [Member] | One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 155	$ 201

Loans and Allowance for Loan 42

Loans and Allowance for Loan Losses - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	$ 2,839	$ 2,438
Unpaid Principal Balance without a valuation allowance	2,795	2,393
Recorded Investment with a valuation allowance	3,183	3,241
Unpaid Principal Balance with a valuation allowance	3,162	3,221
Related Allowance, Total impaired loans	194	200
Recorded Investment, Total impaired loans	6,022	5,679
Unpaid Principal Balance, Total impaired loans	5,957	5,614
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	267	270
Unpaid Principal Balance without a valuation allowance	267	270
Recorded Investment with a valuation allowance	521	562
Unpaid Principal Balance with a valuation allowance	521	562
Related Allowance, Total impaired loans	9	8
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	2,325	1,922
Unpaid Principal Balance without a valuation allowance	2,281	1,877
Recorded Investment with a valuation allowance	2,632	2,648
Unpaid Principal Balance with a valuation allowance	2,612	2,629
Related Allowance, Total impaired loans	184	190
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	247	246
Unpaid Principal Balance without a valuation allowance	247	246
Recorded Investment with a valuation allowance	30	31
Unpaid Principal Balance with a valuation allowance	29	30
Related Allowance, Total impaired loans	$ 1	$ 2

Loans and Allowance for Loan 43

Loans and Allowance for Loan Losses - Summary of Additional Information Pertaining to Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 5,953	$ 6,680
Interest Income Recognized	50	57
Cash Basis Interest Recognized	16	13
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	4,870	4,946
Interest Income Recognized	41	41
Cash Basis Interest Recognized	16	13
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	276	277
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	807	1,441
Interest Income Recognized	$ 9	16
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		$ 16

Loans and Allowance for Loan 44

Loans and Allowance for Loan Losses - Summary of Company's Loans by Risk Rating (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 355,185	$ 335,086
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	26,538	23,629
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	91,828	88,394
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	12,001	2,067
Pass [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	26,188	23,286
Pass [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	91,622	88,186
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	12,001	2,067
Special Mention [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	350	343
Substandard [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 206	$ 208

Loan Servicing - Additional Inf

Loan Servicing - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Transfers And Servicing [Abstract]
Unpaid principal balance of residential mortgage loans serviced for others	$ 1,074,511,000		$ 1,046,551,000
Increased in valuation allowance of mortgage servicing rights	$ 280,000	$ 0

Loan Servicing - Summary of Act

Loan Servicing - Summary of Activity Relating to Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Mortgage servicing rights:
Balance at beginning of year	$ 8,910	$ 2,601
Additions through originations	451	206
Amortization	(339)	(120)
Balance at end of period	9,022	2,687
Valuation allowance:
Balance at beginning of year	424	34
Provision (credit)	(280)
Balance at end of period	144	34
Amortized cost, net	8,878	2,653
Fair value	$ 8,907	$ 2,898

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Federal tax benefit	$ 26,000	$ 0
State tax expense	$ 3,000	$ 2,000

On-Balance Sheet Derivative I48

On-Balance Sheet Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional amount	$ 43,620,000	$ 32,904,000
Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative, Notional amount	48,575,000	29,481,000
Other Assets [Member] | Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative fair value, Asset	812,000	617,000
Other Assets [Member] | Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative fair value, Asset	32,000	65,000
Other Liabilities [Member] | Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative fair value, Liability	$ 104,000	$ 47,000

Employee Stock Ownership Plan -

Employee Stock Ownership Plan - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017USD ($)shares
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Number of allocated shares	18,780
Annual allocation of shares, expiration year	2,040
Shares committed to be released	4,695
Fair value of shares under employee stock ownership plan | $	$ 72,000
Unallocated and uncommitted shares	446,023
Unallocated and uncommitted shares, value | $	$ 6,913,400
The Randolph Savings Charitable Foundation, Inc. [Member]
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Sale of share in employee stock ownership plan	469,498
Percentage of stock issued during period shares employee stock ownership plan	8.00%

Earnings (Loss) Per Share - Add

Earnings (Loss) Per Share - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Potentially dilutive common stock equivalents outstanding	0
Common stock, shares outstanding	5,868,726	5,868,726
Weighted Average Number of Shares, Unallocated and uncommitted ESOP shares	448,371
Weighted average common shares outstanding (basic and diluted)	5,420,356

Fair Value of Assets and Liab51

Fair Value of Assets and Liabilities - Additional information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gain on sales of mortgage loans	$ 2,038,000	$ 681,000
Increased in valuation allowance of mortgage servicing rights	280,000	$ 0
Liabilities measured at fair value on nonrecurring basis	0		$ 0
Residential Mortgage [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Aggregate fair value of loans held for sale	19,900,000
Contractual balance of loans held for sale	19,500,000
Net gain on sales of mortgage loans	$ 427,000

Fair Value of Assets and Liab52

Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 67,441	$ 68,637
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	66,905	68,099
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	536	538
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	67,441	68,637
Fair value, Loans held for sale	19,923	30,452
Derivative assets	844	682
Forward loan sale commitments	104	47
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Loans held for sale	19,923	30,452
Forward loan sale commitments	104	47
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	66,905	68,099
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	536	538
Fair Value, Measurements, Recurring [Member] | Derivative Loan Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	812	617
Fair Value, Measurements, Recurring [Member] | Forward Loan Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	32	65
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Loans held for sale	19,923	30,452
Forward loan sale commitments	104	47
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	66,905	68,099
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	536	538
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Derivative Loan Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	812	617
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Forward Loan Sale Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 32	$ 65

Fair Value of Assets and Liab53

Fair Value of Assets and Liabilities - Schedule of Assets Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	$ 8,907		$ 2,898
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	8,878	$ 8,486
Assets, Fair Value Disclosure	8,878	8,486
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Collateral dependent impaired loans	1,585	518
Assets, Fair Value Disclosure	$ 1,585	$ 518

Fair Value of Assets and Liab54

Fair Value of Assets and Liabilities - Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial assets:
Securities available for sale	$ 67,441	$ 68,637
Level 2 [Member]
Financial assets:
Certificates of deposit	3,200	3,687
Securities available for sale	67,441	68,637
Loans held for sale	19,923	30,452
Derivative assets	844	682
Financial liabilities:
Deposits	361,798	350,979
FHLBB advances	30,371	38,531
Derivative liabilities	104	47
Level 3 [Member]
Financial assets:
Loans, net	353,462	331,132
Carrying Amount [Member]
Financial assets:
Certificates of deposit	3,185	3,675
Securities available for sale	67,441	68,637
Loans held for sale	19,923	30,452
Loans, net	352,962	332,991
Derivative assets	844	682
Financial liabilities:
Deposits	362,097	351,179
FHLBB advances	30,487	38,667
Derivative liabilities	104	47
Fair Value [Member]
Financial assets:
Certificates of deposit	3,200	3,687
Securities available for sale	67,441	68,637
Loans held for sale	19,923	30,452
Loans, net	353,462	331,132
Derivative assets	844	682
Financial liabilities:
Deposits	361,798	350,979
FHLBB advances	30,371	38,531
Derivative liabilities	$ 104	$ 47

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments Outstanding Contract Amounts Represent Credit Risk (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Commitments to Originate Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 28,500	$ 35,682
Unused Lines and Letters of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	36,790	37,045
Unadvanced Funds on Construction Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	1,581	2,699
Overdraft Lines of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 9,119	$ 9,189