Randolph Bancorp (RNDB) 10-Q 9 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 08, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
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	Accelerated Filer
Entity Common Stock, Shares Outstanding		6,017,276

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 4,216	$ 3,562
Interest-bearing deposits	4,748	5,260
Total cash and cash equivalents	8,964	8,822
Certificates of deposit	2,695	2,940
Securities available for sale, at fair value	59,621	61,576
Loans held for sale, at fair value	22,090	25,390
Loans, net of allowance for loan losses of $3,844 in 2018 and $3,737 in 2017	407,309	400,373
Federal Home Loan Bank of Boston stock, at cost	2,604	3,310
Accrued interest receivable	1,335	1,432
Mortgage servicing rights, net	6,599	6,397
Premises and equipment, net	9,256	8,670
Bank-owned life insurance	8,075	8,037
Foreclosed real estate	193	193
Other assets	4,795	4,752
Total assets	533,536	531,892
Deposits:
Non-interest bearing	60,378	62,130
Interest bearing	335,214	304,706
Total deposits	395,592	366,836
Federal Home Loan Bank of Boston advances	50,920	75,954
Mortgagors' escrow accounts	1,676	907
Post-employment benefit obligations	2,634	2,750
Other liabilities	2,843	3,962
Total liabilities	453,665	450,409
Commitments and contingencies (Note 14)
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: 6,029,776 shares at March 31, 2018 and 6,034,276 at December 31, 2017	61	61
Additional paid-in capital	56,657	56,493
Retained earnings	29,708	30,415
ESOP-Unearned compensation	(4,272)	(4,319)
Accumulated other comprehensive loss, net of tax	(2,283)	(1,167)
Total stockholders' equity	79,871	81,483
Total liabilities and stockholders' equity	$ 533,536	$ 531,892

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Loans, allowance for loan losses	$ 3,844	$ 3,737
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	6,029,776	6,034,276
Common stock, shares outstanding	6,029,776	6,034,276

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest and dividend income:
Loans	$ 4,295	$ 3,416
Securities-taxable	338	358
Securities-tax exempt	65	89
Interest-bearing deposits and certificates of deposit	29	21
Total interest and dividend income	4,727	3,884
Interest expense:
Deposits	480	336
Federal Home Loan Bank of Boston advances	265	64
Total interest expense	745	400
Net interest income	3,982	3,484
Provision for loan losses	95	235
Net interest income after provision for loan losses	3,887	3,249
Non-interest income:
Customer service fees	301	372
Net gain on sales of mortgage loans	1,547	2,038
Mortgage servicing fees, net	334	660
Gain on sales of securities	49
Increase in cash surrender value of life insurance	38	38
Other	139	302
Total non-interest income	2,408	3,410
Non-interest expenses:
Salaries and employee benefits	4,436	4,676
Occupancy and equipment	699	656
Data processing	170	182
Professional fees	252	302
Marketing	303	148
FDIC insurance	40	43
Merger and integration costs		167
Other	1,098	955
Total non-interest expenses	6,998	7,129
Loss before income taxes	(703)	(470)
Income tax expense (benefit)	4	(23)
Net loss	$ (707)	$ (447)
Weighted average common shares outstanding (basic and diluted)	5,603,886	5,420,356
Loss per common share (basic and diluted)	$ (0.13)	$ (0.08)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Net loss		$ (707)	$ (447)
Securities available for sale:
Unrealized holding gains (losses)		(1,055)	74
Reclassification adjustment for net gains realized in income	[1]	(49)
Net unrealized gains (losses)		(1,104)	74
Related tax effect			(26)
Net-of-tax amount		(1,104)	48
Related tax effect		0	0
Net-of-tax amount		(12)	(13)
Total other comprehensive income (loss)		(1,116)	35
Comprehensive loss		(1,823)	(412)
Supplemental Retirement Plan [Member]
Securities available for sale:
Actuarial losses	[2]	9	9
Prior service credits recognized	[2]	(21)	(22)
Post-retirement benefit plans		$ (12)	$ (13)
[1]	Amounts are included in gain on sales of securities in the consolidated statements of operations.
[2]	Amounts are included in other non-interest expenses in the consolidated statements of operations.

Consolidated Statements Changes

Consolidated Statements Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Unearned Compensation ESOP [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance at Dec. 31, 2016	$ 83,302	$ 59	$ 56,373	$ 32,661	$ (4,507)	$ (1,284)
Beginning balance, shares at Dec. 31, 2016		5,868,726,000
Net loss	(447)			(447)
Other comprehensive income (loss)	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		5,868,726,000
Beginning balance at Dec. 31, 2016	83,302	$ 59	56,373	32,661	(4,507)	(1,284)
Beginning balance, shares at Dec. 31, 2016		5,868,726,000
Ending balance at Dec. 31, 2017	81,483	$ 61	56,493	30,415	(4,319)	(1,167)
Ending balance, shares at Dec. 31, 2017		6,034,276,000
Net loss	(707)			(707)
Other comprehensive income (loss)	(1,116)					(1,116)
ESOP shares committed to be released	74		27		47
Stock repurchased	(70)		(70)
Stock repurchased, shares		(4,500,000)
Stock-based compensation	207		207
Ending balance at Mar. 31, 2018	$ 79,871	$ 61	$ 56,657	$ 29,708	$ (4,272)	$ (2,283)
Ending balance, shares at Mar. 31, 2018		6,029,776,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (707,000)	$ (447,000)
Adjustments to reconcile net loss to net cash provided by operating activities:
Provision for loan losses	95,000	235,000
Loans originated for sale	(70,797,000)	(89,440,000)
Net gain on sales of mortgage loans	(1,547,000)	(2,038,000)
Proceeds from sales of mortgage loans	75,644,000	102,007,000
Net amortization of securities	53,000	70,000
Net change in deferred loan costs and fees	(7,000)	(38,000)
Gain on sales of securities	(49,000)
Depreciation and amortization	145,000	135,000
Stock-based compensation	207,000
ESOP expense	74,000	72,000
Increase in cash surrender value of life insurance	(38,000)	(38,000)
Net increase in mortgage servicing rights	(202,000)	(392,000)
Other, net	(1,181,000)	(827,000)
Net cash provided by operating activities	1,690,000	9,299,000
Cash flows from investing activities:
Redemption of certificates of deposit	245,000	490,000
Securities available for sale:
Calls/maturities	930,000	135,000
Purchases	(9,993,000)
Sales	8,958,000
Principal payments on mortgage-backed securities	952,000	1,039,000
Loan originations, net of principal repayments	(7,036,000)	(9,779,000)
Loans purchased, net of principal repayments		(10,390,000)
Redemption of Federal Home Loan Bank of Boston stock	706,000	277,000
Purchases of premises and equipment	(731,000)	(374,000)
Net cash used in investing activities	(5,969,000)	(18,602,000)
Cash flows from financing activities:
Net increase in deposits	28,756,000	10,918,000
Net decrease in short-term Federal Home Loan Bank of Boston borrowings	(22,904,000)	(8,016,000)
Repayments of long-term Federal Home Loan Bank of Boston advances	(2,130,000)	(164,000)
Net increase in mortgagors' escrow accounts	769,000	132,000
Repurchase of common stock	(70,000)
Net cash provided by financing activities	4,421,000	2,870,000
Net change in cash and cash equivalents	142,000	(6,433,000)
Cash and cash equivalents at beginning of period	8,822,000	14,849,000
Cash and cash equivalents at end of period	8,964,000	8,416,000
Supplemental cash flow information:
Interest paid on deposits and borrowed funds	734,000	404,000
Income taxes paid	$ 16,000	$ 3,000

Basis of Financial Statement Pr

Basis of Financial Statement Presentation	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Financial Statement Presentation	1. BASIS OF FINANCIAL STATEMENT PRESENTATION The consolidated financial statements include the accounts of Randolph Bancorp, Inc. (“Bancorp”) and its wholly-owned subsidiary, Envision Bank (the “Bank”, together with Bancorp, 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, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or any other interim period. Prior to 2018, the Company’s operations were managed, and financial performance was evaluated, by the chief operating decision-maker on a company-wide basis. As a result, management had determined there to be a single business segment for financial reporting purposes through December 31, 2017. Due to the significance of the Company’s mortgage banking operations and its strategic focus on this business, management prepared its 2018 operating budget by breaking-out its mortgage banking activities, including residential loan origination and loan servicing. As a result, effective January 1, 2018, the Company is reporting two business segments, namely, “Envision Bank” and “Envision Mortgage”. As part of this process, management analyzed costs incurred by departments providing services to both segments (indirect costs), such as IT, Marketing, Accounting and Administration, to determine the allocation of indirect costs to each business segment in order to fully measure each segment’s results of operations. See Note 15 for disclosure of the Company’s segment information. 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, 2017, as filed with the SEC.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	1. RECENT ACCOUNTING PRONOUNCEMENTS In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers In January 2016, FASB issued ASU 2016-01, Financial Instruments In February 2016, FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses In April 2017, the FASB issued ASU 2017-08 Receivables – Non-refundable Fees and Other Costs

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 2018
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, 2018 2017 (In thousands) Securities available for sale: Net unrealized loss $ (1,728 ) $ (624 ) Tax effect (313 ) (313 ) Net-of-tax amount (2,041 ) (937 ) Supplemental retirement plan Unrecognized net actuarial loss (658 ) (667 ) Unrecognized net prior service credit 463 484 (195 ) (183 ) Tax effect (47 ) (47 ) Net-of-tax amount (242 ) (230 ) Accumulated other comprehensive loss $ (2,283 ) $ (1,167 )

Securities Available for Sale

Securities Available for Sale	3 Months Ended
	Mar. 31, 2018
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, 2018 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 27 $ (39 ) $ 3,987 Corporate 1,532 12 (21 ) 1,523 Municipal 3,496 41 — 3,537 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 28,149 64 (860 ) 27,353 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,393 — (708 ) 13,685 U.S. Government-guaranteed 1,866 — (35 ) 1,831 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 1,806 — (33 ) 1,773 U.S. Government-guaranteed 5,563 — (154 ) 5,409 Total debt securities 60,804 144 (1,850 ) 59,098 Mutual fund 545 — (22 ) 523 Total securities available for sale $ 61,349 $ 144 $ (1,872 ) $ 59,621 December 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 50 $ (24 ) $ 4,025 Corporate 2,005 27 (8 ) 2,024 Municipal 12,707 179 (18 ) 12,868 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 18,729 118 (450 ) 18,397 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,451 13 (403 ) 14,061 U.S. Government-guaranteed 2,132 — (6 ) 2,126 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 1,871 12 (5 ) 1,878 U.S. Government-guaranteed 5,760 4 (100 ) 5,664 Total debt securities 61,654 403 (1,014 ) 61,043 Mutual fund 545 — (12 ) 533 Total securities available for sale $ 62,199 $ 403 $ (1,026 ) $ 61,576 For the three months ended March 31, 2018, proceeds from sales of available-for-sale securities amounted to $9.0 million with gross realized gains of $49,000 and no gross realized losses. The amortized cost and fair value of debt securities by contractual maturity at March 31, 2018 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 $ 1,606 $ 1,610 After 1 year through 5 years 6,582 6,582 After 5 years through 10 years 839 855 9,027 9,047 Mortgage-backed securities 51,777 50,051 $ 60,804 $ 59,098 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, 2018 (In thousands) Debt securities: U.S. Government-sponsored enterprises $ — $ — $ (39 ) $ 1,960 Corporate (6 ) 497 (15 ) 509 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (61 ) 5,210 (799 ) 19,159 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (61 ) 5,153 (647 ) 8,532 U.S. Government-guaranteed (35 ) 1,831 — — Collaterlized mortgage obligations: U.S. Government-sponsored enterprises (33 ) 1,773 — — U.S. Government-guaranteed (29 ) 1,861 (125 ) 3,548 Total debt securities (225 ) 16,325 (1,625 ) 33,708 Mutual Fund — — (22 ) 523 $ (225 ) $ 16,325 $ (1,647 ) $ 34,231 December 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ — $ — $ (24 ) $ 19,676 Corporate — — (8 ) 988 Municipal (11 ) 1,919 (7 ) 479 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (1 ) 1,623 (449 ) 13,163 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises — — (403 ) 8,805 U.S. Government-guaranteed (6 ) 2,126 — — Collaterlized mortgage obligations: U.S. Government-sponsored enterprises (5 ) 678 — — U.S. Government-guaranteed (1 ) 295 (99 ) 3,756 Total debt securities (24 ) 6,641 (990 ) 46,867 Mutual Fund — — (12 ) 533 $ (24 ) $ 6,641 $ (1,002 ) $ 47,400 At March 31, 2018, 22 debt securities have unrealized losses with aggregate depreciation of 3.57% from the Company’s amortized cost basis. The unrealized losses at March 31, 2018, which related primarily to securities issued by U.S. government-sponsored enterprises, were primarily caused by interest rate increases. 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 securities would not be settled at a price less than the par value of the investment. Because the Company does not intend to sell any debt securities and it is more likely than not that the Company will not be required to sell any debt securities before recovery of its amortized cost basis, it does not consider these investments to be other-than-temporarily impaired at March 31, 2018.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2018
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, 2018 December 31, 2017 (In thousands) Mortgage loans on real estate: Residential: One-to-four family $ 202,728 $ 198,475 Home equity loans and lines of credit 39,425 38,968 Commercial 107,116 101,755 Construction 24,873 25,357 374,142 364,555 Commercial and industrial 20,853 21,766 Consumer 14,699 16,337 Total loans 409,694 402,658 Allowance for loan losses (3,844 ) (3,737 ) Net deferred loan costs and fees, and purchase premiums 1,459 1,452 $ 407,309 $ 400,373 The following table summarizes the changes in the allowance for loan losses, by portfolio segment, for the three months ended March 31, 2018 and 2017: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total (In thousands) Three Months Ended March 31, 2018 Allowance at December 31, 2017 $ 854 $ 359 $ 1,620 $ 351 $ 335 $ 218 $ 3,737 Provision (credit) for loan losses (3 ) 6 80 35 (16 ) (7 ) 95 Loans charged-off — — — — — (15 ) (15 ) Recoveries 25 — — — — 2 27 Balance at March 31, 2018 $ 876 $ 365 $ 1,700 $ 386 $ 319 $ 198 $ 3,844 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 Additional information pertaining to the allowance for loan losses at March 31, 2018 and December 31, 2017 is as follows: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total March 31, 2018 (In thousands) Allowance for impaired loans $ 152 $ 1 $ — $ — $ — $ — $ 153 Allowance for non-impaired loans 724 364 1,700 386 319 198 3,691 Total allowance for loan losses $ 876 $ 365 $ 1,700 $ 386 $ 319 $ 198 $ 3,844 Impaired loans $ 5,450 $ 271 $ 318 $ — $ — $ — $ 6,039 Non-impaired loans 197,278 39,154 106,798 24,873 20,853 14,699 403,655 Total loans $ 202,728 $ 39,425 $ 107,116 $ 24,873 $ 20,853 $ 14,699 $ 409,694 December 31, 2017 Allowance for impaired loans $ 160 $ 1 $ 1 $ — $ — $ — $ 162 Allowance for non-impaired loans 694 358 1,619 351 335 218 3,575 Total allowance for loan losses $ 854 $ 359 $ 1,620 $ 351 $ 335 $ 218 $ 3,737 Impaired loans $ 5,205 $ 276 $ 352 $ — $ — $ — $ 5,833 Non-impaired loans 193,270 38,692 101,403 25,357 21,766 16,337 396,825 Total loans $ 198,475 $ 38,968 $ 101,755 $ 25,357 $ 21,766 $ 16,337 $ 402,658 The following is a summary of past due and non-accrual loans at March 31, 2018 and December 31, 2017: 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, 2018 Residential one-to-four family $ 594 $ — $ 635 $ 1,229 $ 1,963 Home equity loans and lines of credit 123 — — 123 272 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer — — — — — Total $ 717 $ — $ 635 $ 1,352 $ 2,235 December 31, 2017 Residential one-to-four family $ 737 $ — $ — $ 737 $ 1,976 Home equity loans and lines of credit 96 — — 96 276 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer — — — — — Total $ 833 $ — $ — $ 833 $ 2,252 The following is a summary of impaired loans at March 31, 2018 and December 31, 2017: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) March 31, 2018 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,962 $ 2,901 $ — Home equity loans and lines of credit 243 243 — Commercial real estate 318 318 — Total 3,523 3,462 — Impaired loans with a valuation allowance: Residential one-to-four family 2,568 2,549 152 Home equity loans and lines of credit 29 28 1 Commercial real estate — — — Total 2,597 2,577 153 Total impaired loans $ 6,120 $ 6,039 $ 153 December 31, 2017 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,685 $ 2,641 $ — Home equity loans and lines of credit 247 247 — Commercial real estate 257 257 — Total 3,189 3,145 — Impaired loans with a valuation allowance: Residential one-to-four family 2,584 2,564 160 Home equity loans and lines of credit 29 29 1 Commercial real estate 95 95 1 Total 2,708 2,688 162 Total impaired loans $ 5,897 $ 5,833 $ 162 Additional information pertaining to impaired loans follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Three Months Ended March 31, 2018 Residential one-to-four family $ 5,440 $ 54 $ 20 Home equity loans and lines of credit 272 3 21 Commercial real estate 329 5 — Total $ 6,041 $ 62 $ 41 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 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 thirty years for residential real estate loans, and for periods up to one year for commercial real estate loans. At March 31, 2018, the Company had nineteen residential real estate loans and two commercial real estate loans aggregating $3,959,000 and $120,000, respectively, which were subject to troubled debt restructuring agreements. At March 31, 2017, the Company had eighteen 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. As of March 31, 2018 and 2017, $4,079,000 and $5,068,000, respectively, in troubled debt restructurings were performing in accordance with the terms of the modified loan agreements. Included in such amounts are $1,107,000 and $1,756,000, respectively, that are being accounted for as non-accrual loans. For the three months ended March 31, 2018 and 2017 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, 2018 and 2017, 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, 2018 and 2017, 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, 2018 December 31, 2017 Commercial Real Construction Commercial and Industrial Commercial Real Construction Commercial and Industrial (In thousands) Loans rated 1 - 3B $ 106,918 $ 24,873 $ 20,853 $ 101,556 $ 25,357 $ 21,766 Loans rated 4 — — — — — — Loans rated 5 198 — — 199 — — $ 107,116 $ 24,873 $ 20,853 $ 101,755 $ 25,357 $ 21,766 Residential mortgages, home equity loans and lines of credit, and consumer loans are monitored for credit quality based primarily on their payment status. When one of these loans becomes more than 90 days delinquent, it is assigned an internal loan rating. At March 31, 2018, $706,000 in residential mortgages and $28,000 in home equity loans were rated as substandard and $2,778,000 in residential mortgages and $244,000 in home equity loans were rated as special mention. At December 31, 2017, $712,000 in residential mortgages were rated as substandard and $2,512,000 in residential mortgages and $247,000 in home equity loans were rated as special mention.

Loan Servicing

Loan Servicing	3 Months Ended
	Mar. 31, 2018
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 $795,123,000 and $771,407,000 at March 31, 2018 and December 31, 2017, respectively. The following table summarizes the activity relating to mortgage servicing rights for the three months ended March 31, 2018 and 2017 (in thousands): March 31, 2018 March 31, 2017 Mortgage servicing rights: Balance at beginning of year $ 6,487 $ 8,910 Additions through originations 390 451 Amortization (245 ) (339 ) Balance at end of period $ 6,632 $ 9,022 Valuation allowance: Balance at beginning of year $ 90 $ 424 Provision (credit) (57 ) (280 ) Balance at end of period $ 33 $ 144 Amortized cost, net $ 6,599 $ 8,878 Fair value $ 6,961 $ 8,907 During the three months ended March 31, 2018 and 2017, the Company recorded partial reversals of the valuation allowance for its mortgage servicing rights of $57,000 and $280,000, respectively, due to increases in fair value caused by lower expected loan prepayments.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	1. INCOME TAXES During the three months ended March 31, 2018 and 2017, the Company recorded a federal tax benefit of $0 and $26,000, respectively, and state tax expense of $4,000 and $3,000, 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, 2018
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 $30,122,000 and $24,222,000 at March 31, 2018 and December 31, 2017, respectively. The fair value of such commitments was an asset of $383,000 and $363,000 as of March 31, 2018 and December 31, 2017, 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 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 $29,973,000 and $29,613,000 at March 31, 2018 and December 31, 2017, respectively. The fair value of certain of these commitments was an asset of $20,000 and $4,000 at March 31, 2018 and December 31, 2017, respectively, and is included in other assets in the consolidated balance sheets while the fair value of other such commitments was a liability of $31,000 and $19,000 at March 31, 2018 and December 31, 2017, 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, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Employee Stock Ownership Plan	1. EMPLOYEE STOCK OWNERSHIP PLAN The Company maintains an Employee Stock Ownership Plan (“ESOP”), which is a tax-qualified retirement plan providing eligible employees the opportunity to own Bancorp stock. Bancorp granted a loan to the ESOP for the purchase of 469,498 shares of its common stock at $10.00 per share. The loan is payable annually over 25 years with interest at the prime rate to be reset each January 1 st Shares are committed to be released on a monthly basis and allocated as of December 31 st

Share Repurchase Program

Share Repurchase Program	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Share Repurchase Program	1. SHARE REPURCHASE PROGRAM In September 2017, the Company’s Board of Directors adopted a share repurchase program under which the Company may repurchase up to 10%, or 586,854 shares of its then outstanding common shares. Repurchases under the program may be made in open market or in privately negotiated transactions and pursuant to any trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities and Exchange Commission. Any repurchased shares will be held by the Company as authorized but unissued shares. The repurchase program may be suspended or terminated at any time without prior notice, and it will expire on September 14, 2018. As of March 31, 2018, the Company had repurchased 14,500 shares at a cost of $219,000 in connection with this program.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	3 Months Ended
	Mar. 31, 2018
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. Unvested restricted shares of common stock having dividend rights are treated as “participating securities” and, accordingly, are considered outstanding in computing basic earnings (loss) per share. Unallocated ESOP shares are not considered to be outstanding for purposes of computing earnings per share. None of the Company’s 336,509 stock options were included in the computation of diluted earnings (loss) per share for the three months ended March 31, 2018. Due to the net loss for the period, inclusion of the stock options in the computation would have been anti-dilutive. During the three months ended March 31, 2018 and 2017, there were 6,033,476 and 5,868,726 weighted average shares outstanding, while the average of unallocated and uncommitted ESOP shares totaled 429,590 and 448,371, resulting in a total of 5,603,886 and 5,420,356 shares being used to compute basic and diluted loss per share, respectively.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	1. STOCK-BASED COMPENSATION Under the Randolph Bancorp, Inc. 2017 Stock Option and Incentive Plan (the “Equity Plan”), the Company may grant options, restricted stock, restricted units or performance awards to its directors, officers and employees. Both incentive stock options and non-qualified stock options may be granted under the Equity Plan with 586,872 shares reserved for options. The exercise price of each option equals the market price of the Company’s stock on the date of the grant and the maximum term of each options is 10 years. The total number of shares reserved for restricted stock is 237,749. Options and awards generally vest ratably over five years. The fair value of shares awarded is based on the market price at the date of grant. Stock Options The fair value of each option grant is estimated on the date of the grant using the Black-Scholes option-pricing model with the following assumptions: • Volatility is based on peer group volatility because the Company does not have a sufficient trading history. • Expected life represents the period of time that the option is expected to be outstanding, taking into account the contractual term, and the vesting period. • Expected dividend yield is based on the Company's history and expectation of dividend payouts. • The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant for a period equivalent to the expected life of the option. During the three months ended March 31, 2018, the Company made the following grants of options to purchase shares of common stock and used the following assumptions in measuring the fair value of such grants: Date of grant March 15, 2018 Options granted 20,500 Vesting period (years) 3-5 Expiration period (years) 10 Expected volatility 29.87 % Expected life (years) 4.6 Expected dividend yield — Risk free interest rate 2.68 % Option fair value $ 5.78 A summary of the status of the Company's stock option grants for three months ended March 31, 2018 is presented in the table below: Options Stock Option Grants Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Balance at December 31, 2017 316,009 $ 14.66 9.78 $ 219,374 Granted 20,500 16.07 10.00 — Forfeited — — — — Balance at March 31, 2018 (all non-vested) 336,509 $ 14.75 9.56 $ 501,030 Exercisable at March 31, 2018 — $ — — — Unrecognized compensation cost $ 1,383,000 Weighted average remaining recognition period (years) 4.35 For the three months ended March 31, 2018, stock-based compensation expense applicable to stock options was $74,000. Restricted Stock Shares issued upon vesting may be either authorized but unissued shares or reacquired shares held by the Company. Any shares not issued because vesting requirements are not met will again be available for issuance under the Equity Plan. The fair market value of shares awarded, based on the market price at the date of grant, is recorded as unearned compensation and amortized over the applicable vesting period. Restricted stock awarded in 2017 was at no cost to the awardee. The following table presents the activity in restricted stock awards under the Equity Plan for the three months ended March 31, 2018: Restricted Stock Awards Weighted Average Grant Price Restricted stock awards at December 31, 2017 176,239 $ 14.66 Granted — — Forfeited — — Restricted stock awards at March 31, 2018 (all non-vested) 176,239 $ 14.66 Unrecognized compensation cost $ 2,331,000 Weighted average remaining recognition period (years) 4.36 For the three months ended March 31, 2018, stock-based compensation expense applicable to restricted stock was $133,000.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	3 Months Ended
	Mar. 31, 2018
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. 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, 2018 Assets: Securities available for sale: Debt securities $ — $ 59,098 $ — $ 59,098 Mutual fund — 523 — 523 Loans held for sale — 22,090 — 22,090 Derivative loan commitments — 383 — 383 Forward loan sale commitments — 20 — 20 Liabilities: Forward loan sale commitments — 31 — 31 December 31, 2017 Assets: Securities available for sale: Debt securities $ — $ 61,043 $ — $ 61,043 Mutual fund — 533 — 533 Loans held for sale — 25,390 — 25,390 Derivative loan commitments — 363 — 363 Forward loan sale commitments — 4 — 4 Liabilities: Forward loan sale commitments — 19 — 19 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, 2018 and December 31, 2017. Period Ended March 31, 2018 March 31, 2018 Level 1 Level 2 Level 3 Total Gains (Losses) (In thousands) Collateral dependent impaired loans $ — $ — $ 1,264 $ — Mortgage servicing rights — 6,599 — 57 Assets held for sale — — 828 — Foreclosed real estate — — 193 — $ — $ 6,599 $ 2,285 $ 57 December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 1,630 Mortgage servicing rights — 6,397 — Assets held for sale — — 828 Foreclosed real estate — — 193 $ — $ 6,397 $ 2,651 The Company recorded partial reversals of the valuation allowance for its mortgage servicing rights of $57,000 and $280,000 during the three months ended March 31, 2018 and 2017, respectively, due to increases in fair value caused by lower expected loan prepayments. There were no liabilities measured at fair value on a non-recurring basis at March 31, 2018 and December 31, 2017. 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, FHLBB stock and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include non-maturity deposits, short-term FHLBB borrowings, mortgagors’ escrow accounts and accrued interest payable. March 31, 2018 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 2,695 $ 2,680 $ — $ 2,680 $ — Securities available for sale 59,621 59,621 — 59,621 — Loans held for sale 22,090 22,090 — 22,090 — Loans, net 407,309 399,293 — — 399,293 Derivative assets 403 403 — 403 — Financial liabilities: Deposits $ 395,592 $ 394,156 $ — $ 394,156 $ — FHLBB advances 50,920 50,753 — 50,753 — Derivative liabilities 31 31 — 31 — December 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 2,940 $ 2,932 $ — $ 2,932 $ — Securities available for sale 61,576 61,576 — 61,576 — Loans held for sale 25,390 25,390 — 25,390 — Loans, net 400,373 398,407 — — 398,407 Derivative assets 367 367 — 367 — Financial liabilities: Deposits $ 366,836 $ 365,997 $ — $ 365,997 $ — FHLBB advances 75,954 75,821 — 75,821 — Derivative liabilities 19 19 — 19 —

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
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, 2018 December 31, 2017 (In thousands) Commitments to originate loans $ 35,727 $ 35,549 Unused lines and letters of credit 42,004 39,968 Unadvanced funds on construction loans 8,560 6,967 Overdraft lines of credit 8,869 8,996 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 The Company is not currently a party to any pending legal proceedings that it believes would have a material adverse effect on its financial condition, results of operations or cash flows.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Segment Information	1. SEGMENT INFORMATION Effective January 1, 2018, management began reporting its activities in one of two business segments, namely Envision Bank (“EB”) and Envision Mortgage (“EM”). Comparative information for the 2017 period has been prepared on a basis consistent with the methodology used in 2018. Envision Bank operations primarily consist of accepting deposits from customers within the communities surrounding the Bank’s six full service branch offices and investing those funds in residential and commercial real estate loans, home equity lines of credit, construction loans, commercial and industrial loans, and consumer loans. Envision Mortgage’s operations primarily consist of the origination and sale of residential mortgage loans and the servicing of loans sold to government-sponsored entities. A portion of the loans originated by Envision Mortgage are held in the loan portfolio of Envision Bank. Segment information as of and for the three months ended March 31, 2018 follows: For the Three Months Ended March 31, 2018 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 3,740 $ 242 $ 3,982 Provision for loan losses 95 — 95 Net interest income after provision for loan losses 3,645 242 3,887 Non-interest income: Customer service fees 270 31 301 Net gain on sales of mortgage loans (253 ) 1,800 1,547 Mortgage servicing fees, net (68 ) 402 334 Other 144 82 226 Total non-interest income 93 2,315 2,408 Non-interest expenses: Salaries and employee benefits 1,636 2,800 4,436 Occupancy and equipment 400 299 699 Other non-interest expenses 1,069 794 1,863 Total non-interest expenses 3,105 3,893 6,998 Income (loss) before income taxes 633 (1,336 ) (703 ) Income tax expense 4 — 4 Net income (loss) $ 629 $ (1,336 ) $ (707 ) Total assets, March 31, 2018 $ 473,513 $ 60,023 $ 533,536 The information above was derived from the internal management reporting system used by management to measure performance of the segments. The Company’s internal transfer pricing arrangements determined by management primarily consist of the following: 1. EM’s cost of funds is based on the weighted average rate of overnight advances from the FHLBB for the period. 2. EM is credited with service released premiums and a sales premium totaling 1.50% for new loans transferred to EB’s loans held for investment, and a 1.00% fee for HELOC originations. This income for the three months ended March 31, 2018 totaled $253,000. 3. Loan servicing fees are charged to EB by EM based on the number of residential mortgage loans held in portfolio at a rate of 0.14% per annum and amounted to $68,000 for the three months ended March 31, 2018. 4. Certain cost centers provide services to both business segments. The cost centers include Finance, Marketing, IT and Administration. Costs which are common to both business segments are referred to as “indirect costs” and are allocated using relevant benchmarks, e.g. head count, number of accounts, etc. Segment information as of and for the three months ended March 31, 2017 follows: For the Three Months Ended March 31, 2017 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 3,224 $ 260 $ 3,484 Provision for loan losses 235 — 235 Net interest income after provision for loan losses 2,989 260 3,249 Non-interest income: Customer service fees 372 — 372 Net gain on sales of mortgage loans (174 ) 2,212 2,038 Mortgage servicing fees, net (61 ) 721 660 Other 191 149 340 Total non-interest income 328 3,082 3,410 Non-interest expenses: Salaries and employee benefits 1,627 3,049 4,676 Occupancy and equipment 347 309 656 Other non-interest expenses 864 933 1,797 Total non-interest expenses 2,838 4,291 7,129 Income (loss) before income taxes 479 (949 ) (470 ) Income tax benefit (23 ) — (23 ) Net income (loss) $ 502 $ (949 ) $ (447 ) Total assets, March 31, 2017 $ 422,456 $ 60,038 $ 482,494 The information above was derived from the internal management reporting system used by management to measure performance of the segments. The Company’s internal transfer pricing arrangements determined by management primarily consist of the following: 1. EM’s cost of funds is based on the weighted average rate of overnight advances from the FHLBB for the period. 2. EM is credited with service released premiums and a sales premium totaling 1.50% for new loans transferred to EB’s loans held for investment, and a 1.00% fee for HELOC originations. This income for the three months ended March 31, 2017 totaled $174,000. 3. Loan servicing fees are charged to EB by EM based on the number of residential mortgage loans held in portfolio at a rate of 0.14% per annum and amounted to $61,000 for the three months ended March 31, 2017. 4. Certain cost centers provide services to both business segments. The cost centers include Finance, Marketing, IT and Administration. Costs which are common to both business segments are referred to as “indirect costs” and are allocated using relevant benchmarks, e.g. head count, number of accounts, etc.

Basis of Financial Statement 23

Basis of Financial Statement Presentation (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of Financial Statement Presentation	The consolidated financial statements include the accounts of Randolph Bancorp, Inc. (“Bancorp”) and its wholly-owned subsidiary, Envision Bank (the “Bank”, together with Bancorp, 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, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or any other interim period. Prior to 2018, the Company’s operations were managed, and financial performance was evaluated, by the chief operating decision-maker on a company-wide basis. As a result, management had determined there to be a single business segment for financial reporting purposes through December 31, 2017. Due to the significance of the Company’s mortgage banking operations and its strategic focus on this business, management prepared its 2018 operating budget by breaking-out its mortgage banking activities, including residential loan origination and loan servicing. As a result, effective January 1, 2018, the Company is reporting two business segments, namely, “Envision Bank” and “Envision Mortgage”. As part of this process, management analyzed costs incurred by departments providing services to both segments (indirect costs), such as IT, Marketing, Accounting and Administration, to determine the allocation of indirect costs to each business segment in order to fully measure each segment’s results of operations. See Note 15 for disclosure of the Company’s segment information. 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, 2017, as filed with the SEC.
Recent Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers In January 2016, FASB issued ASU 2016-01, Financial Instruments In February 2016, FASB issued ASU 2016-02, Leases In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses In April 2017, the FASB issued ASU 2017-08 Receivables – Non-refundable Fees and Other Costs

Accumulated Other Comprehensi24

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 2017 (In thousands) Securities available for sale: Net unrealized loss $ (1,728 ) $ (624 ) Tax effect (313 ) (313 ) Net-of-tax amount (2,041 ) (937 ) Supplemental retirement plan Unrecognized net actuarial loss (658 ) (667 ) Unrecognized net prior service credit 463 484 (195 ) (183 ) Tax effect (47 ) (47 ) Net-of-tax amount (242 ) (230 ) Accumulated other comprehensive loss $ (2,283 ) $ (1,167 )

Securities Available for Sale (

Securities Available for Sale (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 27 $ (39 ) $ 3,987 Corporate 1,532 12 (21 ) 1,523 Municipal 3,496 41 — 3,537 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 28,149 64 (860 ) 27,353 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,393 — (708 ) 13,685 U.S. Government-guaranteed 1,866 — (35 ) 1,831 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 1,806 — (33 ) 1,773 U.S. Government-guaranteed 5,563 — (154 ) 5,409 Total debt securities 60,804 144 (1,850 ) 59,098 Mutual fund 545 — (22 ) 523 Total securities available for sale $ 61,349 $ 144 $ (1,872 ) $ 59,621 December 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ 3,999 $ 50 $ (24 ) $ 4,025 Corporate 2,005 27 (8 ) 2,024 Municipal 12,707 179 (18 ) 12,868 Residential mortgage-backed securities: U.S. Government-sponsored enterprises 18,729 118 (450 ) 18,397 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises 14,451 13 (403 ) 14,061 U.S. Government-guaranteed 2,132 — (6 ) 2,126 Collateralized mortgage obligations: U.S. Government-sponsored enterprises 1,871 12 (5 ) 1,878 U.S. Government-guaranteed 5,760 4 (100 ) 5,664 Total debt securities 61,654 403 (1,014 ) 61,043 Mutual fund 545 — (12 ) 533 Total securities available for sale $ 62,199 $ 403 $ (1,026 ) $ 61,576
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of debt securities by contractual maturity at March 31, 2018 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 $ 1,606 $ 1,610 After 1 year through 5 years 6,582 6,582 After 5 years through 10 years 839 855 9,027 9,047 Mortgage-backed securities 51,777 50,051 $ 60,804 $ 59,098
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, 2018 (In thousands) Debt securities: U.S. Government-sponsored enterprises $ — $ — $ (39 ) $ 1,960 Corporate (6 ) 497 (15 ) 509 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (61 ) 5,210 (799 ) 19,159 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises (61 ) 5,153 (647 ) 8,532 U.S. Government-guaranteed (35 ) 1,831 — — Collaterlized mortgage obligations: U.S. Government-sponsored enterprises (33 ) 1,773 — — U.S. Government-guaranteed (29 ) 1,861 (125 ) 3,548 Total debt securities (225 ) 16,325 (1,625 ) 33,708 Mutual Fund — — (22 ) 523 $ (225 ) $ 16,325 $ (1,647 ) $ 34,231 December 31, 2017 Debt securities: U.S. Government-sponsored enterprises $ — $ — $ (24 ) $ 19,676 Corporate — — (8 ) 988 Municipal (11 ) 1,919 (7 ) 479 Residential mortgage-backed securities: U.S. Government-sponsored enterprises (1 ) 1,623 (449 ) 13,163 Commercial mortgage-backed securities: U.S. Government-sponsored enterprises — — (403 ) 8,805 U.S. Government-guaranteed (6 ) 2,126 — — Collaterlized mortgage obligations: U.S. Government-sponsored enterprises (5 ) 678 — — U.S. Government-guaranteed (1 ) 295 (99 ) 3,756 Total debt securities (24 ) 6,641 (990 ) 46,867 Mutual Fund — — (12 ) 533 $ (24 ) $ 6,641 $ (1,002 ) $ 47,400

Loans and Allowance for Loan 26

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Summary of Loan Portfolio	A summary of the loan portfolio at the dates indicated is as follows: March 31, 2018 December 31, 2017 (In thousands) Mortgage loans on real estate: Residential: One-to-four family $ 202,728 $ 198,475 Home equity loans and lines of credit 39,425 38,968 Commercial 107,116 101,755 Construction 24,873 25,357 374,142 364,555 Commercial and industrial 20,853 21,766 Consumer 14,699 16,337 Total loans 409,694 402,658 Allowance for loan losses (3,844 ) (3,737 ) Net deferred loan costs and fees, and purchase premiums 1,459 1,452 $ 407,309 $ 400,373
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, 2018 and 2017: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total (In thousands) Three Months Ended March 31, 2018 Allowance at December 31, 2017 $ 854 $ 359 $ 1,620 $ 351 $ 335 $ 218 $ 3,737 Provision (credit) for loan losses (3 ) 6 80 35 (16 ) (7 ) 95 Loans charged-off — — — — — (15 ) (15 ) Recoveries 25 — — — — 2 27 Balance at March 31, 2018 $ 876 $ 365 $ 1,700 $ 386 $ 319 $ 198 $ 3,844 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
Summary of Additional Information Pertaining to the Allowance for Loan Losses	Additional information pertaining to the allowance for loan losses at March 31, 2018 and December 31, 2017 is as follows: Second Residential Mortgages Commercial Commercial 1-4 Family and Real Estate Construction and Industrial Consumer Total March 31, 2018 (In thousands) Allowance for impaired loans $ 152 $ 1 $ — $ — $ — $ — $ 153 Allowance for non-impaired loans 724 364 1,700 386 319 198 3,691 Total allowance for loan losses $ 876 $ 365 $ 1,700 $ 386 $ 319 $ 198 $ 3,844 Impaired loans $ 5,450 $ 271 $ 318 $ — $ — $ — $ 6,039 Non-impaired loans 197,278 39,154 106,798 24,873 20,853 14,699 403,655 Total loans $ 202,728 $ 39,425 $ 107,116 $ 24,873 $ 20,853 $ 14,699 $ 409,694 December 31, 2017 Allowance for impaired loans $ 160 $ 1 $ 1 $ — $ — $ — $ 162 Allowance for non-impaired loans 694 358 1,619 351 335 218 3,575 Total allowance for loan losses $ 854 $ 359 $ 1,620 $ 351 $ 335 $ 218 $ 3,737 Impaired loans $ 5,205 $ 276 $ 352 $ — $ — $ — $ 5,833 Non-impaired loans 193,270 38,692 101,403 25,357 21,766 16,337 396,825 Total loans $ 198,475 $ 38,968 $ 101,755 $ 25,357 $ 21,766 $ 16,337 $ 402,658
Schedule of Past Due and Non-Accrual Loans	The following is a summary of past due and non-accrual loans at March 31, 2018 and December 31, 2017: 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, 2018 Residential one-to-four family $ 594 $ — $ 635 $ 1,229 $ 1,963 Home equity loans and lines of credit 123 — — 123 272 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer — — — — — Total $ 717 $ — $ 635 $ 1,352 $ 2,235 December 31, 2017 Residential one-to-four family $ 737 $ — $ — $ 737 $ 1,976 Home equity loans and lines of credit 96 — — 96 276 Commercial real estate — — — — — Construction — — — — — Commercial and industrial — — — — — Consumer — — — — — Total $ 833 $ — $ — $ 833 $ 2,252
Summary of Impaired Loans and Additional Information Pertaining to Impaired Loans	The following is a summary of impaired loans at March 31, 2018 and December 31, 2017: Recorded Investment Unpaid Principal Balance Related Allowance (In thousands) March 31, 2018 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,962 $ 2,901 $ — Home equity loans and lines of credit 243 243 — Commercial real estate 318 318 — Total 3,523 3,462 — Impaired loans with a valuation allowance: Residential one-to-four family 2,568 2,549 152 Home equity loans and lines of credit 29 28 1 Commercial real estate — — — Total 2,597 2,577 153 Total impaired loans $ 6,120 $ 6,039 $ 153 December 31, 2017 Impaired loans without a valuation allowance: Residential one-to-four family $ 2,685 $ 2,641 $ — Home equity loans and lines of credit 247 247 — Commercial real estate 257 257 — Total 3,189 3,145 — Impaired loans with a valuation allowance: Residential one-to-four family 2,584 2,564 160 Home equity loans and lines of credit 29 29 1 Commercial real estate 95 95 1 Total 2,708 2,688 162 Total impaired loans $ 5,897 $ 5,833 $ 162 Additional information pertaining to impaired loans follows: Average Interest Cash Basis Recorded Income Interest Investment Recognized Recognized (In thousands) Three Months Ended March 31, 2018 Residential one-to-four family $ 5,440 $ 54 $ 20 Home equity loans and lines of credit 272 3 21 Commercial real estate 329 5 — Total $ 6,041 $ 62 $ 41 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
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, 2018 December 31, 2017 Commercial Real Construction Commercial and Industrial Commercial Real Construction Commercial and Industrial (In thousands) Loans rated 1 - 3B $ 106,918 $ 24,873 $ 20,853 $ 101,556 $ 25,357 $ 21,766 Loans rated 4 — — — — — — Loans rated 5 198 — — 199 — — $ 107,116 $ 24,873 $ 20,853 $ 101,755 $ 25,357 $ 21,766

Loan Servicing (Tables)

Loan Servicing (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 and 2017 (in thousands): March 31, 2018 March 31, 2017 Mortgage servicing rights: Balance at beginning of year $ 6,487 $ 8,910 Additions through originations 390 451 Amortization (245 ) (339 ) Balance at end of period $ 6,632 $ 9,022 Valuation allowance: Balance at beginning of year $ 90 $ 424 Provision (credit) (57 ) (280 ) Balance at end of period $ 33 $ 144 Amortized cost, net $ 6,599 $ 8,878 Fair value $ 6,961 $ 8,907

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Grants of Options to Purchase Shares of Common Stock	During the three months ended March 31, 2018, the Company made the following grants of options to purchase shares of common stock and used the following assumptions in measuring the fair value of such grants: Date of grant March 15, 2018 Options granted 20,500 Vesting period (years) 3-5 Expiration period (years) 10 Expected volatility 29.87 % Expected life (years) 4.6 Expected dividend yield — Risk free interest rate 2.68 % Option fair value $ 5.78
Summary of Stock Options Grants	A summary of the status of the Company's stock option grants for three months ended March 31, 2018 is presented in the table below: Options Stock Option Grants Weighted Average Exercise Price Weighted Average Remaining Contractual Term Aggregate Intrinsic Value Balance at December 31, 2017 316,009 $ 14.66 9.78 $ 219,374 Granted 20,500 16.07 10.00 — Forfeited — — — — Balance at March 31, 2018 (all non-vested) 336,509 $ 14.75 9.56 $ 501,030 Exercisable at March 31, 2018 — $ — — — Unrecognized compensation cost $ 1,383,000 Weighted average remaining recognition period (years) 4.35
Summary of Activity in Restricted Stock Awards Under Equity Plan	The following table presents the activity in restricted stock awards under the Equity Plan for the three months ended March 31, 2018: Restricted Stock Awards Weighted Average Grant Price Restricted stock awards at December 31, 2017 176,239 $ 14.66 Granted — — Forfeited — — Restricted stock awards at March 31, 2018 (all non-vested) 176,239 $ 14.66 Unrecognized compensation cost $ 2,331,000 Weighted average remaining recognition period (years) 4.36

Fair Value of Assets and Liab29

Fair Value of Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 Assets: Securities available for sale: Debt securities $ — $ 59,098 $ — $ 59,098 Mutual fund — 523 — 523 Loans held for sale — 22,090 — 22,090 Derivative loan commitments — 383 — 383 Forward loan sale commitments — 20 — 20 Liabilities: Forward loan sale commitments — 31 — 31 December 31, 2017 Assets: Securities available for sale: Debt securities $ — $ 61,043 $ — $ 61,043 Mutual fund — 533 — 533 Loans held for sale — 25,390 — 25,390 Derivative loan commitments — 363 — 363 Forward loan sale commitments — 4 — 4 Liabilities: Forward loan sale commitments — 19 — 19
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, 2018 and December 31, 2017. Period Ended March 31, 2018 March 31, 2018 Level 1 Level 2 Level 3 Total Gains (Losses) (In thousands) Collateral dependent impaired loans $ — $ — $ 1,264 $ — Mortgage servicing rights — 6,599 — 57 Assets held for sale — — 828 — Foreclosed real estate — — 193 — $ — $ 6,599 $ 2,285 $ 57 December 31, 2017 Level 1 Level 2 Level 3 (In thousands) Collateral dependent impaired loans $ — $ — $ 1,630 Mortgage servicing rights — 6,397 — Assets held for sale — — 828 Foreclosed real estate — — 193 $ — $ 6,397 $ 2,651
Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments	March 31, 2018 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 2,695 $ 2,680 $ — $ 2,680 $ — Securities available for sale 59,621 59,621 — 59,621 — Loans held for sale 22,090 22,090 — 22,090 — Loans, net 407,309 399,293 — — 399,293 Derivative assets 403 403 — 403 — Financial liabilities: Deposits $ 395,592 $ 394,156 $ — $ 394,156 $ — FHLBB advances 50,920 50,753 — 50,753 — Derivative liabilities 31 31 — 31 — December 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 (In thousands) Financial assets: Certificates of deposit $ 2,940 $ 2,932 $ — $ 2,932 $ — Securities available for sale 61,576 61,576 — 61,576 — Loans held for sale 25,390 25,390 — 25,390 — Loans, net 400,373 398,407 — — 398,407 Derivative assets 367 367 — 367 — Financial liabilities: Deposits $ 366,836 $ 365,997 $ — $ 365,997 $ — FHLBB advances 75,954 75,821 — 75,821 — Derivative liabilities 19 19 — 19 —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
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, 2018 December 31, 2017 (In thousands) Commitments to originate loans $ 35,727 $ 35,549 Unused lines and letters of credit 42,004 39,968 Unadvanced funds on construction loans 8,560 6,967 Overdraft lines of credit 8,869 8,996

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Summary of Segment Information	Segment information as of and for the three months ended March 31, 2018 follows: For the Three Months Ended March 31, 2018 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 3,740 $ 242 $ 3,982 Provision for loan losses 95 — 95 Net interest income after provision for loan losses 3,645 242 3,887 Non-interest income: Customer service fees 270 31 301 Net gain on sales of mortgage loans (253 ) 1,800 1,547 Mortgage servicing fees, net (68 ) 402 334 Other 144 82 226 Total non-interest income 93 2,315 2,408 Non-interest expenses: Salaries and employee benefits 1,636 2,800 4,436 Occupancy and equipment 400 299 699 Other non-interest expenses 1,069 794 1,863 Total non-interest expenses 3,105 3,893 6,998 Income (loss) before income taxes 633 (1,336 ) (703 ) Income tax expense 4 — 4 Net income (loss) $ 629 $ (1,336 ) $ (707 ) Total assets, March 31, 2018 $ 473,513 $ 60,023 $ 533,536 Segment information as of and for the three months ended March 31, 2017 follows: For the Three Months Ended March 31, 2017 Envision Bank Envision Mortgage Consolidated Total (in thousands) Net interest income $ 3,224 $ 260 $ 3,484 Provision for loan losses 235 — 235 Net interest income after provision for loan losses 2,989 260 3,249 Non-interest income: Customer service fees 372 — 372 Net gain on sales of mortgage loans (174 ) 2,212 2,038 Mortgage servicing fees, net (61 ) 721 660 Other 191 149 340 Total non-interest income 328 3,082 3,410 Non-interest expenses: Salaries and employee benefits 1,627 3,049 4,676 Occupancy and equipment 347 309 656 Other non-interest expenses 864 933 1,797 Total non-interest expenses 2,838 4,291 7,129 Income (loss) before income taxes 479 (949 ) (470 ) Income tax benefit (23 ) — (23 ) Net income (loss) $ 502 $ (949 ) $ (447 ) Total assets, March 31, 2017 $ 422,456 $ 60,038 $ 482,494

Basis of Financial Statement 32

Basis of Financial Statement Presentation- Additional Information (Detail)	Jan. 01, 2018Segment
Accounting Policies [Abstract]
Number of business segments	2

Accumulated Other Comprehensi33

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, 2018	Mar. 31, 2017	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss)	$ (1,116)	$ 35
Accumulated other comprehensive loss, net of tax	(2,283)		$ (1,167)
Accumulated Net Investment Gain (Loss) Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(1,728)		(624)
Other comprehensive Loss, Tax effect	(313)		(313)
Total other comprehensive income (loss)	(2,041)		(937)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(658)		(667)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	463		484
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized loss	(195)		(183)
Other comprehensive Loss, Tax effect	(47)		(47)
Total other comprehensive income (loss)	$ (242)		$ (230)

Securities Available for Sale -

Securities Available for Sale - Schedule of Amortized Cost and Fair Value of Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 61,349	$ 62,199
Gross Unrealized Gains	144	403
Gross Unrealized Losses	(1,872)	(1,026)
Fair Value	59,621	61,576
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	60,804	61,654
Gross Unrealized Gains	144	403
Gross Unrealized Losses	(1,850)	(1,014)
Fair Value	59,098	61,043
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	27	50
Gross Unrealized Losses	(39)	(24)
Fair Value	3,987	4,025
Debt Securities [Member] | Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,532	2,005
Gross Unrealized Gains	12	27
Gross Unrealized Losses	(21)	(8)
Fair Value	1,523	2,024
Debt Securities [Member] | Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,496	12,707
Gross Unrealized Gains	41	179
Gross Unrealized Losses		(18)
Fair Value	3,537	12,868
Debt Securities [Member] | Residential Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,149	18,729
Gross Unrealized Gains	64	118
Gross Unrealized Losses	(860)	(450)
Fair Value	27,353	18,397
Debt Securities [Member] | Commercial Mortgage-backed Securities, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,393	14,451
Gross Unrealized Gains		13
Gross Unrealized Losses	(708)	(403)
Fair Value	13,685	14,061
Debt Securities [Member] | Commercial Mortgage Backed Securities, U.S. Government-guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,866	2,132
Gross Unrealized Losses	(35)	(6)
Fair Value	1,831	2,126
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,806	1,871
Gross Unrealized Gains		12
Gross Unrealized Losses	(33)	(5)
Fair Value	1,773	1,878
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,563	5,760
Gross Unrealized Gains		4
Gross Unrealized Losses	(154)	(100)
Fair Value	5,409	5,664
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	545	545
Gross Unrealized Losses	(22)	(12)
Fair Value	$ 523	$ 533

Securities Available for Sale35

Securities Available for Sale - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)Debt_Security
Investments Debt And Equity Securities [Abstract]
Proceeds from sales of available-for-sale securities	$ 8,958,000
Gross realized gains from sales of available-for-sale securities	49,000
Gross realized losses from sales of available-for-sale securities	$ 0
Number of debt securities with unrealized losses | Debt_Security	22
Unrealized losses debt securities aggregate depreciation percentage	3.57%

Securities Available for Sale36

Securities Available for Sale - Investments Classified by Contractual Maturity Date (Detail) $ in Thousands	Mar. 31, 2018USD ($)
Available-for-sale Securities, Debt Maturities, Amortized Cost
Within 1 year	$ 1,606
After 1 year through 5 years	6,582
After 5 years through 10 years	839
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis, Total	9,027
Mortgage-backed securities	51,777
Available-for-sale Debt Securities, Amortized Cost Basis, Total	60,804
Available-for-sale Securities, Debt Maturities, Fair Value
Within 1 year	1,610
After 1 year through 5 years	6,582
After 5 years through 10 years	855
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair Value Total	9,047
Mortgage-backed securities	50,051
Available-for-sale Securities, Debt Securities, Fair Value Total	$ 59,098

Securities Available for Sale37

Securities Available for Sale - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	$ (225)	$ (24)
Less Than Twelve Months, Fair Value	16,325	6,641
Over Twelve Months, Gross Unrealized Losses	(1,647)	(1,002)
Over Twelve Months, Fair Value	34,231	47,400
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(225)	(24)
Less Than Twelve Months, Fair Value	16,325	6,641
Over Twelve Months, Gross Unrealized Losses	(1,625)	(990)
Over Twelve Months, Fair Value	33,708	46,867
Debt Securities [Member] | US Government-sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Over Twelve Months, Gross Unrealized Losses	(39)	(24)
Over Twelve Months, Fair Value	1,960	19,676
Debt Securities [Member] | Corporate [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(6)
Less Than Twelve Months, Fair Value	497
Over Twelve Months, Gross Unrealized Losses	(15)	(8)
Over Twelve Months, Fair Value	509	988
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	(61)	(1)
Less Than Twelve Months, Fair Value	5,210	1,623
Over Twelve Months, Gross Unrealized Losses	(799)	(449)
Over Twelve Months, Fair Value	19,159	13,163
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	(61)
Less Than Twelve Months, Fair Value	5,153
Over Twelve Months, Gross Unrealized Losses	(647)	(403)
Over Twelve Months, Fair Value	8,532	8,805
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	(35)	(6)
Less Than Twelve Months, Fair Value	1,831	2,126
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(33)	(5)
Less Than Twelve Months, Fair Value	1,773	678
Debt Securities [Member] | Collateralized Mortgage Obligations, US Government Guaranteed [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses	(29)	(1)
Less Than Twelve Months, Fair Value	1,861	295
Over Twelve Months, Gross Unrealized Losses	(125)	(99)
Over Twelve Months, Fair Value	3,548	3,756
Debt Securities [Member] | Municipal [Member]
Schedule of Available-for-sale Securities [Line Items]
Less Than Twelve Months, Gross Unrealized Losses		(11)
Less Than Twelve Months, Fair Value		1,919
Over Twelve Months, Gross Unrealized Losses		(7)
Over Twelve Months, Fair Value		479
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Over Twelve Months, Gross Unrealized Losses	(22)	(12)
Over Twelve Months, Fair Value	$ 523	$ 533

Loans and Allowance for Loan 38

Loans and Allowance for Loan Losses - Summary of Loan Portfolio (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 409,694	$ 402,658
Allowance for loan losses	(3,844)	(3,737)
Net deferred loan costs and fees, and purchase premiums	1,459	1,452
Net loans	407,309	400,373
Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	374,142	364,555
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	107,116	101,755
Commercial Real Estate Loans [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	107,116	101,755
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	20,853	21,766
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	14,699	16,337
One-to-Four Family [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	202,728	198,475
One-to-Four Family [Member] | Residential Real Estate [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	202,728	198,475
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	39,425	38,968
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	24,873	25,357
Construction [Member] | Real Estate Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 24,873	$ 25,357

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, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 3,737	$ 3,271
Provision (credit) for loan losses	95	235
Loans charged-off	(15)	(76)
Recoveries	27	7
Ending balance	3,844	3,437
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,620	1,410
Provision (credit) for loan losses	80	109
Ending balance	1,700	1,519
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	335	37
Provision (credit) for loan losses	(16)	157
Recoveries		1
Ending balance	319	195
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	218	145
Provision (credit) for loan losses	(7)	85
Loans charged-off	(15)	(76)
Recoveries	2	2
Ending balance	198	156
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	854	1,018
Provision (credit) for loan losses	(3)	(61)
Recoveries	25	4
Ending balance	876	961
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	359	436
Provision (credit) for loan losses	6	(41)
Ending balance	365	395
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	351	225
Provision (credit) for loan losses	35	(14)
Ending balance	$ 386	$ 211

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, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	$ 153	$ 162
Allowance for non-impaired loans	3,691	3,575
Total allowance for loan losses	3,844	3,737	$ 3,437	$ 3,271
Impaired loans	6,039	5,833
Non-impaired loans	403,655	396,825
Total loans	409,694	402,658
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans		1
Allowance for non-impaired loans	1,700	1,619
Total allowance for loan losses	1,700	1,620	1,519	1,410
Impaired loans	318	352
Non-impaired loans	106,798	101,403
Total loans	107,116	101,755
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	319	335
Total allowance for loan losses	319	335	195	37
Non-impaired loans	20,853	21,766
Total loans	20,853	21,766
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	198	218
Total allowance for loan losses	198	218	156	145
Non-impaired loans	14,699	16,337
Total loans	14,699	16,337
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	152	160
Allowance for non-impaired loans	724	694
Total allowance for loan losses	876	854	961	1,018
Impaired loans	5,450	5,205
Non-impaired loans	197,278	193,270
Total loans	202,728	198,475
Second Mortgages and HELOC [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for impaired loans	1	1
Allowance for non-impaired loans	364	358
Total allowance for loan losses	365	359	395	436
Impaired loans	271	276
Non-impaired loans	39,154	38,692
Total loans	39,425	38,968
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for non-impaired loans	386	351
Total allowance for loan losses	386	351	$ 211	$ 225
Non-impaired loans	24,873	25,357
Total loans	$ 24,873	$ 25,357

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, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,352	$ 833
Non-accrual Loans	2,235	2,252
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,229	737
Non-accrual Loans	1,963	1,976
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	123	96
Non-accrual Loans	272	276
30 - 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	717	833
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	594	737
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	123	$ 96
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	635
90 Days or More Past Due [Member] | One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 635

Loans and Allowance for Loan 42

Loans and Allowance for Loan Losses - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	$ 3,523	$ 3,189
Unpaid Principal Balance without a valuation allowance	3,462	3,145
Recorded Investment with a valuation allowance	2,597	2,708
Unpaid Principal Balance with a valuation allowance	2,577	2,688
Related Allowance, Total impaired loans	153	162
Recorded Investment, Total impaired loans	6,120	5,897
Unpaid Principal Balance, Total impaired loans	6,039	5,833
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	318	257
Unpaid Principal Balance without a valuation allowance	318	257
Recorded Investment with a valuation allowance		95
Unpaid Principal Balance with a valuation allowance		95
Related Allowance, Total impaired loans		1
One-to-Four Family [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	2,962	2,685
Unpaid Principal Balance without a valuation allowance	2,901	2,641
Recorded Investment with a valuation allowance	2,568	2,584
Unpaid Principal Balance with a valuation allowance	2,549	2,564
Related Allowance, Total impaired loans	152	160
Home Equity Loans and Lines of Credit [Member] | Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment without a valuation allowance	243	247
Unpaid Principal Balance without a valuation allowance	243	247
Recorded Investment with a valuation allowance	29	29
Unpaid Principal Balance with a valuation allowance	28	29
Related Allowance, Total impaired loans	$ 1	$ 1

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, 2018	Mar. 31, 2017
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 6,041	$ 5,953
Interest Income Recognized	62	50
Cash Basis Interest Recognized	41	16
Residential Real Estate [Member] | One-to-Four Family [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	5,440	4,870
Interest Income Recognized	54	41
Cash Basis Interest Recognized	20	16
Residential Real Estate [Member] | Home Equity Loans and Lines of Credit [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	272	276
Interest Income Recognized	3
Cash Basis Interest Recognized	21
Commercial Real Estate Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	329	807
Interest Income Recognized	$ 5	$ 9

Loans and Allowance for Loan 44

Loans and Allowance for Loan Losses - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)TDR	Mar. 31, 2017USD ($)TDR	Dec. 31, 2017USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans, additional funds committed	$ 0
Loans subject to troubled debt restructurings | TDR	0	0
Troubled debt restructuring amount	$ 4,079,000	$ 5,068,000
Changes to allowance for loan losses	$ 0	0
Minimum past due days for loan rating	90 days
Total loans	$ 409,694,000		$ 402,658,000
Residential Mortgage [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	706,000		712,000
Residential Mortgage [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,778,000		2,512,000
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	1,107,000	$ 1,756,000
Home Equity Loans and Lines of Credit [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	28,000
Home Equity Loans and Lines of Credit [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 244,000		247,000
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans subject to troubled debt restructurings | TDR	19	18
Loans subject to troubled debt restructurings, amount	$ 3,959,000	$ 4,479,000
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans subject to troubled debt restructurings | TDR	2	3
Loans subject to troubled debt restructurings, amount	$ 120,000	$ 589,000
Total loans	107,116,000		101,755,000
Commercial Real Estate Loans [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 198,000		$ 199,000
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 45

Loans and Allowance for Loan Losses - Summary of Company's Loans by Risk Rating (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 409,694	$ 402,658
Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	24,873	25,357
Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	107,116	101,755
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	20,853	21,766
Pass [Member] | Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	24,873	25,357
Pass [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	106,918	101,556
Pass [Member] | Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	20,853	21,766
Substandard [Member] | Commercial Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 198	$ 199

Loan Servicing - Additional Inf

Loan Servicing - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Transfers And Servicing [Abstract]
Unpaid principal balance of residential mortgage loans serviced for others	$ 795,123,000		$ 771,407,000
Increased in valuation allowance of mortgage servicing rights	$ 57,000	$ 280,000

Loan Servicing - Summary of Act

Loan Servicing - Summary of Activity Relating to Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Mortgage servicing rights:
Balance at beginning of year	$ 6,487	$ 8,910
Additions through originations	390	451
Amortization	(245)	(339)
Balance at end of period	6,632	9,022
Valuation allowance:
Balance at beginning of year	90	424
Provision (credit)	(57)	(280)
Balance at end of period	33	144
Amortized cost, net	6,599	8,878
Fair value	$ 6,961	$ 8,907

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Federal tax benefit	$ 0	$ 26,000
State tax expense	$ 4,000	$ 3,000

On-Balance Sheet Derivative I49

On-Balance Sheet Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative, Notional amount	$ 30,122,000	$ 24,222,000
Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative, Notional amount	29,973,000	29,613,000
Other Assets [Member] | Derivative Loan Commitments [Member]
Derivative [Line Items]
Derivative fair value, Asset	383,000	363,000
Other Assets [Member] | Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative fair value, Asset	20,000	4,000
Other Liabilities [Member] | Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivative fair value, Liability	$ 31,000	$ 19,000

Employee Stock Ownership Plan -

Employee Stock Ownership Plan - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Loan repaid term	25 years
Number of allocated shares	18,780
Annual allocation of shares, expiration year	2,040
ESOP expense	$ 74,000	$ 72,000
Unallocated shares	427,243
Unallocated shares, value	$ 6,936,000
Common Stock [Member]
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Sale of stock, price per share	$ 10
The Randolph Savings Charitable Foundation, Inc. [Member]
Employee Stock Ownership Plan E S O P Disclosures [Line Items]
Sale of share in employee stock ownership plan	469,498

Share Repurchase Program - Addi

Share Repurchase Program - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Sep. 30, 2017	Mar. 31, 2018
Class Of Stock [Line Items]
Cost of shares repurchased		$ 70,000
September 2017 Share Repurchase Program [Member]
Class Of Stock [Line Items]
Stock repurchase program percentage of outstanding shares repurchased	10.00%
Number of shares authorized to repurchase	586,854
Number of shares repurchased		14,500
Cost of shares repurchased		$ 219,000

Earnings (Loss) Per Share - Add

Earnings (Loss) Per Share - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Earnings Per Share [Abstract]
Potentially dilutive common stock equivalents outstanding	0
Stock options outstanding	336,509		316,009
Weighted average number of outstanding shares	6,033,476	5,868,726
Weighted Average Number of Shares, Unallocated and uncommitted ESOP shares	429,590	448,371
Weighted average common shares outstanding (basic and diluted)	5,603,886	5,420,356

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)shares
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options term	10 years
Stock-based compensation expense | $	$ 74,000
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense | $	$ 133,000
Two Thousand Seventeen Stock Option and Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options and awards vesting period	5 years
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance | shares	586,872
Stock options term	10 years
Two Thousand Seventeen Stock Option and Incentive Plan [Member] | Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance | shares	237,749

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Grants of Options to Purchase Shares of Common Stock (Detail)	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Date of grant	Mar. 15, 2018
Options granted | shares	20,500
Option fair value | $ / shares	$ 5.78
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration period (years)	10 years
Expected volatility	29.87%
Expected life (years)	4 years 6 months
Risk free interest rate	2.68%
Minimum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period (years)	3 years
Maximum [Member] | Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period (years)	5 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Options Grants (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Stock Option Grants
Beginning Balance	316,009
Granted	20,500
Ending Balance	336,509	316,009
Exercisable at March 31, 2018	0
Unrecognized compensation cost	$ 1,383,000
Weighted Average Exercise Price
Beginning Balance	$ 14.66
Granted	16.07
Ending Balance	$ 14.75	$ 14.66
Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value
Weighted Average Remaining Contractual Term	9 years 6 months 29 days	9 years 9 months 10 days
Aggregate Intrinsic Value, Outstanding	$ 219,374
Aggregate Intrinsic Value, Outstanding	$ 501,030	$ 219,374
Weighted Average Remaining Contractual Term, Granted	10 years
Aggregate Intrinsic Value, Exercisable	$ 0
Stock Options [Member]
Stock Option Grants
Weighted average remaining recognition period (years)	4 years 4 months 6 days

Stock-Based Compensation - Su56

Stock-Based Compensation - Summary of Activity in Restricted Stock Awards Under Equity Plan (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Restricted Stock Awards
Beginning Balance | shares	176,239
Beginning Balance | shares	176,239
Unrecognized compensation cost | $	$ 2,331,000
Weighted Average Grant Price
Beginning Balance | $ / shares	$ 14.66
Ending Balance | $ / shares	$ 14.66
Restricted Stock [Member]
Restricted Stock Awards
Weighted average remaining recognition period (years)	4 years 4 months 9 days

Fair Value of Assets and Liab57

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, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 59,621	$ 61,576
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	59,098	61,043
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	523	533
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	59,621	61,576
Fair value, Loans held for sale	22,090	25,390
Derivative assets	403	367
Forward loan sale commitments	31	19
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, Loans held for sale	22,090	25,390
Forward loan sale commitments	31	19
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	59,098	61,043
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	523	533
Fair Value, Measurements, Recurring [Member] | Derivative Loan Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	383	363
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	20	4
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	22,090	25,390
Forward loan sale commitments	31	19
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	59,098	61,043
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	523	533
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	383	363
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	$ 20	$ 4

Fair Value of Assets and Liab58

Fair Value of Assets and Liabilities - Schedule of Assets Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage servicing rights, fair value	$ 6,961		$ 8,907
Gains (losses) on assets held, mortgage servicing rights	57
Gains (Losses) on assets held	57
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	6,599	$ 6,397
Assets, Fair Value Disclosure	6,599	6,397
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	1,264	1,630
Fair value, Assets held for sale	828	828
Fair value, Foreclosed real estate	193	193
Assets, Fair Value Disclosure	$ 2,285	$ 2,651

Fair Value of Assets and Liab59

Fair Value of Assets and Liabilities - Additional information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Increased in valuation allowance of mortgage servicing rights	$ 57,000	$ 280,000
Liabilities measured at fair value on nonrecurring basis	$ 0		$ 0

Fair Value of Assets and Liab60

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, 2018	Dec. 31, 2017
Financial assets:
Securities available for sale	$ 59,621	$ 61,576
Level 2 [Member]
Financial assets:
Certificates of deposit	2,680	2,932
Securities available for sale	59,621	61,576
Loans held for sale	22,090	25,390
Derivative assets	403	367
Financial liabilities:
Deposits	394,156	365,997
FHLBB advances	50,753	75,821
Derivative liabilities	31	19
Level 3 [Member]
Financial assets:
Loans, net	399,293	398,407
Carrying Amount [Member]
Financial assets:
Certificates of deposit	2,695	2,940
Securities available for sale	59,621	61,576
Loans held for sale	22,090	25,390
Loans, net	407,309	400,373
Derivative assets	403	367
Financial liabilities:
Deposits	395,592	366,836
FHLBB advances	50,920	75,954
Derivative liabilities	31	19
Fair Value [Member]
Financial assets:
Certificates of deposit	2,680	2,932
Securities available for sale	59,621	61,576
Loans held for sale	22,090	25,390
Loans, net	399,293	398,407
Derivative assets	403	367
Financial liabilities:
Deposits	394,156	365,997
FHLBB advances	50,753	75,821
Derivative liabilities	$ 31	$ 19

Commitments and Contingencies -

Commitments and Contingencies - Summary of Financial Instruments Outstanding Contract Amounts Represent Credit Risk (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Commitments to Originate Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 35,727	$ 35,549
Unused Lines and Letters of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	42,004	39,968
Unadvanced Funds on Construction Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	8,560	6,967
Overdraft Lines of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Financial instruments with off-balance-sheet risk	$ 8,869	$ 8,996

Segment Information - Additiona

Segment Information - Additional Information (Detail)	Jan. 01, 2018SegmentOffice	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of business segments | Segment	2
Number of branch offices | Office	6
Servicing fees amount		$ (334,000)	$ (660,000)
Envision Mortgage [Member]
Segment Reporting Information [Line Items]
Premium percentage for new loans		1.50%	1.50%
Prermium income		$ 253,000	$ 174,000
Percentage of fees for HELOC		1.00%	1.00%
Servicing fees amount		$ (402,000)	$ (721,000)
Envision Bank [Member]
Segment Reporting Information [Line Items]
Percentage of loan servicing fees		0.14%	0.14%
Servicing fees amount		$ 68,000	$ 61,000

Segment Information - Summary o

Segment Information - Summary of Segment Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net interest income	$ 3,982,000	$ 3,484,000
Provision for loan losses	95,000	235,000
Net interest income after provision for loan losses	3,887,000	3,249,000
Non-interest income:
Customer service fees	301,000	372,000
Net gain on sales of mortgage loans	1,547,000	2,038,000
Mortgage servicing fees, net	334,000	660,000
Other	226,000	340,000
Total non-interest income	2,408,000	3,410,000
Non-interest expenses:
Salaries and employee benefits	4,436,000	4,676,000
Occupancy and equipment	699,000	656,000
Other non-interest expenses	1,863,000	1,797,000
Total non-interest expenses	6,998,000	7,129,000
Loss before income taxes	(703,000)	(470,000)
Income tax expense (benefit)	4,000	(23,000)
Net loss	(707,000)	(447,000)
Total assets, March 31, 2018	533,536,000	482,494,000	$ 531,892,000
Envision Bank [Member]
Segment Reporting Information [Line Items]
Net interest income	3,740,000	3,224,000
Provision for loan losses	95,000	235,000
Net interest income after provision for loan losses	3,645,000	2,989,000
Non-interest income:
Customer service fees	270,000	372,000
Net gain on sales of mortgage loans	(253,000)	(174,000)
Mortgage servicing fees, net	(68,000)	(61,000)
Other	144,000	191,000
Total non-interest income	93,000	328,000
Non-interest expenses:
Salaries and employee benefits	1,636,000	1,627,000
Occupancy and equipment	400,000	347,000
Other non-interest expenses	1,069,000	864,000
Total non-interest expenses	3,105,000	2,838,000
Loss before income taxes	633,000	479,000
Income tax expense (benefit)	4,000	(23,000)
Net loss	629,000	502,000
Total assets, March 31, 2018	473,513,000	422,456,000
Envision Mortgage [Member]
Segment Reporting Information [Line Items]
Net interest income	242,000	260,000
Net interest income after provision for loan losses	242,000	260,000
Non-interest income:
Customer service fees	31,000
Net gain on sales of mortgage loans	1,800,000	2,212,000
Mortgage servicing fees, net	402,000	721,000
Other	82,000	149,000
Total non-interest income	2,315,000	3,082,000
Non-interest expenses:
Salaries and employee benefits	2,800,000	3,049,000
Occupancy and equipment	299,000	309,000
Other non-interest expenses	794,000	933,000
Total non-interest expenses	3,893,000	4,291,000
Loss before income taxes	(1,336,000)	(949,000)
Net loss	(1,336,000)	(949,000)
Total assets, March 31, 2018	$ 60,023,000	$ 60,038,000