PCSB Financial (PCSB) 10-K 13 Sep 18 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Sep. 13, 2018	Dec. 29, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	PCSB
Entity Registrant Name	PCSB Financial Corp
Entity Central Index Key	1,691,337
Current Fiscal Year End Date	--06-30
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 306.8
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		18,165,110

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
ASSETS
Cash and due from banks	$ 60,684	$ 59,115
Federal funds sold	1,461	1,371
Total cash and cash equivalents	62,145	60,486
Investment securities:
Held to maturity investment securities, at amortized cost (fair value of $343,188 and $383,588, respectively)	353,183	383,551
Available for sale securities, at fair value	105,504	111,889
Total investment securities	458,687	495,440
Loans receivable, net of allowance for loan losses of $4,904 and $5,150, respectively	902,336	809,648
Accrued interest receivable	4,358	3,693
Federal Home Loan Bank stock	2,050	3,132
Premises and equipment, net	11,598	12,959
Deferred tax asset, net	2,622	4,770
Foreclosed real estate	460	977
Bank-owned life insurance	23,747	23,179
Goodwill	6,106	6,106
Other intangible assets	433	559
Other assets	5,645	5,509
Total assets	1,480,187	1,426,458
LIABILITIES AND SHAREHOLDERS' EQUITY
Interest bearing deposits	1,025,574	952,109
Non-interest bearing deposits	131,883	136,352
Total deposits	1,157,457	1,088,461
Mortgage escrow funds	8,803	8,084
Advances from Federal Home Loan Bank	18,841	42,598
Other liabilities	7,527	7,469
Total liabilities	1,192,628	1,146,612
Commitments and contingencies (Notes 1, 4 and 10)
Shareholders' equity:
Preferred stock ($0.01 par value, 10,000,000 shares authorized, no shares issued or outstanding as of June 30, 2018 and June 30, 2017)
Common stock ($0.01 par value, 200,000,000 shares authorized, 18,165,110 shares issued and outstanding as of June 30, 2018 and June 30, 2017)	182	182
Additional paid in capital	179,045	177,993
Retained earnings	128,365	121,148
Unearned compensation - ESOP	(13,083)	(14,262)
Accumulated other comprehensive loss, net of income taxes	(6,950)	(5,215)
Total shareholders' equity	287,559	279,846
Total liabilities and shareholders' equity	$ 1,480,187	$ 1,426,458

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Statement Of Financial Position [Abstract]
Held to maturity investment securities, fair value	$ 343,188	$ 383,588
Allowance for loan losses	$ 4,904	$ 5,150
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	10,000,000	10,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares, issued	18,165,110	18,165,110
Common Stock, shares outstanding	18,165,110	18,165,110

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Interest and dividend income
Loans	$ 37,798,000	$ 33,664,000	$ 32,832,000
Investment securities	9,266,000	6,661,000	5,897,000
Federal funds and other	896,000	633,000	315,000
Total interest and dividend income	47,960,000	40,958,000	39,044,000
Interest expense
Deposits and escrow interest	5,554,000	5,083,000	4,613,000
FHLB advances	769,000	210,000	199,000
Total interest expense	6,323,000	5,293,000	4,812,000
Net interest income	41,637,000	35,665,000	34,232,000
Provision for loan losses	414,000	823,000	1,859,000
Net interest income after provision for loan losses	41,223,000	34,842,000	32,373,000
Noninterest income
Fees and service charges	1,070,000	1,178,000	1,053,000
Bank-owned life insurance	568,000	622,000	458,000
Gains on sale of securities	236,000	0	0
Settlement on acquired loan		1,615,000
Other	645,000	669,000	440,000
Total noninterest income	2,519,000	4,084,000	1,951,000
Noninterest expense
Salaries and employee benefits	19,235,000	16,901,000	16,961,000
Occupancy and equipment	5,193,000	5,864,000	5,122,000
Communications and data processing	1,974,000	1,768,000	1,790,000
Professional fees	1,709,000	1,308,000	1,644,000
Postage, printing, stationary and supplies	578,000	547,000	681,000
Loss on other receivable	570,000
Advertising	456,000	529,000	388,000
FDIC assessment	328,000	558,000	888,000
Amortization of intangible assets	126,000	143,000	158,000
Charitable foundation contribution		5,000,000
Merger and acquisition related expenses			790,000
Other operating expenses	1,947,000	1,813,000	1,843,000
Total noninterest expense	32,116,000	34,431,000	30,265,000
Net income before income tax expense	11,626,000	4,495,000	4,059,000
Income tax expense	5,022,000	1,266,000	1,133,000
Net income	$ 6,604,000	$ 3,229,000	$ 2,926,000
Earnings per common share:
Basic	$ 0.39
Diluted	$ 0.39
Weighted average common shares outstanding - basic and diluted	16,802,894

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Net Income	$ 6,604	$ 3,229	$ 2,926
Unrealized gains (losses) on available for sale securities:
Net change in unrealized gains/losses before reclassification adjustment	(1,835)	(735)	255
Reclassification adjustment for gains realized in net income	(164)
Net change in unrealized gains/losses	(1,999)	(735)	255
Tax effect	558	249	(55)
Net of tax	(1,441)	(486)	200
Defined benefit pension plan and supplemental retirement plans:
Total other comprehensive (loss) income	(618)	2,755	(3,248)
Comprehensive income (loss)	5,986	5,984	(322)
Pension Benefits [Member]
Defined benefit pension plan and supplemental retirement plans:
Net gain (loss) arising during the period	335	3,973	(5,022)
Reclassification adjustment for amortization of prior service cost and net gain (loss) included in net periodic pension cost	725	89	398
Net change in unrealized gains/losses	1,060	4,062	(4,624)
Tax effect	(270)	(1,381)	1,252
Net of tax	790	2,681	(3,372)
SERP Benefits [Member]
Defined benefit pension plan and supplemental retirement plans:
Net gain (loss) arising during the period	10	(755)	89
Reclassification adjustment for amortization of prior service cost and net gain (loss) included in net periodic pension cost	34	93	84
Net change in unrealized gains/losses	44	(662)	173
Tax effect	(11)	1,222	(249)
Net of tax	$ 33	$ 560	$ (76)

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands		Total	PCSB Community Foundation [Member]	Common Stock [Member]	Common Stock [Member]PCSB Community Foundation [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]PCSB Community Foundation [Member]	Retained Earnings [Member]	Unallocated Common Stock of ESOP [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Jun. 30, 2015		$ 110,271						$ 114,993		$ (4,722)
Net Income		2,926						2,926
Other comprehensive income		(3,248)								(3,248)
Ending Balance at Jun. 30, 2016		109,949						117,919		(7,970)
Net Income		3,229						3,229
Other comprehensive income		2,755								2,755
Issuance of common stock		174,604		$ 179		$ 174,425
Issuance of common stock (in shares)				17,826,408
Issuance of common stock to PCSB Community Foundation			$ 3,387		$ 3		$ 3,384
Issuance of common stock to PCSB Community Foundation (in shares)					338,702
Stock purchased by the ESOP		(14,532)							$ (14,532)
ESOP shares committed to be released		454				184			270
Ending Balance at Jun. 30, 2017		279,846		$ 182		177,993		121,148	(14,262)	(5,215)
Ending Balance (in shares) at Jun. 30, 2017				18,165,110
Net Income		6,604						6,604
Other comprehensive income		(618)								(618)
Reclassification of certain tax effects on other comprehensive income	[1]							1,117		(1,117)
Common stock dividends declared ($0.03 per share)		(504)						(504)
Issuance of common stock	[2]	(17)				(17)
ESOP shares committed to be released		2,248				1,069			1,179
Ending Balance at Jun. 30, 2018		$ 287,559		$ 182		$ 179,045		$ 128,365	$ (13,083)	$ (6,950)
Ending Balance (in shares) at Jun. 30, 2018				18,165,110
[1]	The adoption of ASU 2018-02 requires the reclassification from accumulated other comprehensive income to retained earnings of certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017. Refer to Footnote 2 - Recent Accounting Pronouncements for additional information
[2]	Represents costs incurred in association with the Company's initial public offering completed in the prior period

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Statement Of Stockholders Equity [Abstract]
ESOP shares committed to be released (in shares)	117,948	26,975
Common stock dividends declared (per share)	$ 0.03

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
OPERATING ACTIVITIES
Net income	$ 6,604,000	$ 3,229,000	$ 2,926,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan loss	414,000	823,000	1,859,000
Depreciation and amortization	1,432,000	1,427,000	1,265,000
Amortization of net premiums on securities and net deferred loan origination costs	1,679,000	1,002,000	943,000
Deferred income tax expense (credit), net of valuation reserves	2,425,000	(26,000)	1,299,000
Net increase in accrued interest receivable	(665,000)	(332,000)	(127,000)
Net loss (gain) on sale of foreclosed real estate	7,000	(99,000)	(9,000)
Net gains on sale of securities	(236,000)	0	0
Write-downs on foreclosed real estate			30,000
Contribution to PCSB Community Foundation		3,387,000
ESOP Compensation	2,248,000	454,000
Earnings from cash surrender value of BOLI	(568,000)	(622,000)	(458,000)
Net accretion of purchase account adjustments	(563,000)	(820,000)	(1,352,000)
Other adjustments, principally net changes in other assets and liabilities	1,834,000	(588,000)	(431,000)
Net cash provided by operating activities	14,611,000	7,835,000	5,945,000
Purchases of investment securities:
Held to maturity	(51,218,000)	(195,566,000)	(112,896,000)
Available for sale	(27,498,000)	(23,314,000)	(56,420,000)
Sales of investment securities available for sale	7,511,000
Maturities and calls of investment securities:
Held to maturity	80,997,000	72,152,000	107,656,000
Available for sale	24,202,000	32,750,000	33,058,000
Principal repayments net of disbursement for loan originations	(818,000)	(1,131,000)	(14,314,000)
Purchase of loans	(93,166,000)	(30,926,000)	(43,981,000)
Net redemption (purchase) of FHLB stock	1,082,000	(1,085,000)	(328,000)
Purchase of bank premises and equipment	(753,000)	(3,469,000)	(3,902,000)
Purchase of BOLI			(11,275,000)
Proceeds from sale of foreclosed real estate	1,249,000	2,121,000	1,030,000
Net cash used in investing activities	(58,412,000)	(148,468,000)	(101,372,000)
FINANCING ACTIVITIES
Net increase (decrease) in deposits	69,019,000	(24,109,000)	52,778,000
Net increase (decrease) in short-term FHLB advances	(23,636,000)	23,636,000	(5,019,000)
Proceeds from long-term FHLB advances		15,000,000	20,100,000
Repayment of long-term FHLB advances	(121,000)	(16,119,000)	(9,000,000)
Net increase in mortgage escrow funds	719,000	1,061,000	385,000
Common stock dividends paid	(504,000)
Issuance of common stock	(17,000)	160,072,000
Net cash provided by financing activities	45,460,000	159,541,000	59,244,000
Net increase (decrease) in cash and cash equivalents	1,659,000	18,908,000	(36,183,000)
Cash and cash equivalents:
Cash and cash equivalents at beginning of period	60,486,000	41,578,000	77,761,000
Cash and cash equivalents at end of period	62,145,000	60,486,000	41,578,000
Cash paid for:
Interest	6,204,000	5,293,000	4,814,000
Income taxes (net of refunds)	2,766,000	1,100,000	(351,000)
Loans transferred to foreclosed real estate and other assets	$ 739,000	$ 2,075,000	$ 1,575,000

Basis of Presentation

Basis of Presentation	12 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Note 1. Basis of Presentation Nature of Operations PCSB Bank is a community-oriented financial institution that provides financial services to individuals and businesses within its market area of Putnam, Southern Dutchess, Rockland and Westchester Counties in New York. The Bank is a state-chartered stock savings bank and its deposits are insured up to applicable limits by the Deposit Insurance Fund of the Federal Deposit Insurance Corporation (“FDIC”). The Bank’s primary regulators are the FDIC and the New York State Department of Financial Services. Merger with CMS Bancorp Basis of Presentation UpCounty Realty Corp. (formerly PCSB Realty Ltd.) Use of Estimates Cash Flows Securities Securities available for sale are reported at fair value. Unrealized gains and losses on securities available for sale are excluded from earnings and reported as accumulated other comprehensive income or loss (a separate component of equity), net of related income taxes. Premiums and discounts on debt securities are amortized to interest income on a level-yield basis over the terms of the securities. Realized gains and losses on sales of securities are determined based on the amortized cost of the specific securities sold. Management evaluates securities for other-than-temporary impairment (OTTI) on at least a quarterly basis, and more frequently when economic or market conditions warrant such an evaluation. For securities in an unrealized loss position, management considers the extent and duration of the unrealized loss, and the financial condition and near-term prospects of the issuer. Management also assesses whether it intends to sell, or it is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. For debt securities that do not meet the aforementioned criteria, the amount of impairment is split into two components as follows: 1) OTTI related to credit loss, which must be recognized in the income statement and 2) OTTI related to other factors, which is recognized in other comprehensive income. The credit loss is defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis. For equity securities, the entire amount of impairment is recognized through earnings. Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at the principal balance outstanding, net of deferred loan fees and costs, unamortized purchase premiums and discounts, and an allowance for loan losses. Interest income is accrued on the unpaid principal balance. Interest income on loans is discontinued at the time the loan is ninety days delinquent unless the loan is well secured and in process of collection. Loan purchase premiums and discounts are amortized over the contractual term of the loans Loan origination fees and certain direct loan origination costs are deferred and amortized to interest income as an adjustment to yield over the contractual term of the loans. Unamortized fees and costs on prepaid loans are recognized in interest income at the time of prepayment. Purchased Credit Impaired Loans Such purchased credit impaired loans are accounted for individually or aggregated into pools of loans based on common risk characteristics, such as credit score, loan type, and date of origination. The Company estimates the amount and timing of expected cash flows for each loan or pool, and the expected cash flows in excess of amount paid is recorded as interest income over the remaining life of the loan or pool (accretable yield). The excess of the loan’s or pool’s contractual principal and interest over expected cash flows is not recorded (nonaccretable difference). Over the life of the loan or pool, expected cash flows continue to be estimated. If the present value of expected cash flows is less than the carrying amount, an allowance is recorded as a provision for loan losses. If the present value of expected cash flows is greater than the carrying amount, it is recognized as part of future interest income. Allowance for Loan Losses Establishing the allowance for loan losses involves significant management judgments utilizing the best information available at the time. Those judgments are subject to further examination by the Bank’s regulators. Future adjustments to the allowance for loan losses may be necessary based on changes in economic and real estate market conditions, further information obtained regarding known problem loans, the identification of additional problem loans, and other factors. The allowance consists of specific and general components. The specific component relates to loans that are individually classified as impaired. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. Impairment is measured on a loan-by-loan basis for loans evaluated under the Company’s normal loan review procedures. Loans evaluated on an individual basis for impairment may be measured by the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s observable market price, or the fair value of the collateral if the loan is collateral dependent. The Company’s impaired loans are generally collateral dependent. If the fair value of an impaired loan is less than its recorded investment, an impairment allowance is recognized and included in the allowance for loan losses. Troubled debt restructurings are separately identified for impairment disclosures and are measured at the present value of estimated future cash flows using the loan’s effective rate at inception. If a troubled debt restructuring is considered to be a collateral dependent loan, the loan is reported at the fair value of the collateral. For troubled debt restructurings that subsequently default, the Company determines the amount of reserve in accordance with the accounting policy for the allowance for loan losses. The general component of the allowance covers non-impaired loans and is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over a thirty-six month period, with heaviest weight placed on the most recent periods. This actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: lending policies, underwriting, charge-off and collection procedures; national and local economic trends and conditions; trends in nature and volume of the loan portfolio; experience, ability, and depth of lending management and other relevant staff; trends in delinquencies, classified loans and restructurings; quality of the loan review system and Board oversight; value of underlying collateral for collateral dependent loans; existence and effect of concentrations and levels; and effects of external factors, such as competition, legal and regulatory factors. The following portfolio segments have been identified: residential, commercial mortgage, construction, commercial, home equity and consumer and overdrafts. The risk characteristics of each of the identified portfolio segments are as follows: Residential Loans – residential loans are generally made on the basis of the borrower’s ability to make repayment from his or her employment income or other income, and are secured by real property whose value tends to be more easily ascertainable. Repayment of residential loans is subject to adverse employment conditions in the local economy leading to increased default rates and decreased market values from oversupply in a geographic area. In general, these loans depend on the borrower’s continuing financial stability and, therefore, are likely to be adversely affected by various factors, including job loss, divorce, illness, or personal bankruptcy. Furthermore, the application of various federal and state laws, including federal and state bankruptcy and insolvency laws, may limit the amount that can be recovered on such loans. Commercial Mortgage – commercial mortgage loans, including multifamily real estate loans, are secured by multifamily and nonresidential real estate and generally have larger balances and involve a greater degree of risk than residential real estate loans. Repayment of commercial mortgage loans depend on the global cash flow analysis of the borrower and the net operating income of the property, the borrower’s expertise, credit history and profitability, and the value of the underlying property. Of primary concern in commercial real estate lending is the borrower’s creditworthiness and the cash flow generated from the property securing the loan. As a result, repayment of such loans may be subject, to a greater extent than residential real estate loans, to adverse conditions in the real estate market or the economy. Commercial real estate is also subject to adverse market conditions that cause a decrease in market value or lease rates, obsolescence in location or function and market conditions associated with over supply of units in a specific region. Construction – construction financing is generally considered to involve a higher degree of risk of loss than long-term financing on improved, occupied real estate. Risk of loss on a construction loan depends largely upon the accuracy of the initial estimate of the property’s value at completion of construction and the estimated cost of construction. During the construction phase, a number of factors could result in delays and cost overruns. If the estimate of construction costs proves to be inaccurate, additional funds may be required to be advanced in excess of the amount originally committed to permit completion of the building. If the estimate of value proves to be inaccurate, the value of the building may be insufficient to assure full repayment if liquidation is required. If foreclosure is required on a building before or at completion due to a default, there can be no assurance that all of the unpaid balance of, and accrued interest on, the loan as well as related foreclosure and holding costs will be recovered. Commercial – commercial loans are generally of higher risk than other types of loans and typically are made on the basis of the borrower’s ability to make repayment from the cash flow of the borrower’s business. As a result, the availability of funds for the repayment of commercial loans may depend substantially on the success of the business itself. Furthermore, any collateral securing such loans may depreciate over time, may be difficult to appraise, and may fluctuate in value. Home Equity Lines of Credit – home equity lines of credit consist of both fixed and variable interest rate products. These are primarily home equity loans to residential mortgage customers within the footprint of the primary lending territory. These loans generally will not exceed a combined (i.e., first and second mortgage) loan-to-value ratio of 75 percent at origination. Consumer and overdraft loans – consumer loans generally have shorter terms and higher interest rates than one-to-four family mortgage loans. In addition, consumer loans expand the products and services we offer to better meet the financial services needs of our customers. Consumer loans generally involve greater credit risk than residential mortgage loans because of the difference in the underlying collateral. Repossessed collateral for a defaulted consumer loan may not provide an adequate source of repayment of the outstanding loan balance because of the greater likelihood of damage to, loss of, or depreciation in the underlying collateral. The remaining deficiency often does not warrant further substantial collection efforts against the borrower beyond obtaining a deficiency judgment. In addition, consumer loan collections depend on the borrower’s personal financial stability. Furthermore, the application of various federal and state laws, including federal and state bankruptcy and insolvency laws, may limit the amount that can be recovered on such loans. Foreclosed Real Estate Federal Home Loan Bank (FHLB) Stock Premises and Equipment Bank Owned Life Insurance (BOLI) Goodwill and Other Intangible Assets Other intangible assets, consisting of a core deposit intangible asset arising from a whole bank acquisition, are amortized on an accelerated method over their estimated useful lives of 10 years. Loan Commitments and Related Financial Instruments Income Taxes Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in future years. The effect on deferred tax assets and liabilities of a change in tax laws or rates is recognized in the period that includes the enactment date of the change. A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company recognizes interest and/or penalties related to income tax matters in income tax expense. Employee Benefit Plans: Employee 401(k) expense is the amount of matching contributions. Pension expense is the net of service and interest cost, return on plan assets and amortization of gains and losses not immediately recognized. SERP expense is the net of interest cost and service cost, which allocates the benefits over years of service. The Holding Company and Bank maintain the PCSB Bank Employee Stock Ownership Plan (the “ESOP”). Compensation expense related to the ESOP is recorded during the period in which the shares become committed to be released to participants. The compensation expense is measured based upon the average fair market value of the stock during the period, and, to the extent that the fair value of the shares committed to be released differs from the original cost of such shares, the difference is recorded as an adjustment to additional paid-in capital. Loss Contingencies Fair Value of Financial Instruments Segment Reporting Reclassifications Earnings per share

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Jun. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recent Accounting Pronouncements	N ote 2 . Recent Accounting Pronouncements The pronouncements discussed below are not intended to be an all-inclusive list, but rather only those pronouncements that could potentially have a material impact on our financial position, results of operations or disclosures. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09 “Revenue from Contracts with Customers,” and was later amended by ASU 2015-14, ASU 2016-08, ASU 2016-10, ASU 2016-12 and 2016-20. These updates provide a comprehensive framework for addressing revenue recognition issues that can be applied to all contracts with customers. The amendments also include improved disclosures to enable users of financial statements to better understand the nature, amount, timing and uncertainty of revenue that is recognized. While the guidance in ASU 2014-09 supersedes most existing industry-specific revenue recognition accounting guidance, much of PCSB Bank’s revenue comes from financial instruments such as debt securities and loans that are outside the scope of the guidance. The Company’s material revenue streams that are in the scope of ASU 2014-09 are fees on deposit accounts (including interchange fees) and foreclosed real estate gains and losses. All other revenue streams are immaterial or are in the scope of other GAAP requirements which take precedence and therefore are not in the scope of ASU 2014-09. Based on the Company’s analysis, ASU 2014-09 will not materially change the recognition of revenue on service fees on deposit accounts as the contracts are day to day and recognized as the service is provided. Gains and losses on the sale of foreclosed real estate are generally accounted for under ASC 610. However, ASU 2014-09 also added a new Subtopic 610-20 which addresses the recognition of gains and losses on the transfer of nonfinancial and in-substance nonfinancial assets. Gain and loss recognition is not expected to change except for foreclosed real estate and other nonfinancial asset sales that are financed by the Company. In the case of financed sales, the Company will need to evaluate each contract to determine whether each contract criteria are met, including whether it is probable that it will collect substantially all consideration to which it is entitled. The Company will also need to evaluate whether the financing terms offered to the buyer of the nonfinancial asset are market terms when determining the transaction price. The Company has evaluated the impact of ASU 2014-09 and the amendments upon adoption as of July 1, 2018. In evaluating this standard, management has determined that the majority of revenue earned by the Company is from revenue streams not included in the scope of this standard and for in scope revenue streams management determined that, based on the modified retrospective method, a cumulative-effect adjustment to opening retained earnings as a result of adopting this standard is not needed. ASU 2014-09 will require additional disclosures beginning with the quarter ending September 30, 2018. In January 2016, the FASB issued ASU 2016-01, an amendment to “Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendments in ASU 2016-01 are intended to improve the recognition, measurement, presentation and disclosure of financial assets and liabilities to provide users of financial statements with information that is more useful for decision-making purposes. Among other changes, ASU 2016-01 would: (1) require equity securities to be reclassified out of available for sale and measured at fair value with changes in fair value recognized through net income but would allow equity securities that do not have readily determinable fair values to be re-measured at fair value either upon the occurrence of an observable price change or upon identification of an impairment, (2) simplify the impairment assessment of such equity securities and would require enhanced disclosure about these investments, (3) require separate presentation of financial assets and liabilities by measurement category and type of instrument, such as securities or loans, on the balance sheet or in the notes, and would eliminate certain other disclosures relating to the methods and assumptions used to estimate fair value for financial assets measured at amortized cost on the balance sheet, and (4) require the use of an exit price notion when measuring the fair value of financial instruments. The Company has evaluated the impact of ASU 2016-01 and subsequent amendments upon adoption on July 1, 2018 and has concluded that there is not a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02 “Leases.” ASU 2016-02 affects any entity that enters into a lease and is intended to increase the transparency and comparability of financial statements among organizations. The ASU requires, among other changes, a lessee to recognize on its balance sheet a lease asset and a lease liability for those leases previously classified as operating leases. The lease asset would represent the right to use the underlying asset for the lease term and the lease liability would represent the discounted value of the required lease payments to the lessor. The ASU would also require entities to disclose key information about leasing arrangements. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2019, including interim periods within that fiscal year. Early adoption is permitted. The Company currently leases eleven branches and two administrative offices. ASU 2016-02 will result in the establishment of a right to use asset and corresponding lease obligation, the materiality of which has yet to be determined by management, however the ASU is not expected to have a material impact on the Company’s consolidated results of operations or disclosures. In June 2016, the FASB issued ASU 2016-13 “Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 affects entities holding financial assets that are not accounted for at fair value through net income, including loans, debt securities, and other financial assets. The ASU requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected by recording an allowance for current expected credit losses. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2020, including interim periods within that fiscal year. Early adoption is permitted beginning after December 15, 2018, including interim periods within those fiscal years. The Company is actively working through the provisions of the Update. Management has established a steering committee which is identifying the methodologies and the additional data requirements necessary to implement the Update and is evaluating the need for a third-party software service provider to assist in the Company's implementation. In January 2017, the FASB issued ASU 2017-04 “Intangibles – Goodwill and Other (Topic 350).” In March 2017, the FASB issued ASU 2017-07 “Compensation – Retirement Benefits”. The ASU requires companies that offer employee defined pension plans, other postretirement benefit plans, or other types of benefit plans accounted for under Topic 715 to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. Management has evaluated the impact of ASU 2017-07 upon adoption on July 1, 2018 and has concluded that there is not a material impact on the Company’s consolidated financial statements. In March 2017, the FASB issued ASU 2017-08 "Receivables - Non-Refundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities." The ASU requires premiums on callable debt securities to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2020, including interim periods within that fiscal year. Early adoption is permitted beginning after December 15, 2018, including interim periods within those fiscal years. ASU 2017-08 will not have a material impact on the Company’s consolidated financial position, results of operations or disclosures. On February 14, 2018, the FASB issued ASU 2018-02 "Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of certain tax effects from accumulated other comprehensive income." The ASU intended to help organizations reclassify certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017. The ASU requires the reclassification of stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the TAX Cuts and Job Act 2017 (or portion thereof) is recorded. The amount of the reclassification is the difference between the historical corporate income tax rate (34 percent) and the newly enacted 21 percent corporate income tax rate. The Company has elected to early adopt the ASU as of March 31, 2018, resulting in a $1.1 million reclassification between accumulated other comprehensive income and retained earnings. There is no impact to current earnings and no prior period information has been retroactively adjusted as a result of implementing the ASU. No additional reclassifications will be required in the future periods as a result of this guidance. The ASU is applied specifically to the impacts of the Tax Cuts and Jobs Act of 2017 and is not effective for other or future state or federal tax law changes.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Shareholders' Equity	Note 3. Shareholders' Equity The Company completed its IPO on April 20, 2017, in connection with the Bank’s mutual-to-stock conversion, resulting in gross proceeds of $178.3 million, through the sale of 17,826,408 shares, including 1,453,209 shares sold to the PCSB Bank Employee Stock Ownership Plan (ESOP), at the offering price of $10.00 per share. In addition, the Company also contributed 338,702 shares of its common stock and $1.6 million in cash to the PCSB Community Foundation. Expenses related to the offering were approximately $3.7 million, which resulted in net proceeds of approximately $174.6 million prior to the contribution to PCSB Community Foundation. The Company lent approximately $14.5 million to the ESOP and retained approximately $87.3 million of the net proceeds of the offering prior to the contribution to PCSB Community Foundation. The remainder of the net proceeds was contributed to the Bank. Prior to the IPO, the Company had no outstanding shares.

Investment Securities

Investment Securities	12 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Investment Securities	Note 4 . Investment Securities The amortized cost, gross unrealized/unrecognized gains and losses and fair value of available for sale and held to maturity securities at June 30, 2018 and 2017 were as follows: June 30, 2018 Amortized Gross Unrealized/Unrecognized Fair Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government and agency obligations $ 64,389 $ - $ (959 ) $ 63,430 Corporate and other debt securities 8,406 - (171 ) 8,235 Mortgage-backed securities – residential 34,619 81 (893 ) 33,807 Equity securities 32 - - 32 Total available for sale $ 107,446 $ 81 $ (2,023 ) $ 105,504 Held to maturity: U.S. Government and agency obligations $ 122,048 $ - $ (2,274 ) $ 119,774 Corporate and other debt securities 4,000 - (126 ) 3,874 Mortgage-backed securities – residential 140,478 32 (4,846 ) 135,664 Mortgage-backed securities – collateralized mortgage obligations 53,547 - (1,815 ) 51,732 Mortgage-backed securities – commercial 33,110 11 (977 ) 32,144 Total held to maturity $ 353,183 $ 43 $ (10,038 ) $ 343,188 June 30, 2017 Amortized Gross Unrealized/Unrecognized Fair Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government and agency obligations $ 63,630 $ 31 $ (216 ) $ 63,445 Corporate and other debt securities 8,460 58 (36 ) 8,482 Mortgage-backed securities – residential 39,710 363 (143 ) 39,930 Equity securities 32 - - 32 Total available for sale $ 111,832 $ 452 $ (395 ) $ 111,889 Held to maturity: U.S. Government and agency obligations $ 155,559 $ 23 $ (574 ) $ 155,008 Corporate and other debt securities 999 - - 999 Mortgage-backed securities – residential 143,452 828 (497 ) 143,783 Mortgage-backed securities – collateralized mortgage obligations 59,476 146 (235 ) 59,387 Mortgage-backed securities – commercial 24,065 412 (66 ) 24,411 Total held to maturity $ 383,551 $ 1,409 $ (1,372 ) $ 383,588 For the year ended June 30, 2018, the Company sold securities with a carrying amount of $8.6 million, resulting in $236,000 of net realized gains. Included was a disposal of $1.3 million of securities classified as held to maturity, resulting in net realized gains of $72,000. These securities were comprised of seasoned mortgage-backed securities where the Company collected a substantial portion (at least 85%) of the principal outstanding at acquisition due to prepayments or scheduled payments payable in equal installments, comparing both principal and interest over terms. There were no sales of or realized gains or losses on investment securities for the years ended June 30, 2017 or 2016. The following table presents the fair value and carrying amount of debt securities at June 30, 2018 and 2017, by contractual maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Held to maturity Available for sale Carrying Fair Amortized Fair Amount Value Cost Value (in thousands) June 30, 2018: 1 year or less $ 25,504 $ 25,342 $ 12,402 $ 12,353 1 to 5 years 96,544 94,432 58,393 57,335 5 to 10 years - - 2,000 1,977 Mortgage-backed securities and other 231,135 223,414 34,619 33,807 Total $ 353,183 $ 343,188 $ 107,414 $ 105,472 Held to maturity Available for sale Carrying Fair Amortized Fair Amount Value Cost Value (in thousands) June 30, 2017: 1 year or less $ 50,486 $ 50,413 $ 16,005 $ 15,988 1 to 5 years 106,073 105,594 54,085 53,975 5 to 10 years - - 2,000 1,964 Mortgage-backed securities and other 226,992 227,581 39,710 39,930 Total $ 383,551 $ 383,588 $ 111,800 $ 111,857 Securities pledged had carrying amounts of $140.5 million and $95.5 million at June 30, 2018 and 2017, respectively, and were pledged principally to secure FHLB advances and public deposits. The following table provides information regarding investment securities with unrealized/unrecognized losses, aggregated by investment category and length of time that individual securities had been in a continuous unrealized loss position at June 30, 2018 and 2017: June 30, 2018 Less than 12 months Greater than 12 months Total Unrealized/ Unrealized/ Unrealized/ Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Loss Value Loss Value Loss (in thousands) Available for sale: U.S. Government and agency obligations $ 41,762 $ (569 ) $ 21,668 $ (390 ) $ 63,430 $ (959 ) Corporate and other debt securities 6,258 (148 ) 1,977 (23 ) 8,235 (171 ) Mortgage-backed securities – residential 13,397 (379 ) 14,718 (514 ) 28,115 (893 ) Total available for sale $ 61,417 $ (1,096 ) $ 38,363 $ (927 ) $ 99,780 $ (2,023 ) Held to maturity: U.S. Government and agency obligations $ 46,163 $ (871 ) $ 71,611 $ (1,403 ) $ 117,774 $ (2,274 ) Corporate and other debt securities 3,874 (126 ) - - 3,874 (126 ) Mortgage-backed securities – residential 102,496 (3,338 ) 32,490 (1,508 ) 134,986 (4,846 ) Mortgage-backed securities – collateralized mortgage obligations 31,124 (884 ) 20,608 (931 ) 51,732 (1,815 ) Mortgage-backed securities – commercial 21,762 (582 ) 8,629 (395 ) 30,391 (977 ) Total held to maturity $ 205,419 $ (5,801 ) $ 133,338 $ (4,237 ) $ 338,757 $ (10,038 ) June 30, 2017 Less than 12 months Greater than 12 months Total Unrealized/ Unrealized/ Unrealized/ Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Loss Value Loss Value Loss (in thousands) Available for sale U.S. Government and agency obligations $ 41,900 $ (200 ) $ 3,993 $ (16 ) $ 45,893 $ (216 ) Corporate and other debt securities 1,964 (36 ) - - 1,964 (36 ) Mortgage-backed securities – residential 18,861 (111 ) 3,200 (32 ) 22,061 (143 ) Total available for sale $ 62,725 $ (347 ) $ 7,193 $ (48 ) $ 69,918 $ (395 ) Held to maturity U.S. Government and agency obligations $ 113,511 $ (531 ) $ 5,981 $ (43 ) $ 119,492 $ (574 ) Corporate and other debt securities 999 - - - 999 0 Mortgage-backed securities – residential 39,754 (467 ) 1,626 (30 ) 41,380 (497 ) Mortgage-backed securities – collateralized mortgage obligations 26,622 (141 ) 4,444 (94 ) 31,066 (235 ) Mortgage-backed securities – commercial 9,092 (66 ) - - 9,092 (66 ) Total held to maturity $ 189,978 $ (1,205 ) $ 12,051 $ (167 ) $ 202,029 $ (1,372 ) For the year ended June 30, 2018, the Company’s securities portfolio consisted of $458.7 million in securities, of which 254 securities with a fair value of $438.5 million were in an unrealized loss position. The majority of unrealized losses are related to the Company’s U.S. Government and agency obligations and mortgage-backed securities. For the year ended June 30, 2017, the Company’s securities portfolio consisted of $495.4 million in securities, of which 156 securities with a fair value of $271.9 million were in an unrealized loss position. The majority of unrealized losses are related to the Company’s U.S. Government and agency obligations and mortgage-backed securities. There were no securities for which the Company believes it is not probable that it will collect all amounts due according to the contractual terms of the security as of June 30, 2018 and 2017. Management believes the unrealized losses are primarily a result of changing interest rates. The Company has determined that it does not intend to sell, or it is not more likely than not that it will be required to sell, its securities that are in an unrealized loss position prior to the recovery of its amortized cost basis. Therefore, the Company did not consider any securities to be other-than-temporarily impaired as of June 30, 2018 and 2017.

Loans Receivable

Loans Receivable	12 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Loans Receivable	Note 5. Loans Receivable Loans receivable are summarized as follows at June 30 (in thousands): June 30, 2018 2017 Mortgage loans: Residential $ 250,578 $ 217,778 Commercial 495,265 437,651 Construction 17,352 22,404 Net deferred loan origination costs 1,041 397 Total mortgages 764,236 678,230 Commercial and consumer loans: Commercial loans 104,135 93,631 Home equity lines of credit 37,395 41,927 Consumer and overdrafts 745 233 Net deferred loan origination costs 729 777 Total commercial and consumer loans 143,004 136,568 Total loans receivable 907,240 814,798 Allowance for loan losses (4,904 ) (5,150 ) Loans receivable, net $ 902,336 $ 809,648 In 2015, the Bank completed a merger with CMS Bancorp and its wholly owned subsidiary, CMS Bank. References to acquired loans in this note pertain only to those loans acquired as part of the merger. The following tables present the activity in the allowance for loan losses by portfolio segment for the years ended June 30, 2018, 2017 and 2016 (in thousands): For the year ended June 30, 2018 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 360 $ 161 $ (136 ) $ 1 $ 386 Commercial 2,589 114 - 370 3,073 Construction 1,150 352 (997 ) - 505 Commercial loans 949 (335 ) (54 ) 220 780 Home equity lines of credit 76 45 (60 ) 19 80 Consumer and overdrafts - 30 (23 ) - 7 Acquired: - Residential 26 47 - - 73 Total $ 5,150 $ 414 $ (1,270 ) $ 610 $ 4,904 For the year ended June 30, 2017 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 237 $ 290 $ (237 ) $ 70 $ 360 Commercial 2,149 421 - 19 2,589 Construction 269 989 (108 ) - 1,150 Commercial loans 1,313 (944 ) (741 ) 1,321 949 Home equity lines of credit 73 3 - - 76 Consumer and overdrafts 1 (5 ) - 4 - Acquired: - Residential - 64 (38 ) - 26 Commercial loans - 2 (2 ) - - Consumer and overdrafts - 3 (3 ) - - Total $ 4,042 $ 823 $ (1,129 ) $ 1,414 $ 5,150 For the year ended June 30, 2016 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 193 $ 444 $ (400 ) $ - $ 237 Commercial 1,766 215 (10 ) 178 2,149 Construction 100 (23 ) - 192 269 Commercial loans 1,793 1,172 (1,677 ) 25 1,313 Home equity lines of credit 69 28 (24 ) - 73 Consumer and overdrafts - 23 (22 ) - 1 Total $ 3,921 $ 1,859 $ (2,133 ) $ 395 $ 4,042 The following tables present the balance in the allowance for loan losses and the recorded investment in loans, excluding net deferred fees and accrued interest, by portfolio segment, and based on impairment method as of June 30, 2018 and June 30, 2017 (in thousands): June 30, 2018 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Residential $ 2,360 $ 246,913 $ 1,305 $ 250,578 $ 154 $ 232 $ 73 $ 459 Commercial 1,683 492,105 1,477 495,265 - 3,073 - 3,073 Construction 2,260 15,092 - 17,352 276 229 - 505 Commercial loans 2,451 101,684 - 104,135 9 771 - 780 Home equity lines of credit 360 36,867 168 37,395 12 68 - 80 Consumer and overdrafts - 745 - 745 - 7 - 7 Total $ 9,114 $ 893,406 $ 2,950 $ 905,470 $ 451 $ 4,380 $ 73 $ 4,904 June 30, 2017 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Residential $ 4,471 $ 211,983 $ 1,324 $ 217,778 $ 131 $ 229 $ 26 $ 386 Commercial 2,411 433,416 1,824 437,651 - 2,589 - 2,589 Construction 3,661 18,743 - 22,404 997 153 - 1,150 Commercial loans 6,169 87,420 42 93,631 9 940 - 949 Home equity lines of credit 610 41,140 177 41,927 5 71 - 76 Consumer and overdrafts - 233 - 233 - - - - Total $ 17,322 $ 792,935 $ 3,367 $ 813,624 $ 1,142 $ 3,982 $ 26 $ 5,150 The following tables present information related to loans individually evaluated for impairment (excluding loans acquired with deteriorated credit quality) by class of loans as of and for the years ended June 30, 2018, 2017 and 2016 (in thousands): June 30, 2018 Unpaid Principal Balance Recorded Investment Allowance for Loan Losses With no related allowance recorded: Residential $ 1,659 $ 1,576 $ - Commercial 1,765 1,683 - Commercial loans 2,254 2,098 - Home equity lines of credit 341 341 - With an allowance recorded: Residential 742 784 154 Construction 3,257 2,260 276 Commercial loans 353 353 9 Home equity lines of credit 84 19 12 Total $ 10,455 $ 9,114 $ 451 June 30, 2017 Unpaid Principal Balance Recorded Investment Allowance for Loan Losses With no related allowance recorded: Residential $ 4,216 $ 4,014 $ - Commercial 2,935 2,411 - Construction 404 404 - Commercial loans 9,433 4,979 - Home equity lines of credit 599 599 - With an allowance recorded: Residential 395 457 131 Construction 3,257 3,257 997 Commercial loans 1,190 1,190 9 Home equity lines of credit 11 11 5 Total $ 22,440 $ 17,322 $ 1,142 For the year ended For the year ended For the year ended June 30, 2018 June 30, 2017 June 30, 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized With no related allowance recorded: Residential $ 3,041 $ 184 $ 4,238 $ 42 $ 5,577 $ 6 Commercial 2,350 248 2,448 137 9,324 88 Construction 93 17 406 12 13 - Commercial loans 3,457 1,049 5,065 239 10,755 71 Home equity lines of credit 507 22 599 (2 ) 430 - With an allowance recorded: Residential 453 15 432 15 - - Construction 2,720 - 3,015 71 132 - Commercial loans 1,491 66 1,224 61 422 12 Home equity lines of credit 11 - 11 - - - Total $ 14,123 $ 1,601 $ 17,438 $ 575 $ 26,653 $ 177 The following table presents the recorded investment in nonaccrual loans and in loans past due over 90 days still on accrual status, by class of loans as of June 30, 2018 and June 30, 2017 (in thousands): Loans Past Due Over 90 Days Nonaccrual and Still Accruing June 30, June 30, June 30, June 30, 2018 2017 2018 2017 Originated: Residential $ 604 $ 2,581 $ - $ - Commercial 262 - - - Construction 2,260 3,661 - - Commercial loans 788 2,959 - - Home equity lines of credit 45 302 - - Acquired: Residential 1,308 1,776 - - Commercial 532 497 - - Home equity lines of credit 303 296 - - Total $ 6,102 $ 12,072 $ - $ - Nonperforming loans include both smaller-balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. The table above excludes acquired loans that are accounted for as purchased credit impaired loans totaling $1.8 million and $2.7 million as of June 30, 2018 and June 30, 2017, respectively. Such loans are excluded because the loans are in pools that are considered performing. The discounts arising from recording these loans at fair value upon acquisition were due in part to credit quality and the accretable yield is being recognized as interest income over the life of the loans based on expected cash flows. The following tables present the aging of the recorded investment in past due loans by class of loans as of June 30, 2018 and June 30, 2017 (in thousands): June 30, 2018 90 Days or 30-59 60-89 More Past Total Past Days Past Due Days Past Due Due Due Current Total Originated: Residential $ - $ 394 $ 210 $ 604 $ 194,986 $ 195,590 Commercial - - 262 262 420,320 420,582 Construction - - 2,260 2,260 15,092 17,352 Commercial loans - - 500 500 102,767 103,267 Home equity lines of credit - - 45 45 32,311 32,356 Consumer and overdrafts - - - - 733 733 Total originated - 394 3,277 3,671 766,209 769,880 Acquired: Residential - 232 1,806 2,038 52,950 54,988 Commercial - - 1,112 1,112 73,571 74,683 Construction - - - - - - Commercial loans - - - - 868 868 Home equity lines of credit 30 - 296 326 4,713 5,039 Consumer and overdrafts - - - - 12 12 Total acquired 30 232 3,214 3,476 132,114 135,590 Total $ 30 $ 626 $ 6,491 $ 7,147 $ 898,323 $ 905,470 June 30, 2017 90 Days or 30-59 60-89 More Past Total Past Days Past Due Days Past Due Due Due Current Total Originated: Residential $ 94 $ 275 $ 1,973 $ 2,342 $ 153,390 $ 155,732 Commercial - - - - 355,247 355,247 Construction - - 3,661 3,661 18,743 22,404 Commercial loans - - 544 544 88,449 88,993 Home equity lines of credit - 199 103 302 35,246 35,548 Consumer and overdrafts - - - - 211 211 Total originated 94 474 6,281 6,849 651,286 658,135 Acquired: Residential 237 463 1,472 2,172 59,874 62,046 Commercial - - 1,054 1,054 81,350 82,404 Construction - - - - - - Commercial loans - - - - 4,638 4,638 Home equity lines of credit - - 296 296 6,083 6,379 Consumer and overdrafts - - - 22 22 Total acquired 237 463 2,822 3,522 151,967 155,489 Total $ 331 $ 937 $ 9,103 $ 10,371 $ 803,253 $ 813,624 Troubled Debt Restructurings The terms of certain loans were modified as troubled debt restructurings. The modification of the terms of such loans included one or a combination of the following: a reduction of the stated interest rate of the loan; an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; or a permanent reduction of the recorded investment in the loan. As of June 30, 2018 and June 30, 2017, the Company had 12 and 20 loans classified as troubled debt restructurings totaling $3.8 million and $9.9 million, respectively. The Company has allocated $139,000 and $145,000, respectively, of specific reserves to customers whose loan terms have been modified in troubled debt restructurings as of June 30, 2018 and June 30, 2017, and has not committed to lend additional amounts to customers with outstanding loans that are classified as troubled debt restructurings. The following table presents loans by modified in troubled debt restructurings that occurred during the years ended June 30, 2018, 2017 and 2016 (dollars in thousands): Number of loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Year ended June 30, 2018: Commercial loans 1 $ 275 $ 289 Total 1 $ 275 $ 289 Year ended June 30, 2017: Residential 1 $ 165 $ 210 Commercial loans 1 276 276 Total 2 $ 441 $ 486 Year ended June 30, 2016: Residential 3 $ 1,697 $ 1,697 Commercial 1 1,178 1,178 Commercial loans 1 64 64 Home equity lines of credit 1 200 200 Total 4 $ 3,139 $ 3,139 The Company had two troubled debt restructurings, both commercial loans, for which there was a payment default in the year ended June 30, 2018 that were modified in the twelve months prior to default, which resulted in a $2,000 increase to the allowance for loan loss. There were two troubled debt restructurings, one residential mortgage and one home equity line of credit, for which there was a payment default in the year ended June 30, 2017 that were modified in the twelve months prior to default, and resulted in no increase to the allowance for loan loss. There was one such default, on a residential mortgage, in the year ended June 30, 2016 which resulted in no increase to the allowance for loan losses. In order to determine whether a borrower is experiencing financial difficulty, an evaluation is performed of the probability that the borrower will be in payment default on any of its debt in the foreseeable future without the modification. This evaluation is performed under the Company’s internal underwriting policy. Credit Quality Indicators The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt such as: current financial information, historical payment experience, credit documentation, public information, and current economic trends, among other factors. The Company analyzes loans individually by classifying the loans as to credit risk. This analysis includes non-homogeneous loans, such as commercial and commercial real estate loans. This analysis is performed on a monthly basis. The Company utilized the same grading process for acquired loans as it does for originated loans. The Company uses the following definitions for risk ratings: Special Mention – Loans classified as special mention have a potential weakness that deserves management's close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan or of the institution's credit position at some future date. Substandard – Loans classified as substandard are inadequately protected by the current net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful – Loans classified as doubtful have all the weaknesses inherent in those classified as substandard, with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. Loans not meeting the criteria above that are analyzed individually as part of the above-described process and loans in groups of homogenous loans are considered to be pass rated loans. These loans are monitored based on delinquency and performance. Based on the most recent analysis performed, the risk category of loans by class of loans is as follows (in thousands): June 30, 2018 Pass Special Mention Substandard Total Originated: Residential $ 194,341 $ 571 $ 678 $ 195,590 Commercial 418,370 - 2,212 420,582 Construction 15,092 - 2,260 17,352 Commercial loans 98,205 167 4,895 103,267 Home equity lines of credit 32,167 144 45 32,356 Consumer and overdrafts 733 - - 733 Total originated 758,908 882 10,090 769,880 Acquired: Residential 51,858 249 2,881 54,988 Commercial 71,832 842 2,009 74,683 Construction - - - - Commercial loans 857 11 - 868 Home equity lines of credit 4,641 - 398 5,039 Consumer and overdrafts 12 - - 12 Total acquired 129,200 1,102 5,288 135,590 Total $ 888,108 $ 1,984 $ 15,378 $ 905,470 June 30, 2017 Pass Special Mention Substandard Total Originated: Residential $ 153,165 $ - $ 2,567 $ 155,732 Commercial 352,203 134 2,910 355,247 Construction 18,743 - 3,661 22,404 Commercial loans 79,406 - 9,587 88,993 Home equity lines of credit 35,246 58 244 35,548 Consumer and overdrafts 211 - 211 Total originated 638,974 192 18,969 658,135 Acquired: Residential 58,665 - 3,381 62,046 Commercial 80,082 - 2,322 82,404 Construction - - - - Commercial loans 4,638 - - 4,638 Home equity lines of credit 5,906 - 473 6,379 Consumer and overdrafts 22 - - 22 Total acquired 149,313 - 6,176 155,489 Total $ 788,287 $ 192 $ 25,145 $ 813,624 Purchased Credit Impaired Loans The Company has acquired loans for which there was, at acquisition, evidence of deterioration of credit quality since origination and it was probable, at acquisition, that all contractually required payments would not be collected. The carrying amount of those loans as of June 30, 2018 and 2017 is as follows (in thousands): June 30, June 30, 2018 2017 Residential $ 1,232 $ 1,298 Commercial 1,477 1,824 Commercial loans - 42 Home equity lines of credit 168 177 Carrying amount, net of allowance of $73 and $26, respectively $ 2,877 $ 3,341 Accretable yield, or income expected to be collected, for acquired loans is as follows (in thousands): Year ended June 30, 2018 2017 2016 Beginning balance $ 403 $ 578 $ 713 New loans acquired - - - Accretion income (70 ) (190 ) (185 ) Reclassification from non-accretable difference 5 15 132 Disposals (93 ) - (82 ) Ending balance $ 245 $ 403 $ 578

Premises and Equipment

Premises and Equipment	12 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Premises and Equipment	Note 6. Premises and Equipment Premises and equipment are summarized as follows at June 30 (in thousands): 2018 2017 Land $ 1,997 $ 1,997 Building and Leasehold improvements 13,430 11,128 Furniture, fixtures and equipment 6,096 5,841 Construction and improvements in process 355 3,015 21,878 21,981 Less: accumulated depreciation and amortization (10,280 ) (9,022 ) Total Bank premises and equipment, net $ 11,598 $ 12,959 Depreciation expense was $1.3 million, $1.3 million and $1.1 million for the years ended June 30, 2018, 2017 and 2016, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Jun. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Note 7 . Goodwill and Intangible Assets The change in goodwill during the years ended June 30, 2018, 2017 and 2016 are as follows (in thousands): 2018 2017 2016 Balance at July 1 $ 6,106 $ 6,106 $ 5,843 Adjustment to CMS goodwill - - 263 Impairment - - - Total at June 30 $ 6,106 $ 6,106 $ 6,106 Impairment exists when a reporting unit’s carrying value of goodwill exceeds its fair value. The Company tests for goodwill impairment on an annual basis as of June 30 th Acquired Intangible Assets: Acquired intangible assets were as follows at June 30 (in thousands): 2018 2017 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Amortized intangible assets: Core deposit intangible $ 887 $ (454 ) $ 887 $ (328 ) Aggregate amortization expense was $126,000, $143,000 and $158,000 for the years ended June 30, 2018, 2017 and 2016, respectively. Estimated amortization expense for each of the next five fiscal years ended June 30 (in thousands): 2019 $ 110 2020 94 2021 78 2022 62 2023 46

Deposits

Deposits	12 Months Ended
	Jun. 30, 2018
Deposits [Abstract]
Deposits	Note 8 . Deposits Deposit balances are summarized as follows at June 30, 2018 and 2017 (in thousands): 2018 2017 Demand $ 131,883 $ 136,361 NOW Accounts 117,875 115,527 Money market accounts 49,885 29,097 Savings 465,441 512,697 Time deposits 392,373 294,779 Total $ 1,157,457 $ 1,088,461 Time deposits that meet or exceed the FDIC insurance limit of $250,000 were $116.0 million and $49.2 million at June 30, 2018 and 2017, respectively. Scheduled maturities of time deposits were as follows as of June 30, 2018 and 2017 and exclude fair value adjustments on acquired time deposits (in thousands): 2018 2017 Within 1 year $ 183,276 $ 107,097 1 year to 2 years 49,350 62,331 2 years to 3 years 56,746 31,143 3 years to 4 years 56,458 41,508 4 years to 5 years 46,339 52,503 Thereafter 204 197 Total $ 392,373 $ 294,779 Deposits of local governments held by PCSB Commercial Bank were $39.1 million and $38.4 million at June 30, 2018 and 2017, respectively. Additionally, as of June 30, 2018, deposits included $60.0 million of brokered time deposits with remaining maturities between five and 47 months. We had no brokered deposits as of June 30, 2017.

FHLB and Other Borrowings

FHLB and Other Borrowings	12 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
FHLB and Other Borrowings	Note 9 . FHLB and Other Borrowings Borrowings consist of advances from the Federal Home Loan Bank of New York. As of June 30, 2018, FHLB advances consisted of $15.0 million of short and long-term advances with original maturities ranging from 3 to 18 months, as well as a $3.8 million amortizing term loan with a balloon payment of $2.8 million in 2026. The maturity schedule of advances is summarized as follows as of June 30 (dollars in thousands): 2018 2017 Amount Due Weighted Avg. Rate Amount Due Weighted Avg. Rate Within 1 year $ 10,125 1.70 % $ 23,757 1.27 % 1 year to 2 years 5,128 1.81 10,125 1.70 2 years to 3 years 131 2.62 5,128 1.81 3 years to 4 years 135 2.62 131 2.62 4 years to 5 years 138 2.62 135 2.62 Thereafter 3,184 2.62 3,322 2.62 Total $ 18,841 1.91 % $ 42,598 1.55 % As a member of the FHLB of New York, the Bank had access to funds in the form of FHLB advances of approximately $314.9 million and $350.7 million from the Federal Home Loan Bank of New York, at June 30, 2018 and June 30, 2017, $18.8 million and $42.6 million of which was outstanding as of June 30, 2018 and June 30, 2017, respectively. Advances are secured by the Bank’s investment in FHLB stock and by a blanket security agreement. This agreement requires the Bank to maintain as collateral certain qualifying assets (such as U.S. Government agency and MBSs) with a discounted fair value, as defined, at least equal to 110% of any outstanding advances. At June 30, 2018, the Bank also had access to funds of approximately $122.1 million in the form of secured borrowings through the discount window of the Federal Reserve Bank of New York. Collateral for these borrowings may include qualifying assets, such as one-to-four family residential loans. The Bank had no outstanding FRB borrowings as of June 30, 2018 or 2017.

Commitment and Contingencies

Commitment and Contingencies	12 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10 . Commitments and Contingencies Financial Instruments with Off-Balance-Sheet Risk described in Note 1 The contract amounts of credit-related financial instruments reflect the extent of the Company’s involvement with those classes of financial instruments. The Company’s exposure to credit loss in the event of non-performance by the counterparty is represented by the contract amount. The Company uses the same credit policies in extending commitments, lines of credit and standby letters of credit as it does for on-balance sheet instruments. The contract amounts of credit-related financial instruments at June 30, 2018 and 2017, are summarized below (in thousands): 2018 2017 Commitments to originate loans $ 102,644 $ 77,600 Unused lines of credit 56,553 45,439 Standby letter of credit 1,420 705 Lines of credit (including undisbursed construction loans) and commitments to originate loans are agreements to lend to a customer as long as there is no violation of any condition established in the contract. These agreements generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since certain lines of credit and commitments are expected to expire without being funded, the contract amounts do not necessarily represent future cash requirements. In extending lines of credit and commitments, the Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on management’s credit evaluation of the customer. The Company issues financial standby letters of credit that are irrevocable undertakings by the Company to guarantee payment of a specified financial obligation. Most of the Company’s financial standby letters of credit arise in connection with lending relationships and have terms of one year or less. The maximum potential future payments the Company could be required to make equals the contract amount of standby letters of credit shown in the preceding table. The Company’s recognized liability for financial standby letters of credit was insignificant at June 30, 2018 and 2017. Operating Lease Commitments Within 1 year $ 2,145 1 year to 2 years 2,026 2 year to 3 years 1,737 3 year to 4 years 1,675 4 year to 5 years 1,639 Thereafter 8,283 Total $ 17,505 Legal Proceedings Company

Comprehensive Income

Comprehensive Income	12 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Comprehensive Income	Note 11 . Comprehensive Income The following is a summary of the accumulated other comprehensive income (loss) balances, net of tax (in thousands): Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2017 $ 37 $ (5,002 ) $ (250 ) $ (5,215 ) Other comprehensive income before reclassifications (1,835 ) 335 10 (1,490 ) Amounts reclassified from accumulated other comprehensive income (164 ) 725 34 595 Tax effect 558 (270 ) (11 ) 277 Net other comprehensive income (1,441 ) 790 33 (618 ) Reclassification of certain tax effects on other comprehensive income (1) (132 ) (938 ) (47 ) (1,117 ) Balance at June 30, 2018 $ (1,536 ) $ (5,150 ) $ (264 ) $ (6,950 ) Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2016 $ 523 $ (7,683 ) $ (810 ) $ (7,970 ) Other comprehensive income before reclassifications (735 ) 3,973 (755 ) 2,483 Amounts reclassified from accumulated other comprehensive income — 89 93 182 Tax effect 249 (1,381 ) 1,222 90 Net other comprehensive income (486 ) 2,681 560 2,755 Balance at June 30, 2017 $ 37 $ (5,002 ) $ (250 ) $ (5,215 ) Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2015 $ 323 $ (4,311 ) $ (734 ) $ (4,722 ) Other comprehensive income before reclassifications 255 (5,022 ) 89 (4,678 ) Amounts reclassified from accumulated other comprehensive income — 398 84 482 Tax effect (55 ) 1,252 (249 ) 948 Net other comprehensive income 200 (3,372 ) (76 ) (3,248 ) Balance at June 30, 2016 $ 523 $ (7,683 ) $ (810 ) $ (7,970 ) (1) Represents the impact of adopting ASU 2018-02 requiring the reclassification of certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017 from accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act of 2017 (or portion thereof) is recorded. The amount of the reclassification is the difference between the historical corporate income tax rate (34 percent) and the newly enacted 21 percent corporate income tax rate. The reclassification is as of March 31, 2018; no prior period information has been retroactively adjusted as a result of implementing the ASU.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Note 12 . Earnings Per Share Basic earnings per share represents income available to common stockholders divided by the weighted-average number of common shares outstanding during the period. Unallocated ESOP shares are not deemed outstanding for earnings per share calculations. There were no potentially dilutive common stock equivalents during the year ended June 30, 2018. Due to the IPO taking place on April 20, 2017, earnings per share for the year-ended June 30, 2017 was deemed not meaningful by management. Year ended June 30, 2018 (dollars in thousands, except per share data) Net income applicable to common stock $ 6,604 Average number of common shares outstanding 18,165,110 Less: Average unallocated ESOP shares 1,362,216 Average number of common shares outstanding used to calculate basic earnings per common share 16,802,894 Earnings per Common share: Basic $ 0.39 Diluted $ 0.39

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Note 13 . Fair Value of Financial Instruments Fair value is the exchange price that would be received for an asset or paid to transfer a liability (exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. There are three levels of inputs that may be used to measure fair values: Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the entity has the ability to access as of the measurement date. Level 2: Significant other observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. Level 3: Significant unobservable inputs that reflect a reporting entity’s own assumptions about the assumptions that market participants would use in pricing an asset or liability. A description of the valuation methodologies used for assets and liabilities measured at fair value, as well as general classification of such instruments pursuant to the valuation hierarchy, is set forth below. While management believes the Company’s valuation methodologies are appropriate and consistent with other financial institutions, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Investment Securities Impaired Loans Foreclosed Real Estate Real estate owned properties are evaluated on a quarterly basis for additional impairment and adjusted accordingly. Appraisals for both collateral-dependent impaired loans and real estate owned are performed by certified general appraisers (for commercial properties) or certified residential appraisers (for residential properties) whose qualifications and licenses have been reviewed and verified by the Company. Once received, a member of the Credit Department, as well as a third-party specialist, where deemed appropriate, reviews the assumptions and approaches utilized in the appraisal as well as the overall resulting fair value in comparison with independent data sources such as recent market data or industry-wide statistics. Once appraisals are considered appropriate, management discounts the appraised value for estimated selling costs, such as legal, broker, and property maintenance and insurance costs. The most recent analysis performed indicated discount rates ranging between 10% and 20% should be applied to properties with appraisals performed. Assets and liabilities measured at fair value are summarized below (in thousands): Fair Value Measurements Level 1 Level 2 Level 3 Total June 30, 2018: Measured on a recurring basis: Available for sale securities: U.S. Government and agency obligations $ - $ 63,430 $ - $ 63,430 Corporate and other debt securities - 8,235 - 8,235 Mortgage-backed securities – residential - 33,807 - 33,807 Equity securities - 32 - 32 Total assets at fair value $ - $ 105,504 $ - $ 105,504 Measured on a non-recurring basis: Impaired loans: Residential mortgages $ - $ - $ 688 $ 688 Construction - - 1,984 1,984 Commercial loans - - 845 845 Home equity lines of credit - - 7 7 Foreclosed real estate - - 460 460 Total assets at fair value $ - $ - $ 3,984 $ 3,984 Fair Value Measurements Level 1 Level 2 Level 3 Total June 30, 2017 Measured on a recurring basis: Available for sale securities: U.S. Government and agency obligations $ - $ 63,445 $ - $ 63,445 Corporate and other debt securities - 8,482 - 8,482 Mortgage-backed securities – residential - 39,930 - 39,930 Equity securities - 32 - 32 Total assets at fair value $ - $ 111,889 $ - $ 111,889 Measured on a non-recurring basis: Impaired loans: Residential mortgages $ - $ - $ 1,126 $ 1,126 Construction - - 2,260 2,260 Commercial loans - - 1,681 1,681 Home equity lines of credit - - 5 5 Foreclosed real estate - - 977 977 Total assets at fair value $ - $ - $ 6,049 $ 6,049 Impaired loans in the table above had a carrying amount of $3.9 million, a remaining valuation allowance of $451,000 at June 30, 2018, incurred $1.1 million of net charge-offs during the year ended June 30, 2018, and resulted in an additional provision for loan losses of $435,000. Impaired loans as of June 30, 2017 in the table above had a carrying amount of $6.3 million, a remaining valuation allowance of $1.1 million at June 30, 2017, and incurred $245,000 of net charge-offs during the year ended June 30, 2017, which resulted in an additional provision for loan losses of $1.4 million for the year. The following tables present quantitative information about Level 3 fair value measurements for selected financial instruments measured at fair value on a non-recurring basis at June 30, 2018 and June 30, 2017 (dollars in thousands): Valuation Unobservable Range or Fair Value Technique(s) Input(s) Rate Used June 30, 2018: Impaired loans - residential mortgages $ 688 Sales comparison Adjustments for differences in sales comparables -5.1% to 20.9% Discounted cash flow Discount rate 5.4% to 6.3% Impaired loans - construction 1,984 Sales contract Discount to sales contract 9.8% Impaired loans - commercial loans 845 Discounted cash flow Discount rate 5.3% to 7.5% Sales contract Discount to sales contract 9.8% Impaired loans - home equity lines of credit 7 Sales comparison Adjustments for differences in sales comparables -5.1% to 20.9% Discounted cash flow Discount rate 6.3% Foreclosed real estate 460 Sales comparison Adjustments for differences in sales comparables -8.1% to -0.4% June 30, 2017: Impaired loans - residential mortgages $ 1,126 Sales comparison Adjustments for differences in sales comparables -5.1% to 7.8% Discounted cash flow Discount rate 5.4% to 6.3% Impaired loans - construction 2,260 Cost approach Discount for distressed property 50.0% Impaired loans - commercial loans 1,681 Discounted cash flow Discount rate 6.0% to 7.5% Sales comparison Adjustments for differences in sales comparables 0.0% Impaired loans - home equity lines of credit 5 Discounted cash flow Discount rate 6.3% Foreclosed real estate 977 Sales comparison Adjustments for differences in sales comparables -23.4% to 7.2% The following is a summary of the carrying amounts and estimated fair values of the Company’s financial assets and liabilities (none of which are held for trading purposes) (in thousands): Carrying Fair Value Measurements Amount Level 1 Level 2 Level 3 Total June 30, 2018: Financial assets: Cash and cash equivalents $ 62,145 $ 62,145 $ - $ - $ 62,145 Investment securities held to maturity 353,183 - 343,188 - 343,188 Investment securities available for sale 105,504 - 105,504 - 105,504 Loans receivable, net 902,336 - - 882,319 882,319 Accrued interest receivable 4,358 - 1,402 2,956 4,358 Federal Home Loan Bank stock 2,050 N/A N/A N/A N/A Financial liabilities: Demand, NOW, money market deposits and savings accounts 765,084 765,084 - - 765,084 Time deposits 392,373 - 394,205 - 394,205 Mortgage escrow funds 8,803 8,803 - - 8,803 FHLB advances 18,841 - 20,574 - 20,574 June 30, 2017: Financial assets: Cash and cash equivalents $ 60,486 $ 60,486 $ - $ - $ 60,486 Investment securities held to maturity 383,551 - 383,318 270 383,588 Investment securities available for sale 111,889 - 111,889 - 111,889 Loans receivable, net 809,648 - - 817,814 817,814 Accrued interest receivable 3,693 - 1,243 2,450 3,693 Federal Home Loan Bank stock 3,132 N/A N/A N/A N/A Financial liabilities: Demand, NOW, money market deposits and savings accounts 793,681 793,681 - - 793,681 Time deposits 294,780 - 297,508 - 297,508 Mortgage escrow funds 8,084 8,084 - - 8,084 FHLB advances 42,598 - 45,504 - 45,504 The methods and assumptions, not previously presented, used to estimate fair values are described as follows: Cash and Cash Equivalents Loans Receivable, Net FHLB Stock Accrued Interest Receivable Deposits and escrow funds FHLB Advances Off Balance Sheet Instruments

Income Taxes

Income Taxes	12 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income Tax	Note 14 . Income Taxes The components of income tax expense (benefit) are summarized as follows for the years ended June 30 (in thousands): 2018 2017 2016 Current tax expense (benefit) Federal $ 2,577 $ 1,344 $ (6 ) State 20 (52 ) (476 ) 2,597 1,292 (482 ) Deferred tax expense (benefit) Federal 2,414 (52 ) 1,216 State 313 (21 ) 250 2,727 (73 ) 1,466 State tax valuation allowances, net of federal benefit (302 ) 47 149 Total $ 5,022 $ 1,266 $ 1,133 On December 22, 2017, as part of the Tax Cuts and Jobs Act, the federal government enacted comprehensive tax reform containing provisions with a number of impacts on corporate income taxes, the most significant of which provides a decrease in the corporate income tax rate from 34% to 21% for tax years beginning on or after January 1, 2018. The company is required to re-measure as of the date the law is enacted, its net deferred tax asset to reflect the income tax rate expected to be effective when deferred tax positions will be realized. As a result, the Company recorded a re-measurement charge through income tax expense of $1.6 million for the year ended June 30, 2018. The Company utilizes a calendar year tax year. As a result of the aforementioned tax reform, a “blended” federal statutory rate of 28.06% is used for 2018, based on the daily weighted average statutory rate effective throughout the fiscal year. Effective tax rates differ from federal statutory rate applied to income before income taxes due to the following (in thousands): 2018 2017 2016 Federal statutory rate 28.06 % 34.00 % 34.00 % Tax at federal statutory rate $ 3,262 $ 1,529 $ 1,380 State Taxes, net of federal benefit 24 — — Tax-exempt income (61 ) (47 ) (49 ) BOLI income (157 ) (211 ) (156 ) ESOP Compensation 300 63 — Deferred tax re-remeasurement charge 1,570 — — Other, net 84 (68 ) (42 ) Total $ 5,022 $ 1,266 $ 1,133 Effective tax rate 43.20 % 28.16 % 27.91 % Year-end deferred tax assets and liabilities were due to the following (in thousands): 2018 2017 Deferred Tax Assets: Allowance for Loan Losses $ 1,222 $ 1,983 Deferred compensation 836 1,071 Accrued incentive compensation 110 — Purchase accounting adjustments 70 277 Deferred rent 182 380 Other compensation loss (defined benefit plans) 1,439 2,706 Depreciation of premises and equipment 413 405 NOL carryforward 131 602 Charitable contribution carryforward 949 1,820 Nonaccrual loan interest 118 540 Other comprehensive loss (securities) 408 — Other — 104 Total deferred tax assets 5,878 9,888 Deferred Tax Liabilities: Prepaid pension costs $ 2,424 $ 3,622 Deferred loan costs and fees, net 451 457 Other comprehensive income (securities) — 19 Other 31 368 Total deferred tax liabilities 2,906 4,466 Deferred tax asset valuation allowance (350 ) (652 ) Net Deferred Tax Asset $ 2,622 $ 4,770 The Company has an apportioned New York State net operating loss carryforward of approximately $2.1 million which will begin to expire in 2034. In addition, the Company has approximately $3.8 million of charitable contribution carryforwards that may be carried forward up to 5 years and will begin to expire in 2022. In 2014, New York State enacted comprehensive tax reform provisions with significant impact on financial institutions. As a result of this legislation, beginning on January 1, 2015, the Company calculated its tax obligation to New York based upon the largest of a calculated income tax liability, a tax liability based upon average equity capital or a fixed minimum fee. It is more likely than not the Company will generate New York tax losses in future years and therefore calculate its New York tax liability on the basis of average equity capital or a fixed minimum fee. Consequently, the Company maintains a valuation allowance against its net New York deferred tax asset, as it is unlikely this deferred tax asset will impact the Company's New York tax liability in future years. Management has determined that it is not required to establish a valuation allowance against any other deferred tax assets in accordance with accounting principles generally accepted in the United States of America Retained earnings at June 30, 2018 included approximately $2.8 million for which deferred income taxes of approximately $588,000 have not been provided. The retained earnings amount represents the base year allocation of income to bad debt deductions for tax purposes only. Base year reserves are subject to recapture if the Bank makes certain non-dividend contributions, repurchases any of its stock, pays dividends in excess of tax earnings and profits, or ceases to maintain a bank charter. Under ASC 740, this amount is treated as a permanent difference and deferred taxes are not recognized unless it appears that it will be reduced and result in taxable income in the foreseeable future. Events that would result in taxation of these reserves include failure to qualify as a bank for tax purposes or distributions in complete or partial liquidation. The Company is subject to U.S. federal income tax as well as income tax of the states of New York, New Jersey and Connecticut. The Company’s federal and state income tax returns are subject to examination for years after December 31, 2014. At June 30, 2018 and 2017, the Company had no unrecognized tax benefits recorded. The Company does not expect the total amount of unrecognized tax benefits to significantly increase or decrease in the next twelve months.

Post-Retirement Benefits

Post-Retirement Benefits	12 Months Ended
	Jun. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Post-Retirement Benefits	Note 15 . Post-Retirement Benefits Employee Pension Plan The following is a summary of the plan’s funded status as of June 30, 2018 and 2017 (the measurement date for financial reporting purposes) (in thousands): 2018 2017 Change in benefit obligation: Beginning benefit obligation $ 25,614 $ 28,670 Service Cost - 602 Interest Cost 968 1,002 Actuarial Loss 8 (2,013 ) Benefits Paid (868 ) (828 ) Settlements (958 ) (1,301 ) Curtailment - (518 ) Ending benefit obligation 24,764 25,614 Change in plan assets, at fair value: Beginning plan assets 27,444 23,215 Actual return 2,357 3,358 Employer contributions - 3,000 Benefits paid (868 ) (828 ) Settlements (958 ) (1,301 ) Ending Plan assets 27,975 27,444 Funded Status $ 3,211 $ 1,830 Accumulated Benefit Obligation $ 24,764 $ 25,614 The following is a summary of net period pension cost, contributions and benefits paid for the years ended June 30 (in thousands): 2018 2017 Net period pension cost $ (321 ) $ (224 ) Employer contributions - 3,000 Benefits paid 868 828 Pre-tax amounts recognized in accumulated other comprehensive loss was $6.5 million and $7.6 million for the years ended June 30, 2018 and 2017 respectively. Net periodic pension cost and other amounts recognized in other comprehensive income for the years ended June 30 (in thousands): 2018 2017 2016 Service cost $ - $ 602 $ 626 Interest cost 968 1,002 1,086 Expected return on plan assets (2,014 ) (1,917 ) (1,796 ) Amortization of prior net loss 725 1,200 854 Amortization of prior service cost - (192 ) (287 ) Gain on curtailment - (919 ) - New past service liability - - - Net periodic cost $ (321 ) $ (224 ) $ 483 The estimated net loss and past service cost for the pension plan that will be amortized from accumulated other comprehensive income into net periodic benefit costs during the year ending June 30, 2019, are $580,000 and $0, respectively. Contributions: Estimated Future Payments 2019 $ 1,232 2020 1,259 2021 1,303 2022 1,347 2023 1,365 Following five years 7,202 Assumptions Weighted-average assumptions used to determine net periodic pension cost are described in the table below. Year ended June 30, 2018 2017 Discount Rate 3.87 % 4.04 % Expected return on plan assets 7.50 % 7.50 % Plan Assets Plan assets are invested in a series of diversified investment funds of RSI Retirement Trust (“the Trust”). The investment funds include equity mutual funds, bond mutual funds, or commingled trust funds, each with its own investment objectives, investment strategies and risks. The Trust has been given discretion by the Company to determine the appropriate strategic asset allocation, as governed by the Trust’s Statement of Investment Objectives and Guidelines. The long-term objective is to be invested 65% in equity securities (equity mutual funds), 34% in debt securities (bond mutual funds) and 1% in cash equivalents. The bond fund portion may be temporarily increased to 50% in order to lessen the volatility of asset values. Asset rebalancing is performed at least annually, with interim adjustments made if the investment mix varies by more than 10% from the target allocation. The weighted average expected long-term rate of return is estimated based on current trends in the plan assets as well as projected future rates of returns on those assets. The long-term rate of return assumption was set based on historical returns earned by equities and fixed income securities, adjusted to reflect expectations of future returns as applied to the plan’s target allocation of asset classes. Equities and fixed income securities were assumed to earn real rates of return in the ranges of 6% to 8% and 3% to 5%, respectively. The long-term inflation rate was estimated to be 2.5%. When these overall return expectations are applied to the plan’s target allocation, the result is an expected rate of return of 7.50%. The plan is only permitted to invest in assets approved by the RSI Trustee Board. All other investments are prohibited. The Company’s actual pension plan asset allocation and target allocation by asset category are as follows: Percentage of Plan Target Assets at Year-End Asset Category Allocation 2018 2017 Equity mutual funds and common/collective trusts 65 % 67 % 65 % Fixed income common/collective trusts 34 % 32 % 34 % Cash equivalents 1 % 1 % 1 % Total 100 % 100 % 100 % Equity, Debt, Investment Funds and Other Securities The fair value of the plan assets at June 30, 2018 and 2017, by asset category, is as follows (in thousands): Fair Value Measurements Using Quoted Prices Significant In Active Other Significant Markets for Observable Unobservable Carrying Identical Assets Inputs Inputs Value (Level 1) (Level 2) (Level 3) June 30, 2018 Plan assets Equity mutual funds and common/collective trusts $ 18,914 $ - $ 18,914 $ - Fixed income common/collective trusts 8,893 - 8,893 - Cash equivalents 168 168 - - Total $ 27,975 $ 168 $ 27,807 $ - June 30, 2017 Plan assets Equity mutual funds and common/collective trusts $ 17,704 $ - $ 17,704 $ - Fixed income common/collective trusts 9,451 - 9,451 - Cash equivalents 289 289 - - Total $ 27,444 $ 289 $ 27,155 $ - Defined Contribution Retirement Plan 401(k) Plan Acquired Pension Plan Supplemental Retirement Plan The Company also maintains unfunded and non-qualified supplemental retirement plans to provide pension benefits in addition to those provided under the qualified pension plan. The accrued benefit cost for the supplemental plans was approximately $3.4 million and $3.0 million at June 30, 2018 and 2017 (included in other liabilities in the consolidated statements of financial condition). Included in accumulated other comprehensive income were pre-tax net losses of $335,000 and $379,000 for the supplemental retirement plans as of June 30, 2018 and 2017, respectively. The projected benefit obligation and accumulated benefit obligation were $3.4 million as of the June 30, 2018 measurement date and $3.0 million as of June 30, 2017 measurement date. Pension expense for the supplemental plans was $655,000, $615,000 and $539,000 for the years ended June 30, 2018, 2017 and 2016, respectively. Supplemental retirement plan benefits of $272,000 were paid in each of the years ended June 30, 2018, 2017 and 2016. Net periodic pension cost and other amounts recognized in other comprehensive income for the years ended June 30 (in thousands): 2018 2017 2016 Service cost $ 518 $ 398 $ 322 Interest cost 103 124 133 Amortization of prior net loss 34 93 84 Net periodic cost $ 655 $ 615 $ 539 The estimated net loss for the supplemental plans that will be amortized from accumulated other comprehensive income into net periodic benefit costs during the year ending June 30, 2019, is $37,000. The following benefit payments, which reflect expected future service, are expected for the years ending June 30 (in thousands): 2019 $ 272 2020 272 2021 3,336 2022 272 2023 272 Following five years 136 As of June 30, 2018, the assumed discount rates used for the supplemental plans range from 3.16% to 4.14%. Employee Stock Ownership Plan On January 1, 2017, the Company established an Employee Stock Ownership Plan (“ESOP”) to provide eligible employees the opportunity to own Company stock. The plan is a tax-qualified retirement plan for the benefit of Company employees. The Company granted a loan to the ESOP for the purchase of 1,453,209 shares of the Company’s common stock at a price of $10.00 per share. The loan obtained by the ESOP from the Company to purchase the common stock is payable annually over 15 years at a rate per annum equal to the Prime Rate, reset annually on January 1st (4.50% for 2018). Loan payments are principally funded by cash contributions from the Bank. The loan is secured by the shares purchased, which are held in a suspense account for allocation among participants as the loan is repaid. The balance of the ESOP loan at June 30, 2018 was $13.6 million. Contributions are allocated to eligible participants on the basis of compensation, subject to federal tax limits. The number of shares committed to be released annually is 96,881 through 2032. Shares held by the ESOP include the following (dollars in thousands): 2018 2017 Allocated to participants 144,923 26,975 Unearned 1,308,286 1,426,234 Total ESOP shares 1,453,209 1,453,209 Fair value of unearned shares $ 25,996 $ 24,332 Total compensation expense recognized in connection with the ESOP for the year ended June 30, 2018 and June 30, 2017 was $2.2 million and $454,000, respectively.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Jun. 30, 2018
Banking And Thrift [Abstract]
Regulatory Matters	Note 16 . Regulatory Matters The following is a summary of the Company’s and Bank’s actual capital amounts and ratios as of June 30, 2018 and June 30, 2017, compared to the required ratios for minimum capital adequacy and for classification as well capitalized (dollars in thousands): To Be Well Capitalized For Capital Under Prompt Adequacy Corrective Action Bank Actual Purposes Provisions Amount Ratio Amount Ratio Amount Ratio June 30, 2018: PCSB Bank Leverage (Tier 1) $ 200,488 13.6 % $ 58,924 4.0 % $ 73,655 5.0 % Risk-based: Common Tier 1 200,488 21.1 42,745 4.5 61,743 6.5 Tier 1 200,488 21.1 56,994 6.0 75,991 8.0 Total 205,392 21.6 75,991 8.0 94,989 10.0 PCSB Financial Corporation Leverage (Tier 1) $ 287,991 19.5 % $ 58,948 4.0 % N/A N/A Risk-based: Common Tier 1 287,991 30.3 42,783 4.5 N/A N/A Tier 1 287,991 30.3 57,044 6.0 N/A N/A Total 292,895 30.8 76,058 8.0 N/A N/A June 30, 2017: PCSB Bank Leverage (Tier 1) $ 190,990 13.7 % $ 55,949 4.0 % $ 69,936 5.0 % Risk-based: Common Tier 1 190,990 21.7 39,631 4.5 57,245 6.5 Tier 1 190,990 21.7 52,841 6.0 70,455 8.0 Total 196,140 22.3 70,455 8.0 88,069 10.0 PCSB Financial Corporation Leverage (Tier 1) $ 278,528 20.0 % $ 55,839 4.0 % N/A N/A Risk-based: Common Tier 1 278,528 31.6 39,631 4.5 N/A N/A Tier 1 278,528 31.6 52,841 6.0 N/A N/A Total 283,678 32.2 70,455 8.0 N/A N/A In addition to the ratios above, the Basel III Capital Rules established that community banking institutions must maintain a capital conservation buffer of common equity Tier 1 capital in an amount greater than 2.5% of total risk-weighted assets to avoid being subject to limitations on capital distributions and discretionary bonus payments to executive officers. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and will be phased in over a four-year period (increasing by that amount on each subsequent January 1, until it reaches 2.5% on January 1, 2019). Management believes that as of June 30, 2018 and June 30, 2017, the Bank and Company each met all capital adequacy requirements to which they were subject, including the capital conservation buffer of 1.875% as of June 30, 2018 and 1.250% as of June 30, 2017. Further, the most recent FDIC notification categorized the Bank as a well-capitalized institution under the prompt corrective action regulations. There have been no conditions or events since that notification that management believes have changed the Bank’s capital classification.

Related Party Disclosures

Related Party Disclosures	12 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Party Disclosures	Note 17 . Related Party Disclosures The Company's authority to extend credit to its directors, executive officers, and stockholders owning 10% or more of the Holding Company's outstanding common stock, as well as to entities controlled by such persons, is additionally governed by the requirements of Sections 22(g) and 22(h) of the FRA and Regulation O of the FRB enacted thereunder. Among other matters, these provisions require that extensions of credit to insiders: (i) be made on terms substantially the same as, and follow credit underwriting procedures not less stringent than, those prevailing for comparable transactions with unaffiliated persons and that do not involve more than the normal risk of repayment or present other unfavorable features; and (ii) not exceed certain amount limitations individually and in the aggregate, which limits are based, in part, on the amount of the bank's capital. Regulation O additionally requires that extensions of credit in excess of certain limits be approved in advance by the bank's board of directors. New York banking regulations impose certain limits and requirements on various transactions with "insiders," as defined in the New York banking regulations to include certain executive officers, directors and principal stockholders. For the year ended June 30, 2018 and 2017, the Company and the Bank had no insider loans.

Parent Company Only Financial S

Parent Company Only Financial Statements	12 Months Ended
	Jun. 30, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Parent Company Only Financial Statements	Note 18 The following are the financial statements of the Company (Parent only) as of and for the years ended June 30, 2018 and June 30, 2017 (in thousands). The Company was established as of December 9, 2016; therefore, financial information prior to that date is not available. June 30, 2018 2017 Assets Cash and cash equivalents $ 72,140 $ 71,273 Investment in Bank 200,058 192,308 ESOP Loan receivable 13,563 14,532 Other Assets 1,798 1,888 Total Assets $ 287,559 $ 280,001 Liabilities and stockholders' equity Other Liabilities $ - $ 155 Stockholders' equity 287,559 279,846 Total Liabilities and stockholders' equity $ 287,559 $ 280,001 Years Ended June 30, 2018 2017 Interest Income $ 668 $ 125 Equity in income of Bank 7,188 1,055 Contribution to PCSB Foundation — 5,000 Other non-interest expenses 689 105 Income (loss) before income tax 7,167 (3,925 ) Income tax expense (benefit) 563 (1,693 ) Net Income (loss) $ 6,604 $ (2,232 ) Year Ended June 30, 2018 2017 Cash Flows from Operating Activities: Net income (loss) $ 6,604 $ (2,232 ) Adjustments to reconcile net income to net cash provided by operating activities: Equity in income of Bank (7,188 ) (1,055 ) Issuance of common stock to PCSB Foundation — 3,387 Deferred tax expense (benefit) 733 (1,482 ) Net increase in accrued interest receivable (230 ) (113 ) Other adjustments, principally net changes in other assets and liabilities (569 ) (138 ) Net cash used in operating activities (650 ) (1,633 ) Cash Flows from Investing Activities: Investment in PCSB Bank — (87,350 ) Decrease (increase) in ESOP loan 969 (14,532 ) Net cash provided by (used in) investing activities 969 (101,882 ) Cash Flows from Financing Activities: Common stock dividends declared (504 ) — Allocation of ESOP shares 1,069 184 Issuance of common stock (17 ) 174,604 Net cash provided by financing activities 548 174,788 Net increase in cash and cash equivalents 867 71,273 Cash and cash equivalents at beginning of year 71,273 — Cash and cash equivalents at end of year $ 72,140 $ 71,273

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Jun. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Note 19 . Quarterly Financial Information (unaudited) 2018 2017 In thousands, except per share amounts Fourth Third Second First Fourth Third Second First Interest income $ 13,358 $ 11,648 $ 11,657 $ 11,297 $ 10,723 $ 10,276 $ 9,850 $ 10,109 Interest expense 1,926 1,505 1,471 1,421 1,318 1,318 1,323 1,334 Net interest income 11,432 10,143 10,186 9,876 9,405 8,958 8,527 8,775 Provision for loan losses 25 54 200 135 - 235 562 26 Non-interest income (1) 601 512 692 714 647 626 2,259 552 Non-interest expense (2) 8,264 7,833 8,125 7,894 12,859 6,580 7,794 7,198 Income before taxes 3,744 2,768 2,553 2,561 (2,807 ) 2,769 2,430 2,103 Income tax expense (3) 1,075 591 2,551 805 (1,017 ) 878 758 647 Net Income (loss) $ 2,669 $ 2,177 $ 2 $ 1,756 $ (1,790 ) $ 1,891 $ 1,672 $ 1,456 Earnings per share Basic $ 0.16 $ 0.13 $ - $ 0.10 N/A N/A N/A N/A Diluted $ 0.16 $ 0.13 $ - $ 0.10 N/A N/A N/A N/A (1) Non-interest income for the second quarter of 2017 includes a $1.6 million settlement on a loan charged-off by CMS Bank before the 2015 merger. (2) Non-interest expense for the fourth quarter of 2017 includes a $5.0 million contribution expense related to Company’s establishment of the PCSB Community Foundation. (3) Income tax expense for the second quarter of 2018 includes $1.6 million charge reflecting a re-measurement of our deferred tax assets resulting from a decrease in the corporate income tax rate from 34% to 21%.

Basis of Presentation (Policies

Basis of Presentation (Policies)	12 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations PCSB Bank is a community-oriented financial institution that provides financial services to individuals and businesses within its market area of Putnam, Southern Dutchess, Rockland and Westchester Counties in New York. The Bank is a state-chartered stock savings bank and its deposits are insured up to applicable limits by the Deposit Insurance Fund of the Federal Deposit Insurance Corporation (“FDIC”). The Bank’s primary regulators are the FDIC and the New York State Department of Financial Services.
Merger with CMS Bancorp	Merger with CMS Bancorp
Basis of Presentation	Basis of Presentation UpCounty Realty Corp. (formerly PCSB Realty Ltd.)
Use of Estimates	Use of Estimates
Cash Flows	Cash Flows
Securities	Securities Securities available for sale are reported at fair value. Unrealized gains and losses on securities available for sale are excluded from earnings and reported as accumulated other comprehensive income or loss (a separate component of equity), net of related income taxes. Premiums and discounts on debt securities are amortized to interest income on a level-yield basis over the terms of the securities. Realized gains and losses on sales of securities are determined based on the amortized cost of the specific securities sold. Management evaluates securities for other-than-temporary impairment (OTTI) on at least a quarterly basis, and more frequently when economic or market conditions warrant such an evaluation. For securities in an unrealized loss position, management considers the extent and duration of the unrealized loss, and the financial condition and near-term prospects of the issuer. Management also assesses whether it intends to sell, or it is more likely than not that it will be required to sell, a security in an unrealized loss position before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the entire difference between amortized cost and fair value is recognized as impairment through earnings. For debt securities that do not meet the aforementioned criteria, the amount of impairment is split into two components as follows: 1) OTTI related to credit loss, which must be recognized in the income statement and 2) OTTI related to other factors, which is recognized in other comprehensive income. The credit loss is defined as the difference between the present value of the cash flows expected to be collected and the amortized cost basis. For equity securities, the entire amount of impairment is recognized through earnings.
Loans	Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at the principal balance outstanding, net of deferred loan fees and costs, unamortized purchase premiums and discounts, and an allowance for loan losses. Interest income is accrued on the unpaid principal balance. Interest income on loans is discontinued at the time the loan is ninety days delinquent unless the loan is well secured and in process of collection. Loan purchase premiums and discounts are amortized over the contractual term of the loans Loan origination fees and certain direct loan origination costs are deferred and amortized to interest income as an adjustment to yield over the contractual term of the loans. Unamortized fees and costs on prepaid loans are recognized in interest income at the time of prepayment.
Purchased Credit Impaired Loans	Purchased Credit Impaired Loans Such purchased credit impaired loans are accounted for individually or aggregated into pools of loans based on common risk characteristics, such as credit score, loan type, and date of origination. The Company estimates the amount and timing of expected cash flows for each loan or pool, and the expected cash flows in excess of amount paid is recorded as interest income over the remaining life of the loan or pool (accretable yield). The excess of the loan’s or pool’s contractual principal and interest over expected cash flows is not recorded (nonaccretable difference). Over the life of the loan or pool, expected cash flows continue to be estimated. If the present value of expected cash flows is less than the carrying amount, an allowance is recorded as a provision for loan losses. If the present value of expected cash flows is greater than the carrying amount, it is recognized as part of future interest income.
Allowance For Loan Losses	Allowance for Loan Losses Establishing the allowance for loan losses involves significant management judgments utilizing the best information available at the time. Those judgments are subject to further examination by the Bank’s regulators. Future adjustments to the allowance for loan losses may be necessary based on changes in economic and real estate market conditions, further information obtained regarding known problem loans, the identification of additional problem loans, and other factors. The allowance consists of specific and general components. The specific component relates to loans that are individually classified as impaired. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. Impairment is measured on a loan-by-loan basis for loans evaluated under the Company’s normal loan review procedures. Loans evaluated on an individual basis for impairment may be measured by the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s observable market price, or the fair value of the collateral if the loan is collateral dependent. The Company’s impaired loans are generally collateral dependent. If the fair value of an impaired loan is less than its recorded investment, an impairment allowance is recognized and included in the allowance for loan losses. Troubled debt restructurings are separately identified for impairment disclosures and are measured at the present value of estimated future cash flows using the loan’s effective rate at inception. If a troubled debt restructuring is considered to be a collateral dependent loan, the loan is reported at the fair value of the collateral. For troubled debt restructurings that subsequently default, the Company determines the amount of reserve in accordance with the accounting policy for the allowance for loan losses. The general component of the allowance covers non-impaired loans and is based on historical loss experience adjusted for current factors. The historical loss experience is determined by portfolio segment and is based on the actual loss history experienced by the Company over a thirty-six month period, with heaviest weight placed on the most recent periods. This actual loss experience is supplemented with other economic factors based on the risks present for each portfolio segment. These economic factors include consideration of the following: lending policies, underwriting, charge-off and collection procedures; national and local economic trends and conditions; trends in nature and volume of the loan portfolio; experience, ability, and depth of lending management and other relevant staff; trends in delinquencies, classified loans and restructurings; quality of the loan review system and Board oversight; value of underlying collateral for collateral dependent loans; existence and effect of concentrations and levels; and effects of external factors, such as competition, legal and regulatory factors. The following portfolio segments have been identified: residential, commercial mortgage, construction, commercial, home equity and consumer and overdrafts. The risk characteristics of each of the identified portfolio segments are as follows: Residential Loans – residential loans are generally made on the basis of the borrower’s ability to make repayment from his or her employment income or other income, and are secured by real property whose value tends to be more easily ascertainable. Repayment of residential loans is subject to adverse employment conditions in the local economy leading to increased default rates and decreased market values from oversupply in a geographic area. In general, these loans depend on the borrower’s continuing financial stability and, therefore, are likely to be adversely affected by various factors, including job loss, divorce, illness, or personal bankruptcy. Furthermore, the application of various federal and state laws, including federal and state bankruptcy and insolvency laws, may limit the amount that can be recovered on such loans. Commercial Mortgage – commercial mortgage loans, including multifamily real estate loans, are secured by multifamily and nonresidential real estate and generally have larger balances and involve a greater degree of risk than residential real estate loans. Repayment of commercial mortgage loans depend on the global cash flow analysis of the borrower and the net operating income of the property, the borrower’s expertise, credit history and profitability, and the value of the underlying property. Of primary concern in commercial real estate lending is the borrower’s creditworthiness and the cash flow generated from the property securing the loan. As a result, repayment of such loans may be subject, to a greater extent than residential real estate loans, to adverse conditions in the real estate market or the economy. Commercial real estate is also subject to adverse market conditions that cause a decrease in market value or lease rates, obsolescence in location or function and market conditions associated with over supply of units in a specific region. Construction – construction financing is generally considered to involve a higher degree of risk of loss than long-term financing on improved, occupied real estate. Risk of loss on a construction loan depends largely upon the accuracy of the initial estimate of the property’s value at completion of construction and the estimated cost of construction. During the construction phase, a number of factors could result in delays and cost overruns. If the estimate of construction costs proves to be inaccurate, additional funds may be required to be advanced in excess of the amount originally committed to permit completion of the building. If the estimate of value proves to be inaccurate, the value of the building may be insufficient to assure full repayment if liquidation is required. If foreclosure is required on a building before or at completion due to a default, there can be no assurance that all of the unpaid balance of, and accrued interest on, the loan as well as related foreclosure and holding costs will be recovered. Commercial – commercial loans are generally of higher risk than other types of loans and typically are made on the basis of the borrower’s ability to make repayment from the cash flow of the borrower’s business. As a result, the availability of funds for the repayment of commercial loans may depend substantially on the success of the business itself. Furthermore, any collateral securing such loans may depreciate over time, may be difficult to appraise, and may fluctuate in value. Home Equity Lines of Credit – home equity lines of credit consist of both fixed and variable interest rate products. These are primarily home equity loans to residential mortgage customers within the footprint of the primary lending territory. These loans generally will not exceed a combined (i.e., first and second mortgage) loan-to-value ratio of 75 percent at origination. Consumer and overdraft loans – consumer loans generally have shorter terms and higher interest rates than one-to-four family mortgage loans. In addition, consumer loans expand the products and services we offer to better meet the financial services needs of our customers. Consumer loans generally involve greater credit risk than residential mortgage loans because of the difference in the underlying collateral. Repossessed collateral for a defaulted consumer loan may not provide an adequate source of repayment of the outstanding loan balance because of the greater likelihood of damage to, loss of, or depreciation in the underlying collateral. The remaining deficiency often does not warrant further substantial collection efforts against the borrower beyond obtaining a deficiency judgment. In addition, consumer loan collections depend on the borrower’s personal financial stability. Furthermore, the application of various federal and state laws, including federal and state bankruptcy and insolvency laws, may limit the amount that can be recovered on such loans.
Foreclosed Real Estate	Foreclosed Real Estate
Federal Home Loan Bank (FHLB) Stock	Federal Home Loan Bank (FHLB) Stock
Premises and Equipment	Premises and Equipment
Bank Owned Life Insurance (BOLI)	Bank Owned Life Insurance (BOLI)
Goodwill And Other Intangible Assets	Goodwill and Other Intangible Assets Other intangible assets, consisting of a core deposit intangible asset arising from a whole bank acquisition, are amortized on an accelerated method over their estimated useful lives of 10 years.
Loan Commitments And Related Financial Instruments	Loan Commitments and Related Financial Instruments
Income Taxes	Income Taxes Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in future years. The effect on deferred tax assets and liabilities of a change in tax laws or rates is recognized in the period that includes the enactment date of the change. A tax position is recognized as a benefit only if it is “more likely than not” that the tax position would be sustained in a tax examination, with a tax examination being presumed to occur. The amount recognized is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the “more likely than not” test, no tax benefit is recorded. The Company recognizes interest and/or penalties related to income tax matters in income tax expense.
Employee Benefit Plans	Employee Benefit Plans: Employee 401(k) expense is the amount of matching contributions. Pension expense is the net of service and interest cost, return on plan assets and amortization of gains and losses not immediately recognized. SERP expense is the net of interest cost and service cost, which allocates the benefits over years of service. The Holding Company and Bank maintain the PCSB Bank Employee Stock Ownership Plan (the “ESOP”). Compensation expense related to the ESOP is recorded during the period in which the shares become committed to be released to participants. The compensation expense is measured based upon the average fair market value of the stock during the period, and, to the extent that the fair value of the shares committed to be released differs from the original cost of such shares, the difference is recorded as an adjustment to additional paid-in capital.
Loss Contingencies	Loss Contingencies
Fair Value of Financial Instrument	Fair Value of Financial Instruments
Segment Reporting	Segment Reporting
Reclassification	Reclassifications
Earnings per share	Earnings per share
Recent Accounting Pronouncements	The pronouncements discussed below are not intended to be an all-inclusive list, but rather only those pronouncements that could potentially have a material impact on our financial position, results of operations or disclosures. In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09 “Revenue from Contracts with Customers,” and was later amended by ASU 2015-14, ASU 2016-08, ASU 2016-10, ASU 2016-12 and 2016-20. These updates provide a comprehensive framework for addressing revenue recognition issues that can be applied to all contracts with customers. The amendments also include improved disclosures to enable users of financial statements to better understand the nature, amount, timing and uncertainty of revenue that is recognized. While the guidance in ASU 2014-09 supersedes most existing industry-specific revenue recognition accounting guidance, much of PCSB Bank’s revenue comes from financial instruments such as debt securities and loans that are outside the scope of the guidance. The Company’s material revenue streams that are in the scope of ASU 2014-09 are fees on deposit accounts (including interchange fees) and foreclosed real estate gains and losses. All other revenue streams are immaterial or are in the scope of other GAAP requirements which take precedence and therefore are not in the scope of ASU 2014-09. Based on the Company’s analysis, ASU 2014-09 will not materially change the recognition of revenue on service fees on deposit accounts as the contracts are day to day and recognized as the service is provided. Gains and losses on the sale of foreclosed real estate are generally accounted for under ASC 610. However, ASU 2014-09 also added a new Subtopic 610-20 which addresses the recognition of gains and losses on the transfer of nonfinancial and in-substance nonfinancial assets. Gain and loss recognition is not expected to change except for foreclosed real estate and other nonfinancial asset sales that are financed by the Company. In the case of financed sales, the Company will need to evaluate each contract to determine whether each contract criteria are met, including whether it is probable that it will collect substantially all consideration to which it is entitled. The Company will also need to evaluate whether the financing terms offered to the buyer of the nonfinancial asset are market terms when determining the transaction price. The Company has evaluated the impact of ASU 2014-09 and the amendments upon adoption as of July 1, 2018. In evaluating this standard, management has determined that the majority of revenue earned by the Company is from revenue streams not included in the scope of this standard and for in scope revenue streams management determined that, based on the modified retrospective method, a cumulative-effect adjustment to opening retained earnings as a result of adopting this standard is not needed. ASU 2014-09 will require additional disclosures beginning with the quarter ending September 30, 2018. In January 2016, the FASB issued ASU 2016-01, an amendment to “Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendments in ASU 2016-01 are intended to improve the recognition, measurement, presentation and disclosure of financial assets and liabilities to provide users of financial statements with information that is more useful for decision-making purposes. Among other changes, ASU 2016-01 would: (1) require equity securities to be reclassified out of available for sale and measured at fair value with changes in fair value recognized through net income but would allow equity securities that do not have readily determinable fair values to be re-measured at fair value either upon the occurrence of an observable price change or upon identification of an impairment, (2) simplify the impairment assessment of such equity securities and would require enhanced disclosure about these investments, (3) require separate presentation of financial assets and liabilities by measurement category and type of instrument, such as securities or loans, on the balance sheet or in the notes, and would eliminate certain other disclosures relating to the methods and assumptions used to estimate fair value for financial assets measured at amortized cost on the balance sheet, and (4) require the use of an exit price notion when measuring the fair value of financial instruments. The Company has evaluated the impact of ASU 2016-01 and subsequent amendments upon adoption on July 1, 2018 and has concluded that there is not a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02 “Leases.” ASU 2016-02 affects any entity that enters into a lease and is intended to increase the transparency and comparability of financial statements among organizations. The ASU requires, among other changes, a lessee to recognize on its balance sheet a lease asset and a lease liability for those leases previously classified as operating leases. The lease asset would represent the right to use the underlying asset for the lease term and the lease liability would represent the discounted value of the required lease payments to the lessor. The ASU would also require entities to disclose key information about leasing arrangements. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2019, including interim periods within that fiscal year. Early adoption is permitted. The Company currently leases eleven branches and two administrative offices. ASU 2016-02 will result in the establishment of a right to use asset and corresponding lease obligation, the materiality of which has yet to be determined by management, however the ASU is not expected to have a material impact on the Company’s consolidated results of operations or disclosures. In June 2016, the FASB issued ASU 2016-13 “Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 affects entities holding financial assets that are not accounted for at fair value through net income, including loans, debt securities, and other financial assets. The ASU requires financial assets measured at amortized cost basis to be presented at the net amount expected to be collected by recording an allowance for current expected credit losses. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2020, including interim periods within that fiscal year. Early adoption is permitted beginning after December 15, 2018, including interim periods within those fiscal years. The Company is actively working through the provisions of the Update. Management has established a steering committee which is identifying the methodologies and the additional data requirements necessary to implement the Update and is evaluating the need for a third-party software service provider to assist in the Company's implementation. In January 2017, the FASB issued ASU 2017-04 “Intangibles – Goodwill and Other (Topic 350).” In March 2017, the FASB issued ASU 2017-07 “Compensation – Retirement Benefits”. The ASU requires companies that offer employee defined pension plans, other postretirement benefit plans, or other types of benefit plans accounted for under Topic 715 to report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. Management has evaluated the impact of ASU 2017-07 upon adoption on July 1, 2018 and has concluded that there is not a material impact on the Company’s consolidated financial statements. In March 2017, the FASB issued ASU 2017-08 "Receivables - Non-Refundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities." The ASU requires premiums on callable debt securities to be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments in this update will be effective for the Company for the fiscal year beginning on July 1, 2020, including interim periods within that fiscal year. Early adoption is permitted beginning after December 15, 2018, including interim periods within those fiscal years. ASU 2017-08 will not have a material impact on the Company’s consolidated financial position, results of operations or disclosures. On February 14, 2018, the FASB issued ASU 2018-02 "Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of certain tax effects from accumulated other comprehensive income." The ASU intended to help organizations reclassify certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017. The ASU requires the reclassification of stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the TAX Cuts and Job Act 2017 (or portion thereof) is recorded. The amount of the reclassification is the difference between the historical corporate income tax rate (34 percent) and the newly enacted 21 percent corporate income tax rate. The Company has elected to early adopt the ASU as of March 31, 2018, resulting in a $1.1 million reclassification between accumulated other comprehensive income and retained earnings. There is no impact to current earnings and no prior period information has been retroactively adjusted as a result of implementing the ASU. No additional reclassifications will be required in the future periods as a result of this guidance. The ASU is applied specifically to the impacts of the Tax Cuts and Jobs Act of 2017 and is not effective for other or future state or federal tax law changes.

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Schedule of Amortized Cost, Gross Unrealized/Unrecognized Gains and Losses and Fair Value of Available for Sale and Held to Maturity Securities	The amortized cost, gross unrealized/unrecognized gains and losses and fair value of available for sale and held to maturity securities at June 30, 2018 and 2017 were as follows: June 30, 2018 Amortized Gross Unrealized/Unrecognized Fair Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government and agency obligations $ 64,389 $ - $ (959 ) $ 63,430 Corporate and other debt securities 8,406 - (171 ) 8,235 Mortgage-backed securities – residential 34,619 81 (893 ) 33,807 Equity securities 32 - - 32 Total available for sale $ 107,446 $ 81 $ (2,023 ) $ 105,504 Held to maturity: U.S. Government and agency obligations $ 122,048 $ - $ (2,274 ) $ 119,774 Corporate and other debt securities 4,000 - (126 ) 3,874 Mortgage-backed securities – residential 140,478 32 (4,846 ) 135,664 Mortgage-backed securities – collateralized mortgage obligations 53,547 - (1,815 ) 51,732 Mortgage-backed securities – commercial 33,110 11 (977 ) 32,144 Total held to maturity $ 353,183 $ 43 $ (10,038 ) $ 343,188 June 30, 2017 Amortized Gross Unrealized/Unrecognized Fair Cost Gains Losses Value (Dollars in thousands) Available for sale: U.S. Government and agency obligations $ 63,630 $ 31 $ (216 ) $ 63,445 Corporate and other debt securities 8,460 58 (36 ) 8,482 Mortgage-backed securities – residential 39,710 363 (143 ) 39,930 Equity securities 32 - - 32 Total available for sale $ 111,832 $ 452 $ (395 ) $ 111,889 Held to maturity: U.S. Government and agency obligations $ 155,559 $ 23 $ (574 ) $ 155,008 Corporate and other debt securities 999 - - 999 Mortgage-backed securities – residential 143,452 828 (497 ) 143,783 Mortgage-backed securities – collateralized mortgage obligations 59,476 146 (235 ) 59,387 Mortgage-backed securities – commercial 24,065 412 (66 ) 24,411 Total held to maturity $ 383,551 $ 1,409 $ (1,372 ) $ 383,588
Fair Value and Carrying Amount of Debt Securities by Contractual Maturity	The following table presents the fair value and carrying amount of debt securities at June 30, 2018 and 2017, by contractual maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Held to maturity Available for sale Carrying Fair Amortized Fair Amount Value Cost Value (in thousands) June 30, 2018: 1 year or less $ 25,504 $ 25,342 $ 12,402 $ 12,353 1 to 5 years 96,544 94,432 58,393 57,335 5 to 10 years - - 2,000 1,977 Mortgage-backed securities and other 231,135 223,414 34,619 33,807 Total $ 353,183 $ 343,188 $ 107,414 $ 105,472 Held to maturity Available for sale Carrying Fair Amortized Fair Amount Value Cost Value (in thousands) June 30, 2017: 1 year or less $ 50,486 $ 50,413 $ 16,005 $ 15,988 1 to 5 years 106,073 105,594 54,085 53,975 5 to 10 years - - 2,000 1,964 Mortgage-backed securities and other 226,992 227,581 39,710 39,930 Total $ 383,551 $ 383,588 $ 111,800 $ 111,857
Investment Securities with Fair Value and Unrealized Losses	The following table provides information regarding investment securities with unrealized/unrecognized losses, aggregated by investment category and length of time that individual securities had been in a continuous unrealized loss position at June 30, 2018 and 2017: June 30, 2018 Less than 12 months Greater than 12 months Total Unrealized/ Unrealized/ Unrealized/ Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Loss Value Loss Value Loss (in thousands) Available for sale: U.S. Government and agency obligations $ 41,762 $ (569 ) $ 21,668 $ (390 ) $ 63,430 $ (959 ) Corporate and other debt securities 6,258 (148 ) 1,977 (23 ) 8,235 (171 ) Mortgage-backed securities – residential 13,397 (379 ) 14,718 (514 ) 28,115 (893 ) Total available for sale $ 61,417 $ (1,096 ) $ 38,363 $ (927 ) $ 99,780 $ (2,023 ) Held to maturity: U.S. Government and agency obligations $ 46,163 $ (871 ) $ 71,611 $ (1,403 ) $ 117,774 $ (2,274 ) Corporate and other debt securities 3,874 (126 ) - - 3,874 (126 ) Mortgage-backed securities – residential 102,496 (3,338 ) 32,490 (1,508 ) 134,986 (4,846 ) Mortgage-backed securities – collateralized mortgage obligations 31,124 (884 ) 20,608 (931 ) 51,732 (1,815 ) Mortgage-backed securities – commercial 21,762 (582 ) 8,629 (395 ) 30,391 (977 ) Total held to maturity $ 205,419 $ (5,801 ) $ 133,338 $ (4,237 ) $ 338,757 $ (10,038 ) June 30, 2017 Less than 12 months Greater than 12 months Total Unrealized/ Unrealized/ Unrealized/ Fair Unrecognized Fair Unrecognized Fair Unrecognized Value Loss Value Loss Value Loss (in thousands) Available for sale U.S. Government and agency obligations $ 41,900 $ (200 ) $ 3,993 $ (16 ) $ 45,893 $ (216 ) Corporate and other debt securities 1,964 (36 ) - - 1,964 (36 ) Mortgage-backed securities – residential 18,861 (111 ) 3,200 (32 ) 22,061 (143 ) Total available for sale $ 62,725 $ (347 ) $ 7,193 $ (48 ) $ 69,918 $ (395 ) Held to maturity U.S. Government and agency obligations $ 113,511 $ (531 ) $ 5,981 $ (43 ) $ 119,492 $ (574 ) Corporate and other debt securities 999 - - - 999 0 Mortgage-backed securities – residential 39,754 (467 ) 1,626 (30 ) 41,380 (497 ) Mortgage-backed securities – collateralized mortgage obligations 26,622 (141 ) 4,444 (94 ) 31,066 (235 ) Mortgage-backed securities – commercial 9,092 (66 ) - - 9,092 (66 ) Total held to maturity $ 189,978 $ (1,205 ) $ 12,051 $ (167 ) $ 202,029 $ (1,372 )

Loans Receivable (Tables)

Loans Receivable (Tables)	12 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Summary of Loans Receivable	Loans receivable are summarized as follows at June 30 (in thousands): June 30, 2018 2017 Mortgage loans: Residential $ 250,578 $ 217,778 Commercial 495,265 437,651 Construction 17,352 22,404 Net deferred loan origination costs 1,041 397 Total mortgages 764,236 678,230 Commercial and consumer loans: Commercial loans 104,135 93,631 Home equity lines of credit 37,395 41,927 Consumer and overdrafts 745 233 Net deferred loan origination costs 729 777 Total commercial and consumer loans 143,004 136,568 Total loans receivable 907,240 814,798 Allowance for loan losses (4,904 ) (5,150 ) Loans receivable, net $ 902,336 $ 809,648
Summary of Activity in Allowance for Loan Losses by Portfolio Segment	The following tables present the activity in the allowance for loan losses by portfolio segment for the years ended June 30, 2018, 2017 and 2016 (in thousands): For the year ended June 30, 2018 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 360 $ 161 $ (136 ) $ 1 $ 386 Commercial 2,589 114 - 370 3,073 Construction 1,150 352 (997 ) - 505 Commercial loans 949 (335 ) (54 ) 220 780 Home equity lines of credit 76 45 (60 ) 19 80 Consumer and overdrafts - 30 (23 ) - 7 Acquired: - Residential 26 47 - - 73 Total $ 5,150 $ 414 $ (1,270 ) $ 610 $ 4,904 For the year ended June 30, 2017 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 237 $ 290 $ (237 ) $ 70 $ 360 Commercial 2,149 421 - 19 2,589 Construction 269 989 (108 ) - 1,150 Commercial loans 1,313 (944 ) (741 ) 1,321 949 Home equity lines of credit 73 3 - - 76 Consumer and overdrafts 1 (5 ) - 4 - Acquired: - Residential - 64 (38 ) - 26 Commercial loans - 2 (2 ) - - Consumer and overdrafts - 3 (3 ) - - Total $ 4,042 $ 823 $ (1,129 ) $ 1,414 $ 5,150 For the year ended June 30, 2016 Beginning Allowance Provision (Credit) Charge-offs Recoveries Ending Allowance Originated: Residential $ 193 $ 444 $ (400 ) $ - $ 237 Commercial 1,766 215 (10 ) 178 2,149 Construction 100 (23 ) - 192 269 Commercial loans 1,793 1,172 (1,677 ) 25 1,313 Home equity lines of credit 69 28 (24 ) - 73 Consumer and overdrafts - 23 (22 ) - 1 Total $ 3,921 $ 1,859 $ (2,133 ) $ 395 $ 4,042
Summary of Balance in Allowance for Loan Losses and Recorded investment in Loans by Portfolio Segment, and Based on Impairment Method	The following tables present the balance in the allowance for loan losses and the recorded investment in loans, excluding net deferred fees and accrued interest, by portfolio segment, and based on impairment method as of June 30, 2018 and June 30, 2017 (in thousands): June 30, 2018 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Residential $ 2,360 $ 246,913 $ 1,305 $ 250,578 $ 154 $ 232 $ 73 $ 459 Commercial 1,683 492,105 1,477 495,265 - 3,073 - 3,073 Construction 2,260 15,092 - 17,352 276 229 - 505 Commercial loans 2,451 101,684 - 104,135 9 771 - 780 Home equity lines of credit 360 36,867 168 37,395 12 68 - 80 Consumer and overdrafts - 745 - 745 - 7 - 7 Total $ 9,114 $ 893,406 $ 2,950 $ 905,470 $ 451 $ 4,380 $ 73 $ 4,904 June 30, 2017 Loans Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Acquired With Deteriorated Credit Quality Total Residential $ 4,471 $ 211,983 $ 1,324 $ 217,778 $ 131 $ 229 $ 26 $ 386 Commercial 2,411 433,416 1,824 437,651 - 2,589 - 2,589 Construction 3,661 18,743 - 22,404 997 153 - 1,150 Commercial loans 6,169 87,420 42 93,631 9 940 - 949 Home equity lines of credit 610 41,140 177 41,927 5 71 - 76 Consumer and overdrafts - 233 - 233 - - - - Total $ 17,322 $ 792,935 $ 3,367 $ 813,624 $ 1,142 $ 3,982 $ 26 $ 5,150
Summary of Loans Individually Evaluated for Impairment (Excluding Loans Acquired with Deteriorated Credit Quality) by Class of Loans	The following tables present information related to loans individually evaluated for impairment (excluding loans acquired with deteriorated credit quality) by class of loans as of and for the years ended June 30, 2018, 2017 and 2016 (in thousands): June 30, 2018 Unpaid Principal Balance Recorded Investment Allowance for Loan Losses With no related allowance recorded: Residential $ 1,659 $ 1,576 $ - Commercial 1,765 1,683 - Commercial loans 2,254 2,098 - Home equity lines of credit 341 341 - With an allowance recorded: Residential 742 784 154 Construction 3,257 2,260 276 Commercial loans 353 353 9 Home equity lines of credit 84 19 12 Total $ 10,455 $ 9,114 $ 451 June 30, 2017 Unpaid Principal Balance Recorded Investment Allowance for Loan Losses With no related allowance recorded: Residential $ 4,216 $ 4,014 $ - Commercial 2,935 2,411 - Construction 404 404 - Commercial loans 9,433 4,979 - Home equity lines of credit 599 599 - With an allowance recorded: Residential 395 457 131 Construction 3,257 3,257 997 Commercial loans 1,190 1,190 9 Home equity lines of credit 11 11 5 Total $ 22,440 $ 17,322 $ 1,142
Summary of Average Recorded Investment and Interest Income Recognized on Loans Individually Evaluated for Impairment, by Class of Loans	For the year ended For the year ended For the year ended June 30, 2018 June 30, 2017 June 30, 2016 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized With no related allowance recorded: Residential $ 3,041 $ 184 $ 4,238 $ 42 $ 5,577 $ 6 Commercial 2,350 248 2,448 137 9,324 88 Construction 93 17 406 12 13 - Commercial loans 3,457 1,049 5,065 239 10,755 71 Home equity lines of credit 507 22 599 (2 ) 430 - With an allowance recorded: Residential 453 15 432 15 - - Construction 2,720 - 3,015 71 132 - Commercial loans 1,491 66 1,224 61 422 12 Home equity lines of credit 11 - 11 - - - Total $ 14,123 $ 1,601 $ 17,438 $ 575 $ 26,653 $ 177
Nonaccrual Loans and in Loans Past Due over 90 Days Still on Accrual Status by Class of Loans	The following table presents the recorded investment in nonaccrual loans and in loans past due over 90 days still on accrual status, by class of loans as of June 30, 2018 and June 30, 2017 (in thousands): Loans Past Due Over 90 Days Nonaccrual and Still Accruing June 30, June 30, June 30, June 30, 2018 2017 2018 2017 Originated: Residential $ 604 $ 2,581 $ - $ - Commercial 262 - - - Construction 2,260 3,661 - - Commercial loans 788 2,959 - - Home equity lines of credit 45 302 - - Acquired: Residential 1,308 1,776 - - Commercial 532 497 - - Home equity lines of credit 303 296 - - Total $ 6,102 $ 12,072 $ - $ -
Aging of Recorded Investment in Past Due Loans by Class of Loans	The following tables present the aging of the recorded investment in past due loans by class of loans as of June 30, 2018 and June 30, 2017 (in thousands): June 30, 2018 90 Days or 30-59 60-89 More Past Total Past Days Past Due Days Past Due Due Due Current Total Originated: Residential $ - $ 394 $ 210 $ 604 $ 194,986 $ 195,590 Commercial - - 262 262 420,320 420,582 Construction - - 2,260 2,260 15,092 17,352 Commercial loans - - 500 500 102,767 103,267 Home equity lines of credit - - 45 45 32,311 32,356 Consumer and overdrafts - - - - 733 733 Total originated - 394 3,277 3,671 766,209 769,880 Acquired: Residential - 232 1,806 2,038 52,950 54,988 Commercial - - 1,112 1,112 73,571 74,683 Construction - - - - - - Commercial loans - - - - 868 868 Home equity lines of credit 30 - 296 326 4,713 5,039 Consumer and overdrafts - - - - 12 12 Total acquired 30 232 3,214 3,476 132,114 135,590 Total $ 30 $ 626 $ 6,491 $ 7,147 $ 898,323 $ 905,470 June 30, 2017 90 Days or 30-59 60-89 More Past Total Past Days Past Due Days Past Due Due Due Current Total Originated: Residential $ 94 $ 275 $ 1,973 $ 2,342 $ 153,390 $ 155,732 Commercial - - - - 355,247 355,247 Construction - - 3,661 3,661 18,743 22,404 Commercial loans - - 544 544 88,449 88,993 Home equity lines of credit - 199 103 302 35,246 35,548 Consumer and overdrafts - - - - 211 211 Total originated 94 474 6,281 6,849 651,286 658,135 Acquired: Residential 237 463 1,472 2,172 59,874 62,046 Commercial - - 1,054 1,054 81,350 82,404 Construction - - - - - - Commercial loans - - - - 4,638 4,638 Home equity lines of credit - - 296 296 6,083 6,379 Consumer and overdrafts - - - 22 22 Total acquired 237 463 2,822 3,522 151,967 155,489 Total $ 331 $ 937 $ 9,103 $ 10,371 $ 803,253 $ 813,624
Summary of Loans by Class Modified in Troubled Debt Restructurings	The following table presents loans by modified in troubled debt restructurings that occurred during the years ended June 30, 2018, 2017 and 2016 (dollars in thousands): Number of loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Year ended June 30, 2018: Commercial loans 1 $ 275 $ 289 Total 1 $ 275 $ 289 Year ended June 30, 2017: Residential 1 $ 165 $ 210 Commercial loans 1 276 276 Total 2 $ 441 $ 486 Year ended June 30, 2016: Residential 3 $ 1,697 $ 1,697 Commercial 1 1,178 1,178 Commercial loans 1 64 64 Home equity lines of credit 1 200 200 Total 4 $ 3,139 $ 3,139
Summary of Risk Category of Loans by Class of Loans	Based on the most recent analysis performed, the risk category of loans by class of loans is as follows (in thousands): June 30, 2018 Pass Special Mention Substandard Total Originated: Residential $ 194,341 $ 571 $ 678 $ 195,590 Commercial 418,370 - 2,212 420,582 Construction 15,092 - 2,260 17,352 Commercial loans 98,205 167 4,895 103,267 Home equity lines of credit 32,167 144 45 32,356 Consumer and overdrafts 733 - - 733 Total originated 758,908 882 10,090 769,880 Acquired: Residential 51,858 249 2,881 54,988 Commercial 71,832 842 2,009 74,683 Construction - - - - Commercial loans 857 11 - 868 Home equity lines of credit 4,641 - 398 5,039 Consumer and overdrafts 12 - - 12 Total acquired 129,200 1,102 5,288 135,590 Total $ 888,108 $ 1,984 $ 15,378 $ 905,470 June 30, 2017 Pass Special Mention Substandard Total Originated: Residential $ 153,165 $ - $ 2,567 $ 155,732 Commercial 352,203 134 2,910 355,247 Construction 18,743 - 3,661 22,404 Commercial loans 79,406 - 9,587 88,993 Home equity lines of credit 35,246 58 244 35,548 Consumer and overdrafts 211 - 211 Total originated 638,974 192 18,969 658,135 Acquired: Residential 58,665 - 3,381 62,046 Commercial 80,082 - 2,322 82,404 Construction - - - - Commercial loans 4,638 - - 4,638 Home equity lines of credit 5,906 - 473 6,379 Consumer and overdrafts 22 - - 22 Total acquired 149,313 - 6,176 155,489 Total $ 788,287 $ 192 $ 25,145 $ 813,624
Schedule of Carrying Amount of Purchased Credit Impaired Loans	The carrying amount of those loans as of June 30, 2018 and 2017 is as follows (in thousands): June 30, June 30, 2018 2017 Residential $ 1,232 $ 1,298 Commercial 1,477 1,824 Commercial loans - 42 Home equity lines of credit 168 177 Carrying amount, net of allowance of $73 and $26, respectively $ 2,877 $ 3,341
Summary of Accretable Yield, or Income Expected to be Collected for Acquired Loans	Accretable yield, or income expected to be collected, for acquired loans is as follows (in thousands): Year ended June 30, 2018 2017 2016 Beginning balance $ 403 $ 578 $ 713 New loans acquired - - - Accretion income (70 ) (190 ) (185 ) Reclassification from non-accretable difference 5 15 132 Disposals (93 ) - (82 ) Ending balance $ 245 $ 403 $ 578

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Jun. 30, 2018
Property Plant And Equipment [Abstract]
Summary of Premises and Equipment	Premises and equipment are summarized as follows at June 30 (in thousands): 2018 2017 Land $ 1,997 $ 1,997 Building and Leasehold improvements 13,430 11,128 Furniture, fixtures and equipment 6,096 5,841 Construction and improvements in process 355 3,015 21,878 21,981 Less: accumulated depreciation and amortization (10,280 ) (9,022 ) Total Bank premises and equipment, net $ 11,598 $ 12,959

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Jun. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Change in Goodwill	The change in goodwill during the years ended June 30, 2018, 2017 and 2016 are as follows (in thousands): 2018 2017 2016 Balance at July 1 $ 6,106 $ 6,106 $ 5,843 Adjustment to CMS goodwill - - 263 Impairment - - - Total at June 30 $ 6,106 $ 6,106 $ 6,106
Schedule of Acquired Intangible Assets	Acquired Intangible Assets: Acquired intangible assets were as follows at June 30 (in thousands): 2018 2017 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Amortized intangible assets: Core deposit intangible $ 887 $ (454 ) $ 887 $ (328 )
Schedule of Estimated Amortization Expense	Estimated amortization expense for each of the next five fiscal years ended June 30 (in thousands): 2019 $ 110 2020 94 2021 78 2022 62 2023 46

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Jun. 30, 2018
Deposits [Abstract]
Summary of Deposit Balances	Deposit balances are summarized as follows at June 30, 2018 and 2017 (in thousands): 2018 2017 Demand $ 131,883 $ 136,361 NOW Accounts 117,875 115,527 Money market accounts 49,885 29,097 Savings 465,441 512,697 Time deposits 392,373 294,779 Total $ 1,157,457 $ 1,088,461
Scheduled Maturities of Time Deposits	Scheduled maturities of time deposits were as follows as of June 30, 2018 and 2017 and exclude fair value adjustments on acquired time deposits (in thousands): 2018 2017 Within 1 year $ 183,276 $ 107,097 1 year to 2 years 49,350 62,331 2 years to 3 years 56,746 31,143 3 years to 4 years 56,458 41,508 4 years to 5 years 46,339 52,503 Thereafter 204 197 Total $ 392,373 $ 294,779

FHLB and Other Borrowings (Tabl

FHLB and Other Borrowings (Tables)	12 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Maturity Schedule of Advances	The maturity schedule of advances is summarized as follows as of June 30 (dollars in thousands): 2018 2017 Amount Due Weighted Avg. Rate Amount Due Weighted Avg. Rate Within 1 year $ 10,125 1.70 % $ 23,757 1.27 % 1 year to 2 years 5,128 1.81 10,125 1.70 2 years to 3 years 131 2.62 5,128 1.81 3 years to 4 years 135 2.62 131 2.62 4 years to 5 years 138 2.62 135 2.62 Thereafter 3,184 2.62 3,322 2.62 Total $ 18,841 1.91 % $ 42,598 1.55 %

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Contract Amounts of Credit-related Financial Instruments	The contract amounts of credit-related financial instruments at June 30, 2018 and 2017, are summarized below (in thousands): 2018 2017 Commitments to originate loans $ 102,644 $ 77,600 Unused lines of credit 56,553 45,439 Standby letter of credit 1,420 705
Summary of Rent Commitments Before Considering Renewal Options	Rent commitments, before considering renewal options that generally are present, were as follows as of June 30, 2018 (in thousands): Within 1 year $ 2,145 1 year to 2 years 2,026 2 year to 3 years 1,737 3 year to 4 years 1,675 4 year to 5 years 1,639 Thereafter 8,283 Total $ 17,505

Comprehensive Income (Tables)

Comprehensive Income (Tables)	12 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Summary of Accumulated Other Comprehensive Income (Loss)	The following is a summary of the accumulated other comprehensive income (loss) balances, net of tax (in thousands): Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2017 $ 37 $ (5,002 ) $ (250 ) $ (5,215 ) Other comprehensive income before reclassifications (1,835 ) 335 10 (1,490 ) Amounts reclassified from accumulated other comprehensive income (164 ) 725 34 595 Tax effect 558 (270 ) (11 ) 277 Net other comprehensive income (1,441 ) 790 33 (618 ) Reclassification of certain tax effects on other comprehensive income (1) (132 ) (938 ) (47 ) (1,117 ) Balance at June 30, 2018 $ (1,536 ) $ (5,150 ) $ (264 ) $ (6,950 ) Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2016 $ 523 $ (7,683 ) $ (810 ) $ (7,970 ) Other comprehensive income before reclassifications (735 ) 3,973 (755 ) 2,483 Amounts reclassified from accumulated other comprehensive income — 89 93 182 Tax effect 249 (1,381 ) 1,222 90 Net other comprehensive income (486 ) 2,681 560 2,755 Balance at June 30, 2017 $ 37 $ (5,002 ) $ (250 ) $ (5,215 ) Net unrealized gain (loss) on available for sale securities Unrealized loss on pension benefits Unrealized loss on SERP benefits Total Balance at July 1, 2015 $ 323 $ (4,311 ) $ (734 ) $ (4,722 ) Other comprehensive income before reclassifications 255 (5,022 ) 89 (4,678 ) Amounts reclassified from accumulated other comprehensive income — 398 84 482 Tax effect (55 ) 1,252 (249 ) 948 Net other comprehensive income 200 (3,372 ) (76 ) (3,248 ) Balance at June 30, 2016 $ 523 $ (7,683 ) $ (810 ) $ (7,970 ) (1) Represents the impact of adopting ASU 2018-02 requiring the reclassification of certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017 from accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act of 2017 (or portion thereof) is recorded. The amount of the reclassification is the difference between the historical corporate income tax rate (34 percent) and the newly enacted 21 percent corporate income tax rate. The reclassification is as of March 31, 2018; no prior period information has been retroactively adjusted as a result of implementing the ASU.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share	Year ended June 30, 2018 (dollars in thousands, except per share data) Net income applicable to common stock $ 6,604 Average number of common shares outstanding 18,165,110 Less: Average unallocated ESOP shares 1,362,216 Average number of common shares outstanding used to calculate basic earnings per common share 16,802,894 Earnings per Common share: Basic $ 0.39 Diluted $ 0.39

Fair Value of Financial Instr38

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Measured at Fair Value	Assets and liabilities measured at fair value are summarized below (in thousands): Fair Value Measurements Level 1 Level 2 Level 3 Total June 30, 2018: Measured on a recurring basis: Available for sale securities: U.S. Government and agency obligations $ - $ 63,430 $ - $ 63,430 Corporate and other debt securities - 8,235 - 8,235 Mortgage-backed securities – residential - 33,807 - 33,807 Equity securities - 32 - 32 Total assets at fair value $ - $ 105,504 $ - $ 105,504 Measured on a non-recurring basis: Impaired loans: Residential mortgages $ - $ - $ 688 $ 688 Construction - - 1,984 1,984 Commercial loans - - 845 845 Home equity lines of credit - - 7 7 Foreclosed real estate - - 460 460 Total assets at fair value $ - $ - $ 3,984 $ 3,984 Fair Value Measurements Level 1 Level 2 Level 3 Total June 30, 2017 Measured on a recurring basis: Available for sale securities: U.S. Government and agency obligations $ - $ 63,445 $ - $ 63,445 Corporate and other debt securities - 8,482 - 8,482 Mortgage-backed securities – residential - 39,930 - 39,930 Equity securities - 32 - 32 Total assets at fair value $ - $ 111,889 $ - $ 111,889 Measured on a non-recurring basis: Impaired loans: Residential mortgages $ - $ - $ 1,126 $ 1,126 Construction - - 2,260 2,260 Commercial loans - - 1,681 1,681 Home equity lines of credit - - 5 5 Foreclosed real estate - - 977 977 Total assets at fair value $ - $ - $ 6,049 $ 6,049
Summary of Quantitative Information about Level 3 Fair Value Measurements for Selected Financial Instruments Measured at Fair Value on Non-recurring Basis	The following tables present quantitative information about Level 3 fair value measurements for selected financial instruments measured at fair value on a non-recurring basis at June 30, 2018 and June 30, 2017 (dollars in thousands): Valuation Unobservable Range or Fair Value Technique(s) Input(s) Rate Used June 30, 2018: Impaired loans - residential mortgages $ 688 Sales comparison Adjustments for differences in sales comparables -5.1% to 20.9% Discounted cash flow Discount rate 5.4% to 6.3% Impaired loans - construction 1,984 Sales contract Discount to sales contract 9.8% Impaired loans - commercial loans 845 Discounted cash flow Discount rate 5.3% to 7.5% Sales contract Discount to sales contract 9.8% Impaired loans - home equity lines of credit 7 Sales comparison Adjustments for differences in sales comparables -5.1% to 20.9% Discounted cash flow Discount rate 6.3% Foreclosed real estate 460 Sales comparison Adjustments for differences in sales comparables -8.1% to -0.4% June 30, 2017: Impaired loans - residential mortgages $ 1,126 Sales comparison Adjustments for differences in sales comparables -5.1% to 7.8% Discounted cash flow Discount rate 5.4% to 6.3% Impaired loans - construction 2,260 Cost approach Discount for distressed property 50.0% Impaired loans - commercial loans 1,681 Discounted cash flow Discount rate 6.0% to 7.5% Sales comparison Adjustments for differences in sales comparables 0.0% Impaired loans - home equity lines of credit 5 Discounted cash flow Discount rate 6.3% Foreclosed real estate 977 Sales comparison Adjustments for differences in sales comparables -23.4% to 7.2%
Summary of Carrying Amounts and Estimated Fair Values of Bank's Financial Assets and Liabilities	The following is a summary of the carrying amounts and estimated fair values of the Company’s financial assets and liabilities (none of which are held for trading purposes) (in thousands): Carrying Fair Value Measurements Amount Level 1 Level 2 Level 3 Total June 30, 2018: Financial assets: Cash and cash equivalents $ 62,145 $ 62,145 $ - $ - $ 62,145 Investment securities held to maturity 353,183 - 343,188 - 343,188 Investment securities available for sale 105,504 - 105,504 - 105,504 Loans receivable, net 902,336 - - 882,319 882,319 Accrued interest receivable 4,358 - 1,402 2,956 4,358 Federal Home Loan Bank stock 2,050 N/A N/A N/A N/A Financial liabilities: Demand, NOW, money market deposits and savings accounts 765,084 765,084 - - 765,084 Time deposits 392,373 - 394,205 - 394,205 Mortgage escrow funds 8,803 8,803 - - 8,803 FHLB advances 18,841 - 20,574 - 20,574 June 30, 2017: Financial assets: Cash and cash equivalents $ 60,486 $ 60,486 $ - $ - $ 60,486 Investment securities held to maturity 383,551 - 383,318 270 383,588 Investment securities available for sale 111,889 - 111,889 - 111,889 Loans receivable, net 809,648 - - 817,814 817,814 Accrued interest receivable 3,693 - 1,243 2,450 3,693 Federal Home Loan Bank stock 3,132 N/A N/A N/A N/A Financial liabilities: Demand, NOW, money market deposits and savings accounts 793,681 793,681 - - 793,681 Time deposits 294,780 - 297,508 - 297,508 Mortgage escrow funds 8,084 8,084 - - 8,084 FHLB advances 42,598 - 45,504 - 45,504

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) are summarized as follows for the years ended June 30 (in thousands): 2018 2017 2016 Current tax expense (benefit) Federal $ 2,577 $ 1,344 $ (6 ) State 20 (52 ) (476 ) 2,597 1,292 (482 ) Deferred tax expense (benefit) Federal 2,414 (52 ) 1,216 State 313 (21 ) 250 2,727 (73 ) 1,466 State tax valuation allowances, net of federal benefit (302 ) 47 149 Total $ 5,022 $ 1,266 $ 1,133
Schedule of Effective Income Tax Rate Reconciliation	Effective tax rates differ from federal statutory rate applied to income before income taxes due to the following (in thousands): 2018 2017 2016 Federal statutory rate 28.06 % 34.00 % 34.00 % Tax at federal statutory rate $ 3,262 $ 1,529 $ 1,380 State Taxes, net of federal benefit 24 — — Tax-exempt income (61 ) (47 ) (49 ) BOLI income (157 ) (211 ) (156 ) ESOP Compensation 300 63 — Deferred tax re-remeasurement charge 1,570 — — Other, net 84 (68 ) (42 ) Total $ 5,022 $ 1,266 $ 1,133 Effective tax rate 43.20 % 28.16 % 27.91 %
Schedule of Deferred Tax Assets and Liabilities	Year-end deferred tax assets and liabilities were due to the following (in thousands): 2018 2017 Deferred Tax Assets: Allowance for Loan Losses $ 1,222 $ 1,983 Deferred compensation 836 1,071 Accrued incentive compensation 110 — Purchase accounting adjustments 70 277 Deferred rent 182 380 Other compensation loss (defined benefit plans) 1,439 2,706 Depreciation of premises and equipment 413 405 NOL carryforward 131 602 Charitable contribution carryforward 949 1,820 Nonaccrual loan interest 118 540 Other comprehensive loss (securities) 408 — Other — 104 Total deferred tax assets 5,878 9,888 Deferred Tax Liabilities: Prepaid pension costs $ 2,424 $ 3,622 Deferred loan costs and fees, net 451 457 Other comprehensive income (securities) — 19 Other 31 368 Total deferred tax liabilities 2,906 4,466 Deferred tax asset valuation allowance (350 ) (652 ) Net Deferred Tax Asset $ 2,622 $ 4,770

Post-Retirement Benefits (Table

Post-Retirement Benefits (Tables)	12 Months Ended
	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Shares Held by ESOP	Shares held by the ESOP include the following (dollars in thousands): 2018 2017 Allocated to participants 144,923 26,975 Unearned 1,308,286 1,426,234 Total ESOP shares 1,453,209 1,453,209 Fair value of unearned shares $ 25,996 $ 24,332
Employee Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Summary of Plan's Funded Status	The following is a summary of the plan’s funded status as of June 30, 2018 and 2017 (the measurement date for financial reporting purposes) (in thousands): 2018 2017 Change in benefit obligation: Beginning benefit obligation $ 25,614 $ 28,670 Service Cost - 602 Interest Cost 968 1,002 Actuarial Loss 8 (2,013 ) Benefits Paid (868 ) (828 ) Settlements (958 ) (1,301 ) Curtailment - (518 ) Ending benefit obligation 24,764 25,614 Change in plan assets, at fair value: Beginning plan assets 27,444 23,215 Actual return 2,357 3,358 Employer contributions - 3,000 Benefits paid (868 ) (828 ) Settlements (958 ) (1,301 ) Ending Plan assets 27,975 27,444 Funded Status $ 3,211 $ 1,830 Accumulated Benefit Obligation $ 24,764 $ 25,614
Summary of Net Period Pension Cost, Contributions and Benefits Paid	The following is a summary of net period pension cost, contributions and benefits paid for the years ended June 30 (in thousands): 2018 2017 Net period pension cost $ (321 ) $ (224 ) Employer contributions - 3,000 Benefits paid 868 828
Schedule of Net Periodic Pension Cost and Other Amounts Recognized in Other Comprehensive Income	Net periodic pension cost and other amounts recognized in other comprehensive income for the years ended June 30 (in thousands): 2018 2017 2016 Service cost $ - $ 602 $ 626 Interest cost 968 1,002 1,086 Expected return on plan assets (2,014 ) (1,917 ) (1,796 ) Amortization of prior net loss 725 1,200 854 Amortization of prior service cost - (192 ) (287 ) Gain on curtailment - (919 ) - New past service liability - - - Net periodic cost $ (321 ) $ (224 ) $ 483
Schedule of Benefit Payments which Reflects Expected Future Service	The following benefit payments are expected for the years ending June 30, (in thousands): 2019 $ 1,232 2020 1,259 2021 1,303 2022 1,347 2023 1,365 Following five years 7,202
Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Pension Cost	Weighted-average assumptions used to determine net periodic pension cost are described in the table below. Year ended June 30, 2018 2017 Discount Rate 3.87 % 4.04 % Expected return on plan assets 7.50 % 7.50 %
Schedule of Actual Pension Plan Asset Allocation and Target Allocation by Asset Category	The Company’s actual pension plan asset allocation and target allocation by asset category are as follows: Percentage of Plan Target Assets at Year-End Asset Category Allocation 2018 2017 Equity mutual funds and common/collective trusts 65 % 67 % 65 % Fixed income common/collective trusts 34 % 32 % 34 % Cash equivalents 1 % 1 % 1 % Total 100 % 100 % 100 %
Schedule of Fair Value of Plan Assets	The fair value of the plan assets at June 30, 2018 and 2017, by asset category, is as follows (in thousands): Fair Value Measurements Using Quoted Prices Significant In Active Other Significant Markets for Observable Unobservable Carrying Identical Assets Inputs Inputs Value (Level 1) (Level 2) (Level 3) June 30, 2018 Plan assets Equity mutual funds and common/collective trusts $ 18,914 $ - $ 18,914 $ - Fixed income common/collective trusts 8,893 - 8,893 - Cash equivalents 168 168 - - Total $ 27,975 $ 168 $ 27,807 $ - June 30, 2017 Plan assets Equity mutual funds and common/collective trusts $ 17,704 $ - $ 17,704 $ - Fixed income common/collective trusts 9,451 - 9,451 - Cash equivalents 289 289 - - Total $ 27,444 $ 289 $ 27,155 $ -
Supplemental Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Periodic Pension Cost and Other Amounts Recognized in Other Comprehensive Income	Net periodic pension cost and other amounts recognized in other comprehensive income for the years ended June 30 (in thousands): 2018 2017 2016 Service cost $ 518 $ 398 $ 322 Interest cost 103 124 133 Amortization of prior net loss 34 93 84 Net periodic cost $ 655 $ 615 $ 539
Schedule of Benefit Payments which Reflects Expected Future Service	The following benefit payments, which reflect expected future service, are expected for the years ending June 30 (in thousands): 2019 $ 272 2020 272 2021 3,336 2022 272 2023 272 Following five years 136

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Jun. 30, 2018
Banking And Thrift [Abstract]
Summary of Company's and Bank's Actual Capital Amounts and Ratios Compared to Required Ratios for Minimum Capital Adequacy and for Classification as Well Capitalized	The following is a summary of the Company’s and Bank’s actual capital amounts and ratios as of June 30, 2018 and June 30, 2017, compared to the required ratios for minimum capital adequacy and for classification as well capitalized (dollars in thousands): To Be Well Capitalized For Capital Under Prompt Adequacy Corrective Action Bank Actual Purposes Provisions Amount Ratio Amount Ratio Amount Ratio June 30, 2018: PCSB Bank Leverage (Tier 1) $ 200,488 13.6 % $ 58,924 4.0 % $ 73,655 5.0 % Risk-based: Common Tier 1 200,488 21.1 42,745 4.5 61,743 6.5 Tier 1 200,488 21.1 56,994 6.0 75,991 8.0 Total 205,392 21.6 75,991 8.0 94,989 10.0 PCSB Financial Corporation Leverage (Tier 1) $ 287,991 19.5 % $ 58,948 4.0 % N/A N/A Risk-based: Common Tier 1 287,991 30.3 42,783 4.5 N/A N/A Tier 1 287,991 30.3 57,044 6.0 N/A N/A Total 292,895 30.8 76,058 8.0 N/A N/A June 30, 2017: PCSB Bank Leverage (Tier 1) $ 190,990 13.7 % $ 55,949 4.0 % $ 69,936 5.0 % Risk-based: Common Tier 1 190,990 21.7 39,631 4.5 57,245 6.5 Tier 1 190,990 21.7 52,841 6.0 70,455 8.0 Total 196,140 22.3 70,455 8.0 88,069 10.0 PCSB Financial Corporation Leverage (Tier 1) $ 278,528 20.0 % $ 55,839 4.0 % N/A N/A Risk-based: Common Tier 1 278,528 31.6 39,631 4.5 N/A N/A Tier 1 278,528 31.6 52,841 6.0 N/A N/A Total 283,678 32.2 70,455 8.0 N/A N/A

Parent Company Only Financial42

Parent Company Only Financial Statements (Tables)	12 Months Ended
	Jun. 30, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Consolidated Balance Sheets	The following are the financial statements of the Company (Parent only) as of and for the years ended June 30, 2018 and June 30, 2017 (in thousands). The Company was established as of December 9, 2016; therefore, financial information prior to that date is not available. June 30, 2018 2017 Assets Cash and cash equivalents $ 72,140 $ 71,273 Investment in Bank 200,058 192,308 ESOP Loan receivable 13,563 14,532 Other Assets 1,798 1,888 Total Assets $ 287,559 $ 280,001 Liabilities and stockholders' equity Other Liabilities $ - $ 155 Stockholders' equity 287,559 279,846 Total Liabilities and stockholders' equity $ 287,559 $ 280,001
Consolidated Statements of Operations	Years Ended June 30, 2018 2017 Interest Income $ 668 $ 125 Equity in income of Bank 7,188 1,055 Contribution to PCSB Foundation — 5,000 Other non-interest expenses 689 105 Income (loss) before income tax 7,167 (3,925 ) Income tax expense (benefit) 563 (1,693 ) Net Income (loss) $ 6,604 $ (2,232 )
Consolidated Statements of Cash Flows	Year Ended June 30, 2018 2017 Cash Flows from Operating Activities: Net income (loss) $ 6,604 $ (2,232 ) Adjustments to reconcile net income to net cash provided by operating activities: Equity in income of Bank (7,188 ) (1,055 ) Issuance of common stock to PCSB Foundation — 3,387 Deferred tax expense (benefit) 733 (1,482 ) Net increase in accrued interest receivable (230 ) (113 ) Other adjustments, principally net changes in other assets and liabilities (569 ) (138 ) Net cash used in operating activities (650 ) (1,633 ) Cash Flows from Investing Activities: Investment in PCSB Bank — (87,350 ) Decrease (increase) in ESOP loan 969 (14,532 ) Net cash provided by (used in) investing activities 969 (101,882 ) Cash Flows from Financing Activities: Common stock dividends declared (504 ) — Allocation of ESOP shares 1,069 184 Issuance of common stock (17 ) 174,604 Net cash provided by financing activities 548 174,788 Net increase in cash and cash equivalents 867 71,273 Cash and cash equivalents at beginning of year 71,273 — Cash and cash equivalents at end of year $ 72,140 $ 71,273

Quarterly Financial Informati43

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Jun. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	2018 2017 In thousands, except per share amounts Fourth Third Second First Fourth Third Second First Interest income $ 13,358 $ 11,648 $ 11,657 $ 11,297 $ 10,723 $ 10,276 $ 9,850 $ 10,109 Interest expense 1,926 1,505 1,471 1,421 1,318 1,318 1,323 1,334 Net interest income 11,432 10,143 10,186 9,876 9,405 8,958 8,527 8,775 Provision for loan losses 25 54 200 135 - 235 562 26 Non-interest income (1) 601 512 692 714 647 626 2,259 552 Non-interest expense (2) 8,264 7,833 8,125 7,894 12,859 6,580 7,794 7,198 Income before taxes 3,744 2,768 2,553 2,561 (2,807 ) 2,769 2,430 2,103 Income tax expense (3) 1,075 591 2,551 805 (1,017 ) 878 758 647 Net Income (loss) $ 2,669 $ 2,177 $ 2 $ 1,756 $ (1,790 ) $ 1,891 $ 1,672 $ 1,456 Earnings per share Basic $ 0.16 $ 0.13 $ - $ 0.10 N/A N/A N/A N/A Diluted $ 0.16 $ 0.13 $ - $ 0.10 N/A N/A N/A N/A (1) Non-interest income for the second quarter of 2017 includes a $1.6 million settlement on a loan charged-off by CMS Bank before the 2015 merger. (2) Non-interest expense for the fourth quarter of 2017 includes a $5.0 million contribution expense related to Company’s establishment of the PCSB Community Foundation. (3) Income tax expense for the second quarter of 2018 includes $1.6 million charge reflecting a re-measurement of our deferred tax assets resulting from a decrease in the corporate income tax rate from 34% to 21%.

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018USD ($)SubsidiarySegment	Jun. 30, 2017USD ($)
Basis Of Presentation [Line Items]
Number of subsidiaries | Subsidiary	3
Trading securities	$ 0
Other intangible assets, estimated useful life	10 years
Tax position recognized largest amount of tax benefit greater than likely realized percentage	50.00%
Tax benefit related to taxo positions	$ 0	$ 0
Dilutive instruments	$ 0	$ 0
Financial Service Operations [Member]
Basis Of Presentation [Line Items]
Number of reportable operating segments | Segment	1
Maximum [Member] | Home Equity Lines of Credit [Member]
Basis Of Presentation [Line Items]
Loan-to-value ratio	75.00%

Recent Accounting Pronounceme45

Recent Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Corporate income tax rate		21.00%	34.00%	28.06%	34.00%	34.00%
Retained Earnings [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain tax effects on other comprehensive income	[1]			$ 1,117
Accumulated Other Comprehensive Income [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain tax effects on other comprehensive income	[1]			$ (1,117)
[1]	The adoption of ASU 2018-02 requires the reclassification from accumulated other comprehensive income to retained earnings of certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017. Refer to Footnote 2 - Recent Accounting Pronouncements for additional information

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Apr. 20, 2017	Jun. 30, 2018	Jun. 30, 2017	Apr. 19, 2017
Subsidiary Sale Of Stock [Line Items]
Initial public offering in connection with banks's mutual-to-stock conversion completion date	Apr. 20, 2017
Gross proceeds from offering	$ 178.3
Sale of stock	17,826,408
Expenses related to offering	$ 3.7
Net proceeds from offering	174.6
ESOP borrowing		$ 13.6
Amount retained from net proceeds of the offering prior to the contribution	$ 87.3
Common Stock, shares outstanding		18,165,110	18,165,110	0
PCSB Bank Employee Stock Ownership Plan [Member]
Subsidiary Sale Of Stock [Line Items]
Sale of stock	1,453,209
Stock price	$ 10
ESOP borrowing	$ 14.5
PCSB Community Foundation [Member]
Subsidiary Sale Of Stock [Line Items]
Contributions in shares	338,702
Contributions in cash	$ 1.6

Investment Securities - Schedul

Investment Securities - Schedule of Amortized Cost, Gross Unrealized/Unrecognized Gains and Losses and Fair Value of Available for Sale and Held to Maturity Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Schedule of Investments [Line Items]
Available for sale, Amortized Cost	$ 107,446	$ 111,832
Available for sale, Gross Unrealized/Unrecognized Gains	81	452
Available for sale, Gross Unrealized/Unrecognized Losses	(2,023)	(395)
Available for sale, Fair Value	105,504	111,889
Held to maturity, Amortized Cost	353,183	383,551
Held to maturity, Gross Unrealized/Unrecognized Gains	43	1,409
Held to maturity, Gross Unrealized/Unrecognized Losses	(10,038)	(1,372)
Held to maturity, Fair Value	343,188	383,588
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Available for sale, Amortized Cost	64,389	63,630
Available for sale, Gross Unrealized/Unrecognized Gains		31
Available for sale, Gross Unrealized/Unrecognized Losses	(959)	(216)
Available for sale, Fair Value	63,430	63,445
Held to maturity, Amortized Cost	122,048	155,559
Held to maturity, Gross Unrealized/Unrecognized Gains		23
Held to maturity, Gross Unrealized/Unrecognized Losses	(2,274)	(574)
Held to maturity, Fair Value	119,774	155,008
Corporate and Other Debt Securities [Member]
Schedule of Investments [Line Items]
Available for sale, Amortized Cost	8,406	8,460
Available for sale, Gross Unrealized/Unrecognized Gains		58
Available for sale, Gross Unrealized/Unrecognized Losses	(171)	(36)
Available for sale, Fair Value	8,235	8,482
Held to maturity, Amortized Cost	4,000	999
Held to maturity, Gross Unrealized/Unrecognized Losses	(126)	0
Held to maturity, Fair Value	3,874	999
Mortgage-backed Securities - Residential [Member]
Schedule of Investments [Line Items]
Available for sale, Amortized Cost	34,619	39,710
Available for sale, Gross Unrealized/Unrecognized Gains	81	363
Available for sale, Gross Unrealized/Unrecognized Losses	(893)	(143)
Available for sale, Fair Value	33,807	39,930
Held to maturity, Amortized Cost	140,478	143,452
Held to maturity, Gross Unrealized/Unrecognized Gains	32	828
Held to maturity, Gross Unrealized/Unrecognized Losses	(4,846)	(497)
Held to maturity, Fair Value	135,664	143,783
Equity Securities [Member]
Schedule of Investments [Line Items]
Available for sale, Amortized Cost	32	32
Available for sale, Fair Value	32	32
Mortgage-backed Securities - Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Held to maturity, Amortized Cost	53,547	59,476
Held to maturity, Gross Unrealized/Unrecognized Gains		146
Held to maturity, Gross Unrealized/Unrecognized Losses	(1,815)	(235)
Held to maturity, Fair Value	51,732	59,387
Mortgage-backed Securities - Commercial [Member]
Schedule of Investments [Line Items]
Held to maturity, Amortized Cost	33,110	24,065
Held to maturity, Gross Unrealized/Unrecognized Gains	11	412
Held to maturity, Gross Unrealized/Unrecognized Losses	(977)	(66)
Held to maturity, Fair Value	$ 32,144	$ 24,411

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018USD ($)Security	Jun. 30, 2017USD ($)Security	Jun. 30, 2016USD ($)
Schedule of Investments [Line Items]
Sale of investment securities	$ 8,600,000
Realized gains or losses on investment securities	236,000	$ 0	$ 0
Disposal of securities held to maturity	1,300,000
Realized gains from sale of securities held to maturity	72,000
Carrying amounts of securities pledged	140,500,000	95,500,000
Total investment securities	$ 458,687,000	$ 495,440,000
Number of securities in unrealized loss position | Security	254	156
Fair value of securities in unrealized loss position	$ 438,500,000	$ 271,900,000
Other-than-temporarily impaired securities	$ 0	$ 0
Minimum [Member]
Schedule of Investments [Line Items]
Held to maturity substantial portion of principal outstanding percentage	85.00%

Investment Securities - Fair Va

Investment Securities - Fair Value and Carrying Amount of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Investments Debt And Equity Securities [Abstract]
Held to maturity, carrying amount, 1 year or less	$ 25,504	$ 50,486
Held to maturity, carrying amount, 1 to 5 years	96,544	106,073
Held to maturity, carrying amount, Mortgage-backed securities and other	231,135	226,992
Held to maturity, Amortized Cost	353,183	383,551
Held to maturity, fair value, 1 year or less	25,342	50,413
Held to maturity, fair value, 1 to 5 years	94,432	105,594
Held to maturity, fair value, Mortgage-backed securities and other	223,414	227,581
Held to maturity, fair value, Total	343,188	383,588
Available for sale, amortized cost, 1 year or less	12,402	16,005
Available for sale, amortized cost, 1 to 5 years	58,393	54,085
Available for sale, amortized cost, 5 to 10 years	2,000	2,000
Available for sale, amortized cost, Mortgage-backed securities and other	34,619	39,710
Available for sale, amortized cost, Total	107,414	111,800
Available for sale, fair value, 1 year or less	12,353	15,988
Available for sale, fair value, 1 to 5 years	57,335	53,975
Available for sale, fair value, 5 to 10 years	1,977	1,964
Available for sale, fair value, Mortgage-backed securities and other	33,807	39,930
Available for sale, fair value, Total	$ 105,472	$ 111,857

Investment Securities - Investm

Investment Securities - Investment Securities with Fair Value and Unrealized Losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Schedule of Investments [Line Items]
Available for sale, Less than 12 months, Fair Value	$ 61,417	$ 62,725
Available for sale, Less than 12 months, Unrealized/Unrecognized Loss	(1,096)	(347)
Available for sale, Greater than 12 months, Fair Value	38,363	7,193
Available for sale, Greater than 12 months, Unrealized/Unrecognized Loss	(927)	(48)
Available for sale, Total, Fair Value	99,780	69,918
Available for sale, Total, Unrealized/Unrecognized Loss	(2,023)	(395)
Held to maturity, Less than 12 months, Fair Value	205,419	189,978
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(5,801)	(1,205)
Held to maturity, Greater than 12 months, Fair Value	133,338	12,051
Held to maturity, Greater than 12 months,Unrealized/ Unrecognized Loss	(4,237)	(167)
Held to maturity, Total, Fair Value	338,757	202,029
Held to maturity, Total, Unrealized/ Unrecognized Loss	(10,038)	(1,372)
U.S. Government and Agency Obligations [Member]
Schedule of Investments [Line Items]
Available for sale, Less than 12 months, Fair Value	41,762	41,900
Available for sale, Less than 12 months, Unrealized/Unrecognized Loss	(569)	(200)
Available for sale, Greater than 12 months, Fair Value	21,668	3,993
Available for sale, Greater than 12 months, Unrealized/Unrecognized Loss	(390)	(16)
Available for sale, Total, Fair Value	63,430	45,893
Available for sale, Total, Unrealized/Unrecognized Loss	(959)	(216)
Held to maturity, Less than 12 months, Fair Value	46,163	113,511
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(871)	(531)
Held to maturity, Greater than 12 months, Fair Value	71,611	5,981
Held to maturity, Greater than 12 months,Unrealized/ Unrecognized Loss	(1,403)	(43)
Held to maturity, Total, Fair Value	117,774	119,492
Held to maturity, Total, Unrealized/ Unrecognized Loss	(2,274)	(574)
Corporate and Other Debt Securities [Member]
Schedule of Investments [Line Items]
Available for sale, Less than 12 months, Fair Value	6,258	1,964
Available for sale, Less than 12 months, Unrealized/Unrecognized Loss	(148)	(36)
Available for sale, Greater than 12 months, Fair Value	1,977
Available for sale, Greater than 12 months, Unrealized/Unrecognized Loss	(23)
Available for sale, Total, Fair Value	8,235	1,964
Available for sale, Total, Unrealized/Unrecognized Loss	(171)	(36)
Held to maturity, Less than 12 months, Fair Value	3,874	999
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(126)
Held to maturity, Total, Fair Value	3,874	999
Held to maturity, Total, Unrealized/ Unrecognized Loss	(126)	0
Mortgage-backed Securities - Residential [Member]
Schedule of Investments [Line Items]
Available for sale, Less than 12 months, Fair Value	13,397	18,861
Available for sale, Less than 12 months, Unrealized/Unrecognized Loss	(379)	(111)
Available for sale, Greater than 12 months, Fair Value	14,718	3,200
Available for sale, Greater than 12 months, Unrealized/Unrecognized Loss	(514)	(32)
Available for sale, Total, Fair Value	28,115	22,061
Available for sale, Total, Unrealized/Unrecognized Loss	(893)	(143)
Held to maturity, Less than 12 months, Fair Value	102,496	39,754
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(3,338)	(467)
Held to maturity, Greater than 12 months, Fair Value	32,490	1,626
Held to maturity, Greater than 12 months,Unrealized/ Unrecognized Loss	(1,508)	(30)
Held to maturity, Total, Fair Value	134,986	41,380
Held to maturity, Total, Unrealized/ Unrecognized Loss	(4,846)	(497)
Mortgage-backed Securities - Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Held to maturity, Less than 12 months, Fair Value	31,124	26,622
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(884)	(141)
Held to maturity, Greater than 12 months, Fair Value	20,608	4,444
Held to maturity, Greater than 12 months,Unrealized/ Unrecognized Loss	(931)	(94)
Held to maturity, Total, Fair Value	51,732	31,066
Held to maturity, Total, Unrealized/ Unrecognized Loss	(1,815)	(235)
Mortgage-backed Securities - Commercial [Member]
Schedule of Investments [Line Items]
Held to maturity, Less than 12 months, Fair Value	21,762	9,092
Held to maturity, Less than 12 months, Unrealized/ Unrecognized Loss	(582)	(66)
Held to maturity, Greater than 12 months, Fair Value	8,629
Held to maturity, Greater than 12 months,Unrealized/ Unrecognized Loss	(395)
Held to maturity, Total, Fair Value	30,391	9,092
Held to maturity, Total, Unrealized/ Unrecognized Loss	$ (977)	$ (66)

Loans Receivable - Summary of L

Loans Receivable - Summary of Loans Receivable (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	$ 905,470	$ 813,624
Loans receivable	907,240	814,798
Allowance for loan losses	(4,904)	(5,150)	$ (4,042)	$ (3,921)
Loans receivable, net	902,336	809,648
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	250,578	217,778
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	495,265	437,651
Allowance for loan losses	(3,073)	(2,589)
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	17,352	22,404
Allowance for loan losses	(505)	(1,150)
Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	104,135	93,631
Allowance for loan losses	(780)	(949)
Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	37,395	41,927
Allowance for loan losses	(80)	(76)
Consumer and Overdrafts [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans receivable, before fees	745	233
Allowance for loan losses	(7)
Mortgage Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Net deferred loan origination costs	1,041	397
Loans receivable	764,236	678,230
Commercial and Consumer Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Net deferred loan origination costs	729	777
Loans receivable	$ 143,004	$ 136,568

Loans Receivable - Summary of A

Loans Receivable - Summary of Activity in Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				$ 5,150			$ 4,042	$ 5,150	$ 4,042	$ 3,921
Allowance for Loan Losses, Provision (Credit)	$ 25	$ 54	$ 200	135	$ 235	$ 562	26	414	823	1,859
Allowance for Loan Losses, Charge-offs								(1,270)	(1,129)	(2,133)
Allowance for Loan Losses, Recoveries								610	1,414	395
Allowance for Loan Losses, Ending Allowance	4,904							4,904	5,150	4,042
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				2,589				2,589
Allowance for Loan Losses, Ending Allowance	3,073							3,073	2,589
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				1,150				1,150
Allowance for Loan Losses, Ending Allowance	505							505	1,150
Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				949				949
Allowance for Loan Losses, Ending Allowance	780							780	949
Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				76				76
Allowance for Loan Losses, Ending Allowance	80							80	76
Consumer and Overdrafts [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Ending Allowance	7							7
Originated [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				360			237	360	237	193
Allowance for Loan Losses, Provision (Credit)								161	290	444
Allowance for Loan Losses, Charge-offs								(136)	(237)	(400)
Allowance for Loan Losses, Recoveries								1	70
Allowance for Loan Losses, Ending Allowance	386							386	360	237
Originated [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				2,589			2,149	2,589	2,149	1,766
Allowance for Loan Losses, Provision (Credit)								114	421	215
Allowance for Loan Losses, Charge-offs										(10)
Allowance for Loan Losses, Recoveries								370	19	178
Allowance for Loan Losses, Ending Allowance	3,073							3,073	2,589	2,149
Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				1,150			269	1,150	269	100
Allowance for Loan Losses, Provision (Credit)								352	989	(23)
Allowance for Loan Losses, Charge-offs								(997)	(108)
Allowance for Loan Losses, Recoveries										192
Allowance for Loan Losses, Ending Allowance	505							505	1,150	269
Originated [Member] | Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				949			1,313	949	1,313	1,793
Allowance for Loan Losses, Provision (Credit)								(335)	(944)	1,172
Allowance for Loan Losses, Charge-offs								(54)	(741)	(1,677)
Allowance for Loan Losses, Recoveries								220	1,321	25
Allowance for Loan Losses, Ending Allowance	780							780	949	1,313
Originated [Member] | Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				76			73	76	73	69
Allowance for Loan Losses, Provision (Credit)								45	3	28
Allowance for Loan Losses, Charge-offs								(60)		(24)
Allowance for Loan Losses, Recoveries								19
Allowance for Loan Losses, Ending Allowance	80							80	76	73
Originated [Member] | Consumer and Overdrafts [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance							$ 1		1
Allowance for Loan Losses, Provision (Credit)								30	(5)	23
Allowance for Loan Losses, Charge-offs								(23)		(22)
Allowance for Loan Losses, Recoveries									4
Allowance for Loan Losses, Ending Allowance	7							7		$ 1
Acquired [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Beginning Allowance				$ 26				26
Allowance for Loan Losses, Provision (Credit)								47	64
Allowance for Loan Losses, Charge-offs									(38)
Allowance for Loan Losses, Ending Allowance	$ 73							$ 73	26
Acquired [Member] | Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Provision (Credit)									2
Allowance for Loan Losses, Charge-offs									(2)
Acquired [Member] | Consumer and Overdrafts [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Provision (Credit)									3
Allowance for Loan Losses, Charge-offs									$ (3)

Loans Receivable - Summary of B

Loans Receivable - Summary of Balance in Allowance for Loan Losses and Recorded investment in Loans by Portfolio Segment, and Based on Impairment Method (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	$ 9,114	$ 17,322
Loans, Collectively Evaluated for Impairment	893,406	792,935
Total	905,470	813,624
Allowance for Loan Losses, Individually Evaluated for Impairment	451	1,142
Allowance for Loan Losses, Collectively Evaluated for Impairment	4,380	3,982
Allowance for Loan Losses, Total	4,904	5,150	$ 4,042	$ 3,921
Originated And Acquired Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Total	4,904	5,150
Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Acquired With Deteriorated Credit Quality	2,950	3,367
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	73	26
Residential [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	2,360	4,471
Loans, Collectively Evaluated for Impairment	246,913	211,983
Total	250,578	217,778
Allowance for Loan Losses, Individually Evaluated for Impairment	154	131
Allowance for Loan Losses, Collectively Evaluated for Impairment	232	229
Residential [Member] | Originated And Acquired Loans
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Total	459	386
Residential [Member] | Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Acquired With Deteriorated Credit Quality	1,305	1,324
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	73	26
Commercial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	1,683	2,411
Loans, Collectively Evaluated for Impairment	492,105	433,416
Total	495,265	437,651
Allowance for Loan Losses, Collectively Evaluated for Impairment	3,073	2,589
Allowance for Loan Losses, Total	3,073	2,589
Commercial [Member] | Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Acquired With Deteriorated Credit Quality	1,477	1,824
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	0	0
Construction [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	2,260	3,661
Loans, Collectively Evaluated for Impairment	15,092	18,743
Total	17,352	22,404
Allowance for Loan Losses, Individually Evaluated for Impairment	276	997
Allowance for Loan Losses, Collectively Evaluated for Impairment	229	153
Allowance for Loan Losses, Total	505	1,150
Construction [Member] | Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	0	0
Commercial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	2,451	6,169
Loans, Collectively Evaluated for Impairment	101,684	87,420
Total	104,135	93,631
Allowance for Loan Losses, Individually Evaluated for Impairment	9	9
Allowance for Loan Losses, Collectively Evaluated for Impairment	771	940
Allowance for Loan Losses, Total	780	949
Commercial Loans [Member] | Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Acquired With Deteriorated Credit Quality		42
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	0	0
Home Equity Lines Of Credit [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment	360	610
Loans, Collectively Evaluated for Impairment	36,867	41,140
Total	37,395	41,927
Allowance for Loan Losses, Individually Evaluated for Impairment	12	5
Allowance for Loan Losses, Collectively Evaluated for Impairment	68	71
Allowance for Loan Losses, Total	80	76
Home Equity Lines Of Credit [Member] | Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Acquired With Deteriorated Credit Quality	168	177
Allowance for Loan Losses, Acquired With Deteriorated Credit Quality	0	0
Consumer and Overdrafts [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Loans, Collectively Evaluated for Impairment	745	233
Total	745	$ 233
Allowance for Loan Losses, Collectively Evaluated for Impairment	7
Allowance for Loan Losses, Total	$ 7

Loans Receivable - Summary of54

Loans Receivable - Summary of Loans Individually Evaluated for Impairment (Excluding Loans Acquired with Deteriorated Credit Quality) by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable Impaired [Line Items]
Impaired loans, unpaid principal balance	$ 10,455	$ 22,440
Impaired loans, recorded investment	9,114	17,322
Allowance for loan losses	451	1,142
Residential [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, unpaid principal balance	1,659	4,216
Impaired loans with no related allowance recorded, recorded investment	1,576	4,014
Impaired loans with an allowance recorded, unpaid principal balance	742	395
Impaired loans with an allowance recorded, recorded investment	784	457
Impaired loans, recorded investment	2,360	4,471
Allowance for loan losses	154	131
Commercial [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, unpaid principal balance	1,765	2,935
Impaired loans with no related allowance recorded, recorded investment	1,683	2,411
Impaired loans, recorded investment	1,683	2,411
Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, unpaid principal balance	2,254	9,433
Impaired loans with no related allowance recorded, recorded investment	2,098	4,979
Impaired loans with an allowance recorded, unpaid principal balance	353	1,190
Impaired loans with an allowance recorded, recorded investment	353	1,190
Impaired loans, recorded investment	2,451	6,169
Allowance for loan losses	9	9
Home Equity Lines Of Credit [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, unpaid principal balance	341	599
Impaired loans with no related allowance recorded, recorded investment	341	599
Impaired loans with an allowance recorded, unpaid principal balance	84	11
Impaired loans with an allowance recorded, recorded investment	19	11
Impaired loans, recorded investment	360	610
Allowance for loan losses	12	5
Construction [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, unpaid principal balance		404
Impaired loans with no related allowance recorded, recorded investment		404
Impaired loans with an allowance recorded, unpaid principal balance	3,257	3,257
Impaired loans with an allowance recorded, recorded investment	2,260	3,257
Impaired loans, recorded investment	2,260	3,661
Allowance for loan losses	$ 276	$ 997

Loans Receivable - Summary of55

Loans Receivable - Summary of Average Recorded Investment and Interest Income Recognized on Loans Individually Evaluated for Impairment, by Class of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable Impaired [Line Items]
Impaired loans average recorded investment	$ 14,123	$ 17,438	$ 26,653
Impaired loans interest income recognized	1,601	575	177
Residential [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, average recorded investment	3,041	4,238	5,577
Impaired loans with no related allowance recorded, interest income recognized	184	42	6
Impaired loans with an allowance recorded, average recorded investment	453	432
Impaired loans with an allowance recorded, interest income recognized	15	15
Commercial [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, average recorded investment	2,350	2,448	9,324
Impaired loans with no related allowance recorded, interest income recognized	248	137	88
Construction [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, average recorded investment	93	406	13
Impaired loans with no related allowance recorded, interest income recognized	17	12
Impaired loans with an allowance recorded, average recorded investment	2,720	3,015	132
Impaired loans with an allowance recorded, interest income recognized		71
Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, average recorded investment	3,457	5,065	10,755
Impaired loans with no related allowance recorded, interest income recognized	1,049	239	71
Impaired loans with an allowance recorded, average recorded investment	1,491	1,224	422
Impaired loans with an allowance recorded, interest income recognized	66	61	12
Home Equity Lines Of Credit [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, average recorded investment	507	599	$ 430
Impaired loans with no related allowance recorded, interest income recognized	22	(2)
Impaired loans with an allowance recorded, average recorded investment	$ 11	$ 11

Loans Receivable - Nonaccrual L

Loans Receivable - Nonaccrual Loans and in Loans Past Due over 90 Days Still on Accrual Status by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 6,102	$ 12,072
Originated [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	604	2,581
Originated [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	262
Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	2,260	3,661
Originated [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	788	2,959
Originated [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	45	302
Acquired [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	1,308	1,776
Acquired [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	532	497
Acquired [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 303	$ 296

Loans Receivable - Additional I

Loans Receivable - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018USD ($)Loan	Jun. 30, 2017USD ($)Loan	Jun. 30, 2016USD ($)Loan
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans accounted for as purchased credit impaired loans	$ 1,800,000	$ 2,700,000
Number of loans classified as troubled debt restructurings | Loan	12	20
Value of loans classified as troubled debt restructurings	$ 3,800,000	$ 9,900,000
Specific reserves	$ 139,000	$ 145,000
Troubled debt restructurings for which there was a payment default | Loan		2
Commercial Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Troubled debt restructurings for which there was a payment default | Loan	2
Increase allowance for loan loss	$ 2,000
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Troubled debt restructurings for which there was a payment default | Loan		1	1
Increase allowance for loan loss		$ 0	$ 0
Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Troubled debt restructurings for which there was a payment default | Loan		1
Increase allowance for loan loss		$ 0

Loans Receivable - Aging of Rec

Loans Receivable - Aging of Recorded Investment in Past Due Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 7,147	$ 10,371
Current	898,323	803,253
Total	905,470	813,624
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	30	331
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	626	937
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,491	9,103
Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	250,578	217,778
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	495,265	437,651
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	17,352	22,404
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	104,135	93,631
Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	37,395	41,927
Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	745	233
Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,671	6,849
Current	766,209	651,286
Total	769,880	658,135
Originated [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		94
Originated [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	394	474
Originated [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,277	6,281
Originated [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	604	2,342
Current	194,986	153,390
Total	195,590	155,732
Originated [Member] | Residential [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		94
Originated [Member] | Residential [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	394	275
Originated [Member] | Residential [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	210	1,973
Originated [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	262
Current	420,320	355,247
Total	420,582	355,247
Originated [Member] | Commercial [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	262
Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,260	3,661
Current	15,092	18,743
Total	17,352	22,404
Originated [Member] | Construction [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,260	3,661
Originated [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	500	544
Current	102,767	88,449
Total	103,267	88,993
Originated [Member] | Commercial Loans [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	500	544
Originated [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	45	302
Current	32,311	35,246
Total	32,356	35,548
Originated [Member] | Home Equity Lines Of Credit [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		199
Originated [Member] | Home Equity Lines Of Credit [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	45	103
Originated [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	733	211
Total	733	211
Acquired [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,476	3,522
Current	132,114	151,967
Total	135,590	155,489
Acquired [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	30	237
Acquired [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	232	463
Acquired [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,214	2,822
Acquired [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,038	2,172
Current	52,950	59,874
Total	54,988	62,046
Acquired [Member] | Residential [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		237
Acquired [Member] | Residential [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	232	463
Acquired [Member] | Residential [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,806	1,472
Acquired [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,112	1,054
Current	73,571	81,350
Total	74,683	82,404
Acquired [Member] | Commercial [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,112	1,054
Acquired [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	868	4,638
Total	868	4,638
Acquired [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	326	296
Current	4,713	6,083
Total	5,039	6,379
Acquired [Member] | Home Equity Lines Of Credit [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	30
Acquired [Member] | Home Equity Lines Of Credit [Member] | 90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	296	296
Acquired [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	12	22
Total	$ 12	$ 22

Loans Receivable - Summary of59

Loans Receivable - Summary of Loans by Class Modified in Troubled Debt Restructurings (Detail) $ in Thousands	12 Months Ended
	Jun. 30, 2018USD ($)Loan	Jun. 30, 2017USD ($)Loan	Jun. 30, 2016USD ($)Loan
Financing Receivable Modifications [Line Items]
Number of loans | Loan	1	2	4
Pre-Modification Outstanding Recorded Investment	$ 275	$ 441	$ 3,139
Post-Modification Outstanding Recorded Investment	$ 289	$ 486	$ 3,139
Commercial Loans [Member]
Financing Receivable Modifications [Line Items]
Number of loans | Loan	1	1	1
Pre-Modification Outstanding Recorded Investment	$ 275	$ 276	$ 64
Post-Modification Outstanding Recorded Investment	$ 289	$ 276	$ 64
Residential [Member]
Financing Receivable Modifications [Line Items]
Number of loans | Loan		1	3
Pre-Modification Outstanding Recorded Investment		$ 165	$ 1,697
Post-Modification Outstanding Recorded Investment		$ 210	$ 1,697
Commercial [Member]
Financing Receivable Modifications [Line Items]
Number of loans | Loan			1
Pre-Modification Outstanding Recorded Investment			$ 1,178
Post-Modification Outstanding Recorded Investment			$ 1,178
Home Equity Lines Of Credit [Member]
Financing Receivable Modifications [Line Items]
Number of loans | Loan			1
Pre-Modification Outstanding Recorded Investment			$ 200
Post-Modification Outstanding Recorded Investment			$ 200

Loans Receivable - Summary of R

Loans Receivable - Summary of Risk Category of Loans by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 905,470	$ 813,624
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	888,108	788,287
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,984	192
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,378	25,145
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	250,578	217,778
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	495,265	437,651
Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17,352	22,404
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	104,135	93,631
Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	37,395	41,927
Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	745	233
Originated [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	769,880	658,135
Originated [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	758,908	638,974
Originated [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	882	192
Originated [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,090	18,969
Originated [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	195,590	155,732
Originated [Member] | Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	194,341	153,165
Originated [Member] | Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	571
Originated [Member] | Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	678	2,567
Originated [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	420,582	355,247
Originated [Member] | Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	418,370	352,203
Originated [Member] | Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		134
Originated [Member] | Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,212	2,910
Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17,352	22,404
Originated [Member] | Construction [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	15,092	18,743
Originated [Member] | Construction [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,260	3,661
Originated [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	103,267	88,993
Originated [Member] | Commercial Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	98,205	79,406
Originated [Member] | Commercial Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	167
Originated [Member] | Commercial Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,895	9,587
Originated [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	32,356	35,548
Originated [Member] | Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	32,167	35,246
Originated [Member] | Home Equity Lines Of Credit [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	144	58
Originated [Member] | Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	45	244
Originated [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	733	211
Originated [Member] | Consumer and Overdrafts [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	733	211
Acquired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	135,590	155,489
Acquired [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	129,200	149,313
Acquired [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,102
Acquired [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,288	6,176
Acquired [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	54,988	62,046
Acquired [Member] | Residential [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	51,858	58,665
Acquired [Member] | Residential [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	249
Acquired [Member] | Residential [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,881	3,381
Acquired [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	74,683	82,404
Acquired [Member] | Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	71,832	80,082
Acquired [Member] | Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	842
Acquired [Member] | Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,009	2,322
Acquired [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	868	4,638
Acquired [Member] | Commercial Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	857	4,638
Acquired [Member] | Commercial Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	11
Acquired [Member] | Home Equity Lines Of Credit [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,039	6,379
Acquired [Member] | Home Equity Lines Of Credit [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,641	5,906
Acquired [Member] | Home Equity Lines Of Credit [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	398	473
Acquired [Member] | Consumer and Overdrafts [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12	22
Acquired [Member] | Consumer and Overdrafts [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 12	$ 22

Loans Receivable - Schedule of

Loans Receivable - Schedule of Carrying Amount of Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans	$ 902,336	$ 809,648
Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans	2,877	3,341
Acquired with Deteriorated Credit Quality [Member] | Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans	1,232	1,298
Acquired with Deteriorated Credit Quality [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans	1,477	1,824
Acquired with Deteriorated Credit Quality [Member] | Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans		42
Acquired with Deteriorated Credit Quality [Member] | Home Equity Lines Of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans	$ 168	$ 177

Loans Receivable - Schedule o62

Loans Receivable - Schedule of Carrying Amount of Purchased Credit Impaired Loans (Parenthetical) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Acquired with Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount of loans, allowance	$ 73	$ 26

Loans Receivable - Summary of63

Loans Receivable - Summary of Accretable Yield, or Income Expected to be Collected for Acquired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Certain Loans Acquired in Transfer Accounted for as Debt Securities [Abstract]
Beginning balance	$ 403	$ 578	$ 713
Accretion income	(70)	(190)	(185)
Reclassification from non-accretable difference	5	15	132
Disposals	(93)		(82)
Ending balance	$ 245	$ 403	$ 578

Premises and Equipment - Summar

Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 21,878	$ 21,981
Less: accumulated depreciation and amortization	(10,280)	(9,022)
Total Bank premises and equipment, net	11,598	12,959
Land [Member]
Property Plant And Equipment [Line Items]
Premises and equipment, gross	1,997	1,997
Building and Leasehold improvements [Member]
Property Plant And Equipment [Line Items]
Premises and equipment, gross	13,430	11,128
Furniture, fixtures and equipment [Member]
Property Plant And Equipment [Line Items]
Premises and equipment, gross	6,096	5,841
Construction and improvements in process [Member]
Property Plant And Equipment [Line Items]
Premises and equipment, gross	$ 355	$ 3,015

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Property Plant And Equipment [Abstract]
Depreciation expense	$ 1.3	$ 1.3	$ 1.1

Goodwill and Intangible Asset66

Goodwill and Intangible Assets - Schedule of Change in Goodwill (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Goodwill [Line Items]
Beginning Balance	$ 6,106,000	$ 6,106,000	$ 5,843,000
Impairment	0	0	0
Ending Balance	$ 6,106,000	$ 6,106,000	6,106,000
CMS Bancorp [Member]
Goodwill [Line Items]
Adjustment to CMS goodwill			$ 263,000

Goodwill and Intangible Asset67

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of goodwill	$ 0	$ 0	$ 0
Amortization of intangible assets	$ 126,000	$ 143,000	$ 158,000

Goodwill and Intangible Asset68

Goodwill and Intangible Assets - Schedule of Acquired Intangible Assets (Detail) - Core Deposit Intangible [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Goodwill And Intangible Assets Disclosure [Line Items]
Amortized intangible assets, Gross Carrying Amount	$ 887	$ 887
Amortized intangible assets, Accumulated Amortization	$ (454)	$ (328)

Goodwill and Intangible Asset69

Goodwill and Intangible Assets - Schedule of Estimated Amortization Expense (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,019	$ 110
2,020	94
2,021	78
2,022	62
2,023	$ 46

Deposits - Summary of Deposit B

Deposits - Summary of Deposit Balances (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Deposits [Abstract]
Demand	$ 131,883	$ 136,361
NOW Accounts	117,875	115,527
Money market accounts	49,885	29,097
Savings	465,441	512,697
Time deposits	392,373	294,779
Total deposits	$ 1,157,457	$ 1,088,461

Deposits - Additional Informati

Deposits - Additional Information (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Deposits [Line Items]
Time deposits, meet or exceed FDIC insurance limit of $250,000	$ 116,000,000	$ 49,200,000
Brokered time deposits	$ 60,000,000	0
Minimum [Member]
Deposits [Line Items]
Brokered time deposits remaining maturities period	5 months
Maximum [Member]
Deposits [Line Items]
Brokered time deposits remaining maturities period	47 months
PCSB Commercial Bank [Member]
Deposits [Line Items]
Deposits of local governments	$ 39,100,000	$ 38,400,000

Deposits - Scheduled Maturities

Deposits - Scheduled Maturities of Time Deposits (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Deposits [Abstract]
Within 1 year	$ 183,276	$ 107,097
1 year to 2 years	49,350	62,331
2 years to 3 years	56,746	31,143
3 years to 4 years	56,458	41,508
4 years to 5 years	46,339	52,503
Thereafter	204	197
Total	$ 392,373	$ 294,779

FHLB and Other Borrowings - Add

FHLB and Other Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Federal Home Loan Bank Advances [Line Items]
Advances from Federal Home Loan Bank	$ 18,841,000	$ 42,598,000
Percentage of outstanding advances to be maintained as collateral	110.00%
Secured borrowings	$ 122,100,000
FRB borrowings outstanding	0	0
Federal Home Loan Bank of New York [Member]
Federal Home Loan Bank Advances [Line Items]
Advances from Federal Home Loan Bank	18,841,000	42,598,000
Advances from federal home loan banks accessible	314,900,000	$ 350,700,000
Federal Home Loan Bank of New York [Member] | Original Maturities Ranging From 3 To 18 Months [Member]
Federal Home Loan Bank Advances [Line Items]
Advances from Federal Home Loan Bank	15,000,000
Federal Home Loan Bank of New York [Member] | FHLB Advances [Member]
Federal Home Loan Bank Advances [Line Items]
Balloon payment in 2026	2,800,000
Federal Home Loan Bank of New York [Member] | Amortizing Term Loan [Member]
Federal Home Loan Bank Advances [Line Items]
Advances from Federal Home Loan Bank	$ 3,800,000
Federal Home Loan Bank of New York [Member] | Minimum [Member] | FHLB Advances [Member]
Federal Home Loan Bank Advances [Line Items]
FHLB short term advances, original maturities	3 months
Federal Home Loan Bank of New York [Member] | Maximum [Member] | FHLB Advances [Member]
Federal Home Loan Bank Advances [Line Items]
FHLB short term advances, original maturities	18 months

FHLB and Other Borrowings - Mat

FHLB and Other Borrowings - Maturity Schedule of Advances (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Federal Home Loan Bank Advances [Line Items]
Amount Due, Total	$ 18,841	$ 42,598
Federal Home Loan Bank of New York [Member]
Federal Home Loan Bank Advances [Line Items]
Amount Due, Within 1 year	10,125	23,757
Amount Due, 1 year to 2 years	5,128	10,125
Amount Due, 2 years to 3 years	131	5,128
Amount Due, 3 years to 4 years	135	131
Amount Due, 4 years to 5 years	138	135
Amount Due, Thereafter	3,184	3,322
Amount Due, Total	$ 18,841	$ 42,598
Weighted Avg Rate, Within 1 year	1.70%	1.27%
Weighted Avg Rate, 1 year to 2 years	1.81%	1.70%
Weighted Avg Rate, 2 years to 3 years	2.62%	1.81%
Weighted Avg Rate, 3 years to 4 years	2.62%	2.62%
Weighted Avg Rate, 4 years to 5 years	2.62%	2.62%
Weighted Avg Rate, Thereafter	2.62%	2.62%
Weighted Avg Rate, Total	1.91%	1.55%

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Contract Amounts of Credit-related Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Standby Letter of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Credit related financial instruments	$ 1,420	$ 705
Commitments to Originate Loans [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Credit related financial instruments	102,644	77,600
Unused Lines of Credit [Member]
Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]
Credit related financial instruments	$ 56,553	$ 45,439

Commitments and Contingencies76

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Rent expense under operating leases	$ 1.9	$ 2.7	$ 2.1

Commitments and Contingencies77

Commitments and Contingencies - Summary of Rent Commitments Before Considering Renewal Options (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
Within 1 year	$ 2,145
1 year to 2 years	2,026
2 year to 3 years	1,737
3 year to 4 years	1,675
4 year to 5 years	1,639
Thereafter	8,283
Total	$ 17,505

Comprehensive Income - Summary

Comprehensive Income - Summary of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		12 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		$ 279,846	$ 109,949	$ 110,271
Total other comprehensive (loss) income		(618)	2,755	(3,248)
Ending Balance		287,559	279,846	109,949
Net Unrealized Gain (Loss) on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		37	523	323
Other comprehensive income before reclassifications		(1,835)	(735)	255
Amounts reclassified from accumulated other comprehensive income		(164)
Tax effect		558	249	(55)
Total other comprehensive (loss) income		(1,441)	(486)	200
Reclassification of certain tax effects on other comprehensive income		(132)
Ending Balance		(1,536)	37	523
Unrealized Losses on Retirement Plans [Member] | Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(5,002)	(7,683)	(4,311)
Other comprehensive income before reclassifications		335	3,973	(5,022)
Amounts reclassified from accumulated other comprehensive income		725	89	398
Tax effect		(270)	(1,381)	1,252
Total other comprehensive (loss) income		790	2,681	(3,372)
Reclassification of certain tax effects on other comprehensive income		(938)
Ending Balance		(5,150)	(5,002)	(7,683)
Unrealized Losses on Retirement Plans [Member] | SERP Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(250)	(810)	(734)
Other comprehensive income before reclassifications		10	(755)	89
Amounts reclassified from accumulated other comprehensive income		34	93	84
Tax effect		(11)	1,222	(249)
Total other comprehensive (loss) income		33	560	(76)
Reclassification of certain tax effects on other comprehensive income		(47)
Ending Balance		(264)	(250)	(810)
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(5,215)	(7,970)	(4,722)
Other comprehensive income before reclassifications		(1,490)	2,483	(4,678)
Amounts reclassified from accumulated other comprehensive income		595	182	482
Tax effect		277	90	948
Total other comprehensive (loss) income		(618)	2,755	(3,248)
Reclassification of certain tax effects on other comprehensive income	[1]	(1,117)
Ending Balance		$ (6,950)	$ (5,215)	$ (7,970)
[1]	The adoption of ASU 2018-02 requires the reclassification from accumulated other comprehensive income to retained earnings of certain stranded income tax effects in accumulated other comprehensive income resulting from the Tax Cuts and Jobs Act of 2017. Refer to Footnote 2 - Recent Accounting Pronouncements for additional information

Comprehensive Income - Summar79

Comprehensive Income - Summary of Accumulated Other Comprehensive Income (Loss) (Parenthetical) (Detail)	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Corporate income tax rate	21.00%	34.00%	28.06%	34.00%	34.00%

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018shares
Earnings Per Share [Abstract]
Number of dilutive potential common stock equivalents	0

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income applicable to common stock	$ 2,669	$ 2,177	$ 2	$ 1,756	$ (1,790)	$ 1,891	$ 1,672	$ 1,456	$ 6,604	$ 3,229	$ 2,926
Average number of common shares outstanding									18,165,110
Less: Average unallocated ESOP shares									1,362,216
Average number of common shares outstanding used to calculate basic earnings per common share									16,802,894
Earnings per Common share:
Basic	$ 0.16	$ 0.13		$ 0.10					$ 0.39
Diluted	$ 0.16	$ 0.13		$ 0.10					$ 0.39

Fair Value of Financial Instr82

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended							12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying amount of loans	$ 902,336,000							$ 902,336,000	$ 809,648,000
Remaining valuation allowance	4,904,000							4,904,000	5,150,000	$ 4,042,000	$ 3,921,000
Net charge-offs								1,270,000	1,129,000	2,133,000
Provision for loan losses	25,000	$ 54,000	$ 200,000	$ 135,000	$ 235,000	$ 562,000	$ 26,000	414,000	823,000	$ 1,859,000
Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying amount of loans	3,900,000							3,900,000	6,300,000
Remaining valuation allowance	$ 451,000							451,000	1,100,000
Net charge-offs								1,100,000	245,000
Provision for loan losses								$ 435,000	$ 1,400,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates								10.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rates								20.00%

Fair Value of Financial Instr83

Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Measured on a Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 105,504	$ 111,889
Measured on a Recurring Basis [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	63,430	63,445
Measured on a Recurring Basis [Member] | Corporate and Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	8,235	8,482
Measured on a Recurring Basis [Member] | Mortgage-backed Securities - Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	33,807	39,930
Measured on a Recurring Basis [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	32	32
Measured on a Recurring Basis [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	105,504	111,889
Measured on a Recurring Basis [Member] | Level 2 [Member] | U.S. Government and Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	63,430	63,445
Measured on a Recurring Basis [Member] | Level 2 [Member] | Corporate and Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	8,235	8,482
Measured on a Recurring Basis [Member] | Level 2 [Member] | Mortgage-backed Securities - Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	33,807	39,930
Measured on a Recurring Basis [Member] | Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	32	32
Measured on a Non-Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3,984	6,049
Measured on a Non-Recurring Basis [Member] | Impaired Loans [Member] | Residential Mortgages [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	688	1,126
Measured on a Non-Recurring Basis [Member] | Impaired Loans [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1,984	2,260
Measured on a Non-Recurring Basis [Member] | Impaired Loans [Member] | Commercial Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	845	1,681
Measured on a Non-Recurring Basis [Member] | Impaired Loans [Member] | Home Equity Lines Of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	7	5
Measured on a Non-Recurring Basis [Member] | Foreclosed Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	460	977
Measured on a Non-Recurring Basis [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3,984	6,049
Measured on a Non-Recurring Basis [Member] | Level 3 [Member] | Impaired Loans [Member] | Residential Mortgages [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	688	1,126
Measured on a Non-Recurring Basis [Member] | Level 3 [Member] | Impaired Loans [Member] | Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1,984	2,260
Measured on a Non-Recurring Basis [Member] | Level 3 [Member] | Impaired Loans [Member] | Commercial Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	845	1,681
Measured on a Non-Recurring Basis [Member] | Level 3 [Member] | Impaired Loans [Member] | Home Equity Lines Of Credit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	7	5
Measured on a Non-Recurring Basis [Member] | Level 3 [Member] | Foreclosed Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 460	$ 977

Fair Value of Financial Instr84

Fair Value of Financial Instruments - Summary of Quantitative Information about Level 3 Fair Value Measurements for Selected Financial Instruments Measured at Fair Value on Non-recurring Basis (Detail) - Measured on a Non-Recurring Basis [Member] - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 3,984	$ 6,049
Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 3,984	$ 6,049
Valuation Technique(s)	Sales contract	Sales comparison
Unobservable Input(s)	Discount to sales contract	Adjustments for differences in sales comparables
Range or Rate Used	9.80%	0.00%
Impaired Loans [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Valuation Technique(s)	Discounted cash flow	Discounted cash flow
Unobservable Input(s)	Discount rate	Discount rate
Range or Rate Used	6.30%
Impaired Loans [Member] | Residential [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 688	$ 1,126
Impaired Loans [Member] | Residential [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 688	$ 1,126
Valuation Technique(s)	Sales comparison	Sales comparison
Unobservable Input(s)	Adjustments for differences in sales comparables	Adjustments for differences in sales comparables
Impaired Loans [Member] | Construction [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 1,984	$ 2,260
Impaired Loans [Member] | Construction [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 1,984	$ 2,260
Valuation Technique(s)	Sales contract	Cost approach
Unobservable Input(s)	Discount to sales contract	Discount for distressed property
Range or Rate Used	9.80%	50.00%
Impaired Loans [Member] | Home Equity Lines Of Credit [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 7	$ 5
Impaired Loans [Member] | Home Equity Lines Of Credit [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 7	$ 5
Valuation Technique(s)	Sales comparison	Discounted cash flow
Unobservable Input(s)	Adjustments for differences in sales comparables	Discount rate
Range or Rate Used		6.30%
Impaired Loans [Member] | Commercial Loans [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 845	$ 1,681
Impaired Loans [Member] | Commercial Loans [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 845	$ 1,681
Valuation Technique(s)	Discounted cash flow	Discounted cash flow
Unobservable Input(s)	Discount rate	Discount rate
Foreclosed Real Estate [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 460	$ 977
Foreclosed Real Estate [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$ 460	$ 977
Valuation Technique(s)	Sales comparison	Sales comparison
Unobservable Input(s)	Adjustments for differences in sales comparables	Adjustments for differences in sales comparables
Minimum [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	5.40%	5.40%
Minimum [Member] | Impaired Loans [Member] | Residential [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	(5.10%)	(5.10%)
Minimum [Member] | Impaired Loans [Member] | Home Equity Lines Of Credit [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	(5.10%)
Minimum [Member] | Impaired Loans [Member] | Commercial Loans [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	5.30%	6.00%
Minimum [Member] | Foreclosed Real Estate [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	(8.10%)	(23.40%)
Maximum [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	6.30%	6.30%
Maximum [Member] | Impaired Loans [Member] | Residential [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	20.90%	7.80%
Maximum [Member] | Impaired Loans [Member] | Home Equity Lines Of Credit [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	20.90%
Maximum [Member] | Impaired Loans [Member] | Commercial Loans [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	7.50%	7.50%
Maximum [Member] | Foreclosed Real Estate [Member] | Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Range or Rate Used	(0.40%)	7.20%

Fair Value of Financial Instr85

Fair Value of Financial Instruments - Summary of Carrying Amounts and Estimated Fair Values of Bank's Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Financial assets:
Investment securities held to maturity	$ 343,188	$ 383,588
Investment securities available for sale	105,504	111,889
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	62,145	60,486
Investment securities held to maturity	353,183	383,551
Investment securities available for sale	105,504	111,889
Loans receivable, net	902,336	809,648
Accrued interest receivable	4,358	3,693
Federal Home Loan Bank stock	2,050	3,132
Financial liabilities:
Mortgage escrow funds	8,803	8,084
FHLB advances	18,841	42,598
Carrying Amount [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Time deposits	765,084	793,681
Carrying Amount [Member] | Time Deposits [Member]
Financial liabilities:
Time deposits	392,373	294,780
Total [Member]
Financial assets:
Cash and cash equivalents	62,145	60,486
Investment securities held to maturity	343,188	383,588
Investment securities available for sale	105,504	111,889
Loans receivable, net	882,319	817,814
Accrued interest receivable	4,358	3,693
Financial liabilities:
Mortgage escrow funds	8,803	8,084
FHLB advances	20,574	45,504
Total [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Time deposits	765,084	793,681
Total [Member] | Time Deposits [Member]
Financial liabilities:
Time deposits	394,205	297,508
Level 1 [Member]
Financial assets:
Cash and cash equivalents	62,145	60,486
Financial liabilities:
Mortgage escrow funds	8,803	8,084
Level 1 [Member] | Demand, NOW, Money Market Deposits and Savings Accounts [Member]
Financial liabilities:
Time deposits	765,084	793,681
Level 2 [Member]
Financial assets:
Investment securities held to maturity	343,188	383,318
Investment securities available for sale	105,504	111,889
Accrued interest receivable	1,402	1,243
Financial liabilities:
FHLB advances	20,574	45,504
Level 2 [Member] | Time Deposits [Member]
Financial liabilities:
Time deposits	394,205	297,508
Level 3 [Member]
Financial assets:
Investment securities held to maturity		270
Loans receivable, net	882,319	817,814
Accrued interest receivable	$ 2,956	$ 2,450

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Current tax expense (benefit)
Federal									$ 2,577	$ 1,344	$ (6)
State									20	(52)	(476)
Total current tax expense (benefit)									2,597	1,292	(482)
Deferred tax expense (benefit)
Federal									2,414	(52)	1,216
State									313	(21)	250
Total deferred tax expense									2,727	(73)	1,466
State tax valuation allowances, net of federal benefit									(302)	47	149
Total	$ 1,075	$ 591	$ 2,551	$ 805	$ (1,017)	$ 878	$ 758	$ 647	$ 5,022	$ 1,266	$ 1,133

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Taxes [Line Items]
Corporate income tax rate		21.00%	34.00%	28.06%	34.00%	34.00%
Re-measurement charge (benefit) through income tax expense	$ 1,600,000			$ 1,600,000
Effective date for change in corporate income tax rate				Jan. 1, 2018
Charitable contribution carryforwards		$ 3,800,000		$ 3,800,000
Charitable contribution carryforwards expiration year				2,022
Reclassification from deferred income tax to retained earnings				$ 2,800,000
Deferred tax liabilities not been recognized of retained earnings				588,000
Unrecognized tax benefits recorded		0		$ 0	$ 0
Unrecognized tax benefits to significantly increase or decrease in the next twelve months				0
New York State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, net		$ 2,100,000		$ 2,100,000
Operating loss carryforwards expiration year				2,034
Maximum [Member]
Income Taxes [Line Items]
Charitable contribution carryforwards expiration period				5 years

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate									21.00%	34.00%	28.06%	34.00%	34.00%
Tax at federal statutory rate											$ 3,262	$ 1,529	$ 1,380
State Taxes, net of federal benefit											24
Tax-exempt income											(61)	(47)	(49)
BOLI income											(157)	(211)	(156)
ESOP Compensation											300	63
Deferred tax re-remeasurement charge											1,570
Other, net											84	(68)	(42)
Total	$ 1,075	$ 591	$ 2,551	$ 805	$ (1,017)	$ 878	$ 758	$ 647			$ 5,022	$ 1,266	$ 1,133
Effective tax rate											43.20%	28.16%	27.91%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Deferred Tax Assets:
Allowance for Loan Losses	$ 1,222	$ 1,983
Deferred compensation	836	1,071
Accrued incentive compensation	110
Purchase accounting adjustments	70	277
Deferred rent	182	380
Other compensation loss (defined benefit plans)	1,439	2,706
Depreciation of premises and equipment	413	405
NOL carryforward	131	602
Charitable contribution carryforward	949	1,820
Nonaccrual loan interest	118	540
Other comprehensive loss (securities)	408
Other		104
Total deferred tax assets	5,878	9,888
Deferred Tax Liabilities:
Prepaid pension costs	2,424	3,622
Deferred loan costs and fees, net	451	457
Other comprehensive income (securities)		19
Other	31	368
Total deferred tax liabilities	2,906	4,466
Deferred tax asset valuation allowance	(350)	(652)
Net Deferred Tax Asset	$ 2,622	$ 4,770

Post-Retirement Benefits - Addi

Post-Retirement Benefits - Additional Information (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Curtailment gain from reduction to salaries and employee benefits expense			$ 919,000
Effective date of freezing of the defined benefit pension plan		May 1, 2017
Defined benefit plan, contributions by employer		$ 0
Percentage of investment in plan assets		100.00%	100.00%
Estimated long-term inflation rate		2.50%
Expected return on plan assets		7.50%
ESOP shares		1,453,209	1,453,209
Stock price		$ 10
ESOP payable term		15 years
ESOP prime rate percentage		4.50%
ESOP borrowing		$ 13,600,000
Number of shares committed to be released per year through 2032		96,881
ESOP Compensation		$ 2,248,000	$ 454,000
Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		67.00%	65.00%
Equity Mutual Funds [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		6.00%
Equity Mutual Funds [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		8.00%
Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		1.00%	1.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		32.00%	34.00%
Fixed Income Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		3.00%
Fixed Income Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		5.00%
Scenario Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, contributions by employer	$ 0
Employee Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pre-tax amounts recognized in accumulated other comprehensive loss		$ 6,500,000	$ 7,600,000
Defined benefit plan, contributions by employer			$ 3,000,000
Assumed discount rates used		4.14%	3.87%
Temporary increase in percentage of bond fund portion		50.00%
Expected return on plan assets		7.50%	7.50%
Benefits Paid		$ 868,000	$ 828,000
Employee Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset rebalancing threshold		10.00%
Employee Pension Plan [Member] | Equity Mutual Funds [Member] | Long-Term Objective [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		65.00%
Employee Pension Plan [Member] | Debt Securities [Member] | Long-Term Objective [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		34.00%
Employee Pension Plan [Member] | Cash Equivalents [Member] | Long-Term Objective [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of investment in plan assets		1.00%
Employee Pension Plan [Member] | Scenario Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss	580,000
Prior service (credit) cost	0
Defined Contribution Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, description		The Company maintained a defined contribution plan for eligible employees hired after October 1, 2012. All full-time employees who have attained age twenty-one and have a minimum of one year of service received a contribution to their 401(k) account equal to 5% of their salary.
Defined contribution plan for eligible employee who hired after		Oct. 1, 2012
Defined contribution plan, minimum age for eligibility to receive contribution		21 years
Defined contribution plan, minimum period of service to receive contribution		1 year
Rate of contribution receive by employee on salary		5.00%
Plan expense		$ 0	120,000	$ 162,000
401 (k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, minimum age for eligibility to receive contribution		21 years
Defined contribution plan, minimum period of service to receive contribution		1 year
Rate of contribution receive by employee on salary		10.00%
Employee contribution minimum percentage rate		2.00%
Employer matching contribution, percent of match		75.00%
Employer matching contribution, percent of employee gross pay		6.00%
Defined contribution savings plan expense		$ 414,000	418,000	410,000
Defined benefit plan effective date of suspension		Jul. 1, 2018
Acquired Pension Plan [Member] | CMS Bancorp [Member]
Defined Benefit Plan Disclosure [Line Items]
Termination of pension plan and chargeable to earning				629,000
Supplemental Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net loss		$ 335,000	379,000
Accrued benefit cost		3,400,000	3,000,000
Projected benefit obligation and accumulated benefit obligation		3,400,000	3,000,000
Pension expense		655,000	615,000	539,000
Benefits Paid		$ 272,000	$ 272,000	$ 272,000
Supplemental Retirement Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed discount rates used		3.16%
Rates of compensation increases used		3.16%
Supplemental Retirement Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumed discount rates used		4.14%
Rates of compensation increases used		4.14%
Supplemental Retirement Plan [Member] | Scenario Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated amortization of net loss	$ 37,000

Post-Retirement Benefits - Summ

Post-Retirement Benefits - Summary of Plan's Funded Status (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Change in plan assets, at fair value:
Employer contributions	$ 0
Employee Pension Plan [Member]
Change in benefit obligation:
Beginning benefit obligation	25,614,000	$ 28,670,000
Service Cost		602,000
Interest Cost	968,000	1,002,000
Actuarial Loss	8,000	(2,013,000)
Benefits Paid	(868,000)	(828,000)
Settlements	(958,000)	(1,301,000)
Curtailment		(518,000)
Ending benefit obligation	24,764,000	25,614,000
Change in plan assets, at fair value:
Beginning plan assets	27,444,000	23,215,000
Actual return	2,357,000	3,358,000
Employer contributions		3,000,000
Benefits paid	(868,000)	(828,000)
Settlements	(958,000)	(1,301,000)
Ending Plan assets	27,975,000	27,444,000
Funded Status	3,211,000	1,830,000
Accumulated Benefit Obligation	$ 24,764,000	$ 25,614,000

Post-Retirement Benefits - Su92

Post-Retirement Benefits - Summary of Net Period Pension Cost, Contributions and Benefits Paid (Detail) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0
Employee Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net period pension cost	(321,000)	$ (224,000)
Employer contributions		3,000,000
Benefits paid	$ 868,000	$ 828,000

Post-Retirement Benefits - Sche

Post-Retirement Benefits - Schedule of Net Periodic Pension Cost and Other Amounts Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Employee Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 602	$ 626
Interest cost	$ 968	1,002	1,086
Expected return on plan assets	(2,014)	(1,917)	(1,796)
Amortization of prior net loss	725	1,200	854
Amortization of prior service cost		(192)	(287)
Gain on curtailment		(919)
New past service liability		602	626
Net periodic cost	(321)	(224)	483
Service cost		602
Interest cost	968	1,002
Supplemental Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior net loss	34	93	84
Service cost	518	398	322
Interest cost	103	124	133
Net periodic cost	$ 655	$ 615	$ 539

Post-Retirement Benefits - Sc94

Post-Retirement Benefits - Schedule of Benefit Payments which Reflects Expected Future Service (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Employee Pension Plan [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
2,019	$ 1,232
2,020	1,259
2,021	1,303
2,022	1,347
2,023	1,365
Following five years	7,202
Supplemental Retirement Plan [Member]
Defined Benefit Plan Estimated Future Benefit Payments [Line Items]
2,019	272
2,020	272
2,021	3,336
2,022	272
2,023	272
Following five years	$ 136

Post-Retirement Benefits - Sc95

Post-Retirement Benefits - Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Pension Cost (Detail)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	7.50%
Employee Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	3.87%	4.04%
Expected return on plan assets	7.50%	7.50%

Post-Retirement Benefits - Sc96

Post-Retirement Benefits - Schedule of Actual Pension Plan Asset Allocation and Target Allocation by Asset Category (Detail)	Jun. 30, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Percentage of Plan Assets	100.00%	100.00%
Equity Mutual Funds And Common/Collective Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	65.00%
Percentage of Plan Assets	67.00%	65.00%
Fixed Income Common/Collective Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	34.00%
Percentage of Plan Assets	32.00%	34.00%
Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	1.00%
Percentage of Plan Assets	1.00%	1.00%

Post-Retirement Benefits - Sc97

Post-Retirement Benefits - Schedule of Fair Value of Plan Assets (Detail) - Employee Pension Plan [Member] - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 27,975	$ 27,444	$ 23,215
Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,975	27,444
Estimate of Fair Value Measurement [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	168	289
Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,807	27,155
Equity Mutual Funds And Common/Collective Trusts [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,914	17,704
Equity Mutual Funds And Common/Collective Trusts [Member] | Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,914	17,704
Fixed Income Common/Collective Trusts [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,893	9,451
Fixed Income Common/Collective Trusts [Member] | Estimate of Fair Value Measurement [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,893	9,451
Cash Equivalents [Member] | Carrying Amount [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	168	289
Cash Equivalents [Member] | Estimate of Fair Value Measurement [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 168	$ 289

Post-Retirement Benefits - Shar

Post-Retirement Benefits - Shares Held by ESOP (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Allocated to participants	144,923	26,975
Unearned	1,308,286	1,426,234
Total ESOP shares	1,453,209	1,453,209
Fair value of unearned shares	$ 25,996	$ 24,332

Regulatory Matters - Summary of

Regulatory Matters - Summary of Company's and Bank's Actual Capital Amounts and Ratios Compared to Required Ratios for Minimum Capital Adequacy and for Classification as Well Capitalized (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Leverage (Tier 1), Bank Actual Amount	$ 287,991	$ 278,528
Common Tier 1, Bank Actual Amount	287,991	278,528
Tier 1, Bank Actual Amount	287,991	278,528
Total, Bank Actual Amount	$ 292,895	$ 283,678
Leverage (Tier 1), Bank Actual Ratio	19.50%	20.00%
Common Tier 1, Bank Actual Ratio	30.30%	31.60%
Tier 1, Bank Actual Ratio	30.30%	31.60%
Total, Bank Actual Ratio	30.80%	32.20%
Leverage (Tier 1), For Capital Adequacy Purposes Amount	$ 58,948	$ 55,839
Common Tier 1, For Capital Adequacy Purposes Amount	42,783	39,631
Tier 1, For Capital Adequacy Purposes Amount	57,044	52,841
Total, For Capital Adequacy Purposes Amount	$ 76,058	$ 70,455
Leverage (Tier 1), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Common Tier 1, For Capital Adequacy Purposes Ratio	4.50%	4.50%
Tier 1, For Capital Adequacy Purposes Ratio	6.00%	6.00%
Total, For Captial Adequacy Purposes Ratio	8.00%	8.00%
PCSB Commercial Bank [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Leverage (Tier 1), Bank Actual Amount	$ 200,488	$ 190,990
Common Tier 1, Bank Actual Amount	200,488	190,990
Tier 1, Bank Actual Amount	200,488	190,990
Total, Bank Actual Amount	$ 205,392	$ 196,140
Leverage (Tier 1), Bank Actual Ratio	13.60%	13.70%
Common Tier 1, Bank Actual Ratio	21.10%	21.70%
Tier 1, Bank Actual Ratio	21.10%	21.70%
Total, Bank Actual Ratio	21.60%	22.30%
Leverage (Tier 1), For Capital Adequacy Purposes Amount	$ 58,924	$ 55,949
Common Tier 1, For Capital Adequacy Purposes Amount	42,745	39,631
Tier 1, For Capital Adequacy Purposes Amount	56,994	52,841
Total, For Capital Adequacy Purposes Amount	$ 75,991	$ 70,455
Leverage (Tier 1), For Capital Adequacy Purposes Ratio	4.00%	4.00%
Common Tier 1, For Capital Adequacy Purposes Ratio	4.50%	4.50%
Tier 1, For Capital Adequacy Purposes Ratio	6.00%	6.00%
Total, For Captial Adequacy Purposes Ratio	8.00%	8.00%
Leverage (Tier 1), To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 73,655	$ 69,936
Common Tier 1, To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	61,743	57,245
Tier 1, To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	75,991	70,455
Total, To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 94,989	$ 88,069
Leverage (Tier 1), To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%	5.00%
Common Tier 1, To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%	6.50%
Tier 1, To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%	8.00%
Total, To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%	10.00%

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer, phase period	4 years
Capital conservation buffer percentage at beginning period	1.875%	1.25%
Minimum [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer percentage required under regulatory	2.50%

Related Party Disclosures - Add

Related Party Disclosures - Additional Information (Detail) - USD ($)	Jun. 30, 2018	Jun. 30, 2017
PCSB Bank [Member]
Related Party Transaction [Line Items]
Insider loans	$ 0	$ 0

Parent Company Only Financia102

Parent Company Only Financial Statements - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2018
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]
Date of establishment	Dec. 9, 2016

Parent Company Only Financia103

Parent Company Only Financial Statements - Parent Company Only Financial Statements (Consolidated Balance Sheets) (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Assets
Cash and cash equivalents	$ 62,145	$ 60,486	$ 41,578	$ 77,761
Other Assets	5,645	5,509
Total assets	1,480,187	1,426,458
Liabilities and stockholders' equity
Other Liabilities	7,527	7,469
Stockholders' equity	287,559	279,846	$ 109,949	$ 110,271
Total liabilities and shareholders' equity	1,480,187	1,426,458
Parent Company [Member]
Assets
Cash and cash equivalents	72,140	71,273
Investment in Bank	200,058	192,308
ESOP Loan receivable	13,563	14,532
Other Assets	1,798	1,888
Total assets	287,559	280,001
Liabilities and stockholders' equity
Other Liabilities		155
Stockholders' equity	287,559	279,846
Total liabilities and shareholders' equity	$ 287,559	$ 280,001

Parent Company Only Financia104

Parent Company Only Financial Statements - Parent Company Only Financial Statements (Consolidated Statements of Operations) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Condensed Income Statements Captions [Line Items]
Interest Income	$ 11,432	$ 10,143	$ 10,186	$ 9,876	$ 9,405	$ 8,958	$ 8,527	$ 8,775	$ 41,637	$ 35,665	$ 34,232
Contribution to PCSB Foundation										5,000
Other non-interest expenses									1,947	1,813	1,843
Net income before income tax expense	3,744	2,768	2,553	2,561	(2,807)	2,769	2,430	2,103	11,626	4,495	4,059
Income tax expense (benefit)	1,075	591	2,551	805	(1,017)	878	758	647	5,022	1,266	1,133
Net income	$ 2,669	$ 2,177	$ 2	$ 1,756	$ (1,790)	$ 1,891	$ 1,672	$ 1,456	6,604	3,229	$ 2,926
Parent Company [Member]
Condensed Income Statements Captions [Line Items]
Interest Income									668	125
Equity in income of Bank									7,188	1,055
Contribution to PCSB Foundation										5,000
Other non-interest expenses									689	105
Net income before income tax expense									7,167	(3,925)
Income tax expense (benefit)									563	(1,693)
Net income									$ 6,604	$ (2,232)

Parent Company Only Financia105

Parent Company Only Financial Statements - Parent Company Only Financial Statements (Consolidated Statements of Cash Flows) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Cash Flows from Operating Activities:
Net income (loss)	$ 6,604	$ 3,229	$ 2,926
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred tax expense (benefit)	2,425	(26)	1,299
Net increase in accrued interest receivable	(665)	(332)	(127)
Other adjustments, principally net changes in other assets and liabilities	1,834	(588)	(431)
Net cash provided by operating activities	14,611	7,835	5,945
Cash Flows from Investing Activities:
Net cash used in investing activities	(58,412)	(148,468)	(101,372)
Cash Flows from Financing Activities:
Common stock dividends declared	(504)
Issuance of common stock	(17)	160,072
Net cash provided by financing activities	45,460	159,541	59,244
Net increase (decrease) in cash and cash equivalents	1,659	18,908	(36,183)
Cash and cash equivalents at beginning of period	60,486	41,578	77,761
Cash and cash equivalents at end of period	62,145	60,486	$ 41,578
Parent Company [Member]
Cash Flows from Operating Activities:
Net income (loss)	6,604	(2,232)
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income of Bank	(7,188)	(1,055)
Issuance of common stock to PCSB Foundation		3,387
Deferred tax expense (benefit)	733	(1,482)
Net increase in accrued interest receivable	(230)	(113)
Other adjustments, principally net changes in other assets and liabilities	(569)	(138)
Net cash provided by operating activities	(650)	(1,633)
Cash Flows from Investing Activities:
Investment in PCSB Bank		(87,350)
Decrease (increase) in ESOP loan	969	(14,532)
Net cash used in investing activities	969	(101,882)
Cash Flows from Financing Activities:
Common stock dividends declared	(504)
Allocation of ESOP shares	1,069	184
Issuance of common stock	(17)	174,604
Net cash provided by financing activities	548	174,788
Net increase (decrease) in cash and cash equivalents	867	71,273
Cash and cash equivalents at beginning of period	71,273
Cash and cash equivalents at end of period	$ 72,140	$ 71,273

Quarterly Financial Informat106

Quarterly Financial Information (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 13,358	$ 11,648	$ 11,657	$ 11,297	$ 10,723	$ 10,276	$ 9,850	$ 10,109	$ 47,960	$ 40,958	$ 39,044
Interest expense	1,926	1,505	1,471	1,421	1,318	1,318	1,323	1,334	6,323	5,293	4,812
Net interest income	11,432	10,143	10,186	9,876	9,405	8,958	8,527	8,775	41,637	35,665	34,232
Provision for loan losses	25	54	200	135		235	562	26	414	823	1,859
Non-interest income	601	512	692	714	647	626	2,259	552	2,519	4,084	1,951
Non-interest expense	8,264	7,833	8,125	7,894	12,859	6,580	7,794	7,198	32,116	34,431	30,265
Net income before income tax expense	3,744	2,768	2,553	2,561	(2,807)	2,769	2,430	2,103	11,626	4,495	4,059
Income tax expense	1,075	591	2,551	805	(1,017)	878	758	647	5,022	1,266	1,133
Net income	$ 2,669	$ 2,177	$ 2	$ 1,756	$ (1,790)	$ 1,891	$ 1,672	$ 1,456	$ 6,604	$ 3,229	$ 2,926
Earnings per share
Basic	$ 0.16	$ 0.13		$ 0.10					$ 0.39
Diluted	$ 0.16	$ 0.13		$ 0.10					$ 0.39

Quarterly Financial Informat107

Quarterly Financial Information (Unaudited) (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Re-measurement of deferred tax asset	$ 1.6					$ 1.6
Corporate income tax rate				21.00%	34.00%	28.06%	34.00%	34.00%
CMS Bancorp [Member]
Charged-off on loan settlement			$ 1.6
PCSB Community Foundation [Member]
Contribution expenses		$ 5