BankFinancial (BFIN) 10-Q 26 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 22, 2018
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2,018
Entity Registrant Name	BankFinancial CORP
Entity Central Index Key	1,303,942
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Common Stock, Shares Outstanding		16,996,173

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and due from other financial institutions	$ 12,473	$ 13,572
Interest-bearing deposits in other financial institutions	74,461	114,020
Cash and cash equivalents	86,934	127,592
Securities, at fair value	103,921	93,383
Loans receivable, net of allowance for loan losses: September 30, 2018, $8,103 and December 31, 2017, $8,366	1,267,787	1,314,651
Other real estate owned, net	985	2,351
Stock in Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB), at cost	8,026	8,290
Premises held-for-sale	0	5,667
Premises and equipment, net	24,473	24,856
Accrued interest receivable	4,974	4,619
Core deposit intangible	123	286
Bank owned life insurance	18,781	22,859
Deferred taxes	8,911	12,563
Other assets	7,569	8,441
Total assets	1,532,484	1,625,558
Deposits
Noninterest-bearing	225,446	234,354
Interest-bearing	1,070,324	1,105,697
Total deposits	1,295,770	1,340,051
Borrowings	21,232	60,768
Advance payments by borrowers for taxes and insurance	11,015	11,645
Accrued interest payable and other liabilities	12,384	15,460
Total liabilities	1,340,401	1,427,924
Commitments and contingent liabilities
Stockholders’ equity
Preferred Stock, $0.01 par value, 25,000,000 shares authorized, none issued or outstanding	0	0
Common Stock, $0.01 par value, 100,000,000 shares authorized; 17,206,303 shares issued at September 30, 2018 and 17,958,723 issued at December 31, 2017	172	179
Additional paid-in capital	141,230	153,811
Retained earnings	50,437	43,274
Accumulated other comprehensive income	244	370
Total stockholders’ equity	192,083	197,634
Total liabilities and stockholders’ equity	$ 1,532,484	$ 1,625,558

Consolidated Statements of Fi_2

Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for loan losses	$ 8,103	$ 8,366
Preferred Stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized	25,000,000	25,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common Stock, par value (usd per share)	$ 0.01	$ 0.01
Common Stock, shares authorized	100,000,000	100,000,000
Common Stock, shares issued	17,206,303	17,958,723

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest and dividend income
Loans, including fees	$ 14,248	$ 13,345	$ 42,045	$ 39,061
Securities	627	389	1,637	1,095
Other	498	387	1,459	976
Total interest income	15,373	14,121	45,141	41,132
Interest expense
Deposits	2,278	1,419	5,632	3,903
Borrowings	130	196	542	444
Borrowings	2,408	1,615	6,174	4,347
Net interest income	12,965	12,506	38,967	36,785
Recovery of loan losses	(23)	(225)	(258)	(15)
Net interest income after recovery of loan losses	12,988	12,731	39,225	36,800
Noninterest income
Income from product and service	1,003	1,018	2,970	2,964
Loan fee income	71	89	231	212
Commercial mortgage brokerage fees	12	0	138	0
Residential mortgage banking fees	34	41	88	172
Loss on sales of equity securities	0	0	(14)	0
Gain on sale of premises held-for-sale	0	0	93	0
Loss on sales of equity securities		0
Trust and insurance commissions and annuities income	207	210	670	704
Earnings on bank-owned life insurance	35	67	146	196
Bank-owned life insurance death benefit	0	0	1,389	0
Other	208	198	492	526
Total noninterest income	1,570	1,623	6,203	4,774
Noninterest expense
Compensation and benefits	5,120	5,330	16,232	16,792
Office occupancy and equipment	1,629	1,693	5,022	4,914
Advertising and public relations	194	167	611	807
Information technology	717	638	2,066	2,070
Supplies, telephone, and postage	341	337	1,070	1,027
Amortization of intangibles	20	123	163	374
Nonperforming asset management	60	84	313	215
Operations of other real estate owned	59	403	355	861
FDIC insurance premiums	115	150	338	462
Other	1,170	1,275	3,429	3,551
Total noninterest expense	9,425	10,200	29,599	31,073
Income before income taxes	5,133	4,154	15,829	10,501
Income tax expense	1,396	594	3,903	2,488
Net income	$ 3,737	$ 3,560	$ 11,926	$ 8,013
Basic earnings per common share (usd per share)	$ 0.22	$ 0.20	$ 0.68	$ 0.44
Diluted earnings per common share (usd per share)	$ 0.22	$ 0.20	$ 0.68	$ 0.44
Weighted average common shares outstanding (shares)	17,365,679	18,139,659	17,641,308	18,368,742
Diluted weighted average common shares outstanding (shares)	17,365,679	18,140,109	17,641,308	18,369,170

Consolidated Statements Compreh

Consolidated Statements Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income	$ 3,737	$ 3,560	$ 11,926	$ 8,013
Unrealized holding loss arising during the period	49	(16)	173	67
Tax effect	13	(9)	47	22
Net of tax	(36)	7	(126)	(45)
Comprehensive income	$ 3,701	$ 3,567	$ 11,800	$ 7,968

Consolidated Statements of Chan

Consolidated Statements of Changes In Stockholders' Equity - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Unearned Employee Stock Ownership Plan Shares	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2017	$ 197,634	$ 179	$ 153,811	$ 43,274	$ 0	$ 370
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,926			11,926
Other comprehensive loss, net of tax	(126)					(126)
Nonvested stock awards-stock-based compensation expense	6		6
Repurchase and retirement of common stock	(12,594)	(7)	(12,587)
Cash dividends declared on common stock	(4,763)			(4,763)
Ending Balance at Sep. 30, 2018	$ 192,083	$ 172	$ 141,230	$ 50,437	$ 0	$ 244

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Share-based compensation arrangement by share-based payment award, options, exercisable, number (in shares)	0	198,026
Cash dividends declared on common stock (in dollars per share)	$ 0.27	$ 0.20
Repurchase and retirement of common stock (in shares)	752,174	614,673,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flow - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 11,926	$ 8,013
Adjustments to reconcile to net income to net cash from operating activities
Recovery of loan losses	(258)	(15)
Prepayment of ESOP Share Acquisition Loan	0	1,125
Stock–based compensation expense	6	0
Depreciation and amortization	2,513	2,846
Amortization of premiums and discounts on securities and loans	9	(72)
Amortization of core deposit intangible	163	374
Amortization of servicing assets	79	86
Net change in net deferred loan origination costs	53	343
Loss on sale of other real estate owned	56	100
Net gain on sale of loans	0	(70)
Loss on sale of equity securities	(14)	0
Gain on sale of premises held-for-sale	93	0
Loans originated for sale	0	(1,291)
Proceeds from sale of loans	0	1,361
Other real estate owned valuation adjustments	27	301
Net change in:
Accrued interest receivable	(355)	(188)
Earnings on bank owned life insurance	(146)	(196)
Other assets	3,540	4,027
Accrued interest payable and other liabilities	(3,076)	(1,966)
Net cash from operating activities	14,458	14,778
Securities
Proceeds from maturities	76,164	49,695
Proceeds from principal repayments	2,970	2,461
Proceeds from sale of equity securities	487	0
Purchases of securities	(90,355)	(43,808)
Loans receivable
Loan participations sold	0	3,615
Principal payments on loans receivable	729,474	459,706
Purchase of loans	0	(23,451)
Originated for investment	(683,685)	(465,562)
Purchase of FHLB and FRB stock	(21)	(154)
Redemption of FHLB and FRB stock	(285)	(3,514)
Bank-owned life insurance death benefit	4,224	0
Proceeds from sale of premises held-for-sale	5,485	0
Proceeds from sale of other real estate owned	2,172	1,966
Purchase of premises and equipment, net	(512)	(906)
Net cash from (used in) investing activities	46,688	(12,924)
Cash flows from financing activities
Net change in deposits	(44,281)	31,699
Net change in borrowings	(39,536)	9,859
Net change in advance payments by borrowers for taxes and insurance	(630)	(358)
Payments for Repurchase of Common Stock	(12,594)	(9,148)
Payments of Ordinary Dividends, Common Stock	(4,763)	(3,710)
Payments for Deposits Applied to Debt Retirements	0	1,219
Net cash used in financing activities	(101,804)	27,123
Net change in cash and cash equivalents	(40,658)	28,977
Beginning cash and cash equivalents	127,592	96,684
Ending cash and cash equivalents	86,934
Supplemental disclosures of cash flow information:
Interest paid	5,960	4,269
Income taxes paid	250	198
Loans transferred to other real estate owned	$ 1,241	$ 2,041

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Basis of Presentation : BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois, is the owner of all of the issued and outstanding capital stock of BankFinancial, NA (the “Bank”). The interim unaudited consolidated financial statements include the accounts and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BFIN Asset Recovery Company, LLC (collectively, “the Company”), and reflect all normal and recurring adjustments that are, in the opinion of management, considered necessary for a fair presentation of the financial condition and results of operations for the periods presented. Such adjustments are the only adjustments reflected in the accompanying financial statements. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three and nine month periods ended September 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018 or for any other period. Certain information and note disclosures normally included in financial statements prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission. Use of Estimates : To prepare financial statements in conformity with GAAP, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided, and future results could differ. Reclassifications : Certain reclassifications have been made in the prior period’s financial statements to conform them to the current period’s presentation. These unaudited consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , as filed with the Securities and Exchange Commission. Recent Accounting Pronouncements In May 2014, the FASB issued an update (ASU No. 2014-09, Revenue from Contracts with Customers) creating FASB Topic 606, Revenue from Contracts with Customers. The guidance in this update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides steps to follow to achieve the core principle. An entity should disclose sufficient information to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Qualitative and quantitative information is required about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The amendments in this update became effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the update and have concluded that it does not have a significant impact to our consolidated financial statements. The Company’s revenue streams that are in-scope from the update include: financed OREO sales; deposit fees, including ATM fees, overdraft fees, maintenance fees and dormancy fees; debit card fees, and trust fees. For the in-scope revenue streams, our current revenue recognition is not different than our prior revenue recognition under the update. The Company has infrequently financed an OREO sale. Our customer contracts generally do not have performance obligations and fees are assessed and collected as the transaction occurs. The Company’s fee income is not material for any individual income streams. The adoption of ASC 606 did not result in a change to the accounting for any of the in-scope revenue stream; as such, no cumulative effect adjustment was recorded. Refer to Note 8 - Revenue for Contracts with Customers for further discussion on the Company's accounting policies for revenue sources within the scope of ASC 606. In January 2016, the FASB issued an update (ASU No. 2016-01, Financial Instruments - Recognition and Measurement of Financial Assets and Liabilities). The new guidance is intended to improve the recognition and measurement of financial instruments by requiring: equity investments (other than equity method or consolidation) to be measured at fair value with changes in fair value recognized in net income; public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; separate presentation of financial assets and financial liabilities by measurement category and form of financial assets ( i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities; eliminating the requirement for non-public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is to be required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requiring a reporting organization to present separately in other comprehensive income the portion of the total change in fair value of a liability resulting from the change in the instrument-specific credit risk (also referred to as “own credit”) when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance became effective for public business entities for fiscal years beginning after December 15, 2017. The new pronouncement does not have a significant impact on our Statement of Operations, as we had one equity security that was valued at $499,000 at December 31, 2017 and none at September 30, 2018 . In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than 12 months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our preliminary finding is that the new pronouncement will not have a significant impact on our consolidated financial statements as the projected minimum lease payments under existing leases subject to the new pronouncement are less than one percent of our current total assets. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). These amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 ( i.e. , January 1, 2020, for calendar year entities). Early application will be permitted for all organizations for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our initial review indicates that we have maintained sufficient historical loan data to support the requirements of this pronouncement. In addition, we have begun tracking the average life of the various segments of our loan portfolio. We are currently evaluating various loss methodologies to determine their correlation to our various loan categories' historical performance. In August 2018, we contracted with a third-party vendor to provide a model and assist with assessing processes, portfolio segmentation, and model development. In March 2017, the FASB issued ASU No. 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities” (“ASU 2017-08”). This guidance shortens the amortization period for premiums on certain callable debt securities to the earliest call date (with an explicit, noncontingent call feature that is callable at a fixed price and on a preset dates), rather than contractual maturity date as currently required under GAAP. The ASU does not impact instruments without preset call dates such as mortgage-backed securities. For instruments with contingent call features, once the contingency is resolved and the security is callable at a fixed price and preset date, the security is within the scope of the ASU. ASU 2017-08 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early adoption is permitted. Effective January 2017, we early adopted the pronouncement. Adoption of the new pronouncement was immaterial to the consolidated financial statements.

Earnings Per Share (Notes)

Earnings Per Share (Notes)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Amounts reported in earnings per share reflect earnings available to common stockholders for the period divided by the weighted average number of shares of common stock outstanding during the period, exclusive of unearned BankFinancial, NA Employee Stock Ownership Plan (the "ESOP") shares in 2017 and unvested restricted stock shares. Stock options and restricted stock are regarded as potential common stock and are considered in the diluted earnings per share calculations to the extent that they would have a dilutive effect if converted to common stock. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net income available to common stockholders $ 3,737 $ 3,560 $ 11,926 $ 8,013 Average common shares outstanding 17,365,679 18,140,599 17,641,743 18,567,796 Less: Unearned ESOP shares — — — (198,114 ) Unvested restricted stock shares — (940 ) (435 ) (940 ) Weighted average common shares outstanding 17,365,679 18,139,659 17,641,308 18,368,742 Add - Net effect of dilutive unvested restricted stock — 450 — 428 Diluted weighted average common shares outstanding 17,365,679 18,140,109 17,641,308 18,369,170 Basic earnings per common share $ 0.22 $ 0.20 $ 0.68 $ 0.44 Diluted earnings per common share $ 0.22 $ 0.20 $ 0.68 $ 0.44

Securities (Notes)

Securities (Notes)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
SECURITIES	The fair value of securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income are shown below. Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value September 30, 2018 Certificates of deposit $ 89,175 $ — $ — $ 89,175 Mortgage-backed securities - residential 10,593 393 (61 ) 10,925 Collateralized mortgage obligations - residential 3,819 13 (11 ) 3,821 $ 103,587 $ 406 $ (72 ) $ 103,921 December 31, 2017 Certificates of deposit $ 75,916 $ — $ — $ 75,916 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 11,969 520 (17 ) 12,472 Collateralized mortgage obligations - residential 4,481 16 (11 ) 4,486 SBA-guaranteed loan participation certificates 10 — — 10 $ 92,876 $ 536 $ (29 ) $ 93,383 The mortgage-backed securities and collateralized mortgage obligations reflected in the preceding table were issued by U.S. government-sponsored entities or agencies, Freddie Mac, Fannie Mae and Ginnie Mae, and are obligations which the government has affirmed its commitment to support. All securities reflected in the preceding table were classified as available-for-sale at September 30, 2018 and December 31, 2017 . The amortized cost and fair values of securities by contractual maturity are shown below. Securities not due at a single maturity date are shown separately. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2018 Amortized Cost Fair Value Due in one year or less $ 89,175 $ 89,175 Mortgage-backed securities - residential 10,593 10,925 Collateralized mortgage obligations - residential 3,819 3,821 $ 103,587 $ 103,921 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Proceeds $ — $ — $ 487 $ — Gross gains — — — — Gross losses — — (14 ) — Securities with unrealized losses not recognized in income are as follows: Less than 12 Months 12 Months or More Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss September 30, 2018 Mortgage-backed securities - residential $ 924 $ (6 ) $ 1,004 $ (55 ) $ 1,928 $ (61 ) Collateralized mortgage obligations - residential — — 1,796 (11 ) 1,796 (11 ) $ 924 $ (6 ) $ 2,800 $ (66 ) $ 3,724 $ (72 ) December 31, 2017 Equity mutual fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential — — 1,149 (17 ) 1,149 (17 ) Collateralized mortgage obligations - residential — — 2,083 (11 ) 2,083 (11 ) $ 499 $ (1 ) $ 3,232 $ (28 ) $ 3,731 $ (29 ) The Company evaluates marketable investment securities with significant declines in fair value on a quarterly basis to determine whether they should be considered other-than-temporarily impaired under current accounting guidance, which generally provides that if a marketable security is in an unrealized loss position, whether due to general market conditions or industry or issuer-specific factors, the holder of the securities must assess whether the impairment is other-than-temporary. Certain mortgage-backed securities and collateralized mortgage obligations that the Company holds in its investment portfolio were in an unrealized loss position at September 30, 2018 , but the unrealized losses were not considered significant under the Company’s impairment testing methodology. In addition, the Company does not intend to sell these securities, and it is likely that the Company will not be required to sell these securities before their anticipated recovery occurs.

Loans Receivable (Notes)

Loans Receivable (Notes)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Loans receivable are as follows: September 30, 2018 December 31, 2017 One-to-four family residential real estate $ 77,591 $ 97,814 Multi-family mortgage 581,880 588,383 Nonresidential real estate 148,010 169,971 Construction and land 1,130 1,358 Commercial loans 167,547 152,552 Commercial leases 297,103 310,076 Consumer 1,416 1,597 1,274,677 1,321,751 Net deferred loan origination costs 1,213 1,266 Allowance for loan losses (8,103 ) (8,366 ) Loans, net $ 1,267,787 $ 1,314,651 The following tables present the balance in the allowance for loan losses and the loans receivable by portfolio segment and based on impairment method: Allowance for loan losses Loan Balances Individually evaluated for impairment Collectively evaluated for impairment Total Individually evaluated for impairment Collectively evaluated for impairment Total September 30, 2018 One-to-four family residential real estate $ — $ 762 $ 762 $ 2,724 $ 74,867 $ 77,591 Multi-family mortgage — 3,722 3,722 661 581,219 581,880 Nonresidential real estate — 1,410 1,410 — 148,010 148,010 Construction and land — 27 27 — 1,130 1,130 Commercial loans — 1,482 1,482 — 167,547 167,547 Commercial leases — 684 684 — 297,103 297,103 Consumer — 16 16 — 1,416 1,416 $ — $ 8,103 $ 8,103 $ 3,385 $ 1,271,292 1,274,677 Net deferred loan origination costs 1,213 Allowance for loan losses (8,103 ) Loans, net $ 1,267,787 Allowance for loan losses Loan Balances Individually evaluated for impairment Collectively evaluated for impairment Total Individually evaluated for impairment Collectively evaluated for impairment Total December 31, 2017 One-to-four family residential real estate $ — $ 850 $ 850 $ 4,265 $ 93,549 $ 97,814 Multi-family mortgage — 3,849 3,849 949 587,434 588,383 Nonresidential real estate — 1,605 1,605 — 169,971 169,971 Construction and land — 32 32 — 1,358 1,358 Commercial loans — 1,357 1,357 — 152,552 152,552 Commercial leases — 655 655 — 310,076 310,076 Consumer — 18 18 — 1,597 1,597 $ — $ 8,366 $ 8,366 $ 5,214 $ 1,316,537 1,321,751 Net deferred loan origination costs 1,266 Allowance for loan losses (8,366 ) Loans, net $ 1,314,651 Activity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 8,179 $ 8,122 $ 8,366 $ 8,127 Loans charged off: One-to-four family residential real estate (84 ) (89 ) (214 ) (282 ) Multi-family mortgage — (7 ) (35 ) (10 ) Nonresidential real estate — — — (165 ) Commercial loans — — (140 ) — Consumer (6 ) (7 ) (7 ) (7 ) (90 ) (103 ) (396 ) (464 ) Recoveries: One-to-four family residential real estate 25 15 130 100 Multi-family mortgage 8 11 26 62 Nonresidential real estate — 10 — 10 Construction and land 2 — 2 — Commercial loans 2 542 227 552 Commercial leases — 2 5 2 Consumer — — 1 — 37 580 391 726 Net recoveries (charge-offs) (53 ) 477 (5 ) 262 Recovery of loan losses (23 ) (225 ) (258 ) (15 ) Ending balance $ 8,103 $ 8,374 $ 8,103 $ 8,374 The following tables present the recorded investment in nonaccrual loans and loans past due over 90 days still on accrual by class of loans: Loan Balance Recorded Investment Loans Past Due Over 90 Days, Still Accruing September 30, 2018 One-to-four family residential real estate $ 1,646 $ 1,313 $ — One-to-four family residential real estate – non-owner occupied 95 56 — Multi-family mortgage - Illinois 102 102 — $ 1,843 $ 1,471 $ — December 31, 2017 One-to-four family residential real estate $ 3,413 $ 1,918 $ — One-to-four family residential real estate – non-owner occupied 308 109 — Multi-family mortgage - Illinois 376 363 — $ 4,097 $ 2,390 $ — Nonaccrual loans and impaired loans are defined differently. Some loans may be included in both categories, and some loans may only be included in one category. Nonaccrual loans include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. The Company’s reserve for uncollected loan interest was $36,000 and $103,000 at September 30, 2018 and December 31, 2017 , respectively. When a loan is on nonaccrual status and the ultimate collectability of the total principal of an impaired loan is in doubt, all payments are applied to principal under the cost recovery method. Alternatively, when a loan is on non-accrual status but there is doubt concerning only the ultimate collectability of interest, contractual interest is credited to interest income only when received, under the cash basis method pursuant to the provisions of FASB ASC 310–10, as applicable. In all cases, the average balances are calculated based on the month–end balances of the financing receivables within the period reported pursuant to the provisions of FASB ASC 310–10, as applicable. The following tables present the aging of the recorded investment of loans at September 30, 2018 by class of loans: 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Past Due Total Past Due Loans Not Past Due Total One-to-four family residential real estate loans $ 392 $ — $ 1,329 $ 1,721 $ 59,925 $ 61,646 One-to-four family residential real estate loans – non-owner occupied 34 8 48 90 15,817 15,907 Multi-family mortgage - Illinois — — 102 102 275,714 275,816 Multi-family mortgage - Other — — — — 299,469 299,469 Nonresidential real estate 607 — — 607 146,394 147,001 Construction — — — — 932 932 Land — — — — 198 198 Commercial loans: Regional commercial banking — — — — 50,105 50,105 Health care — — — — 69,248 69,248 Direct commercial lessor — — — — 48,942 48,942 Commercial leases: Investment rated commercial leases 787 — — 787 181,402 182,189 Other commercial leases — — — — 116,651 116,651 Consumer 12 5 — 17 1,410 1,427 $ 1,832 $ 13 $ 1,479 $ 3,324 $ 1,266,207 $ 1,269,531 The following tables present the aging of the recorded investment of loans at December 31, 2017 by class of loans: 30-59 Days Past Due 60-89 Days Past Due 90 Days or Total Past Due Loans Not Past Due Total One-to-four family residential real estate loans $ 86 $ 99 $ 1,801 $ 1,986 $ 74,216 $ 76,202 One-to-four family residential real estate loans – non-owner occupied 10 3 86 99 20,944 21,043 Multi-family mortgage - Illinois 172 — 364 536 287,171 287,707 Multi-family mortgage - Other — — — — 296,440 296,440 Nonresidential real estate 608 — — 608 166,071 166,679 Construction — — — — 1,103 1,103 Land — — — — 259 259 Commercial loans: Regional commercial banking — — — — 40,935 40,935 Health care — — — — 71,738 71,738 Direct commercial lessor — — — — 40,237 40,237 Commercial leases: Investment rated commercial leases 934 — — 934 207,747 208,681 Other commercial leases 288 — — 288 102,873 103,161 Consumer — — — — 1,605 1,605 $ 2,098 $ 102 $ 2,251 $ 4,451 $ 1,311,339 $ 1,315,790 The Company evaluates loan extensions or modifications in accordance with FASB ASC 310–40 with respect to the classification of the loan as a Troubled Debt Restructuring ("TDR"). In general, if the Company grants a loan extension or modification to a borrower experiencing financial difficulties for other than an insignificant period of time that includes a below–market interest rate, principal forgiveness, payment forbearance or other concession intended to minimize the economic loss to the Company, the loan extension or loan modification is classified as a TDR. In cases where borrowers are granted new terms that provide for a reduction of either interest or principal then due and payable, management measures any impairment on the restructured loan in the same manner as for impaired loans as noted above. The Company had $17,000 of TDRs at September 30, 2018 and December 31, 2017 . No specific valuation reserves were allocated to those loans at September 30, 2018 and December 31, 2017 . The Company had no outstanding commitments to borrowers whose loans were classified as TDRs at either date. The following table presents loans classified as TDRs: September 30, 2018 December 31, 2017 One-to-four family residential real estate - nonaccrual $ 17 $ 17 During the three and nine months ended September 30, 2018 and 2017 , there were no loans modified and classified as TDRs. The following table presents TDRs for which there was a payment default within twelve months following the modification. 2018 2017 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate — $ — 1 $ 17 A TDR is considered to be in payment default once it is 90 days contractually past due under the modified terms. There were no payment defaults on TDRs within twelve months following the modification during the three and nine months ended September 30, 2018 . There were no loan modifications during the three and nine months ended September 30, 2018 . There were certain loan modifications during the three and nine months ended September 30, 2017 that did not meet the definition of a TDR. These loans had a total recorded investment of $149,000 at September 30, 2017 . The modification of these loans involved either a modification of the terms of a loan to borrowers who were not experiencing financial difficulties or a delay in a payment that was considered to be insignificant. 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. The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt, including 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 based on 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 uses the following definitions for risk ratings: Special Mention. A Special Mention asset has potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the institution’s credit position at some future date. Special Mention assets are not adversely classified and do not expose an institution to sufficient risk to warrant adverse classification. Substandard. Loans categorized as Substandard continue to accrue interest, but exhibit a well-defined weakness or weaknesses that may jeopardize the liquidation of the debt. The loans continue to accrue interest because they are well secured and collection of principal and interest is expected within a reasonable time. The risk rating guidance published by the Office of the Comptroller of the Currency clarifies that a loan with a well-defined weakness does not have to present a probability of default for the loan to be rated Substandard, and that an individual loan’s loss potential does not have to be distinct for the loan to be rated Substandard. Nonaccrual. An asset classified Nonaccrual has all the weaknesses inherent in one classified 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 are considered “Pass” rated loans. As of September 30, 2018 , based on the most recent analysis performed, the risk categories of loans by class of loans are as follows: Pass Special Mention Substandard Nonaccrual Total One-to-four family residential real estate loans $ 59,714 $ 310 $ 372 $ 1,314 $ 61,710 One-to-four family residential real estate loans – non-owner occupied 15,755 33 37 56 15,881 Multi-family mortgage loans - Illinois 276,398 — 310 102 276,810 Multi-family mortgage loans - Other 305,070 — — — 305,070 Nonresidential real estate loans 147,911 — 99 — 148,010 Construction loans 929 — — — 929 Land loans 201 — — — 201 Commercial loans: Regional commercial banking 45,170 4,815 — — 49,985 Health care 64,374 — 4,699 — 69,073 Direct commercial lessor 48,489 — — — 48,489 Commercial leases: Investment rated commercial leases 180,383 748 — — 181,131 Other commercial leases 115,972 — — — 115,972 Consumer 1,401 5 10 — 1,416 $ 1,261,767 $ 5,911 $ 5,527 $ 1,472 $ 1,274,677 As of December 31, 2017 , the risk categories of loans by class of loans are as follows: Pass Special Mention Substandard Nonaccrual Total One-to-four family residential real estate loans $ 74,437 $ — $ 255 $ 1,914 $ 76,606 One-to-four family residential real estate loans – non-owner occupied 21,059 — 40 109 21,208 Multi-family mortgage loans - Illinois 290,765 — 225 368 291,358 Multi-family mortgage loans - Other 297,025 — — — 297,025 Nonresidential real estate loans 169,817 — 154 — 169,971 Construction loans 1,099 — — — 1,099 Land loans 259 — — — 259 Commercial loans: Regional commercial banking 36,373 4,528 — — 40,901 Health care 69,480 — 2,248 — 71,728 Direct commercial lessor 39,923 — — — 39,923 Commercial leases: Investment rated commercial leases 207,460 — — — 207,460 Other commercial leases 102,616 — — — 102,616 Consumer 1,597 — — — 1,597 $ 1,311,910 $ 4,528 $ 2,922 $ 2,391 $ 1,321,751

Other Real Estate Owned (Notes)

Other Real Estate Owned (Notes)	9 Months Ended
	Sep. 30, 2018
Other Real Estate [Abstract]
Real Estate Owned [Text Block]	R eal estate that is acquired through foreclosure or a deed in lieu of foreclosure is classified as other real estate owned ("OREO") until it is sold. When real estate is acquired through foreclosure or by deed in lieu of foreclosure, it is recorded at its fair value, less the estimated costs of disposal. If the fair value of the property is less than the loan balance, the difference is charged against the allowance for loan losses. September 30, 2018 December 31, 2017 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 634 $ — $ 634 $ 836 $ (9 ) $ 827 Multi-family mortgage 276 — 276 — — — Nonresidential real estate 74 — 74 1,772 (252 ) 1,520 Land 24 (23 ) 1 48 (44 ) 4 $ 1,008 $ (23 ) $ 985 $ 2,656 $ (305 ) $ 2,351 The following represents the roll forward of OREO and the composition of OREO properties: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 1,187 $ 4,896 $ 2,351 $ 3,895 New foreclosed properties 403 105 1,241 2,041 Valuation adjustments (1 ) (227 ) (27 ) (301 ) Sales and payments (604 ) (1,205 ) (2,580 ) (2,066 ) Ending balance $ 985 $ 3,569 $ 985 $ 3,569 Activity in the valuation allowance is as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 44 $ 308 $ 305 $ 449 Additions charged to expense 1 227 27 301 Reductions from sales of OREO (22 ) (63 ) (309 ) (278 ) Ending balance $ 23 $ 472 $ 23 $ 472 At September 30, 2018 , the balance of OREO included no foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property without title. At December 31, 2017 the balance of OREO included $352,000 of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property without title. At September 30, 2018 and December 31, 2017 , the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process was $603,000 and $1.5 million , respectively.

Securities Sold Under Agreement

Securities Sold Under Agreements to Repurchase (Notes)	9 Months Ended
	Sep. 30, 2018
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold Under Agreements to Repurchase	Securities sold under agreements to repurchase, included with borrowings on the consolidated balance sheet, are shown below. Overnight and Continuous Up to 30 days 30 - 90 days Greater Than 90 days Total September 30, 2018 Repurchase agreements and repurchase-to-maturity transactions $ 1,232 $ — $ — $ — $ 1,232 Gross amount of recognized liabilities for repurchase agreements in Statement of Condition $ 1,232 December 31, 2017 Repurchase agreements and repurchase-to-maturity transactions $ 768 $ — $ — $ — $ 768 Gross amount of recognized liabilities for repurchase agreements in Statement of Condition $ 768 Securities sold under agreements to repurchase were secured by mortgage-backed securities with a carrying amount of $2.7 million and $3.7 million at September 30, 2018 and December 31, 2017 , respectively. Also included in total borrowings were advances from the FHLB of $20.0 million at September 30, 2018 and $60.0 million at December 31, 2017 . Because security values fluctuate due to market conditions, the Company has no control over the market value of securities sold under agreements to repurchase. The Company is contractually obligated to promptly transfer additional securities to the counterparty if the market value of the securities falls below the repurchase price.

Fair Value (Notes)

Fair Value (Notes)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE 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 company’s own assumptions about the assumptions that market participants would use in pricing an asset or liability. The Company used the following methods and significant assumptions to estimate the fair value of each type of financial instrument: Securities : The fair values of marketable equity securities are generally determined by quoted prices, in active markets, for each specific security (Level 1). If Level 1 measurement inputs are not available for a marketable equity security, we determine its fair value based on the quoted price of a similar security traded in an active market (Level 2). The fair values of debt securities are generally determined by matrix pricing, which is a mathematical technique widely used in the industry to value debt securities without relying exclusively on quoted prices for the specific securities, but rather by relying on the securities’ relationship to other benchmark quoted securities (Level 2). Impaired Loans: The fair value of impaired loans with specific allocations of the allowance for loan losses is generally based on recent real estate appraisals. These appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach. Adjustments are routinely made in the appraisal process by the independent appraisers to adjust for differences between the comparable sales and income data available for similar loans and collateral underlying such loans. Non-real estate collateral may be valued using an appraisal, net book value per the borrower’s financial statements, or aging reports, adjusted or discounted based on management’s historical knowledge, changes in market conditions from the time of the valuation, and management’s expertise and knowledge of the client and client’s business, resulting in a Level 3 fair value classification. Impaired loans are evaluated on a quarterly basis for additional impairment and adjusted in accordance with the allowance policy. Other Real Estate Owned: Assets acquired through or instead of loan foreclosure are initially recorded at fair value less costs to sell when acquired, establishing a new cost basis. These assets are subsequently accounted for at lower of cost or fair value less estimated costs to sell. Fair value is commonly based on recent real estate appraisals which are updated no less frequently than annually. These appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach with data from comparable properties. Adjustments are routinely made in the appraisal process by the independent appraisers to adjust for differences between the comparable sales and income data available. Real estate owned properties are evaluated on a quarterly basis for additional impairment and adjusted accordingly. The following table sets forth the Company’s financial assets that were accounted for at fair value and are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value September 30, 2018 Securities: Certificates of deposit $ — $ 89,175 $ — $ 89,175 Mortgage-backed securities – residential — 10,925 — 10,925 Collateralized mortgage obligations – residential — 3,821 — 3,821 $ — $ 103,921 $ — $ 103,921 December 31, 2017 Securities: Certificates of deposit $ — $ 75,916 $ — $ 75,916 Equity mutual fund 499 — — 499 Mortgage-backed securities - residential — 12,472 — 12,472 Collateralized mortgage obligations – residential — 4,486 — 4,486 SBA-guaranteed loan participation certificates — 10 — 10 $ 499 $ 92,884 $ — $ 93,383 The following table sets forth the Company’s assets that were measured at fair value on a non-recurring basis: Fair Value Measurement Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value September 30, 2018 Other real estate owned: Land $ — $ — $ 1 $ 1 December 31, 2017 Other real estate owned: One-to-four family residential real estate $ — $ — $ 102 $ 102 Nonresidential real estate — — 814 814 $ — $ — $ 916 $ 916 At September 30, 2018 and December 31, 2017 there were no impaired loans that were measured for impairment using the fair value of the collateral for collateral–dependent loans and which had specific valuation allowances. OREO, which is carried at the lower of cost or fair value less costs to sell, and had a carrying value of $24,000 less a valuation allowance of $23,000 , or $1,000 at September 30, 2018 , compared to a carrying value of $1.2 million less a valuation allowance of $261,000 , or $916,000 , at December 31, 2017 . There were $27,000 and $301,000 of valuation adjustments of OREO recorded for the nine months ended September 30, 2018 and 2017 , respectively. The following table presents quantitative information, based on certain empirical data with respect to Level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis: Fair Value Valuation Significant Unobservable Range September 30, 2018 Other real estate owned: Land 1 Sales comparison Discount applied to valuation 12.3% $ 1 December 31, 2017 Other real estate owned One-to-four family residential real estate $ 102 Sales comparison Discount applied to valuation 5.6% Nonresidential real estate 814 Sales comparison Comparison between sales and income approaches -3.66% to 15.22% (11.0%) $ 916 The carrying amount and estimated fair value of financial instruments are as follows: Fair Value Measurements at September 30, 2018 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 86,934 $ 12,473 $ 74,461 $ — $ 86,934 Securities 103,921 — 103,921 — 103,921 Loans receivable, net of allowance for loan losses 1,267,787 — — 1,265,906 1,265,906 FHLB and FRB stock 8,026 — — — N/A Accrued interest receivable 4,974 — 4,974 — 4,974 Financial liabilities Noninterest-bearing demand deposits $ 225,446 $ — $ 225,446 $ — $ 225,446 NOW and money market accounts 549,631 — 549,631 — 549,631 Savings deposits 155,232 — 155,232 — 155,232 Certificates of deposit 365,461 — 362,670 — 362,670 Borrowings 21,232 — 21,214 — 21,214 Accrued interest payable 361 — 361 — 361 Fair Value Measurements at December 31, 2017 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 127,592 $ 13,572 $ 114,020 $ — $ 127,592 Securities 93,383 499 92,884 — 93,383 Loans receivable, net of allowance for loan losses 1,314,651 — 1,323,139 — 1,323,139 FHLB and FRB stock 8,290 — — — N/A Accrued interest receivable 4,619 — 4,619 — 4,619 Financial liabilities Noninterest-bearing demand deposits $ 234,354 $ — $ 234,354 $ — $ 234,354 NOW and money market accounts 589,238 — 589,238 — 589,238 Savings deposits 160,501 — 160,501 — 160,501 Certificates of deposit 355,958 — 353,969 — 353,969 Borrowings 60,768 — 60,627 — 60,627 Accrued interest payable 147 — 147 — 147 For purposes of the above, the following assumptions were used: Cash and Cash Equivalents : The estimated fair values for cash and cash equivalents are based on their carrying value due to the short-term nature of these assets. Loans : At September 30, 2018 , the exit price observations are obtained from an independent third-party using its proprietary valuation model and methodology and may not reflect actual or prospective market valuations. The valuation is based on the probability of default, loss given default, recovery delay, prepayment, and discount rate assumptions. The new methodology is a result of the adoption of ASU 2016-01. At December 31, 2017, the estimated fair value for loans has been determined by calculating the present value of future cash flows based on the current rate the Company would charge for similar loans with similar maturities, applied for an estimated time period until the loan is assumed to be repriced or repaid. The methods utilized to estimate fair value of loans do not necessarily represent an exit price. FHLB and FRB Stock : It is not practicable to determine the fair value of FHLB and FRB stock due to the restrictions placed on their transferability. Deposit Liabilities : The estimated fair value for certificates of deposit has been determined by calculating the present value of future cash flows based on estimates of rates the Company would pay on such deposits, applied for the time period until maturity. The estimated fair values of noninterest-bearing demand, NOW, money market, and savings deposits are assumed to approximate their carrying values as management establishes rates on these deposits at a level that approximates the local market area. Additionally, these deposits can be withdrawn on demand. Borrowings : The estimated fair values of advances from the FHLB and notes payable are based on current market rates for similar financing. The estimated fair value of securities sold under agreements to repurchase is assumed to equal its carrying value due to the short-term nature of the liability. Accrued Interest : The estimated fair values of accrued interest receivable and payable are assumed to equal their carrying value. Off - Balance-Sheet Instruments : Off-balance-sheet items consist principally of unfunded loan commitments, standby letters of credit, and unused lines of credit. The estimated fair values of unfunded loan commitments, standby letters of credit, and unused lines of credit are not material. While the above estimates are based on management’s judgment of the most appropriate factors, as of the balance sheet date, there is no assurance that the estimated fair values would have been realized if the assets were disposed of or the liabilities settled at that date, since market values may differ depending on the various circumstances. The estimated fair values would also not apply to subsequent dates. In addition, other assets and liabilities that are not financial instruments, such as premises and equipment, are not included in the above disclosures.

Revenue From Contracts With Cus

Revenue From Contracts With Customers	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS All of the Company's revenue from contracts with customers in the scope of ASC 606 is recognized within noninterest income. The following table presents the Company's sources of noninterest income. Items outside of the scope of the ASC 606 are noted as such. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Deposit service charges and fees $ 1,003 $ 1,018 $ 2,970 $ 2,964 Loan fee income (1) 71 89 231 212 Commercial mortgage brokerage fees (1) 12 — 138 — Residential mortgage banking fees (1) 34 41 88 172 Loss on sales of equity securities (1) — — (14 ) — Gain on sale of premises held-for-sale — — 93 — Trust and insurance commissions and annuities income 207 210 670 704 Earnings on bank owned life insurance (1) 35 67 146 196 Bank-owned life insurance death benefit (1) — — 1,389 — Other (1) 208 198 492 526 Total noninterest income $ 1,570 $ 1,623 $ 6,203 $ 4,774 (1) Not within the scope of ASC 606 A description of the Company's revenue streams accounted for under ASC 606 follows: Deposit service charges and fees: The Company earns fees from its deposit customers based on specific types of transactions, account maintenance and overdraft services. Transaction-based fees, which include services such as ATM use fees, stop payment charges, statement rendering, and ACH fees, are recognized at the time the transaction is executed as that is the point in time the Company fulfills the customer's request. Account maintenance fees, which relate primarily to monthly maintenance, are earned over the course of a month, representing the period over which the Company satisfies the performance obligation. Overdraft fees are recognized at the point in time that the overdraft occurs. Service charges on deposits are withdrawn from the customer's account balance. Interchange income: The Company earns interchange fees from debit cardholder transactions conducted through the Visa payment network. Interchange fees from cardholder transactions represent a percentage of the underlying transaction value and are recognized daily, concurrently with the transaction processing services provided to the cardholder. Interchange income for the nine months ended September 30, 2018 and 2017 was $1.1 million and $1.1 million , respectively. Interchange income for the three months ended September 30, 2018 and 2017 was $382,000 and $361,000 , respectively. Interchange income is included in deposit service charges and fees. Gain on sale of premises held-for-sale: On April 23, 2018, the Bank sold its office building located at 15W060 North Frontage Road, Burr Ridge, Illinois. The sale was to an unrelated party and title was transferred at closing. As such, the transaction constituted a sale and a net gain was recorded in the second quarter of 2018. Trust and insurance commissions and annuities income: The Company earns trust, insurance commissions and annuities income from its contracts with trust customers to manage assets for investment, and/or to transact on their accounts. These fees are primarily earned over time as the Company provides the contracted monthly or quarterly services and are generally assessed based on a tiered scale of the market value of assets under management (AUM) at month-end. Fees that are transaction based, including trade execution services, are recognized at the point in time that the transaction is executed, i.e., the trade date. Other related services provided include fees the Company earns, which are based on a fixed fee schedule, are recognized when the services are rendered. Gains/losses on sales of OREO: The Company records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of an executed deed. When the Company finances the sale of OREO to the buyer, the Company assesses whether the buyer is committed to perform their obligations under the contract and whether collectability of the transaction price is probable. Once these criteria are met, the OREO asset is derecognized and the gain or loss on sale is recorded upon the transfer of control of the property to the buyer. In determining the gain or loss on the sale, the Company adjusts the transaction price and related gain (loss) on sale if a significant financing component is present. OREO sales for the nine months ended September 30, 2018 and September 30, 2017 were not financed by the Bank.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Basis of Presentation : BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois, is the owner of all of the issued and outstanding capital stock of BankFinancial, NA (the “Bank”). The interim unaudited consolidated financial statements include the accounts and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BFIN Asset Recovery Company, LLC (collectively, “the Company”), and reflect all normal and recurring adjustments that are, in the opinion of management, considered necessary for a fair presentation of the financial condition and results of operations for the periods presented. Such adjustments are the only adjustments reflected in the accompanying financial statements. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three and nine month periods ended September 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018 or for any other period. Certain information and note disclosures normally included in financial statements prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission. Use of Estimates : To prepare financial statements in conformity with GAAP, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided, and future results could differ. Reclassifications : Certain reclassifications have been made in the prior period’s financial statements to conform them to the current period’s presentation. These unaudited consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , as filed with the Securities and Exchange Commission. Recent Accounting Pronouncements In May 2014, the FASB issued an update (ASU No. 2014-09, Revenue from Contracts with Customers) creating FASB Topic 606, Revenue from Contracts with Customers. The guidance in this update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides steps to follow to achieve the core principle. An entity should disclose sufficient information to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Qualitative and quantitative information is required about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The amendments in this update became effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the update and have concluded that it does not have a significant impact to our consolidated financial statements. The Company’s revenue streams that are in-scope from the update include: financed OREO sales; deposit fees, including ATM fees, overdraft fees, maintenance fees and dormancy fees; debit card fees, and trust fees. For the in-scope revenue streams, our current revenue recognition is not different than our prior revenue recognition under the update. The Company has infrequently financed an OREO sale. Our customer contracts generally do not have performance obligations and fees are assessed and collected as the transaction occurs. The Company’s fee income is not material for any individual income streams. The adoption of ASC 606 did not result in a change to the accounting for any of the in-scope revenue stream; as such, no cumulative effect adjustment was recorded. Refer to Note 8 - Revenue for Contracts with Customers for further discussion on the Company's accounting policies for revenue sources within the scope of ASC 606. In January 2016, the FASB issued an update (ASU No. 2016-01, Financial Instruments - Recognition and Measurement of Financial Assets and Liabilities). The new guidance is intended to improve the recognition and measurement of financial instruments by requiring: equity investments (other than equity method or consolidation) to be measured at fair value with changes in fair value recognized in net income; public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; separate presentation of financial assets and financial liabilities by measurement category and form of financial assets ( i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities; eliminating the requirement for non-public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is to be required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requiring a reporting organization to present separately in other comprehensive income the portion of the total change in fair value of a liability resulting from the change in the instrument-specific credit risk (also referred to as “own credit”) when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance became effective for public business entities for fiscal years beginning after December 15, 2017. The new pronouncement does not have a significant impact on our Statement of Operations, as we had one equity security that was valued at $499,000 at December 31, 2017 and none at September 30, 2018 . In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than 12 months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our preliminary finding is that the new pronouncement will not have a significant impact on our consolidated financial statements as the projected minimum lease payments under existing leases subject to the new pronouncement are less than one percent of our current total assets. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). These amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 ( i.e. , January 1, 2020, for calendar year entities). Early application will be permitted for all organizations for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our initial review indicates that we have maintained sufficient historical loan data to support the requirements of this pronouncement. In addition, we have begun tracking the average life of the various segments of our loan portfolio. We are currently evaluating various loss methodologies to determine their correlation to our various loan categories' historical performance. In August 2018, we contracted with a third-party vendor to provide a model and assist with assessing processes, portfolio segmentation, and model development. In March 2017, the FASB issued ASU No. 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities” (“ASU 2017-08”). This guidance shortens the amortization period for premiums on certain callable debt securities to the earliest call date (with an explicit, noncontingent call feature that is callable at a fixed price and on a preset dates), rather than contractual maturity date as currently required under GAAP. The ASU does not impact instruments without preset call dates such as mortgage-backed securities. For instruments with contingent call features, once the contingency is resolved and the security is callable at a fixed price and preset date, the security is within the scope of the ASU. ASU 2017-08 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early adoption is permitted. Effective January 2017, we early adopted the pronouncement. Adoption of the new pronouncement was immaterial to the consolidated financial statements.
Basis of Presentation	Basis of Presentation : BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois, is the owner of all of the issued and outstanding capital stock of BankFinancial, NA (the “Bank”).
Principles of Consolidation	The interim unaudited consolidated financial statements include the accounts and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BFIN Asset Recovery Company, LLC (collectively, “the Company”), and reflect all normal and recurring adjustments that are, in the opinion of management, considered necessary for a fair presentation of the financial condition and results of operations for the periods presented. Such adjustments are the only adjustments reflected in the accompanying financial statements. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three and nine month periods ended September 30, 2018 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2018 or for any other period. Certain information and note disclosures normally included in financial statements prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission. Use of Estimate
Use of Estimates	Use of Estimates : To prepare financial statements in conformity with GAAP, management makes estimates and assumptions based on available information. These estimates and assumptions affect the amounts reported in the financial statements and the disclosures provided, and future results could differ.
Uncollected Interest Policy	The Company’s reserve for uncollected loan interest was $36,000 and $103,000 at September 30, 2018 and December 31, 2017 , respectively. When a loan is on nonaccrual status and the ultimate collectability of the total principal of an impaired loan is in doubt, all payments are applied to principal under the cost recovery method. Alternatively, when a loan is on non-accrual status but there is doubt concerning only the ultimate collectability of interest, contractual interest is credited to interest income only when received, under the cash basis method pursuant to the provisions of FASB ASC 310–10, as applicable. In all cases, the average balances are calculated based on the month–end balances of the financing receivables within the period reported pursuant to the provisions of FASB ASC 310–10, as applicable.
Reclassifications	Reclassifications : Certain reclassifications have been made in the prior period’s financial statements to conform them to the current period’s presentation. These unaudited consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , as filed with the Securities and Exchange Commission.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued an update (ASU No. 2014-09, Revenue from Contracts with Customers) creating FASB Topic 606, Revenue from Contracts with Customers. The guidance in this update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides steps to follow to achieve the core principle. An entity should disclose sufficient information to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Qualitative and quantitative information is required about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The amendments in this update became effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the update and have concluded that it does not have a significant impact to our consolidated financial statements. The Company’s revenue streams that are in-scope from the update include: financed OREO sales; deposit fees, including ATM fees, overdraft fees, maintenance fees and dormancy fees; debit card fees, and trust fees. For the in-scope revenue streams, our current revenue recognition is not different than our prior revenue recognition under the update. The Company has infrequently financed an OREO sale. Our customer contracts generally do not have performance obligations and fees are assessed and collected as the transaction occurs. The Company’s fee income is not material for any individual income streams. The adoption of ASC 606 did not result in a change to the accounting for any of the in-scope revenue stream; as such, no cumulative effect adjustment was recorded. Refer to Note 8 - Revenue for Contracts with Customers for further discussion on the Company's accounting policies for revenue sources within the scope of ASC 606. In January 2016, the FASB issued an update (ASU No. 2016-01, Financial Instruments - Recognition and Measurement of Financial Assets and Liabilities). The new guidance is intended to improve the recognition and measurement of financial instruments by requiring: equity investments (other than equity method or consolidation) to be measured at fair value with changes in fair value recognized in net income; public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; separate presentation of financial assets and financial liabilities by measurement category and form of financial assets ( i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities; eliminating the requirement for non-public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is to be required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requiring a reporting organization to present separately in other comprehensive income the portion of the total change in fair value of a liability resulting from the change in the instrument-specific credit risk (also referred to as “own credit”) when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance became effective for public business entities for fiscal years beginning after December 15, 2017. The new pronouncement does not have a significant impact on our Statement of Operations, as we had one equity security that was valued at $499,000 at December 31, 2017 and none at September 30, 2018 . In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than 12 months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our preliminary finding is that the new pronouncement will not have a significant impact on our consolidated financial statements as the projected minimum lease payments under existing leases subject to the new pronouncement are less than one percent of our current total assets. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). These amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 ( i.e. , January 1, 2020, for calendar year entities). Early application will be permitted for all organizations for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our initial review indicates that we have maintained sufficient historical loan data to support the requirements of this pronouncement. In addition, we have begun tracking the average life of the various segments of our loan portfolio. We are currently evaluating various loss methodologies to determine their correlation to our various loan categories' historical performance. In August 2018, we contracted with a third-party vendor to provide a model and assist with assessing processes, portfolio segmentation, and model development. In March 2017, the FASB issued ASU No. 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities” (“ASU 2017-08”). This guidance shortens the amortization period for premiums on certain callable debt securities to the earliest call date (with an explicit, noncontingent call feature that is callable at a fixed price and on a preset dates), rather than contractual maturity date as currently required under GAAP. The ASU does not impact instruments without preset call dates such as mortgage-backed securities. For instruments with contingent call features, once the contingency is resolved and the security is callable at a fixed price and preset date, the security is within the scope of the ASU. ASU 2017-08 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early adoption is permitted. Effective January 2017, we early adopted the pronouncement. Adoption of the new pronouncement was immaterial to the consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies New Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued an update (ASU No. 2014-09, Revenue from Contracts with Customers) creating FASB Topic 606, Revenue from Contracts with Customers. The guidance in this update affects any entity that either enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards (for example, insurance contracts or lease contracts). The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The guidance provides steps to follow to achieve the core principle. An entity should disclose sufficient information to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. Qualitative and quantitative information is required about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. The amendments in this update became effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the update and have concluded that it does not have a significant impact to our consolidated financial statements. The Company’s revenue streams that are in-scope from the update include: financed OREO sales; deposit fees, including ATM fees, overdraft fees, maintenance fees and dormancy fees; debit card fees, and trust fees. For the in-scope revenue streams, our current revenue recognition is not different than our prior revenue recognition under the update. The Company has infrequently financed an OREO sale. Our customer contracts generally do not have performance obligations and fees are assessed and collected as the transaction occurs. The Company’s fee income is not material for any individual income streams. The adoption of ASC 606 did not result in a change to the accounting for any of the in-scope revenue stream; as such, no cumulative effect adjustment was recorded. Refer to Note 8 - Revenue for Contracts with Customers for further discussion on the Company's accounting policies for revenue sources within the scope of ASC 606. In January 2016, the FASB issued an update (ASU No. 2016-01, Financial Instruments - Recognition and Measurement of Financial Assets and Liabilities). The new guidance is intended to improve the recognition and measurement of financial instruments by requiring: equity investments (other than equity method or consolidation) to be measured at fair value with changes in fair value recognized in net income; public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; separate presentation of financial assets and financial liabilities by measurement category and form of financial assets ( i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities; eliminating the requirement for non-public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is to be required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and requiring a reporting organization to present separately in other comprehensive income the portion of the total change in fair value of a liability resulting from the change in the instrument-specific credit risk (also referred to as “own credit”) when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. The new guidance became effective for public business entities for fiscal years beginning after December 15, 2017. The new pronouncement does not have a significant impact on our Statement of Operations, as we had one equity security that was valued at $499,000 at December 31, 2017 and none at September 30, 2018 . In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”). The standard requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than 12 months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our preliminary finding is that the new pronouncement will not have a significant impact on our consolidated financial statements as the projected minimum lease payments under existing leases subject to the new pronouncement are less than one percent of our current total assets. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). These amendments require the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. In addition, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019 ( i.e. , January 1, 2020, for calendar year entities). Early application will be permitted for all organizations for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the impact that the standard will have on our consolidated financial statements. Our initial review indicates that we have maintained sufficient historical loan data to support the requirements of this pronouncement. In addition, we have begun tracking the average life of the various segments of our loan portfolio. We are currently evaluating various loss methodologies to determine their correlation to our various loan categories' historical performance. In August 2018, we contracted with a third-party vendor to provide a model and assist with assessing processes, portfolio segmentation, and model development. In March 2017, the FASB issued ASU No. 2017-08, “Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities” (“ASU 2017-08”). This guidance shortens the amortization period for premiums on certain callable debt securities to the earliest call date (with an explicit, noncontingent call feature that is callable at a fixed price and on a preset dates), rather than contractual maturity date as currently required under GAAP. The ASU does not impact instruments without preset call dates such as mortgage-backed securities. For instruments with contingent call features, once the contingency is resolved and the security is callable at a fixed price and preset date, the security is within the scope of the ASU. ASU 2017-08 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, and early adoption is permitted. Effective January 2017, we early adopted the pronouncement. Adoption of the new pronouncement was immaterial to the consolidated financial statements.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Amounts reported in earnings per share reflect earnings available to common stockholders for the period divided by the weighted average number of shares of common stock outstanding during the period, exclusive of unearned BankFinancial, NA Employee Stock Ownership Plan (the "ESOP") shares in 2017 and unvested restricted stock shares. Stock options and restricted stock are regarded as potential common stock and are considered in the diluted earnings per share calculations to the extent that they would have a dilutive effect if converted to common stock. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Net income available to common stockholders $ 3,737 $ 3,560 $ 11,926 $ 8,013 Average common shares outstanding 17,365,679 18,140,599 17,641,743 18,567,796 Less: Unearned ESOP shares — — — (198,114 ) Unvested restricted stock shares — (940 ) (435 ) (940 ) Weighted average common shares outstanding 17,365,679 18,139,659 17,641,308 18,368,742 Add - Net effect of dilutive unvested restricted stock — 450 — 428 Diluted weighted average common shares outstanding 17,365,679 18,140,109 17,641,308 18,369,170 Basic earnings per common share $ 0.22 $ 0.20 $ 0.68 $ 0.44 Diluted earnings per common share $ 0.22 $ 0.20 $ 0.68 $ 0.44

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	The fair value of securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income are shown below. Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value September 30, 2018 Certificates of deposit $ 89,175 $ — $ — $ 89,175 Mortgage-backed securities - residential 10,593 393 (61 ) 10,925 Collateralized mortgage obligations - residential 3,819 13 (11 ) 3,821 $ 103,587 $ 406 $ (72 ) $ 103,921 December 31, 2017 Certificates of deposit $ 75,916 $ — $ — $ 75,916 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 11,969 520 (17 ) 12,472 Collateralized mortgage obligations - residential 4,481 16 (11 ) 4,486 SBA-guaranteed loan participation certificates 10 — — 10 $ 92,876 $ 536 $ (29 ) $ 93,383 The mortgage-backed securities and collateralized mortgage obligations reflected in the preceding table were issued by U.S. government-sponsored entities or agencies, Freddie Mac, Fannie Mae and Ginnie Mae, and are obligations which the government has affirmed its commitment to support. All securities reflected in the preceding table were classified as available-for-sale at September 30, 2018 and December 31, 2017 . The amortized cost and fair values of securities by contractual maturity are shown below. Securities not due at a single maturity date are shown separately. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2018 Amortized Cost Fair Value Due in one year or less $ 89,175 $ 89,175 Mortgage-backed securities - residential 10,593 10,925 Collateralized mortgage obligations - residential 3,819 3,821 $ 103,587 $ 103,921 Three Months Ended Nine Months Ended 2018 2017 2018 2017 Proceeds $ — $ — $ 487 $ — Gross gains — — — — Gross losses — — (14 ) — Securities with unrealized losses not recognized in income are as follows: Less than 12 Months 12 Months or More Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss September 30, 2018 Mortgage-backed securities - residential $ 924 $ (6 ) $ 1,004 $ (55 ) $ 1,928 $ (61 ) Collateralized mortgage obligations - residential — — 1,796 (11 ) 1,796 (11 ) $ 924 $ (6 ) $ 2,800 $ (66 ) $ 3,724 $ (72 ) December 31, 2017 Equity mutual fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential — — 1,149 (17 ) 1,149 (17 ) Collateralized mortgage obligations - residential — — 2,083 (11 ) 2,083 (11 ) $ 499 $ (1 ) $ 3,232 $ (28 ) $ 3,731 $ (29 ) The Company evaluates marketable investment securities with significant declines in fair value on a quarterly basis to determine whether they should be considered other-than-temporarily impaired under current accounting guidance, which generally provides that if a marketable security is in an unrealized loss position, whether due to general market conditions or industry or issuer-specific factors, the holder of the securities must assess whether the impairment is other-than-temporary. Certain mortgage-backed securities and collateralized mortgage obligations that the Company holds in its investment portfolio were in an unrealized loss position at September 30, 2018 , but the unrealized losses were not considered significant under the Company’s impairment testing methodology. In addition, the Company does not intend to sell these securities, and it is likely that the Company will not be required to sell these securities before their anticipated recovery occurs.
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)	The fair value of securities and the related gross unrealized gains and losses recognized in accumulated other comprehensive income are shown below. Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value September 30, 2018 Certificates of deposit $ 89,175 $ — $ — $ 89,175 Mortgage-backed securities - residential 10,593 393 (61 ) 10,925 Collateralized mortgage obligations - residential 3,819 13 (11 ) 3,821 $ 103,587 $ 406 $ (72 ) $ 103,921 December 31, 2017 Certificates of deposit $ 75,916 $ — $ — $ 75,916 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 11,969 520 (17 ) 12,472 Collateralized mortgage obligations - residential 4,481 16 (11 ) 4,486 SBA-guaranteed loan participation certificates 10 — — 10 $ 92,876 $ 536 $ (29 ) $ 93,383
Amortized cost and fair values of securities	The amortized cost and fair values of securities by contractual maturity are shown below. Securities not due at a single maturity date are shown separately. Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2018 Amortized Cost Fair Value Due in one year or less $ 89,175 $ 89,175 Mortgage-backed securities - residential 10,593 10,925 Collateralized mortgage obligations - residential 3,819 3,821 $ 103,587 $ 103,921
Securities with unrealized losses	Securities with unrealized losses not recognized in income are as follows: Less than 12 Months 12 Months or More Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss September 30, 2018 Mortgage-backed securities - residential $ 924 $ (6 ) $ 1,004 $ (55 ) $ 1,928 $ (61 ) Collateralized mortgage obligations - residential — — 1,796 (11 ) 1,796 (11 ) $ 924 $ (6 ) $ 2,800 $ (66 ) $ 3,724 $ (72 ) December 31, 2017 Equity mutual fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential — — 1,149 (17 ) 1,149 (17 ) Collateralized mortgage obligations - residential — — 2,083 (11 ) 2,083 (11 ) $ 499 $ (1 ) $ 3,232 $ (28 ) $ 3,731 $ (29 )

Loans Receivable (Tables)

Loans Receivable (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans By Class Modified As Troubled Debt Restructurings With Payment Default [Table Text Block]	2018 2017 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate — $ — 1 $ 17
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Loans receivable are as follows: September 30, 2018 December 31, 2017 One-to-four family residential real estate $ 77,591 $ 97,814 Multi-family mortgage 581,880 588,383 Nonresidential real estate 148,010 169,971 Construction and land 1,130 1,358 Commercial loans 167,547 152,552 Commercial leases 297,103 310,076 Consumer 1,416 1,597 1,274,677 1,321,751 Net deferred loan origination costs 1,213 1,266 Allowance for loan losses (8,103 ) (8,366 ) Loans, net $ 1,267,787 $ 1,314,651 The following tables present the balance in the allowance for loan losses and the loans receivable by portfolio segment and based on impairment method: Allowance for loan losses Loan Balances Individually evaluated for impairment Collectively evaluated for impairment Total Individually evaluated for impairment Collectively evaluated for impairment Total September 30, 2018 One-to-four family residential real estate $ — $ 762 $ 762 $ 2,724 $ 74,867 $ 77,591 Multi-family mortgage — 3,722 3,722 661 581,219 581,880 Nonresidential real estate — 1,410 1,410 — 148,010 148,010 Construction and land — 27 27 — 1,130 1,130 Commercial loans — 1,482 1,482 — 167,547 167,547 Commercial leases — 684 684 — 297,103 297,103 Consumer — 16 16 — 1,416 1,416 $ — $ 8,103 $ 8,103 $ 3,385 $ 1,271,292 1,274,677 Net deferred loan origination costs 1,213 Allowance for loan losses (8,103 ) Loans, net $ 1,267,787 Allowance for loan losses Loan Balances Individually evaluated for impairment Collectively evaluated for impairment Total Individually evaluated for impairment Collectively evaluated for impairment Total December 31, 2017 One-to-four family residential real estate $ — $ 850 $ 850 $ 4,265 $ 93,549 $ 97,814 Multi-family mortgage — 3,849 3,849 949 587,434 588,383 Nonresidential real estate — 1,605 1,605 — 169,971 169,971 Construction and land — 32 32 — 1,358 1,358 Commercial loans — 1,357 1,357 — 152,552 152,552 Commercial leases — 655 655 — 310,076 310,076 Consumer — 18 18 — 1,597 1,597 $ — $ 8,366 $ 8,366 $ 5,214 $ 1,316,537 1,321,751 Net deferred loan origination costs 1,266 Allowance for loan losses (8,366 ) Loans, net $ 1,314,651 Activity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 8,179 $ 8,122 $ 8,366 $ 8,127 Loans charged off: One-to-four family residential real estate (84 ) (89 ) (214 ) (282 ) Multi-family mortgage — (7 ) (35 ) (10 ) Nonresidential real estate — — — (165 ) Commercial loans — — (140 ) — Consumer (6 ) (7 ) (7 ) (7 ) (90 ) (103 ) (396 ) (464 ) Recoveries: One-to-four family residential real estate 25 15 130 100 Multi-family mortgage 8 11 26 62 Nonresidential real estate — 10 — 10 Construction and land 2 — 2 — Commercial loans 2 542 227 552 Commercial leases — 2 5 2 Consumer — — 1 — 37 580 391 726 Net recoveries (charge-offs) (53 ) 477 (5 ) 262 Recovery of loan losses (23 ) (225 ) (258 ) (15 ) Ending balance $ 8,103 $ 8,374 $ 8,103 $ 8,374 The following tables present the recorded investment in nonaccrual loans and loans past due over 90 days still on accrual by class of loans: Loan Balance Recorded Investment Loans Past Due Over 90 Days, Still Accruing September 30, 2018 One-to-four family residential real estate $ 1,646 $ 1,313 $ — One-to-four family residential real estate – non-owner occupied 95 56 — Multi-family mortgage - Illinois 102 102 — $ 1,843 $ 1,471 $ — December 31, 2017 One-to-four family residential real estate $ 3,413 $ 1,918 $ — One-to-four family residential real estate – non-owner occupied 308 109 — Multi-family mortgage - Illinois 376 363 — $ 4,097 $ 2,390 $ — Nonaccrual loans and impaired loans are defined differently. Some loans may be included in both categories, and some loans may only be included in one category. Nonaccrual loans include both smaller balance homogeneous loans that are collectively evaluated for impairment and individually classified impaired loans. The Company’s reserve for uncollected loan interest was $36,000 and $103,000 at September 30, 2018 and December 31, 2017 , respectively. When a loan is on nonaccrual status and the ultimate collectability of the total principal of an impaired loan is in doubt, all payments are applied to principal under the cost recovery method. Alternatively, when a loan is on non-accrual status but there is doubt concerning only the ultimate collectability of interest, contractual interest is credited to interest income only when received, under the cash basis method pursuant to the provisions of FASB ASC 310–10, as applicable. In all cases, the average balances are calculated based on the month–end balances of the financing receivables within the period reported pursuant to the provisions of FASB ASC 310–10, as applicable. The following tables present the aging of the recorded investment of loans at September 30, 2018 by class of loans: 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Past Due Total Past Due Loans Not Past Due Total One-to-four family residential real estate loans $ 392 $ — $ 1,329 $ 1,721 $ 59,925 $ 61,646 One-to-four family residential real estate loans – non-owner occupied 34 8 48 90 15,817 15,907 Multi-family mortgage - Illinois — — 102 102 275,714 275,816 Multi-family mortgage - Other — — — — 299,469 299,469 Nonresidential real estate 607 — — 607 146,394 147,001 Construction — — — — 932 932 Land — — — — 198 198 Commercial loans: Regional commercial banking — — — — 50,105 50,105 Health care — — — — 69,248 69,248 Direct commercial lessor — — — — 48,942 48,942 Commercial leases: Investment rated commercial leases 787 — — 787 181,402 182,189 Other commercial leases — — — — 116,651 116,651 Consumer 12 5 — 17 1,410 1,427 $ 1,832 $ 13 $ 1,479 $ 3,324 $ 1,266,207 $ 1,269,531 The following tables present the aging of the recorded investment of loans at December 31, 2017 by class of loans: 30-59 Days Past Due 60-89 Days Past Due 90 Days or Total Past Due Loans Not Past Due Total One-to-four family residential real estate loans $ 86 $ 99 $ 1,801 $ 1,986 $ 74,216 $ 76,202 One-to-four family residential real estate loans – non-owner occupied 10 3 86 99 20,944 21,043 Multi-family mortgage - Illinois 172 — 364 536 287,171 287,707 Multi-family mortgage - Other — — — — 296,440 296,440 Nonresidential real estate 608 — — 608 166,071 166,679 Construction — — — — 1,103 1,103 Land — — — — 259 259 Commercial loans: Regional commercial banking — — — — 40,935 40,935 Health care — — — — 71,738 71,738 Direct commercial lessor — — — — 40,237 40,237 Commercial leases: Investment rated commercial leases 934 — — 934 207,747 208,681 Other commercial leases 288 — — 288 102,873 103,161 Consumer — — — — 1,605 1,605 $ 2,098 $ 102 $ 2,251 $ 4,451 $ 1,311,339 $ 1,315,790 The Company evaluates loan extensions or modifications in accordance with FASB ASC 310–40 with respect to the classification of the loan as a Troubled Debt Restructuring ("TDR"). In general, if the Company grants a loan extension or modification to a borrower experiencing financial difficulties for other than an insignificant period of time that includes a below–market interest rate, principal forgiveness, payment forbearance or other concession intended to minimize the economic loss to the Company, the loan extension or loan modification is classified as a TDR. In cases where borrowers are granted new terms that provide for a reduction of either interest or principal then due and payable, management measures any impairment on the restructured loan in the same manner as for impaired loans as noted above. The Company had $17,000 of TDRs at September 30, 2018 and December 31, 2017 . No specific valuation reserves were allocated to those loans at September 30, 2018 and December 31, 2017 . The Company had no outstanding commitments to borrowers whose loans were classified as TDRs at either date. The following table presents loans classified as TDRs: September 30, 2018 December 31, 2017 One-to-four family residential real estate - nonaccrual $ 17 $ 17 During the three and nine months ended September 30, 2018 and 2017 , there were no loans modified and classified as TDRs. The following table presents TDRs for which there was a payment default within twelve months following the modification. 2018 2017 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate — $ — 1 $ 17 A TDR is considered to be in payment default once it is 90 days contractually past due under the modified terms. There were no payment defaults on TDRs within twelve months following the modification during the three and nine months ended September 30, 2018 . There were no loan modifications during the three and nine months ended September 30, 2018 . There were certain loan modifications during the three and nine months ended September 30, 2017 that did not meet the definition of a TDR. These loans had a total recorded investment of $149,000 at September 30, 2017 . The modification of these loans involved either a modification of the terms of a loan to borrowers who were not experiencing financial difficulties or a delay in a payment that was considered to be insignificant. 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. The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt, including 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 based on 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 uses the following definitions for risk ratings: Special Mention. A Special Mention asset has potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the asset or in the institution’s credit position at some future date. Special Mention assets are not adversely classified and do not expose an institution to sufficient risk to warrant adverse classification. Substandard. Loans categorized as Substandard continue to accrue interest, but exhibit a well-defined weakness or weaknesses that may jeopardize the liquidation of the debt. The loans continue to accrue interest because they are well secured and collection of principal and interest is expected within a reasonable time. The risk rating guidance published by the Office of the Comptroller of the Currency clarifies that a loan with a well-defined weakness does not have to present a probability of default for the loan to be rated Substandard, and that an individual loan’s loss potential does not have to be distinct for the loan to be rated Substandard. Nonaccrual. An asset classified Nonaccrual has all the weaknesses inherent in one classified 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 are considered “Pass” rated loans. As of September 30, 2018 , based on the most recent analysis performed, the risk categories of loans by class of loans are as follows: Pass Special Mention Substandard Nonaccrual Total One-to-four family residential real estate loans $ 59,714 $ 310 $ 372 $ 1,314 $ 61,710 One-to-four family residential real estate loans – non-owner occupied 15,755 33 37 56 15,881 Multi-family mortgage loans - Illinois 276,398 — 310 102 276,810 Multi-family mortgage loans - Other 305,070 — — — 305,070 Nonresidential real estate loans 147,911 — 99 — 148,010 Construction loans 929 — — — 929 Land loans 201 — — — 201 Commercial loans: Regional commercial banking 45,170 4,815 — — 49,985 Health care 64,374 — 4,699 — 69,073 Direct commercial lessor 48,489 — — — 48,489 Commercial leases: Investment rated commercial leases 180,383 748 — — 181,131 Other commercial leases 115,972 — — — 115,972 Consumer 1,401 5 10 — 1,416 $ 1,261,767 $ 5,911 $ 5,527 $ 1,472 $ 1,274,677 As of December 31, 2017 , the risk categories of loans by class of loans are as follows: Pass Special Mention Substandard Nonaccrual Total One-to-four family residential real estate loans $ 74,437 $ — $ 255 $ 1,914 $ 76,606 One-to-four family residential real estate loans – non-owner occupied 21,059 — 40 109 21,208 Multi-family mortgage loans - Illinois 290,765 — 225 368 291,358 Multi-family mortgage loans - Other 297,025 — — — 297,025 Nonresidential real estate loans 169,817 — 154 — 169,971 Construction loans 1,099 — — — 1,099 Land loans 259 — — — 259 Commercial loans: Regional commercial banking 36,373 4,528 — — 40,901 Health care 69,480 — 2,248 — 71,728 Direct commercial lessor 39,923 — — — 39,923 Commercial leases: Investment rated commercial leases 207,460 — — — 207,460 Other commercial leases 102,616 — — — 102,616 Consumer 1,597 — — — 1,597 $ 1,311,910 $ 4,528 $ 2,922 $ 2,391 $ 1,321,751
Loans receivable	Loans receivable are as follows: September 30, 2018 December 31, 2017 One-to-four family residential real estate $ 77,591 $ 97,814 Multi-family mortgage 581,880 588,383 Nonresidential real estate 148,010 169,971 Construction and land 1,130 1,358 Commercial loans 167,547 152,552 Commercial leases 297,103 310,076 Consumer 1,416 1,597 1,274,677 1,321,751 Net deferred loan origination costs 1,213 1,266 Allowance for loan losses (8,103 ) (8,366 ) Loans, net $ 1,267,787 $ 1,314,651
Loans Receivable Based On Impairment Method [Table Text Block]	The following tables present the balance in the allowance for loan losses and the loans receivable by portfolio segment and based on impairment method: Allowance for loan losses Loan Balances Individually evaluated for impairment Collectively evaluated for impairment Total Individually evaluated for impairment Collectively evaluated for impairment Total September 30, 2018 One-to-four family residential real estate $ — $ 762 $ 762 $ 2,724 $ 74,867 $ 77,591 Multi-family mortgage — 3,722 3,722 661 581,219 581,880 Nonresidential real estate — 1,410 1,410 — 148,010 148,010 Construction and land — 27 27 — 1,130 1,130 Commercial loans — 1,482 1,482 — 167,547 167,547 Commercial leases — 684 684 — 297,103 297,103 Consumer — 16 16 — 1,416 1,416 $ — $ 8,103 $ 8,103 $ 3,385 $ 1,271,292 1,274,677 Net deferred loan origination costs 1,213 Allowance for loan losses (8,103 ) Loans, net $ 1,267,787
Allowance for loan losses	ctivity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 8,179 $ 8,122 $ 8,366 $ 8,127 Loans charged off: One-to-four family residential real estate (84 ) (89 ) (214 ) (282 ) Multi-family mortgage — (7 ) (35 ) (10 ) Nonresidential real estate — — — (165 ) Commercial loans — — (140 ) — Consumer (6 ) (7 ) (7 ) (7 ) (90 ) (103 ) (396 ) (464 ) Recoveries: One-to-four family residential real estate 25 15 130 100 Multi-family mortgage 8 11 26 62 Nonresidential real estate — 10 — 10 Construction and land 2 — 2 — Commercial loans 2 542 227 552 Commercial leases — 2 5 2 Consumer — — 1 — 37 580 391 726 Net recoveries (charge-offs) (53 ) 477 (5 ) 262 Recovery of loan losses (23 ) (225 ) (258 ) (15 ) Ending balance $ 8,103 $ 8,374 $ 8,103 $ 8,374
Schedule of Financing Receivables, Non Accrual Status	The following tables present the recorded investment in nonaccrual loans and loans past due over 90 days still on accrual by class of loans: Loan Balance Recorded Investment Loans Past Due Over 90 Days, Still Accruing September 30, 2018 One-to-four family residential real estate $ 1,646 $ 1,313 $ — One-to-four family residential real estate – non-owner occupied 95 56 — Multi-family mortgage - Illinois 102 102 — $ 1,843 $ 1,471 $ — December 31, 2017 One-to-four family residential real estate $ 3,413 $ 1,918 $ — One-to-four family residential real estate – non-owner occupied 308 109 — Multi-family mortgage - Illinois 376 363 — $ 4,097 $ 2,390 $ —
Past Due Financing Receivables	The following tables present the aging of the recorded investment of loans at September 30, 2018 by class of loans: 30-59 Days Past Due 60-89 Days Past Due 90 Days or Greater Past Due Total Past Due Loans Not Past Due Total One-to-four family residential real estate loans $ 392 $ — $ 1,329 $ 1,721 $ 59,925 $ 61,646 One-to-four family residential real estate loans – non-owner occupied 34 8 48 90 15,817 15,907 Multi-family mortgage - Illinois — — 102 102 275,714 275,816 Multi-family mortgage - Other — — — — 299,469 299,469 Nonresidential real estate 607 — — 607 146,394 147,001 Construction — — — — 932 932 Land — — — — 198 198 Commercial loans: Regional commercial banking — — — — 50,105 50,105 Health care — — — — 69,248 69,248 Direct commercial lessor — — — — 48,942 48,942 Commercial leases: Investment rated commercial leases 787 — — 787 181,402 182,189 Other commercial leases — — — — 116,651 116,651 Consumer 12 5 — 17 1,410 1,427 $ 1,832 $ 13 $ 1,479 $ 3,324 $ 1,266,207 $ 1,269,531
Troubled Debt Restructurings on Financing Receivables	The following table presents loans classified as TDRs: September 30, 2018 December 31, 2017 One-to-four family residential real estate - nonaccrual $ 17 $ 17
Financing Receivable Credit Quality Indicators	As of September 30, 2018 , based on the most recent analysis performed, the risk categories of loans by class of loans are as follows: Pass Special Mention Substandard Nonaccrual Total One-to-four family residential real estate loans $ 59,714 $ 310 $ 372 $ 1,314 $ 61,710 One-to-four family residential real estate loans – non-owner occupied 15,755 33 37 56 15,881 Multi-family mortgage loans - Illinois 276,398 — 310 102 276,810 Multi-family mortgage loans - Other 305,070 — — — 305,070 Nonresidential real estate loans 147,911 — 99 — 148,010 Construction loans 929 — — — 929 Land loans 201 — — — 201 Commercial loans: Regional commercial banking 45,170 4,815 — — 49,985 Health care 64,374 — 4,699 — 69,073 Direct commercial lessor 48,489 — — — 48,489 Commercial leases: Investment rated commercial leases 180,383 748 — — 181,131 Other commercial leases 115,972 — — — 115,972 Consumer 1,401 5 10 — 1,416 $ 1,261,767 $ 5,911 $ 5,527 $ 1,472 $ 1,274,677
Loans By Class Modified As Troubled Debt Restructuring On Financing Receivables [Table Text Block]

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	9 Months Ended
	Sep. 30, 2018
Other Real Estate [Abstract]
Schedule of Real Estate Properties [Table Text Block]	September 30, 2018 December 31, 2017 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 634 $ — $ 634 $ 836 $ (9 ) $ 827 Multi-family mortgage 276 — 276 — — — Nonresidential real estate 74 — 74 1,772 (252 ) 1,520 Land 24 (23 ) 1 48 (44 ) 4 $ 1,008 $ (23 ) $ 985 $ 2,656 $ (305 ) $ 2,351
Real Estate Owned, rollforward [Table Text Block]	September 30, 2018 December 31, 2017 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 634 $ — $ 634 $ 836 $ (9 ) $ 827 Multi-family mortgage 276 — 276 — — — Nonresidential real estate 74 — 74 1,772 (252 ) 1,520 Land 24 (23 ) 1 48 (44 ) 4 $ 1,008 $ (23 ) $ 985 $ 2,656 $ (305 ) $ 2,351 The following represents the roll forward of OREO and the composition of OREO properties: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 1,187 $ 4,896 $ 2,351 $ 3,895 New foreclosed properties 403 105 1,241 2,041 Valuation adjustments (1 ) (227 ) (27 ) (301 ) Sales and payments (604 ) (1,205 ) (2,580 ) (2,066 ) Ending balance $ 985 $ 3,569 $ 985 $ 3,569
OREO valuation allowance, rollforward [Table Text Block]	Activity in the valuation allowance is as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 44 $ 308 $ 305 $ 449 Additions charged to expense 1 227 27 301 Reductions from sales of OREO (22 ) (63 ) (309 ) (278 ) Ending balance $ 23 $ 472 $ 23 $ 472 At September 30, 2018 , the balance of OREO included no foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property without title. At December 31, 2017 the balance of OREO included $352,000 of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property without title. At September 30, 2018 and December 31, 2017 , the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process was $603,000 and $1.5 million , respectively.

Securities Sold Under Agreeme_2

Securities Sold Under Agreements to Repurchase (Tables)	9 Months Ended
	Sep. 30, 2018
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase	Securities sold under agreements to repurchase, included with borrowings on the consolidated balance sheet, are shown below. Overnight and Continuous Up to 30 days 30 - 90 days Greater Than 90 days Total September 30, 2018 Repurchase agreements and repurchase-to-maturity transactions $ 1,232 $ — $ — $ — $ 1,232 Gross amount of recognized liabilities for repurchase agreements in Statement of Condition $ 1,232 December 31, 2017 Repurchase agreements and repurchase-to-maturity transactions $ 768 $ — $ — $ — $ 768 Gross amount of recognized liabilities for repurchase agreements in Statement of Condition $ 768

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Company's financial instruments measured at fair values	The following table sets forth the Company’s financial assets that were accounted for at fair value and are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value September 30, 2018 Securities: Certificates of deposit $ — $ 89,175 $ — $ 89,175 Mortgage-backed securities – residential — 10,925 — 10,925 Collateralized mortgage obligations – residential — 3,821 — 3,821 $ — $ 103,921 $ — $ 103,921 December 31, 2017 Securities: Certificates of deposit $ — $ 75,916 $ — $ 75,916 Equity mutual fund 499 — — 499 Mortgage-backed securities - residential — 12,472 — 12,472 Collateralized mortgage obligations – residential — 4,486 — 4,486 SBA-guaranteed loan participation certificates — 10 — 10 $ 499 $ 92,884 $ — $ 93,383
Schedule of Company's financial instruments measured on non recurring at fair values	The following table sets forth the Company’s assets that were measured at fair value on a non-recurring basis: Fair Value Measurement Using Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Fair Value September 30, 2018 Other real estate owned: Land $ — $ — $ 1 $ 1 December 31, 2017 Other real estate owned: One-to-four family residential real estate $ — $ — $ 102 $ 102 Nonresidential real estate — — 814 814 $ — $ — $ 916 $ 916
Schedule of fair value quantitative information	The following table presents quantitative information, based on certain empirical data with respect to Level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis: Fair Value Valuation Significant Unobservable Range September 30, 2018 Other real estate owned: Land 1 Sales comparison Discount applied to valuation 12.3% $ 1 December 31, 2017 Other real estate owned One-to-four family residential real estate $ 102 Sales comparison Discount applied to valuation 5.6% Nonresidential real estate 814 Sales comparison Comparison between sales and income approaches -3.66% to 15.22% (11.0%) $ 916
Carrying amount and estimated fair value of financial instruments	The carrying amount and estimated fair value of financial instruments are as follows: Fair Value Measurements at September 30, 2018 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 86,934 $ 12,473 $ 74,461 $ — $ 86,934 Securities 103,921 — 103,921 — 103,921 Loans receivable, net of allowance for loan losses 1,267,787 — — 1,265,906 1,265,906 FHLB and FRB stock 8,026 — — — N/A Accrued interest receivable 4,974 — 4,974 — 4,974 Financial liabilities Noninterest-bearing demand deposits $ 225,446 $ — $ 225,446 $ — $ 225,446 NOW and money market accounts 549,631 — 549,631 — 549,631 Savings deposits 155,232 — 155,232 — 155,232 Certificates of deposit 365,461 — 362,670 — 362,670 Borrowings 21,232 — 21,214 — 21,214 Accrued interest payable 361 — 361 — 361 Fair Value Measurements at December 31, 2017 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 127,592 $ 13,572 $ 114,020 $ — $ 127,592 Securities 93,383 499 92,884 — 93,383 Loans receivable, net of allowance for loan losses 1,314,651 — 1,323,139 — 1,323,139 FHLB and FRB stock 8,290 — — — N/A Accrued interest receivable 4,619 — 4,619 — 4,619 Financial liabilities Noninterest-bearing demand deposits $ 234,354 $ — $ 234,354 $ — $ 234,354 NOW and money market accounts 589,238 — 589,238 — 589,238 Savings deposits 160,501 — 160,501 — 160,501 Certificates of deposit 355,958 — 353,969 — 353,969 Borrowings 60,768 — 60,627 — 60,627 Accrued interest payable 147 — 147 — 147

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Noninterest Income Outside the Scope of ASC 606	The following table presents the Company's sources of noninterest income. Items outside of the scope of the ASC 606 are noted as such. Three Months Ended Nine Months Ended 2018 2017 2018 2017 Deposit service charges and fees $ 1,003 $ 1,018 $ 2,970 $ 2,964 Loan fee income (1) 71 89 231 212 Commercial mortgage brokerage fees (1) 12 — 138 — Residential mortgage banking fees (1) 34 41 88 172 Loss on sales of equity securities (1) — — (14 ) — Gain on sale of premises held-for-sale — — 93 — Trust and insurance commissions and annuities income 207 210 670 704 Earnings on bank owned life insurance (1) 35 67 146 196 Bank-owned life insurance death benefit (1) — — 1,389 — Other (1) 208 198 492 526 Total noninterest income $ 1,570 $ 1,623 $ 6,203 $ 4,774 (1) Not within the scope of ASC 606

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Securities, carrying amount	$ 103,921	$ 93,383
Operating Leases, Future Minimum Payments Due, Percent Of Current Assets	1.00%
Equity Funds [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Securities, carrying amount	$ 0	$ 499

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share, Basic and Diluted [Abstract]
Net income available to common stockholders	$ 3,737	$ 3,560	$ 11,926	$ 8,013
Average common shares outstanding (shares)	17,365,679	18,140,599	17,641,743	18,567,796
Less:
Unearned ESOP shares (shares)	0	0	0	(198,114)
Unvested restricted stock shares (shares)	0	(940)	(435)	(940)
Weighted average common shares outstanding (shares)	17,365,679	18,139,659	17,641,308	18,368,742
Add - Net effect of dilutive stock options and unvested restricted stock	0	450	0	428
Weighted average diluted common shares outstanding (shares)	17,365,679	18,140,109	17,641,308	18,369,170
Basic earnings per common share (usd per share)	$ 0.22	$ 0.20	$ 0.68	$ 0.44
Diluted earnings per common share (usd per share)	$ 0.22	$ 0.20	$ 0.68	$ 0.44

Securities - Fair Value of Secu

Securities - Fair Value of Securites (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	$ 103,587	$ 92,876
Gross Unrealized Gains	406	536
Gross Unrealized Losses	(72)	(29)
Total Fair value	103,921	93,383
Certificates of deposit [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	89,175	75,916
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total Fair value	89,175	75,916
Equity mutual fund [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost		500
Gross Unrealized Gains		0
Gross Unrealized Losses		(1)
Total Fair value	0	499
Mortgage - backed securities - residential [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	10,593	11,969
Gross Unrealized Gains	393	520
Gross Unrealized Losses	(61)	(17)
Total Fair value	10,925	12,472
Collateralized mortgage obligations - residential [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	3,819	4,481
Gross Unrealized Gains	13	16
Gross Unrealized Losses	(11)	(11)
Total Fair value	$ 3,821	4,486
SBA-guaranteed loan participation certificates [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost		10
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Total Fair value		$ 10

Securities - Amortized Cost and

Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized cost and fair values of securities
Due in one year or less, amortized cost	$ 89,175
Due in one year or less, fair value	89,175
Total Fair value	103,921	$ 93,383
Total Amortized Cost	103,587	92,876
Equity mutual fund [Member]
Amortized cost and fair values of securities
Total Fair value	0	499
Total Amortized Cost		500
Mortgage - backed securities - residential [Member]
Amortized cost and fair values of securities
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	10,593
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	10,925
Total Fair value	10,925	12,472
Total Amortized Cost	10,593	11,969
Collateralized mortgage obligations - residential [Member]
Amortized cost and fair values of securities
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	3,819
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	3,821
Total Fair value	3,821	4,486
Total Amortized Cost	$ 3,819	4,481
SBA-guaranteed loan participation certificates [Member]
Amortized cost and fair values of securities
Total Fair value		10
Total Amortized Cost		$ 10

Securities - Proceeds and Gross

Securities - Proceeds and Gross Gains (Losses) From Sale of Securities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Proceeds and Gross Gains (Losses) from Sale of Securities [Abstract]
Proceeds	$ 0	$ 0	$ 487	$ 0
Gross gains	0	0	0	0
Gross losses	$ 0	$ 0	$ (14)	$ 0

Securities - Unrealized Losses

Securities - Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized cost and fair values of securities
Less than 12 Months	$ 924	$ 499
12 Months or More	2,800	3,232
Total	3,724	3,731
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	(6)	(1)
12 Months or More	(66)	(28)
Unrealized Loss	72	29
Mortgage Backed Securities Residential [Member]
Amortized cost and fair values of securities
Less than 12 Months	924	0
12 Months or More	1,004	1,149
Total	1,928	1,149
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	(6)	0
12 Months or More	(55)	(17)
Unrealized Loss	61	17
Collateralized mortgage obligations - residential [Member]
Amortized cost and fair values of securities
Less than 12 Months	0	0
12 Months or More	1,796	2,083
Total	1,796	2,083
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	0	0
12 Months or More	(11)	(11)
Unrealized Loss	$ 11	11
Equity Funds [Member]
Amortized cost and fair values of securities
Less than 12 Months		499
12 Months or More		0
Total		499
Unrealized loss of securities
Less than 12 Months, Unrealized Loss		(1)
12 Months or More		0
Unrealized Loss		$ 1

Loans Receivable (Details)

Loans Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Loans receivable
Total loans	$ 1,274,677		$ 1,321,751
Net deferred loan origination costs	1,213		1,266
Allowance for loan losses	(8,103)	$ (8,179)	(8,366)	$ (8,374)	$ (8,374)	$ (8,122)	$ (8,127)
Loans, net	1,267,787		1,314,651
One-to-four family residential real estate loans [Member]
Loans receivable
Total loans	77,591		97,814
Allowance for loan losses	(762)		(850)
Multi-family mortgage loans [Member]
Loans receivable
Total loans	581,880		588,383
Allowance for loan losses	(3,722)		(3,849)
Nonresidential real estate loans [Member]
Loans receivable
Total loans	148,010		169,971
Allowance for loan losses	(1,410)		(1,605)
Construction and land loans [Member]
Loans receivable
Total loans	1,130		1,358
Allowance for loan losses	(27)		(32)
Commercial loans [Member]
Loans receivable
Total loans	167,547		152,552
Allowance for loan losses	(1,482)		(1,357)
Commercial leases [Member]
Loans receivable
Total loans	297,103		310,076
Allowance for loan losses	(684)		(655)
Consumer loans [Member]
Loans receivable
Total loans	1,416		1,597
Allowance for loan losses	$ (16)		$ (18)

Loans Receivable - Loan Origina

Loans Receivable - Loan Origination and Risk Management (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 1,274,677	$ 1,321,751
Multi-family mortgage loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	581,880	588,383
Nonresidential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	148,010	169,971
Commercial leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 297,103	$ 310,076

Loans Receivable - Allowance fo

Loans Receivable - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Allowance for loan losses and the loans receivable by portfolio segment
Net deferred loan origination costs	$ 1,213	$ 1,266
Loans, net	$ 1,267,787	$ 1,314,651

Loans Receivable - Activity in

Loans Receivable - Activity in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance		$ 8,374	$ 8,366	$ 8,127
Loans charged off	$ (90)	(103)	(396)	(464)
Recoveries	37	580	391	726
Net charge-off	53	(477)	5	(262)
Recovery of loan losses	(23)	(225)	(258)	(15)
Ending balance	8,103	8,374	8,103	8,374
One-to-four family residential real estate loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			850
Loans charged off	(84)	(89)	(214)	(282)
Recoveries	25	15	130	100
Ending balance	762		762
Multi-family mortgage loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			3,849
Loans charged off	0	(7)	(35)	(10)
Recoveries	8	11	26	62
Ending balance	3,722		3,722
Nonresidential real estate loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			1,605
Loans charged off	0	0	0	(165)
Recoveries	0	10	0	10
Ending balance	1,410		1,410
Construction and land loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			32
Recoveries	2	0	2	0
Ending balance	27		27
Commercial loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			1,357
Loans charged off	0	0	(140)	0
Recoveries	2	542	227	552
Ending balance	1,482		1,482
Commercial leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			655
Recoveries	0	2	5	2
Ending balance	684		684
Consumer loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			18
Loans charged off	(6)	(7)	(7)	(7)
Recoveries	0	$ 0	1	$ 0
Ending balance	$ 16		$ 16

Loans Receivable - Loans Indivi

Loans Receivable - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 1,274,677	$ 1,274,677	$ 1,321,751
Loans individually evaluated for impairment by class loans
Loan Balance			6,007
Recorded Investment			5,196
Partial Charge-off			806
Average Investment in Impaired Loans			5,059
Interest Income Recognized			238
Allowance for loan losses (With an allowance recorded)	0	0	0
Impaired Loan, Total	4,069	4,069
Recorded Investment, Total	3,388	3,388
Partial Charge-offs, Total	699	699
Average Investment in Impaired Loans, Total	3,866	4,530
Interest Income Recognized, Total	23	65
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	8,103	8,103	8,366
Net deferred loan origination costs	1,213	1,213	1,266
Loans and Leases Receivable, Allowance	8,103	8,103	8,366	$ 8,179	$ 8,374	$ 8,374	$ 8,122	$ 8,127
Financing Receivable, Individually Evaluated for Impairment	3,385	3,385	5,214
Financing Receivable, Collectively Evaluated for Impairment	1,271,292	1,271,292	1,316,537
Loans, net	1,267,787	1,267,787	1,314,651
One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	77,591	77,591	97,814
Loans individually evaluated for impairment by class loans
Loan Balance	3,322	3,322	5,049
Recorded Investment	2,677	2,677	4,248
Partial Charge-off	656	656	806
Average Investment in Impaired Loans	3,154	3,584	4,212
Interest Income Recognized	13	35	197
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	762	762	850
Loans and Leases Receivable, Allowance	762	762	850
Financing Receivable, Individually Evaluated for Impairment	2,724	2,724	4,265
Financing Receivable, Collectively Evaluated for Impairment	74,867	74,867	93,549
One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	15,881	15,881	21,208
Loans individually evaluated for impairment by class loans
Loan Balance	86	86
Recorded Investment	46	46
Partial Charge-off	43	43
Average Investment in Impaired Loans	46	110
Interest Income Recognized	0	0
Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	581,880	581,880	588,383
Loans individually evaluated for impairment by class loans
Loan Balance	661	661	958
Recorded Investment	665	665	948
Partial Charge-off	0	0	0
Average Investment in Impaired Loans	666	836	847
Interest Income Recognized	10	30	41
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	3,722	3,722	3,849
Loans and Leases Receivable, Allowance	3,722	3,722	3,849
Financing Receivable, Individually Evaluated for Impairment	661	661	949
Financing Receivable, Collectively Evaluated for Impairment	581,219	581,219	587,434
Multi Family Mortgage Loans without wholesale [Member] [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	276,810	276,810	291,358
Wholesale commercial lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	305,070	305,070	297,025
Nonresidential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	148,010	148,010	169,971
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,410	1,410	1,605
Loans and Leases Receivable, Allowance	1,410	1,410	1,605
Financing Receivable, Individually Evaluated for Impairment	0	0	0
Financing Receivable, Collectively Evaluated for Impairment	148,010	148,010	169,971
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	929	929	1,099
Land loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	201	201	259
Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	49,985	49,985	40,901
Commercial loans - other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	115,972	115,972	102,616
Consumer loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,416	1,416	1,597
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	16	16	18
Loans and Leases Receivable, Allowance	16	16	18
Financing Receivable, Individually Evaluated for Impairment	0	0	0
Financing Receivable, Collectively Evaluated for Impairment	1,416	1,416	1,597
Construction And Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	1,130	1,130	1,358
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	27	27	32
Loans and Leases Receivable, Allowance	27	27	32
Financing Receivable, Individually Evaluated for Impairment	0	0	0
Financing Receivable, Collectively Evaluated for Impairment	1,130	1,130	1,358
Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	167,547	167,547	152,552
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,482	1,482	1,357
Loans and Leases Receivable, Allowance	1,482	1,482	1,357
Financing Receivable, Individually Evaluated for Impairment	0	0	0
Financing Receivable, Collectively Evaluated for Impairment	167,547	167,547	152,552
Finance Leases Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	297,103	297,103	310,076
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)	0	0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	684	684	655
Loans and Leases Receivable, Allowance	684	684	655
Financing Receivable, Individually Evaluated for Impairment	0	0	0
Financing Receivable, Collectively Evaluated for Impairment	297,103	297,103	310,076
One to Four Family Residential Real Estate Loans-Owner occupied [Member] [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 61,710	$ 61,710	$ 76,606

Loans Receivable - Nonaccrual L

Loans Receivable - Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Reserve For Uncollected Loan Interest	$ 36	$ 103
Unpaid Principal Balance	1,843	4,097
Recorded Investment	1,471	2,390
Loans Past Due Over 90 Days, still accruing	0	0
One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Unpaid Principal Balance	1,646	3,413
Recorded Investment	1,313	1,918
Loans Past Due Over 90 Days, still accruing	0	0
One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Unpaid Principal Balance	95	308
Recorded Investment	56	109
Loans Past Due Over 90 Days, still accruing	0	0
Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Unpaid Principal Balance	102	376
Recorded Investment	102	363
Loans Past Due Over 90 Days, still accruing	$ 0	$ 0

Loans Receivable - Past Due Loa

Loans Receivable - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	$ 3,324	$ 4,451
Recorded Investment, Loans Not Past Due	1,266,207	1,311,339
Recorded investment, total	1,269,531	1,315,790
Commercial Leases Investment Rated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	787	934
Recorded Investment, Loans Not Past Due	181,402	207,747
Recorded investment, total	182,189	208,681
Commercial Loans Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	288
Recorded Investment, Loans Not Past Due	116,651	102,873
Recorded investment, total	116,651	103,161
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	17	0
Recorded Investment, Loans Not Past Due	1,410	1,605
Recorded investment, total	1,427	1,605
Commercial Loans Health Care [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Loans Not Past Due	69,248	71,738
Recorded investment, total	69,248	71,738
Commercial Loans Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	48,942	40,237
Recorded investment, total	48,942	40,237
Commercial loans - unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	50,105	40,935
Recorded investment, total	50,105	40,935
Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	198	259
Recorded investment, total	198	259
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	932	1,103
Recorded investment, total	932	1,103
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	607	608
Recorded Investment, Loans Not Past Due	146,394	166,071
Recorded investment, total	147,001	166,679
Wholesale Commercial Lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	299,469	296,440
Recorded investment, total	299,469	296,440
Multi Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	102	536
Recorded Investment, Loans Not Past Due	275,714	287,171
Recorded investment, total	275,816	287,707
One To Four Family Residential Real Estate Loans Non Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	90	99
Recorded Investment, Loans Not Past Due	15,817	20,944
Recorded investment, total	15,907	21,043
One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	1,721	1,986
Recorded Investment, Loans Not Past Due	59,925	74,216
Recorded investment, total	61,646	76,202
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	1,832	2,098
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Leases Investment Rated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	787	934
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Loans Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	288
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	12	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Loans Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial loans - unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	607	608
Financing Receivables, 30 to 59 Days Past Due [Member] | Wholesale Commercial Lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Multi Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	172
Financing Receivables, 30 to 59 Days Past Due [Member] | One To Four Family Residential Real Estate Loans Non Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	34	10
Financing Receivables, 30 to 59 Days Past Due [Member] | One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	392	86
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	13	102
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Leases Investment Rated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due		0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Loans Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	5	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Loans Health Care [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Loans Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial loans - unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Wholesale Commercial Lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Multi Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | One To Four Family Residential Real Estate Loans Non Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	8	3
Financing Receivables, 60 to 89 Days Past Due [Member] | One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	99
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Leases Investment Rated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	1,479	2,251
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Loans Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Loans Health Care [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Loans Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial loans - unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Wholesale Commercial Lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Multi Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	102	364
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One To Four Family Residential Real Estate Loans Non Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	48	86
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	$ 1,329	$ 1,801

Loans Receivable - Troubled Deb

Loans Receivable - Troubled Debt Restructuring (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Outstanding Commitments To Borrowers Loans Classified As Troubled Debt Restructurings	$ 0	$ 0
Troubled Debt Restructurings
Financing receivable modifications	17,000
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	0	0
One-to-four family residential real estate loans - non-owner occupied loans [Member] | Non Accrual Loans [Member]
Troubled Debt Restructurings
Financing receivable modifications	$ 17,000	$ 17,000

Loans Receivable - Modified Tro

Loans Receivable - Modified Troubled Debt Restructuring (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Modifications [Line Items]
Loans modified	$ 0	$ 149

Loans Receivable - Credit Quali

Loans Receivable - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 3,324	$ 4,451
Financing Receivable Credit Quality Indicators
Total loans	1,274,677	1,321,751
One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,721	1,986
Financing Receivable Credit Quality Indicators
Total loans	77,591	97,814
One to Four Family Residential Real Estate Loans-Owner occupied [Member] [Member]
Financing Receivable Credit Quality Indicators
Total loans	61,710	76,606
One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	90	99
Financing Receivable Credit Quality Indicators
Total loans	15,881	21,208
Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	102	536
Financing Receivable Credit Quality Indicators
Total loans	581,880	588,383
Multi Family Mortgage Loans without wholesale [Member] [Member]
Financing Receivable Credit Quality Indicators
Total loans	276,810	291,358
Wholesale commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	305,070	297,025
Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	148,010	169,971
Construction loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	929	1,099
Land loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	201	259
Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	49,985	40,901
Commercial Loans - Municipal loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	48,489	39,923
Commercial Loans - Warehouse Lines [Member]
Financing Receivable Credit Quality Indicators
Total loans
Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	69,073	71,728
Commercial loans - other [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	288
Financing Receivable Credit Quality Indicators
Total loans	115,972	102,616
Commercial Leases - Investment Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	787	934
Financing Receivable Credit Quality Indicators
Total loans	181,131	207,460
Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,416	1,597
Nonaccrual [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,472	2,391
Nonaccrual [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,314	1,914
Nonaccrual [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	56	109
Nonaccrual [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	102	368
Nonaccrual [Member] | Wholesale commercial lending [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Construction loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Land loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Commercial loans - Secured [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Commercial loans - other [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Nonaccrual [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member]
Financing Receivable Credit Quality Indicators
Total loans	5,527	2,922
Substandard [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	372	255
Substandard [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	37	40
Substandard [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	310	225
Substandard [Member] | Wholesale commercial lending [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	99	154
Substandard [Member] | Construction loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Land loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Commercial loans - Secured [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	4,699	2,248
Substandard [Member] | Commercial loans - other [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Substandard [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	10	0
Pass [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,261,767	1,311,910
Pass [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	59,714	74,437
Pass [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	15,755	21,059
Pass [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	276,398	290,765
Pass [Member] | Wholesale commercial lending [Member]
Financing Receivable Credit Quality Indicators
Total loans	305,070	297,025
Pass [Member] | Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	147,911	169,817
Pass [Member] | Construction loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	929	1,099
Pass [Member] | Land loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	201	259
Pass [Member] | Commercial loans - Secured [Member]
Financing Receivable Credit Quality Indicators
Total loans	45,170	36,373
Pass [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	48,489	39,923
Pass [Member] | Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	64,374	69,480
Pass [Member] | Commercial loans - other [Member]
Financing Receivable Credit Quality Indicators
Total loans	115,972	102,616
Pass [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	180,383	207,460
Pass [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,401	1,597
Special Mention [Member]
Financing Receivable Credit Quality Indicators
Total loans	5,911	4,528
Special Mention [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	310	0
Special Mention [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	33	0
Special Mention [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Wholesale commercial lending [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Construction loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Land loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Commercial loans - Secured [Member]
Financing Receivable Credit Quality Indicators
Total loans	4,815	4,528
Special Mention [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Commercial loans - other [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	748	0
Special Mention [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	5	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,832	2,098
Financing Receivables, 30 to 59 Days Past Due [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	392	86
Financing Receivables, 30 to 59 Days Past Due [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	34	10
Financing Receivables, 30 to 59 Days Past Due [Member] | Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	172
Financing Receivables, 30 to 59 Days Past Due [Member] | Wholesale commercial lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Land loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial loans - other [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	288
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 787	$ 934

Loans Receivable - Narrative (D

Loans Receivable - Narrative (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Receivables [Abstract]
Reserve For Uncollected Loan Interest	$ 36,000		$ 103,000
Financing receivable modifications	17,000
Outstanding Commitments To Borrowers Loans Classified As Troubled Debt Restructurings	0		$ 0
Loans modified	$ 0	$ 149,000

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Mortgage Loans in Process of Foreclosure, Amount	$ 600		$ 600			$ 1,500
Other Real Estate Owned At Carrying Value	985	$ 3,569	985	$ 3,569	$ 1,187	2,351	$ 3,569	$ 4,896	$ 3,895
Real Estate Owned, Valuation Allowance, Amounts Applied	(22)	(63)	(309)	(278)
Real Estate Owned, Valuation Allowance, Valuation Increase	1	227	27	301
Real Estate Owned, Valuation Allowance	(23)	(472)	(23)	(472)	$ (44)	(305)	$ (472)	$ (308)	$ (449)
Other Real Estate, Disposals	(604)	(1,205)	(2,580)	(2,066)
Other Real Estate, Valuation Adjustments	(1)	(227)	(27)	(301)
Other Real Estate, Additions	403	$ 105	1,241	$ 2,041
Other real estate owned at carrying value before valuation allowance	1,008		1,008			2,656
Foreclosed Residential Real Estate [Member]
Real Estate Owned, Valuation Allowance						(352)
Multi Family Mortgage Loans [Member]
Other Real Estate Owned At Carrying Value	276		276			0
Real Estate Owned, Valuation Allowance	0		0			0
Other real estate owned at carrying value before valuation allowance	276		276			0
One to Four Family Residential Real Estate Loans [Member]
Other Real Estate Owned At Carrying Value	634		634			827
Real Estate Owned, Valuation Allowance	0		0			(9)
Other real estate owned at carrying value before valuation allowance	634		634			836
Nonresidential Real Estate [Member]
Other Real Estate Owned At Carrying Value	74		74			1,520
Real Estate Owned, Valuation Allowance	0		0			(252)
Other real estate owned at carrying value before valuation allowance	74		74			1,772
Land [Member]
Other Real Estate Owned At Carrying Value	1		1			4
Real Estate Owned, Valuation Allowance	(23)		(23)			(44)
Other real estate owned at carrying value before valuation allowance	$ 24		$ 24			$ 48

Securities Sold Under Agreeme_3

Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank, Advances [Line Items]
Carrying Value of Federal Funds Purchased, Securities Sold under Agreements to Repurchase, and Deposits Received for Securities Loaned	$ 1,232	$ 768
Federal Home Loan Bank Advances [Member] | Period One [Member]
Federal Home Loan Bank, Advances [Line Items]
Debt, Long-term and Short-term, Combined Amount	20,000	60,000
Collateral Pledged [Member]
Federal Home Loan Bank, Advances [Line Items]
Available-for-sale Securities Pledged as Collateral	$ 2,700	$ 3,700

Fair Value - Financial Assets A

Fair Value - Financial Assets Accounted for at Fair Value (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate	$ 24		$ 24		$ 1,200
Schedule of Company's financial instruments measured at fair values
Total Fair value	103,921		103,921		93,383
Real Estate Acquired Through Foreclosure Fair Value	1		1
Real Estate Owned, Valuation Allowance, Valuation Increase	1	$ 227	27	$ 301
Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	89,175		89,175		75,916
Equity Funds [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		499
Residential Mortgage Backed Securities [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	10,925		10,925		12,472
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	10,925		10,925
Collateralized Debt Obligations [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	3,821		3,821		4,486
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	3,821		3,821
SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					10
Nonrecurring [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	103,921		103,921		93,383
Real Estate Acquired Through Foreclosure Fair Value					916
Nonrecurring [Member] | Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	89,175		89,175		75,916
Nonrecurring [Member] | Equity mutual fund [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					499
Nonrecurring [Member] | Mortgage-backed securities - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	10,925		10,925		12,472
Nonrecurring [Member] | Collateralized mortgage obligations - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	3,821		3,821		4,486
Nonrecurring [Member] | SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					10
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		499
Real Estate Acquired Through Foreclosure Fair Value					0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage-backed securities - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Collateralized mortgage obligations - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	103,921		103,921		92,884
Real Estate Acquired Through Foreclosure Fair Value					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	89,175		89,175
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Equity mutual fund [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Mortgage-backed securities - residential [Member]
Schedule of Company's financial instruments measured at fair values
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	10,925		10,925
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Collateralized mortgage obligations - residential [Member]
Schedule of Company's financial instruments measured at fair values
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	3,821		3,821
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Real Estate Acquired Through Foreclosure Fair Value	1		1		916
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Equity mutual fund [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Mortgage-backed securities - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Collateralized mortgage obligations - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value					0
Nonresidential Real Estate [Member] | Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					814
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					102
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					0
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					0
One to Four Family Residential Real Estate Loans [Member] | Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					102
Commercial Real Estate [Member] | Nonrecurring [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					814
Commercial Real Estate [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					0
Commercial Real Estate [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value					0
Land Loans [Member] | Nonrecurring [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	1		1
Land Loans [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	0		0
Land Loans [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	0		0
Land Loans [Member] | Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	$ 1		$ 1
Sales Comparison Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					$ 916
Impaired Loans [Member] | Sales Comparison Valuation Technique [Member] | Commercial Real Estate [Member]
Schedule of Company's financial instruments measured at fair values
Real estate owned, measurement input					0.056
Impaired Loans [Member] | Sales Comparison Valuation Technique [Member] | Land Loans [Member]
Schedule of Company's financial instruments measured at fair values
Real estate owned, measurement input	0.123		0.123
Measurement Input, Comparability Adjustment [Member] | Maximum [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member]
Schedule of Company's financial instruments measured at fair values
Real estate owned, measurement input					0.1522
Measurement Input, Comparability Adjustment [Member] | Weighted Average [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member]
Schedule of Company's financial instruments measured at fair values
Real estate owned, measurement input					0.1100

Fair Value - Assets Measured at

Fair Value - Assets Measured at Fair Value on a Non-Recurring Basis (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate	$ 24,000		$ 24,000		$ 1,200,000
Real Estate Owned, Valuation Allowance, Component	23,000		23,000		261,000
Fair Value, Other real estate owned	1,000		1,000
Other Real Estate Owned Write Downs	1,000	$ 227,000	27,000	$ 301,000
Nonrecurring [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					916,000
Nonrecurring [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					102,000
Nonrecurring [Member] | Nonresidential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					814,000
Nonrecurring [Member] | Land Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned	1,000		1,000
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Nonresidential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Land Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned	0		0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Nonresidential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned					0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | Land Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned	0		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned	1,000		1,000		916,000
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Nonresidential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					814,000
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					102,000
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Land Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Other real estate owned	$ 1,000		$ 1,000
Sales Comparison Valuation Technique [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Real Estate					$ 916,000
Impaired Loans [Member] | Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Real estate owned, measurement input					0.056
Impaired Loans [Member] | Sales Comparison Valuation Technique [Member] | Land Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Real estate owned, measurement input	0.123		0.123
Measurement Input, Comparability Adjustment [Member] | Maximum [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Real estate owned, measurement input					0.1522
Measurement Input, Comparability Adjustment [Member] | Minimum [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Real estate owned, measurement input					(0.0366)
Measurement Input, Comparability Adjustment [Member] | Weighted Average [Member] | Real Estate Properties [Domain] | Nonresidential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Real estate owned, measurement input					0.1100

Fair Value - Carrying Amount an

Fair Value - Carrying Amount and Estimated Fair Value of Finanical Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 86,934	$ 127,592	$ 125,661	$ 96,684
Financial assets
Securities, carrying amount	103,921	93,383
Loans receivable, net of allowance for loan losses, carrying amounts	1,267,787	1,314,651
FHLBC stock, carrying amount	8,026	8,290
Accrued interest receivable, carrying amount	4,974	4,619
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets
Securities, carrying amount	103,921	93,383
Loans Receivable, Fair Value Disclosure	1,265,906	1,323,139
Accounts Receivable, Fair Value Disclosure	4,974	4,619
Financial liabilities
Cash and Cash Equivalents, Fair Value Disclosure	86,934	127,592
Demand Deposit Accounts Fair Value Disclosure	225,446	234,354
Deposits Savings Deposits Fair Value Disclosure	155,232	160,501
Now Money Market Accounts		589,238
Now Money Market Accounts Fair Value Disclosure	549,631
Certificates Of Deposit Fair Value Disclosure	362,670	353,969
Short Term Borrowings Fair Value Disclosure	21,214	60,627
Accrued Liabilities, Fair Value Disclosure	361	147
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member]
Financial assets
Loans Receivable, Fair Value Disclosure		0
Accounts Receivable, Fair Value Disclosure		0
Financial liabilities
Cash and Cash Equivalents, Fair Value Disclosure	12,473	13,572
Demand Deposit Accounts Fair Value Disclosure		0
Deposits Savings Deposits Fair Value Disclosure		0
Certificates Of Deposit Fair Value Disclosure		0
Short Term Borrowings Fair Value Disclosure		0
Accrued Liabilities, Fair Value Disclosure		0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member]
Financial assets
Securities, carrying amount	103,921	92,884
Loans Receivable, Fair Value Disclosure	0	1,323,139
Accounts Receivable, Fair Value Disclosure	4,974	4,619
Financial liabilities
Cash and Cash Equivalents, Fair Value Disclosure	74,461	114,020
Demand Deposit Accounts Fair Value Disclosure	225,446	234,354
Deposits Savings Deposits Fair Value Disclosure	155,232	160,501
Now Money Market Accounts		589,238
Now Money Market Accounts Fair Value Disclosure	549,631
Certificates of Deposit, at Carrying Value	362,670
Certificates Of Deposit Fair Value Disclosure		353,969
Short-term Debt	21,214	60,627
Accrued Liabilities, Fair Value Disclosure	361	147
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets
Loans Receivable, Fair Value Disclosure	1,265,906	0
Reported Value Measurement [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Cash and Cash Equivalents, at Carrying Value	86,934	127,592
Financial assets
Securities, carrying amount	103,921	93,383
Loans receivable, net of allowance for loan losses, carrying amounts	1,267,787	1,314,651
FHLBC stock, carrying amount	8,026	8,290
Accrued interest receivable, carrying amount	4,974	4,619
Financial liabilities
Demand Deposit Accounts	225,446	234,354
Deposits, Savings Deposits	155,232	160,501
Now Money Market Accounts		589,238
Now Money Market Accounts Fair Value Disclosure	549,631
Certificates of Deposit, at Carrying Value	365,461	355,958
Short-term Debt	21,232	60,768
Accrued Interest Payable	361	147
Equity Funds [Member]
Financial assets
Securities, carrying amount	$ 0	$ 499

Revenue From Contracts With C_3

Revenue From Contracts With Customers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue from External Customer [Line Items]
Income from product and service	$ 1,003	$ 1,018	$ 2,970	$ 2,964
Loan fee income	71	89	231	212
Commercial mortgage brokerage fees	12	0	138	0
Gain (Loss) on Sales of Loans, Net			0	70
Loss on sales of equity securities	0	0	(14)	0
Residential mortgage banking fees	34	41	88	172
Loss on sale of equity securities			(14)	0
Loss on sales of equity securities		0
Gain on sale of premises held-for-sale	0	0	93	0
Trust and insurance commissions and annuities income	207	210	670	704
Earnings on bank-owned life insurance	35	67	146	196
Bank-owned life insurance death benefit	0	0	1,389	0
Other	208	198	492	526
Total noninterest income	1,570	1,623	6,203	4,774
Credit and Debit Card
Revenue from External Customer [Line Items]
Income from product and service	$ 382	$ 361	$ 1,136	$ 1,064

Uncategorized Items - bfin-2018

Label	Element	Value
Dividends, Common Stock, Cash	us-gaap_DividendsCommonStockCash	$ 3,710,000
Other Comprehensive Income (Loss), Net of Tax	us-gaap_OtherComprehensiveIncomeLossNetOfTax	(45,000)
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	9,148,000
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	us-gaap_ProceedsFromRepaymentOfLoansByEmployeeStockOwnershipPlans	1,125,000
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(1,237,000)
Common Stock [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	192,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	180,000
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	6,000
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	us-gaap_ProceedsFromRepaymentOfLoansByEmployeeStockOwnershipPlans	(8,000)
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	2,000
AOCI Attributable to Parent [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	376,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	331,000
Other Comprehensive Income (Loss), Net of Tax	us-gaap_OtherComprehensiveIncomeLossNetOfTax	(45,000)
Retained Earnings [Member]
Dividends, Common Stock, Cash	us-gaap_DividendsCommonStockCash	3,710,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	39,483,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	43,786,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	3,560,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	8,013,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	3,737,000
Additional Paid-in Capital [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	173,047,000
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	155,481,000
Stock Repurchased During Period, Value	us-gaap_StockRepurchasedDuringPeriodValue	9,142,000
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	us-gaap_ProceedsFromRepaymentOfLoansByEmployeeStockOwnershipPlans	(7,185,000)
Stock Issued During Period, Value, Stock Options Exercised	us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised	(1,239,000)
Unearned Employee Stock Ownership Plan Shares [Member]
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	(8,318,000)
Stockholders' Equity Attributable to Parent	us-gaap_StockholdersEquity	0
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	us-gaap_ProceedsFromRepaymentOfLoansByEmployeeStockOwnershipPlans	$ 8,318,000