BankFinancial (BFIN) 10-Q 25 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 27, 2017
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2,017
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 Common Stock, Shares Outstanding		18,049,423
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and due from other financial institutions	$ 10,620	$ 13,053
Interest-bearing deposits in other financial institutions	115,041	83,631
Cash and cash equivalents	125,661	96,684
Securities, at fair value	98,787	107,212
Loans receivable, net of allowance for loan losses: September 30, 2016, $8,334 and December 31, 2015, $9,691	1,335,631	1,312,952
Other Real Estate Owned At Carrying Value	3,569	3,895
Stock in Federal Home Loan Bank, at cost	8,290	11,650
Premises and equipment, net	30,774	31,413
Accrued interest receivable	4,569	4,381
Core deposit intangible	408	782
Bank owned life insurance	22,790	22,594
Deferred Tax Assets, Net, Current	20,214	22,411
Other assets	3,576	6,063
Total assets	1,654,269	1,620,037
Deposits
Noninterest-bearing	231,049	249,539
Interest-bearing	1,140,040	1,089,851
Total deposits	1,371,089	1,339,390
Borrowings	60,928	51,069
Advance payments by borrowers taxes and insurance	10,683	11,041
Accrued interest payable and other liabilities	11,791	13,757
Total liabilities	1,454,491	1,415,257
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; 19,271,211 shares issued at September 30, 2016 and 20,297,317 issued at December 31, 2015	180	192
Additional paid-in capital	155,481	173,047
Retained earnings (deficit)	43,786	39,483
Unearned Employee Stock Ownership Plan shares	0	(8,318)
Accumulated other comprehensive income	331	376
Total stockholders' equity	199,778	204,780
Total liabilities and stockholders' equity	$ 1,654,269	$ 1,620,037

Consolidated Statements of Fin3

Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for loan losses	$ 8,374	$ 8,127
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	18,063,623	20,297,317

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Interest and dividend income
Loans, including fees	$ 13,345	$ 12,388
Securities	389	306
Other	387	151
Total interest income	14,121	12,845
Interest expense
Deposits	1,419	1,012
Borrowings	196	2
Total interest expense	1,615	1,014
Net interest income	12,506	11,831
Provision for (recovery of) loan losses	(225)	(525)
Net interest income	12,731	12,356
Noninterest income
Deposit service charges and fees	584	583
Other fee income	523	478
Insurance commissions and annuities income	41	53
Gain on sale of loans, net	10	38
Loan servicing fees	58	66
Amortization and impairment of servicing assets	(27)	(28)
Bank Owned Life Insurance Income	67	54
Trust	169	167
Other	198	226
Total noninterest income	1,623	1,637
Noninterest expense
Compensation and benefits	5,330	5,315
Office occupancy and equipment	1,693	1,487
Advertising and public relations	167	144
Information technology	638	707
Supplies, telephone, and postage	337	345
Amortization of intangibles	123	129
Nonperforming asset management	84	89
Operations of other real estate owned	403	243
FDIC insurance premiums	150	238
Other	1,275	1,215
Total noninterest expense	10,200	9,912
Income before income taxes	4,154	4,081
Income tax expense	594	1,573
Net income	$ 3,560	$ 2,508
Basic earnings per common share (usd per share)	$ 0.20	$ 0.13
Diluted earnings per common share (usd per share)	$ 0.20	$ 0.13
Weighted average common shares outstanding (shares)	18,139,659	18,788,731
Diluted weighted average common shares outstanding (shares)	18,140,109	18,789,054

Consolidated Statements Compreh

Consolidated Statements Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income	$ 3,560	$ 2,508	$ 8,013	$ 5,243
Unrealized holding gain (loss) arising during the period	(16)	13	67	75
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	(9)	5	22	29
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	7	(8)	(45)	(46)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	0	0	0	(46)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	0	0	0	18
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent, Available-for-sale Securities	0	0	0	(28)
Other Comprehensive Income (Loss), Net of Tax	7	(8)	(45)	(74)
Comprehensive income (loss)	$ 3,567	$ 2,500	$ 7,968	$ 5,169

Consolidated Statements of Chan

Consolidated Statements of Changes In Stockholders' Equity - 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, 2015	$ 212,364	$ 203	$ 184,797	$ 36,114	$ (9,297)	$ 547
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,243			5,243
Other comprehensive income, net of tax effects	(74)					(74)
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	0
Payments for Repurchase of Common Stock	(12,695)	10	12,685
Nonvested stock awards-stock-based compensation expense	875		875	0	0	0
Cash dividends declared on common stock (2015: $0.16, 2016: $0.15, per share)	2,977			2,977
ESOP shares earned	931		198	0	733
Ending Balance at Sep. 30, 2016	203,667	193	173,185	38,380	(8,564)	473
Beginning Balance at Dec. 31, 2016	204,780	192	173,047	39,483	(8,318)	376
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,013			8,013
Other comprehensive income, net of tax effects	(45)					(45)
Proceeds from Stock Options Exercised	(1,237)	(2)	1,239
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	1,125	(8)	(7,185)		8,318
Payments for Repurchase of Common Stock	(9,148)	6	9,142
Cash dividends declared on common stock (2015: $0.16, 2016: $0.15, per share)	3,710			3,710
Ending Balance at Sep. 30, 2017	$ 199,778	$ 180	$ 155,481	$ 43,786	$ 0	$ 331

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common Stock, Dividends, Per Share, Declared	$ 0.15	$ 0.16
Stock Repurchased and Retired During Period, Shares	614,673	600,000,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flow - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities
Net income	$ 8,013	$ 5,243
Adjustments to reconcile to net loss to net cash from operating activities
Provision for (recovery of) loan losses	(15)	300
Proceeds from Repayment of Loans by Employee Stock Ownership Plans	1,125	0
ESOP shares earned	0	931
Stock-based compensation expense	0	875
Depreciation and amortization	2,846	2,815
Amortization of premiums and discounts on securities and loans	(72)	(104)
Amortization Of Intangibles	374	394
Amortization and impairment of servicing assets	86	96
Net change in net deferred loan origination costs	343	(36)
Net loss on sale of other real estate owned	100	(15)
Net gain on sale of loans	(70)	(59)
Loans originated for sale	(1,291)	(1,097)
Proceeds from sale of loans	1,361	1,156
REO valuation adjustments	301	244
Net change in:
Accrued interest receivable	(188)	70
Earnings on bank owned life insurance	(196)	(151)
Other assets	4,027	3,515
Accrued interest payable and other liabilities	(1,966)	(1,279)
Net cash from operating activities	14,778	12,852
Gain on Sale of Securities, Net	0	(46)
Securities
Proceeds from maturities	49,695	58,577
Proceeds from principal repayments	2,461	3,545
Proceeds from Sale of Available-for-sale Securities	0	46
Purchases of securities	(43,808)	(47,423)
Loans receivable
Increase (Decrease) in Participation Liabilities	3,615	3,023
Principal payments on loans receivable	459,706	366,784
Payments to Purchase Loans Held-for-sale	(23,451)	0
Proceeds from Sale of Loans Receivable	0	14,746
Originated for investment	(465,562)	(395,087)
Payments for (Proceeds from) Federal Home Loan Bank Stock	3,514	0
Payments to Acquire Federal Home Loan Bank Stock	154	0
Proceeds from sale of other real estate owned	1,966	2,616
Purchases of premises and equipment, net	(906)	(660)
Net cash from (used in) investing activities	(12,924)	6,167
Cash flows from financing activities
Net change in deposits	31,699	103,776
Net change in borrowings	9,859	(62,912)
Net change in advance payments by borrowers for taxes and insurance	(358)	(3,058)
Payments for Repurchase of Common Stock	(9,148)	(12,695)
Payments of Ordinary Dividends, Common Stock	(3,710)	(2,977)
Payments for Deposits Applied to Debt Retirements	1,219	0
Net cash used in financing activities	27,123	22,134
Net change in cash and cash equivalents	28,977	41,153
Beginning cash and cash equivalents	96,684	59,377
Ending cash and cash equivalents	125,661	100,530
Supplemental disclosures of cash flow information:
Interest paid	4,269	2,704
Income taxes paid	198	182
Loans transferred to other real estate owned	$ 2,041	$ 215

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2017
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 (the “Company”), is the owner of all of the issued and outstanding capital stock of BankFinancial, National Association (the “Bank”). The interim unaudited consolidated financial statements include the accounts of and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BF Asset Recovery Corporation (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. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three- and nine -month periods ended September 30, 2017 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2017 . 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, 2016 , as filed with the Securities and Exchange Commission. Recent Accounti

Earnings Per Share (Notes)

Earnings Per Share (Notes)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	ngs 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 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 2017 2016 2017 2016 Net income available to common stockholders $ 3,560 $ 2,508 $ 8,013 $ 5,243 Average common shares outstanding 18,140,599 19,460,022 18,567,796 19,813,088 Less: Unearned ESOP shares — (670,351 ) (198,114 ) (694,655 ) Unvested restricted stock shares (940 ) (940 ) (940 ) (3,830 ) Weighted average common shares outstanding 18,139,659 18,788,731 18,368,742 19,114,603 Add - Net effect of dilutive unvested restricted stock 450 323 428 315 Diluted weighted average common shares outstanding 18,140,109 18,789,054 18,369,170 19,114,918 Basic earnings per common share $ 0.20 $ 0.13 $ 0.44 $ 0.27 Diluted earnings per common share $ 0.20 $ 0.13 $ 0.44 $ 0.27 Number of antidilutive stock options excluded from the diluted earnings per share calculation — 536,459 — 536,459 Weighted average exercise price of anti-dilutive option shares $ — $ 12.99 $ — $ 12.99

Securities (Notes)

Securities (Notes)	9 Months Ended
	Sep. 30, 2017
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, 2017 Certificates of deposit $ 80,360 $ — $ — $ 80,360 Equity mutual fund 500 2 — 502 Mortgage-backed securities - residential 12,645 553 (10 ) 13,188 Collateralized mortgage obligations - residential 4,728 14 (17 ) 4,725 SBA-guaranteed loan participation certificates 12 — — 12 $ 98,245 $ 569 $ (27 ) $ 98,787 December 31, 2016 Certificates of deposit $ 85,938 $ — $ — $ 85,938 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 14,561 644 (21 ) 15,184 Collateralized mortgage obligations - residential 5,587 15 (28 ) 5,574 SBA-guaranteed loan participation certificates 17 — — 17 $ 106,603 $ 659 $ (50 ) $ 107,212 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, 2017 and December 31, 2016 . 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, 2017 Amortized Cost Fair Value Due in one year or less $ 80,360 $ 80,360 Equity mutual fund 500 502 Mortgage-backed securities - residential 12,645 13,188 Collateralized mortgage obligations - residential 4,728 4,725 SBA-guaranteed loan participation certificates 12 12 $ 98,245 $ 98,787 Sales of securities were as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 Proceeds $ — $ — $ — $ 46 Gross gains — — — 46 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, 2017 Mortgage-backed securities - residential $ 1,182 $ (10 ) $ — $ — $ 1,182 $ (10 ) Collateralized mortgage obligations - residential — — 3,270 (17 ) 3,270 (17 ) $ 1,182 $ (10 ) $ 3,270 $ (17 ) $ 4,452 $ (27 ) December 31, 2016 Equity Mutual Fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential 1,187 (21 ) — — 1,187 (21 ) Collateralized mortgage obligations - residential 3,691 (18 ) 1,028 (10 ) 4,719 (28 ) $ 5,377 $ (40 ) $ 1,028 $ (10 ) $ 6,405 $ (50 ) 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, 2017 , 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, 2017
Receivables [Abstract]
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Loans receivable are as follows: September 30, 2017 December 31, 2016 One-to-four family residential real estate $ 105,186 $ 135,218 Multi-family mortgage 576,425 542,887 Nonresidential real estate 176,301 182,152 Construction and land 2,827 1,302 Commercial loans 147,079 103,063 Commercial leases 333,120 352,539 Consumer 1,747 2,255 1,342,685 1,319,416 Net deferred loan origination costs 1,320 1,663 Allowance for loan losses (8,374 ) (8,127 ) Loans, net $ 1,335,631 $ 1,312,952 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, 2017 One-to-four family residential real estate $ — $ 812 $ 812 $ 4,616 $ 100,570 $ 105,186 Multi-family mortgage — 3,872 3,872 959 575,466 576,425 Nonresidential real estate — 1,590 1,590 — 176,301 176,301 Construction and land — 68 68 — 2,827 2,827 Commercial loans — 1,241 1,241 — 147,079 147,079 Commercial leases — 769 769 — 333,120 333,120 Consumer — 22 22 — 1,747 1,747 $ — $ 8,374 $ 8,374 $ 5,575 $ 1,337,110 1,342,685 Net deferred loan origination costs 1,320 Allowance for loan losses (8,374 ) Loans, net $ 1,335,631 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, 2016 One-to-four family residential real estate $ — $ 1,168 $ 1,168 $ 4,962 $ 130,256 $ 135,218 Multi-family mortgage — 3,647 3,647 787 542,100 542,887 Nonresidential real estate 26 1,768 1,794 260 181,892 182,152 Construction and land — 32 32 — 1,302 1,302 Commercial loans — 733 733 — 103,063 103,063 Commercial leases — 714 714 — 352,539 352,539 Consumer — 39 39 — 2,255 2,255 $ 26 $ 8,101 $ 8,127 $ 6,009 $ 1,313,407 1,319,416 Net deferred loan origination costs 1,663 Allowance for loan losses (8,127 ) Loans, net $ 1,312,952 Activity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 Beginning balance $ 8,122 $ 8,915 $ 8,127 $ 9,691 Loans charged off: One-to-four family residential real estate (89 ) (102 ) (282 ) (509 ) Multi-family mortgage (7 ) — (10 ) (51 ) Nonresidential real estate — (55 ) (165 ) (1,715 ) Consumer (7 ) (6 ) (7 ) (24 ) (103 ) (163 ) (464 ) (2,299 ) Recoveries: One-to-four family residential real estate 15 5 100 92 Multi-family mortgage 11 10 62 156 Nonresidential real estate 10 39 10 200 Construction and land — — — 35 Commercial loans 542 45 552 150 Commercial leases 2 7 2 7 Consumer — 1 — 2 580 107 726 642 Net recoveries (charge-offs) 477 (56 ) 262 (1,657 ) Provision for (recovery of) loan losses (225 ) (525 ) (15 ) 300 Ending balance $ 8,374 $ 8,334 $ 8,374 $ 8,334 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, 2017 One-to-four family residential real estate $ 3,392 $ 1,658 $ — One-to-four family residential real estate – non-owner occupied 751 576 — Multi-family mortgage - Illinois 378 371 — $ 4,521 $ 2,605 $ — December 31, 2016 One-to-four family residential real estate $ 2,861 $ 2,483 $ — One-to-four family residential real estate – non-owner occupied 428 368 — Multi-family mortgage - Illinois 187 185 — Nonresidential real estate 262 260 — $ 3,738 $ 3,296 $ — 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 $250,000 and $199,000 at September 30, 2017 and December 31, 2016 , 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, 2017 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 $ 94 $ 749 $ 1,655 $ 2,498 $ 79,800 $ 82,298 One-to-four family residential real estate loans – non-owner occupied 12 3 577 592 22,321 22,913 Multi-family mortgage - Illinois — — 371 371 288,508 288,879 Multi-family mortgage - Other — — — — 281,887 281,887 Nonresidential real estate — — — — 174,724 174,724 Construction — — — — 2,548 2,548 Land — — — — 281 281 Commercial loans: Regional commercial banking — — — — 40,315 40,315 Health care — — — — 72,685 72,685 Direct commercial lessor 275 369 — 644 33,787 34,431 Commercial leases: Investment rated commercial leases — 2,225 — 2,225 230,009 232,234 Other commercial leases — — — — 102,698 102,698 Consumer — — — — 1,754 1,754 $ 381 $ 3,346 $ 2,603 $ 6,330 $ 1,331,317 $ 1,337,647 The following tables present the aging of the recorded investment of loans at December 31, 2016 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 $ 984 $ 335 $ 2,235 $ 3,554 $ 92,665 $ 96,219 One-to-four family residential real estate loans – non-owner occupied 664 114 368 1,146 37,179 38,325 Multi-family mortgage - Illinois 605 439 184 1,228 294,223 295,451 Multi-family mortgage - Other — — — — 243,944 243,944 Nonresidential real estate — — 260 260 178,644 178,904 Construction — — — — 950 950 Land — — — — 349 349 Commercial loans: Regional commercial banking — — — — 26,480 26,480 Health care — — — — 41,086 41,086 Direct commercial lessor — — — — 31,847 31,847 Commercial leases: Investment rated commercial leases 51 — — 51 273,405 273,456 Other commercial leases — — — — 84,988 84,988 Consumer — — — — 2,263 2,263 $ 2,304 $ 888 $ 3,047 $ 6,239 $ 1,308,023 $ 1,314,262 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 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, 2017 , compared to $341,000 at December 31, 2016 . No specific valuation reserves were allocated to those loans at September 30, 2017 and December 31, 2016 . 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, 2017 December 31, 2016 One-to-four family residential real estate $ — $ 205 Troubled debt restructured loans – accrual loans — 205 One-to-four family residential real estate 17 136 Troubled debt restructured loans – nonaccrual loans 17 136 Total troubled debt restructured loans $ 17 $ 341 During the nine months ended September 30, 2017 , there were no loans modified and classified as TDRs. During the nine months ended September 30, 2016 , the terms of certain loans were modified and classified as TDRs. The modification of the terms of such loans included one or a combination of the following: a reduction of the stated interest rate of the loan; an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; or a permanent reduction of the recorded investment in the loan. The following tables present TDR activity: For the Nine Months Ended September 30, 2017 2016 Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment One-to-four family residential real estate — $ — $ — 1 $ 63 $ 63 Due to Due to Due to Total For the Nine Months Ended September 30, 2016 One-to-four family residential real estate $ — $ 63 $ — $ 63 The TDRs described above had no impact on interest income, resulted in no change to the allowance for loan losses allocated and resulted in no charge-offs for the nine months ended September 30, 2016 . The following table presents TDRs for which there was a payment default during the nine months ended September 30, 2017 and 2016 within twelve months following the modification. 2017 2016 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate 1 $ 17 2 $ 87 A TDR is considered to be in payment default once it is 90 days contractually past due under the modified terms. The TDRs for which there was a payment default resulted in no change to the allowance for loan losses allocated and resulted in no charge-offs during the nine months ended September 30, 2017 and 2016 . There were certain other loan modifications during the three and nine months ended September 30, 2017 and 2016 that did not meet the definition of a TDR. These loans had a total recorded investment of $149,000 and $615,000 at September 30, 2017 and 2016 , respectively. 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. The loans were placed on nonaccrual status. 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, 2017 , 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 $ 80,401 $ — $ 257 $ 1,653 $ 82,311 One-to-four family residential real estate loans – non-owner occupied 22,258 — 40 577 22,875 Multi-family mortgage loans - Illinois 289,175 — 480 372 290,027 Multi-family mortgage loans - Other 286,398 — — — 286,398 Nonresidential real estate loans 176,139 — 162 — 176,301 Construction loans 2,543 — — — 2,543 Land loans 284 — — — 284 Commercial loans: Regional commercial banking 40,251 — — — 40,251 Health care 71,633 — 982 — 72,615 Direct commercial lessor 34,213 — — — 34,213 Commercial leases: Investment rated commercial leases 230,931 — — — 230,931 Other commercial leases 102,189 — — — 102,189 Consumer 1,747 — — — 1,747 $ 1,338,162 $ — $ 1,921 $ 2,602 $ 1,342,685 As of December 31, 2016 , 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 $ 93,514 $ — $ 629 $ 2,486 $ 96,629 One-to-four family residential real estate loans – non-owner occupied 38,179 — 41 369 38,589 Multi-family mortgage loans - Illinois 297,826 122 1,048 187 299,183 Multi-family mortgage loans - Other 243,704 — — — 243,704 Nonresidential real estate loans 180,047 — 1,845 260 182,152 Construction loans 946 — — — 946 Land loans 356 — — — 356 Commercial loans: Regional commercial banking 26,365 — 66 — 26,431 Health care 41,001 — — — 41,001 Direct commercial lessor 30,881 800 — — 31,681 Commercial leases: Investment rated commercial leases 271,972 — — — 271,972 Other commercial leases 84,356 161 — — 84,517 Consumer 2,255 — — — 2,255 $ 1,311,402 $ 1,083 $ 3,629 $ 3,302 $ 1,319,416

Other Real Estate Owned (Notes)

Other Real Estate Owned (Notes)	9 Months Ended
	Sep. 30, 2017
Other Real Estate [Abstract]
Real Estate Owned [Text Block]	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, 2017 December 31, 2016 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 1,955 $ (207 ) $ 1,748 $ 1,702 $ (137 ) $ 1,565 Multi-family mortgage — — — 370 — 370 Nonresidential real estate 1,772 (221 ) 1,551 1,171 (105 ) 1,066 Land 314 (44 ) 270 1,101 (207 ) 894 $ 4,041 $ (472 ) $ 3,569 $ 4,344 $ (449 ) $ 3,895 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, 2017 2016 2017 2016 Beginning balance $ 4,896 $ 5,373 $ 3,895 $ 7,011 New foreclosed properties 105 94 2,041 215 Valuation adjustments (227 ) (115 ) (301 ) (244 ) Sales and Payments (1,205 ) (971 ) (2,066 ) (2,601 ) Ending balance $ 3,569 $ 4,381 $ 3,569 $ 4,381 Activity in the valuation allowance is as follows: For the Three Months Ended September 30, For the Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 308 $ 664 $ 449 $ 1,042 Additions charged to expense 227 115 301 244 Reductions from sales of other real estate owned (63 ) (170 ) (278 ) (677 ) Ending balance $ 472 $ 609 $ 472 $ 609 At September 30, 2017 and December 31, 2016 , 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 September 30, 2017 and December 31, 2016 , the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceeds were in process was $1.4 million and $1.6 million , respectively.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Stock Ownership Plan . On March 29, 2017, the ESOP was terminated and the ESOP repaid all amounts owing under the ESOP’s Term Loan Agreement with the Company (the “Share Acquisition Loan”). The ESOP repaid the Share Acquisition Loan by transferring 753,490 unallocated shares of the Company’s common stock to the Company in exchange for the full satisfaction of the Share Acquisition Loan, using the valuation method provided for in the ESOP. A total of 78,362 unallocated shares remained in the ESOP after the Share Acquisition Loan was repaid, and these shares were released and will be allocated to the accounts of eligible ESOP participants who were actively employed by the Bank as of March 29, 2017, based on their account balances, subject to the receipt of a favorable IRS determination letter. These transactions resulted in the recording of one-time, non-cash, non-tax deductible equity compensation expense of $1.1 million in the first quarter of 2017. The Share Acquisition Loan had no outstanding principal balance at September 30, 2017 and an outstanding principal balance of $10.8 million at December 31, 2016 . The Company made the Share Acquisition Loan to the ESOP in the original principal amount of $19.6 million in connection with the Company’s mutual to stock conversion in June of 2005. The proceeds of the Share Acquisition Loan were used by the ESOP to purchase 1,957,300 shares of the Company’s common stock issued in the subscription offering at a price of $10.00 per share. The Share Acquisition Loan was secured by a pledge of the acquired shares and the ESOP made annual loan payments with funds it received from the Bank’s discretionary contributions to the ESOP in subsequent years and dividends it received on unallocated shares. As loan payments were made, the Company recorded compensation expense based on the allocation of shares released. ESOP benefit expense was recorded based upon the fair value of the awarded shares, net of dividends and interest received on unallocated ESOP shares. ESOP benefit expense totaled $1.3 million for the year ended December 31, 2016 . Shares held by the ESOP were as follows: September 30, 2017 December 31, 2016 Allocated to participants 1,203,810 1,125,448 Distributed to participants (317,914 ) (313,223 ) Unearned — 831,852 Total ESOP shares 885,896 1,644,077 Fair value of unearned shares $ — $ 12,328

Equity Incentive Plans (Notes)

Equity Incentive Plans (Notes)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Incentive Plans	EQUITY INCENTIVE PLAN On June 27, 2006, the Company’s stockholders approved the BankFinancial Corporation 2006 Equity Incentive Plan, which authorized the Human Resources Committee of the Board of Directors of the Company to grant a variety of cash- and equity-based incentive awards, including stock options, stock appreciation rights, restricted stock, performance shares and other incentive awards, to employees and directors aggregating up to 3,425,275 shares of the Company’s common stock. The Plan provides that no awards may be granted under the Plan after the ten -year anniversary of the Effective Date. Consequently, no further awards will be granted under this Plan. As of December 31, 2016 , there were 1,752,156 stock options outstanding. The Company recognized $979,000 of equity-based compensation expense relating to the granting of stock options for the year ended December 31, 2016 . There was no equity-based compensation expense for the nine months ended September 30, 2017 . A summary of the activity in the stock option plan for 2017 and 2016 follows: Stock Options Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Stock options outstanding at December 31, 2015 1,752,156 $ 12.30 1.48 $ 778 Stock options granted — — Stock options exercised — — Stock options outstanding at December 31, 2016 1,752,156 $ 12.30 0.48 $ 4,422 Stock options granted — — Stock options exercised (1,752,156 ) 12.30 Stock options outstanding at September 30, 2017 — $ — 0 $ — (1) Stock option aggregate intrinsic value represents the number of shares subject to options multiplied by the difference (if positive) in the closing market price of the common stock underlying the options on the date shown and the weighted average exercise price. During the nine months ended September 30, 2017 , 1,752,156 stock options were exercised. All stock options were exercised on a net settlement basis, using a portion of the shares obtained upon exercise to pay the exercise price of the stock option. The net settlements resulted in the issuance of 280,554 shares of the Company's common stock. Certain employees also chose to use a portion of the net shares received upon the exercise to pay required tax withholdings. This reduced the net shares issued by 82,528 shares to 198,026 shares.

Fair Value (Notes)

Fair Value (Notes)	9 Months Ended
	Sep. 30, 2017
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, 2017 Securities: Certificates of deposit $ — $ 80,360 $ — $ 80,360 Equity mutual fund 502 — — 502 Mortgage-backed securities – residential — 13,188 — 13,188 Collateralized mortgage obligations – residential — 4,725 — 4,725 SBA-guaranteed loan participation certificates — 12 — 12 $ 502 $ 98,285 $ — $ 98,787 December 31, 2016 Securities: Certificates of deposit $ — $ 85,938 $ — $ 85,938 Equity mutual fund 499 — — 499 Mortgage-backed securities - residential — 15,184 — 15,184 Collateralized mortgage obligations – residential — 5,574 — 5,574 SBA-guaranteed loan participation certificates — 17 — 17 $ 499 $ 106,713 $ — $ 107,212 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, 2017 Other real estate owned: One-to-four family residential real estate $ — $ — $ 1,421 $ 1,421 Nonresidential real estate — — 844 844 $ — $ — $ 2,265 $ 2,265 December 31, 2016 Impaired loans: Nonresidential real estate — — 234 234 $ — $ — $ 234 $ 234 Other real estate owned: One-to-four family residential real estate $ — $ — $ 1,282 $ 1,282 Nonresidential real estate — — 553 553 Land — — 47 47 $ — $ — $ 1,882 $ 1,882 At September 30, 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, compared to one impaired loan with a carrying amount of $260,000 and having specific valuation allowance of $26,000 at December 31, 2016 . The decrease in the valuation allowance resulted in a decrease in the provision for loan losses of $26,000 for the nine months ended September 30, 2017 . There was a decrease in the provision for loan losses of $5,000 for the nine months ended September 30, 2016 . OREO, which is carried at the lower of cost or fair value less costs to sell, had a carrying value of $2.7 million less a valuation allowance of $429,000 , or $2.3 million , at September 30, 2017 , compared to a carrying value of $2.3 million less a valuation allowance of $434,000 , or $1.9 million , at December 31, 2016 . There were $301,000 of valuation adjustments of OREO recorded for the nine months ended September 30, 2017 . There were $244,000 of valuation adjustments of OREO recorded for the nine months ended September 30, 2016 . 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 at September 30, 2017 : Fair Value Valuation Technique(s) Significant Unobservable Input(s) Range (Weighted Average) Other real estate owned: One-to-four family residential real estate $ 1,421 Sales comparison Discount applied to valuation 5.6% - 6.6% (6.5%) Nonresidential real estate loans $ 844 Sales comparison Comparison between sales and income approaches -3.66% - 15.22% Other real estate owned $ 2,265 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 at December 31, 2016 : Fair Value Valuation Technique(s) Significant Unobservable Input(s) Range (Weighted Average) Impaired loans Nonresidential real estate $ 234 Sales comparison Comparison between sales and income approaches -10.2% Income approach Cap Rate 8.5% $ 234 Other real estate owned One-to-four family residential real estate $ 1,282 Sales comparison Discount applied to valuation 8.62% to 20.04% (11.9%) Nonresidential real estate 553 Sales comparison Comparison between sales and income approaches -3.22% to 4.58% (3.7%) Land 47 Sales comparison Discount applied to valuation 5.74% to 31.60% (25.2%) $ 1,882 The carrying amount and estimated fair value of financial instruments are as follows: Fair Value Measurements at September 30, 2017 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 125,661 $ 10,620 $ 115,041 $ — $ 125,661 Securities 98,787 502 98,285 — 98,787 Loans receivable, net of allowance for loan losses 1,335,631 — 1,340,957 — 1,340,957 FHLBC and FRB stock 8,290 — — — N/A Accrued interest receivable 4,569 — 4,569 — 4,569 Financial liabilities Noninterest-bearing demand deposits $ 231,049 $ — $ 231,049 $ — $ 231,049 Savings deposits 158,696 — 158,696 — 158,696 NOW and money market accounts 585,316 — 585,316 — 585,316 Certificates of deposit 396,028 — 394,888 — 394,888 Borrowings 60,928 — 60,932 — 60,932 Accrued interest payable 180 — 180 — 180 Fair Value Measurements at December 31, 2016 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 96,684 $ 13,053 $ 83,631 $ — $ 96,684 Securities 107,212 499 106,713 — 107,212 Loans receivable, net of allowance for loan losses 1,312,952 — 1,322,713 234 1,322,947 FHLBC and FRB stock 11,650 — — — N/A Accrued interest receivable 4,381 — 4,381 — 4,381 Financial liabilities Noninterest-bearing demand deposits $ 249,539 $ — $ 249,539 $ — $ 249,539 Savings deposits 160,002 — 160,002 — 160,002 NOW and money market accounts 578,237 — 578,237 — 578,237 Certificates of deposit 351,612 — 350,593 — 350,593 Borrowings 51,069 — 50,015 — 50,015 Accrued interest payable 102 — 102 — 102 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 : 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. FHLBC and FRB Stock : It is not practicable to determine the fair value of FHLBC 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 FHLBC 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.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
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 (the “Company”), is the owner of all of the issued and outstanding capital stock of BankFinancial, National Association (the “Bank”). The interim unaudited consolidated financial statements include the accounts of and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BF Asset Recovery Corporation (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. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three- and nine -month periods ended September 30, 2017 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2017 . 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, 2016 , as filed with the Securities and Exchange Commission. Recent Accounti
Basis of Presentation	Basis of Presentation : BankFinancial Corporation, a Maryland corporation headquartered in Burr Ridge, Illinois (the “Company”), is the owner of all of the issued and outstanding capital stock of BankFinancial, National Association (the “Bank”).
Principles of Consolidation	The interim unaudited consolidated financial statements include the accounts of and transactions of BankFinancial Corporation, the Bank, and the Bank’s wholly-owned subsidiaries, Financial Assurance Services, Inc. and BF Asset Recovery Corporation (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. All significant intercompany accounts and transactions have been eliminated. The results of operations for the three- and nine -month periods ended September 30, 2017 are not necessarily indicative of the results of operations that may be expected for the year ending December 31, 2017 . 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 $250,000 and $199,000 at September 30, 2017 and December 31, 2016 , 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, 2016 , 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 become effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the new guidance on the consolidated financial statements. Our finding is that the new pronouncement will not have a significant impact on the consolidated financial statements as the majority of our business transactions will not be subject to this pronouncement. 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 is effective for public business entities for fiscal years beginning after December 15, 2017. We have evaluated the impact of adopting the new guidance on the consolidated financial statements. Our finding is that the new pronouncement will not have a significant impact on our Statement of Operations. 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 March 2016, the FASB issued ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”). The standard is intended to simplify several areas of accounting for share-based compensation arrangements, including the income tax impact, classification on the statement of cash flows and forfeitures. ASU 2016-09 was effective January 1, 2017. This new pronouncement affects the effective tax rate reported as existing vested stock options are exercised. The amount of the impact on the effective tax rate is determined by the number of stock options exercised and the stock price of the Company when the stock options are exercised. Excess tax benefits and deficiencies are recorded in the tax expense. 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 March of 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 Accoun18

Summary of Significant Accounting Policies New Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2017
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 become effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. We have evaluated the impact of adopting the new guidance on the consolidated financial statements. Our finding is that the new pronouncement will not have a significant impact on the consolidated financial statements as the majority of our business transactions will not be subject to this pronouncement. 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 is effective for public business entities for fiscal years beginning after December 15, 2017. We have evaluated the impact of adopting the new guidance on the consolidated financial statements. Our finding is that the new pronouncement will not have a significant impact on our Statement of Operations. 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 March 2016, the FASB issued ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”). The standard is intended to simplify several areas of accounting for share-based compensation arrangements, including the income tax impact, classification on the statement of cash flows and forfeitures. ASU 2016-09 was effective January 1, 2017. This new pronouncement affects the effective tax rate reported as existing vested stock options are exercised. The amount of the impact on the effective tax rate is determined by the number of stock options exercised and the stock price of the Company when the stock options are exercised. Excess tax benefits and deficiencies are recorded in the tax expense. 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 March of 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, 2017
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	ngs 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 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 2017 2016 2017 2016 Net income available to common stockholders $ 3,560 $ 2,508 $ 8,013 $ 5,243 Average common shares outstanding 18,140,599 19,460,022 18,567,796 19,813,088 Less: Unearned ESOP shares — (670,351 ) (198,114 ) (694,655 ) Unvested restricted stock shares (940 ) (940 ) (940 ) (3,830 ) Weighted average common shares outstanding 18,139,659 18,788,731 18,368,742 19,114,603 Add - Net effect of dilutive unvested restricted stock 450 323 428 315 Diluted weighted average common shares outstanding 18,140,109 18,789,054 18,369,170 19,114,918 Basic earnings per common share $ 0.20 $ 0.13 $ 0.44 $ 0.27 Diluted earnings per common share $ 0.20 $ 0.13 $ 0.44 $ 0.27 Number of antidilutive stock options excluded from the diluted earnings per share calculation — 536,459 — 536,459 Weighted average exercise price of anti-dilutive option shares $ — $ 12.99 $ — $ 12.99

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2017
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, 2017 Certificates of deposit $ 80,360 $ — $ — $ 80,360 Equity mutual fund 500 2 — 502 Mortgage-backed securities - residential 12,645 553 (10 ) 13,188 Collateralized mortgage obligations - residential 4,728 14 (17 ) 4,725 SBA-guaranteed loan participation certificates 12 — — 12 $ 98,245 $ 569 $ (27 ) $ 98,787 December 31, 2016 Certificates of deposit $ 85,938 $ — $ — $ 85,938 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 14,561 644 (21 ) 15,184 Collateralized mortgage obligations - residential 5,587 15 (28 ) 5,574 SBA-guaranteed loan participation certificates 17 — — 17 $ 106,603 $ 659 $ (50 ) $ 107,212 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, 2017 and December 31, 2016 . 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, 2017 Amortized Cost Fair Value Due in one year or less $ 80,360 $ 80,360 Equity mutual fund 500 502 Mortgage-backed securities - residential 12,645 13,188 Collateralized mortgage obligations - residential 4,728 4,725 SBA-guaranteed loan participation certificates 12 12 $ 98,245 $ 98,787 Sales of securities were as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 Proceeds $ — $ — $ — $ 46 Gross gains — — — 46 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, 2017 Mortgage-backed securities - residential $ 1,182 $ (10 ) $ — $ — $ 1,182 $ (10 ) Collateralized mortgage obligations - residential — — 3,270 (17 ) 3,270 (17 ) $ 1,182 $ (10 ) $ 3,270 $ (17 ) $ 4,452 $ (27 ) December 31, 2016 Equity Mutual Fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential 1,187 (21 ) — — 1,187 (21 ) Collateralized mortgage obligations - residential 3,691 (18 ) 1,028 (10 ) 4,719 (28 ) $ 5,377 $ (40 ) $ 1,028 $ (10 ) $ 6,405 $ (50 ) 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, 2017 , 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, 2017 Certificates of deposit $ 80,360 $ — $ — $ 80,360 Equity mutual fund 500 2 — 502 Mortgage-backed securities - residential 12,645 553 (10 ) 13,188 Collateralized mortgage obligations - residential 4,728 14 (17 ) 4,725 SBA-guaranteed loan participation certificates 12 — — 12 $ 98,245 $ 569 $ (27 ) $ 98,787 December 31, 2016 Certificates of deposit $ 85,938 $ — $ — $ 85,938 Equity mutual fund 500 — (1 ) 499 Mortgage-backed securities - residential 14,561 644 (21 ) 15,184 Collateralized mortgage obligations - residential 5,587 15 (28 ) 5,574 SBA-guaranteed loan participation certificates 17 — — 17 $ 106,603 $ 659 $ (50 ) $ 107,212
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, 2017 Amortized Cost Fair Value Due in one year or less $ 80,360 $ 80,360 Equity mutual fund 500 502 Mortgage-backed securities - residential 12,645 13,188 Collateralized mortgage obligations - residential 4,728 4,725 SBA-guaranteed loan participation certificates 12 12 $ 98,245 $ 98,787
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, 2017 Mortgage-backed securities - residential $ 1,182 $ (10 ) $ — $ — $ 1,182 $ (10 ) Collateralized mortgage obligations - residential — — 3,270 (17 ) 3,270 (17 ) $ 1,182 $ (10 ) $ 3,270 $ (17 ) $ 4,452 $ (27 ) December 31, 2016 Equity Mutual Fund $ 499 $ (1 ) $ — $ — $ 499 $ (1 ) Mortgage-backed securities - residential 1,187 (21 ) — — 1,187 (21 ) Collateralized mortgage obligations - residential 3,691 (18 ) 1,028 (10 ) 4,719 (28 ) $ 5,377 $ (40 ) $ 1,028 $ (10 ) $ 6,405 $ (50 )

Loans Receivable (Tables)

Loans Receivable (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Loans By Class Modified As Troubled Debt Restructurings With Payment Default [Table Text Block]	The following table presents TDRs for which there was a payment default during the nine months ended September 30, 2017 and 2016 within twelve months following the modification. 2017 2016 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate 1 $ 17 2 $ 87
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	Loans receivable are as follows: September 30, 2017 December 31, 2016 One-to-four family residential real estate $ 105,186 $ 135,218 Multi-family mortgage 576,425 542,887 Nonresidential real estate 176,301 182,152 Construction and land 2,827 1,302 Commercial loans 147,079 103,063 Commercial leases 333,120 352,539 Consumer 1,747 2,255 1,342,685 1,319,416 Net deferred loan origination costs 1,320 1,663 Allowance for loan losses (8,374 ) (8,127 ) Loans, net $ 1,335,631 $ 1,312,952 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, 2017 One-to-four family residential real estate $ — $ 812 $ 812 $ 4,616 $ 100,570 $ 105,186 Multi-family mortgage — 3,872 3,872 959 575,466 576,425 Nonresidential real estate — 1,590 1,590 — 176,301 176,301 Construction and land — 68 68 — 2,827 2,827 Commercial loans — 1,241 1,241 — 147,079 147,079 Commercial leases — 769 769 — 333,120 333,120 Consumer — 22 22 — 1,747 1,747 $ — $ 8,374 $ 8,374 $ 5,575 $ 1,337,110 1,342,685 Net deferred loan origination costs 1,320 Allowance for loan losses (8,374 ) Loans, net $ 1,335,631 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, 2016 One-to-four family residential real estate $ — $ 1,168 $ 1,168 $ 4,962 $ 130,256 $ 135,218 Multi-family mortgage — 3,647 3,647 787 542,100 542,887 Nonresidential real estate 26 1,768 1,794 260 181,892 182,152 Construction and land — 32 32 — 1,302 1,302 Commercial loans — 733 733 — 103,063 103,063 Commercial leases — 714 714 — 352,539 352,539 Consumer — 39 39 — 2,255 2,255 $ 26 $ 8,101 $ 8,127 $ 6,009 $ 1,313,407 1,319,416 Net deferred loan origination costs 1,663 Allowance for loan losses (8,127 ) Loans, net $ 1,312,952 Activity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 Beginning balance $ 8,122 $ 8,915 $ 8,127 $ 9,691 Loans charged off: One-to-four family residential real estate (89 ) (102 ) (282 ) (509 ) Multi-family mortgage (7 ) — (10 ) (51 ) Nonresidential real estate — (55 ) (165 ) (1,715 ) Consumer (7 ) (6 ) (7 ) (24 ) (103 ) (163 ) (464 ) (2,299 ) Recoveries: One-to-four family residential real estate 15 5 100 92 Multi-family mortgage 11 10 62 156 Nonresidential real estate 10 39 10 200 Construction and land — — — 35 Commercial loans 542 45 552 150 Commercial leases 2 7 2 7 Consumer — 1 — 2 580 107 726 642 Net recoveries (charge-offs) 477 (56 ) 262 (1,657 ) Provision for (recovery of) loan losses (225 ) (525 ) (15 ) 300 Ending balance $ 8,374 $ 8,334 $ 8,374 $ 8,334 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, 2017 One-to-four family residential real estate $ 3,392 $ 1,658 $ — One-to-four family residential real estate – non-owner occupied 751 576 — Multi-family mortgage - Illinois 378 371 — $ 4,521 $ 2,605 $ — December 31, 2016 One-to-four family residential real estate $ 2,861 $ 2,483 $ — One-to-four family residential real estate – non-owner occupied 428 368 — Multi-family mortgage - Illinois 187 185 — Nonresidential real estate 262 260 — $ 3,738 $ 3,296 $ — 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 $250,000 and $199,000 at September 30, 2017 and December 31, 2016 , 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, 2017 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 $ 94 $ 749 $ 1,655 $ 2,498 $ 79,800 $ 82,298 One-to-four family residential real estate loans – non-owner occupied 12 3 577 592 22,321 22,913 Multi-family mortgage - Illinois — — 371 371 288,508 288,879 Multi-family mortgage - Other — — — — 281,887 281,887 Nonresidential real estate — — — — 174,724 174,724 Construction — — — — 2,548 2,548 Land — — — — 281 281 Commercial loans: Regional commercial banking — — — — 40,315 40,315 Health care — — — — 72,685 72,685 Direct commercial lessor 275 369 — 644 33,787 34,431 Commercial leases: Investment rated commercial leases — 2,225 — 2,225 230,009 232,234 Other commercial leases — — — — 102,698 102,698 Consumer — — — — 1,754 1,754 $ 381 $ 3,346 $ 2,603 $ 6,330 $ 1,331,317 $ 1,337,647 The following tables present the aging of the recorded investment of loans at December 31, 2016 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 $ 984 $ 335 $ 2,235 $ 3,554 $ 92,665 $ 96,219 One-to-four family residential real estate loans – non-owner occupied 664 114 368 1,146 37,179 38,325 Multi-family mortgage - Illinois 605 439 184 1,228 294,223 295,451 Multi-family mortgage - Other — — — — 243,944 243,944 Nonresidential real estate — — 260 260 178,644 178,904 Construction — — — — 950 950 Land — — — — 349 349 Commercial loans: Regional commercial banking — — — — 26,480 26,480 Health care — — — — 41,086 41,086 Direct commercial lessor — — — — 31,847 31,847 Commercial leases: Investment rated commercial leases 51 — — 51 273,405 273,456 Other commercial leases — — — — 84,988 84,988 Consumer — — — — 2,263 2,263 $ 2,304 $ 888 $ 3,047 $ 6,239 $ 1,308,023 $ 1,314,262 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 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, 2017 , compared to $341,000 at December 31, 2016 . No specific valuation reserves were allocated to those loans at September 30, 2017 and December 31, 2016 . 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, 2017 December 31, 2016 One-to-four family residential real estate $ — $ 205 Troubled debt restructured loans – accrual loans — 205 One-to-four family residential real estate 17 136 Troubled debt restructured loans – nonaccrual loans 17 136 Total troubled debt restructured loans $ 17 $ 341 During the nine months ended September 30, 2017 , there were no loans modified and classified as TDRs. During the nine months ended September 30, 2016 , the terms of certain loans were modified and classified as TDRs. The modification of the terms of such loans included one or a combination of the following: a reduction of the stated interest rate of the loan; an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk; or a permanent reduction of the recorded investment in the loan. The following tables present TDR activity: For the Nine Months Ended September 30, 2017 2016 Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment One-to-four family residential real estate — $ — $ — 1 $ 63 $ 63 Due to Due to Due to Total For the Nine Months Ended September 30, 2016 One-to-four family residential real estate $ — $ 63 $ — $ 63 The TDRs described above had no impact on interest income, resulted in no change to the allowance for loan losses allocated and resulted in no charge-offs for the nine months ended September 30, 2016 . The following table presents TDRs for which there was a payment default during the nine months ended September 30, 2017 and 2016 within twelve months following the modification. 2017 2016 Number of loans Recorded investment Number of loans Recorded investment One-to-four family residential real estate 1 $ 17 2 $ 87 A TDR is considered to be in payment default once it is 90 days contractually past due under the modified terms. The TDRs for which there was a payment default resulted in no change to the allowance for loan losses allocated and resulted in no charge-offs during the nine months ended September 30, 2017 and 2016 . There were certain other loan modifications during the three and nine months ended September 30, 2017 and 2016 that did not meet the definition of a TDR. These loans had a total recorded investment of $149,000 and $615,000 at September 30, 2017 and 2016 , respectively. 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. The loans were placed on nonaccrual status. 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, 2017 , 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 $ 80,401 $ — $ 257 $ 1,653 $ 82,311 One-to-four family residential real estate loans – non-owner occupied 22,258 — 40 577 22,875 Multi-family mortgage loans - Illinois 289,175 — 480 372 290,027 Multi-family mortgage loans - Other 286,398 — — — 286,398 Nonresidential real estate loans 176,139 — 162 — 176,301 Construction loans 2,543 — — — 2,543 Land loans 284 — — — 284 Commercial loans: Regional commercial banking 40,251 — — — 40,251 Health care 71,633 — 982 — 72,615 Direct commercial lessor 34,213 — — — 34,213 Commercial leases: Investment rated commercial leases 230,931 — — — 230,931 Other commercial leases 102,189 — — — 102,189 Consumer 1,747 — — — 1,747 $ 1,338,162 $ — $ 1,921 $ 2,602 $ 1,342,685 As of December 31, 2016 , 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 $ 93,514 $ — $ 629 $ 2,486 $ 96,629 One-to-four family residential real estate loans – non-owner occupied 38,179 — 41 369 38,589 Multi-family mortgage loans - Illinois 297,826 122 1,048 187 299,183 Multi-family mortgage loans - Other 243,704 — — — 243,704 Nonresidential real estate loans 180,047 — 1,845 260 182,152 Construction loans 946 — — — 946 Land loans 356 — — — 356 Commercial loans: Regional commercial banking 26,365 — 66 — 26,431 Health care 41,001 — — — 41,001 Direct commercial lessor 30,881 800 — — 31,681 Commercial leases: Investment rated commercial leases 271,972 — — — 271,972 Other commercial leases 84,356 161 — — 84,517 Consumer 2,255 — — — 2,255 $ 1,311,402 $ 1,083 $ 3,629 $ 3,302 $ 1,319,416
Loans receivable	Loans receivable are as follows: September 30, 2017 December 31, 2016 One-to-four family residential real estate $ 105,186 $ 135,218 Multi-family mortgage 576,425 542,887 Nonresidential real estate 176,301 182,152 Construction and land 2,827 1,302 Commercial loans 147,079 103,063 Commercial leases 333,120 352,539 Consumer 1,747 2,255 1,342,685 1,319,416 Net deferred loan origination costs 1,320 1,663 Allowance for loan losses (8,374 ) (8,127 ) Loans, net $ 1,335,631 $ 1,312,952
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, 2017 One-to-four family residential real estate $ — $ 812 $ 812 $ 4,616 $ 100,570 $ 105,186 Multi-family mortgage — 3,872 3,872 959 575,466 576,425 Nonresidential real estate — 1,590 1,590 — 176,301 176,301 Construction and land — 68 68 — 2,827 2,827 Commercial loans — 1,241 1,241 — 147,079 147,079 Commercial leases — 769 769 — 333,120 333,120 Consumer — 22 22 — 1,747 1,747 $ — $ 8,374 $ 8,374 $ 5,575 $ 1,337,110 1,342,685 Net deferred loan origination costs 1,320 Allowance for loan losses (8,374 ) Loans, net $ 1,335,631
Allowance for loan losses	ctivity in the allowance for loan losses is as follows: Three Months Ended Nine Months Ended 2017 2016 2017 2016 Beginning balance $ 8,122 $ 8,915 $ 8,127 $ 9,691 Loans charged off: One-to-four family residential real estate (89 ) (102 ) (282 ) (509 ) Multi-family mortgage (7 ) — (10 ) (51 ) Nonresidential real estate — (55 ) (165 ) (1,715 ) Consumer (7 ) (6 ) (7 ) (24 ) (103 ) (163 ) (464 ) (2,299 ) Recoveries: One-to-four family residential real estate 15 5 100 92 Multi-family mortgage 11 10 62 156 Nonresidential real estate 10 39 10 200 Construction and land — — — 35 Commercial loans 542 45 552 150 Commercial leases 2 7 2 7 Consumer — 1 — 2 580 107 726 642 Net recoveries (charge-offs) 477 (56 ) 262 (1,657 ) Provision for (recovery of) loan losses (225 ) (525 ) (15 ) 300 Ending balance $ 8,374 $ 8,334 $ 8,374 $ 8,334
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, 2017 One-to-four family residential real estate $ 3,392 $ 1,658 $ — One-to-four family residential real estate – non-owner occupied 751 576 — Multi-family mortgage - Illinois 378 371 — $ 4,521 $ 2,605 $ — December 31, 2016 One-to-four family residential real estate $ 2,861 $ 2,483 $ — One-to-four family residential real estate – non-owner occupied 428 368 — Multi-family mortgage - Illinois 187 185 — Nonresidential real estate 262 260 — $ 3,738 $ 3,296 $ —
Past Due Financing Receivables	The following tables present the aging of the recorded investment of loans at September 30, 2017 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 $ 94 $ 749 $ 1,655 $ 2,498 $ 79,800 $ 82,298 One-to-four family residential real estate loans – non-owner occupied 12 3 577 592 22,321 22,913 Multi-family mortgage - Illinois — — 371 371 288,508 288,879 Multi-family mortgage - Other — — — — 281,887 281,887 Nonresidential real estate — — — — 174,724 174,724 Construction — — — — 2,548 2,548 Land — — — — 281 281 Commercial loans: Regional commercial banking — — — — 40,315 40,315 Health care — — — — 72,685 72,685 Direct commercial lessor 275 369 — 644 33,787 34,431 Commercial leases: Investment rated commercial leases — 2,225 — 2,225 230,009 232,234 Other commercial leases — — — — 102,698 102,698 Consumer — — — — 1,754 1,754 $ 381 $ 3,346 $ 2,603 $ 6,330 $ 1,331,317 $ 1,337,647
Troubled Debt Restructurings on Financing Receivables	The following table presents loans classified as TDRs: September 30, 2017 December 31, 2016 One-to-four family residential real estate $ — $ 205 Troubled debt restructured loans – accrual loans — 205 One-to-four family residential real estate 17 136 Troubled debt restructured loans – nonaccrual loans 17 136 Total troubled debt restructured loans $ 17 $ 341
Financing Receivable Credit Quality Indicators	As of September 30, 2017 , 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 $ 80,401 $ — $ 257 $ 1,653 $ 82,311 One-to-four family residential real estate loans – non-owner occupied 22,258 — 40 577 22,875 Multi-family mortgage loans - Illinois 289,175 — 480 372 290,027 Multi-family mortgage loans - Other 286,398 — — — 286,398 Nonresidential real estate loans 176,139 — 162 — 176,301 Construction loans 2,543 — — — 2,543 Land loans 284 — — — 284 Commercial loans: Regional commercial banking 40,251 — — — 40,251 Health care 71,633 — 982 — 72,615 Direct commercial lessor 34,213 — — — 34,213 Commercial leases: Investment rated commercial leases 230,931 — — — 230,931 Other commercial leases 102,189 — — — 102,189 Consumer 1,747 — — — 1,747 $ 1,338,162 $ — $ 1,921 $ 2,602 $ 1,342,685
Loans By Class Modified As Troubled Debt Restructuring On Financing Receivables [Table Text Block]	The following tables present TDR activity: For the Nine Months Ended September 30, 2017 2016 Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment Number of loans Pre- Modification outstanding recorded investment Post- Modification outstanding recorded investment One-to-four family residential real estate — $ — $ — 1 $ 63 $ 63 Due to Due to Due to Total For the Nine Months Ended September 30, 2016 One-to-four family residential real estate $ — $ 63 $ — $ 63 The TDRs described above had no impact on interest income, resulted in no change to the allowance for loan losses allocated and resulted in no charge-offs for the nine months ended September 30, 2016 .

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	9 Months Ended
	Sep. 30, 2017
Other Real Estate [Abstract]
Schedule of Real Estate Properties [Table Text Block]	September 30, 2017 December 31, 2016 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 1,955 $ (207 ) $ 1,748 $ 1,702 $ (137 ) $ 1,565 Multi-family mortgage — — — 370 — 370 Nonresidential real estate 1,772 (221 ) 1,551 1,171 (105 ) 1,066 Land 314 (44 ) 270 1,101 (207 ) 894 $ 4,041 $ (472 ) $ 3,569 $ 4,344 $ (449 ) $ 3,895
Real Estate Owned, rollforward [Table Text Block]	September 30, 2017 December 31, 2016 Balance Valuation Allowance Net OREO Balance Balance Valuation Allowance Net OREO Balance One–to–four family residential $ 1,955 $ (207 ) $ 1,748 $ 1,702 $ (137 ) $ 1,565 Multi-family mortgage — — — 370 — 370 Nonresidential real estate 1,772 (221 ) 1,551 1,171 (105 ) 1,066 Land 314 (44 ) 270 1,101 (207 ) 894 $ 4,041 $ (472 ) $ 3,569 $ 4,344 $ (449 ) $ 3,895 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, 2017 2016 2017 2016 Beginning balance $ 4,896 $ 5,373 $ 3,895 $ 7,011 New foreclosed properties 105 94 2,041 215 Valuation adjustments (227 ) (115 ) (301 ) (244 ) Sales and Payments (1,205 ) (971 ) (2,066 ) (2,601 ) Ending balance $ 3,569 $ 4,381 $ 3,569 $ 4,381
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, 2017 2016 2017 2016 Beginning balance $ 308 $ 664 $ 449 $ 1,042 Additions charged to expense 227 115 301 244 Reductions from sales of other real estate owned (63 ) (170 ) (278 ) (677 ) Ending balance $ 472 $ 609 $ 472 $ 609 At September 30, 2017 and December 31, 2016 , 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 September 30, 2017 and December 31, 2016 , the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceeds were in process was $1.4 million and $1.6 million , respectively.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Compensation and Retirement Disclosure [Abstract]
Schedule of Employee Stock Ownership Plan (ESOP) Disclosures	Shares held by the ESOP were as follows: September 30, 2017 December 31, 2016 Allocated to participants 1,203,810 1,125,448 Distributed to participants (317,914 ) (313,223 ) Unearned — 831,852 Total ESOP shares 885,896 1,644,077 Fair value of unearned shares $ — $ 12,328

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Option Activity	A summary of the activity in the stock option plan for 2017 and 2016 follows: Stock Options Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (1) Stock options outstanding at December 31, 2015 1,752,156 $ 12.30 1.48 $ 778 Stock options granted — — Stock options exercised — — Stock options outstanding at December 31, 2016 1,752,156 $ 12.30 0.48 $ 4,422 Stock options granted — — Stock options exercised (1,752,156 ) 12.30 Stock options outstanding at September 30, 2017 — $ — 0 $ — (1) Stock option aggregate intrinsic value represents the number of shares subject to options multiplied by the difference (if positive) in the closing market price of the common stock underlying the options on the date shown and the weighted average exercise price.

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2017
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, 2017 Securities: Certificates of deposit $ — $ 80,360 $ — $ 80,360 Equity mutual fund 502 — — 502 Mortgage-backed securities – residential — 13,188 — 13,188 Collateralized mortgage obligations – residential — 4,725 — 4,725 SBA-guaranteed loan participation certificates — 12 — 12 $ 502 $ 98,285 $ — $ 98,787 December 31, 2016 Securities: Certificates of deposit $ — $ 85,938 $ — $ 85,938 Equity mutual fund 499 — — 499 Mortgage-backed securities - residential — 15,184 — 15,184 Collateralized mortgage obligations – residential — 5,574 — 5,574 SBA-guaranteed loan participation certificates — 17 — 17 $ 499 $ 106,713 $ — $ 107,212
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, 2017 Other real estate owned: One-to-four family residential real estate $ — $ — $ 1,421 $ 1,421 Nonresidential real estate — — 844 844 $ — $ — $ 2,265 $ 2,265 December 31, 2016 Impaired loans: Nonresidential real estate — — 234 234 $ — $ — $ 234 $ 234 Other real estate owned: One-to-four family residential real estate $ — $ — $ 1,282 $ 1,282 Nonresidential real estate — — 553 553 Land — — 47 47 $ — $ — $ 1,882 $ 1,882
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 at September 30, 2017 : Fair Value Valuation Technique(s) Significant Unobservable Input(s) Range (Weighted Average) Other real estate owned: One-to-four family residential real estate $ 1,421 Sales comparison Discount applied to valuation 5.6% - 6.6% (6.5%) Nonresidential real estate loans $ 844 Sales comparison Comparison between sales and income approaches -3.66% - 15.22% Other real estate owned $ 2,265
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, 2017 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 125,661 $ 10,620 $ 115,041 $ — $ 125,661 Securities 98,787 502 98,285 — 98,787 Loans receivable, net of allowance for loan losses 1,335,631 — 1,340,957 — 1,340,957 FHLBC and FRB stock 8,290 — — — N/A Accrued interest receivable 4,569 — 4,569 — 4,569 Financial liabilities Noninterest-bearing demand deposits $ 231,049 $ — $ 231,049 $ — $ 231,049 Savings deposits 158,696 — 158,696 — 158,696 NOW and money market accounts 585,316 — 585,316 — 585,316 Certificates of deposit 396,028 — 394,888 — 394,888 Borrowings 60,928 — 60,932 — 60,932 Accrued interest payable 180 — 180 — 180 Fair Value Measurements at December 31, 2016 Using: Carrying Amount Level 1 Level 2 Level 3 Total Financial assets Cash and cash equivalents $ 96,684 $ 13,053 $ 83,631 $ — $ 96,684 Securities 107,212 499 106,713 — 107,212 Loans receivable, net of allowance for loan losses 1,312,952 — 1,322,713 234 1,322,947 FHLBC and FRB stock 11,650 — — — N/A Accrued interest receivable 4,381 — 4,381 — 4,381 Financial liabilities Noninterest-bearing demand deposits $ 249,539 $ — $ 249,539 $ — $ 249,539 Savings deposits 160,002 — 160,002 — 160,002 NOW and money market accounts 578,237 — 578,237 — 578,237 Certificates of deposit 351,612 — 350,593 — 350,593 Borrowings 51,069 — 50,015 — 50,015 Accrued interest payable 102 — 102 — 102

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Basic and Diluted [Abstract]
Net income available to common stockholders	$ 3,560	$ 2,508	$ 8,013	$ 5,243
Average common shares outstanding (shares)	18,140,599	19,460,022	18,567,796	19,813,088
Less:
Unearned ESOP shares (shares)	0	(670,351)	(198,114)	(694,655)
Unvested restricted stock shares (shares)	(940)	(940)	940	3,830
Weighted average common shares outstanding (shares)	18,139,659	18,788,731	18,368,742	19,114,603
Add - Net effect of dilutive stock options and unvested restricted stock	450	323	428	315
Weighted average diluted common shares outstanding (shares)	18,140,109	18,789,054	18,369,170	19,114,918
Basic earnings per common share (usd per share)	$ 0.20	$ 0.13	$ 0.44	$ 0.27
Diluted earnings per common share (usd per share)	$ 0.20	$ 0.13	$ 0.44	$ 0.27
Number of antidilutive stock options excluded from the diluted earnings per share calculation (shares)	0	536,459	0	536,459
Weighted average exercise price of anti-dilutive option shares (usd per share)	$ 0	$ 12.99	$ 0	$ 12.99

Securities - Fair Value of Secu

Securities - Fair Value of Securites (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	$ 98,245	$ 106,603
Available for sale securities, accumulated gross unrealized gain before tax	569	659
Available for sale securities, accumulated gross unrealized loss before tax	(27)	(50)
Total Fair value	98,787	107,212
Certificates of deposit [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	80,360	85,938
Available for sale securities, accumulated gross unrealized gain before tax	0	0
Available for sale securities, accumulated gross unrealized loss before tax	0	0
Total Fair value	80,360	85,938
Equity mutual fund [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	500	500
Available for sale securities, accumulated gross unrealized gain before tax	2	0
Available for sale securities, accumulated gross unrealized loss before tax	0	(1)
Total Fair value	502	499
Mortgage - backed securities - residential [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	12,645	14,561
Available for sale securities, accumulated gross unrealized gain before tax	553	644
Available for sale securities, accumulated gross unrealized loss before tax	(10)	(21)
Total Fair value	13,188	15,184
Collateralized mortgage obligations - residential [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	4,728	5,587
Available for sale securities, accumulated gross unrealized gain before tax	14	15
Available for sale securities, accumulated gross unrealized loss before tax	(17)	(28)
Total Fair value	4,725	5,574
SBA-guaranteed loan participation certificates [Member]
Unrealized gains and losses recognized in accumulated other comprehensive income (loss)
Amortized Cost	12	17
Available for sale securities, accumulated gross unrealized gain before tax	0	0
Available for sale securities, accumulated gross unrealized loss before tax	0	0
Total Fair value	$ 12	$ 17

Securities - Amortized Cost and

Securities - Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Amortized cost and fair values of securities
Due in one year or less, amortized cost	$ 80,360
Due in one year or less, fair value	80,360
Total amortized cost	98,245	$ 106,603
Total Fair value	98,787	107,212
Equity mutual fund [Member]
Amortized cost and fair values of securities
Total amortized cost	500	500
Total Fair value	502	499
Mortgage - backed securities - residential [Member]
Amortized cost and fair values of securities
Total amortized cost	12,645	14,561
Total Fair value	13,188	15,184
Collateralized mortgage obligations - residential [Member]
Amortized cost and fair values of securities
Total amortized cost	4,728	5,587
Total Fair value	4,725	5,574
SBA-guaranteed loan participation certificates [Member]
Amortized cost and fair values of securities
Total amortized cost	12	17
Total Fair value	$ 12	$ 17

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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Proceeds and Gross Gains (Losses) from Sale of Securities [Abstract]
Proceeds from Sale of Available-for-sale Securities, Equity			$ 0	$ 46
Available-for-sale Securities, Gross Realized Gains	$ 0	$ 0
Gain on Sale of Securities, Net			0	46
Proceeds from Sale of Available-for-sale Securities	$ 0	$ 0	$ 0	$ 46

Securities - Unrealized Losses

Securities - Unrealized Losses (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Amortized cost and fair values of securities
Less than 12 Months, Fair Value	$ 1,182	$ 5,377
12 Months or More, Fair Value	3,270	1,028
Fair Value, Total	4,452	6,405
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	(10)	(40)
12 Months or More, Unrealized Loss	(17)	(10)
Unrealized Loss, Total	(27)	(50)
Mortgage Backed Securities Residential [Member]
Amortized cost and fair values of securities
Less than 12 Months, Fair Value	1,182	1,187
12 Months or More, Fair Value	0	0
Fair Value, Total	1,182	1,187
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	(10)	(21)
12 Months or More, Unrealized Loss	0	0
Unrealized Loss, Total	(10)	(21)
Collateralized mortgage obligations - residential [Member]
Amortized cost and fair values of securities
Less than 12 Months, Fair Value	0	3,691
12 Months or More, Fair Value	3,270	1,028
Fair Value, Total	3,270	4,719
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	0	(18)
12 Months or More, Unrealized Loss	(17)	(10)
Unrealized Loss, Total	(17)	(28)
Equity Funds [Member]
Amortized cost and fair values of securities
Less than 12 Months, Fair Value	0	499
12 Months or More, Fair Value	0	0
Fair Value, Total	0	499
Unrealized loss of securities
Less than 12 Months, Unrealized Loss	0	(1)
12 Months or More, Unrealized Loss	0	0
Unrealized Loss, Total	$ 0	$ (1)

Securities - Narrative (Details

Securities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Proceeds and Gross Gains (Losses) from Sale of Securities [Abstract]
Proceeds from Sale of Available-for-sale Securities	$ 0	$ 0	$ 0	$ 46

Loans Receivable (Details)

Loans Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Loans receivable
Total loans	$ 1,342,685		$ 1,319,416
Net deferred loan origination costs	1,320		1,663
Allowance for loan losses	(8,374)	$ (8,122)	(8,127)	$ (8,334)	$ (8,915)	$ (9,691)
Loans, net	1,335,631		1,312,952
One-to-four family residential real estate loans [Member]
Loans receivable
Total loans	105,186		135,218
Allowance for loan losses	(812)		(1,168)
Multi-family mortgage loans [Member]
Loans receivable
Total loans	576,425		542,887
Allowance for loan losses	(3,872)		(3,647)
Nonresidential real estate loans [Member]
Loans receivable
Total loans	176,301		182,152
Allowance for loan losses	(1,590)		(1,794)
Construction and land loans [Member]
Loans receivable
Total loans	2,827		1,302
Allowance for loan losses	(68)		(32)
Commercial loans [Member]
Loans receivable
Total loans	147,079		103,063
Allowance for loan losses	(1,241)		(733)
Commercial leases [Member]
Loans receivable
Total loans	333,120		352,539
Allowance for loan losses	(769)		(714)
Consumer loans [Member]
Loans receivable
Total loans	1,747		2,255
Allowance for loan losses	$ (22)		$ (39)

Loans Receivable - Loan Origina

Loans Receivable - Loan Origination and Risk Management (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 1,342,685	$ 1,319,416
Multi-family mortgage loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	576,425	542,887
Nonresidential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	176,301	182,152
Commercial leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, amount	$ 333,120	$ 352,539

Loans Receivable - Allowance fo

Loans Receivable - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Allowance for loan losses and the loans receivable by portfolio segment
Net deferred loan origination costs	$ 1,320	$ 1,663
Loans, net	$ 1,335,631	$ 1,312,952

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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 8,122	$ 8,915	$ 8,127	$ 9,691
Loans charged off	103	163	464	2,299
Recoveries	580	107	726	642
Net charge-off	(477)	56	(262)	1,657
Provision for (recovery of) loan losses	(225)	(525)	(15)	300
Ending balance	8,374	8,334	8,374	8,334
One-to-four family residential real estate loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			1,168
Loans charged off	(89)	(102)	(282)	(509)
Recoveries	15	5	100	92
Ending balance	812		812
Multi-family mortgage loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			3,647
Loans charged off	(7)	0	(10)	(51)
Recoveries	11	10	62	156
Ending balance	3,872		3,872
Nonresidential real estate loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			1,794
Loans charged off	0	(55)	(165)	(1,715)
Ending balance	1,590		1,590
Construction and land loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			32
Recoveries	0	0	0	35
Ending balance	68		68
Commercial loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			733
Recoveries	542	45	552	150
Ending balance	1,241		1,241
Commercial leases [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			714
Ending balance	769		769
Consumer loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance			39
Loans charged off	(7)	(6)	(7)	(24)
Recoveries	0	$ 1	0	$ 2
Ending balance	$ 22		$ 22

Loans Receivable - Loans Indivi

Loans Receivable - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2016	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		$ 1,319,416	$ 1,342,685
Loans individually evaluated for impairment by class loans
Loan Balance		6,669
Recorded Investment		5,721
Partial Charge-off		1,005
Average Investment in Impaired Loans		4,178
Interest Income Recognized		120
Loan Balance (With an allowance recorded)		262
Recorded Investment (With an allowance recorded)		260
Partial Charge-offs (With an allowance recorded)		21
Allowance for loan losses (With an allowance recorded)		26	0
Average Investment in Impaired Loans (With an allowance recorded)		164
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method		0
Impaired Loan, Total		6,931	6,516
Recorded Investment, Total		5,981	5,568
Partial Charge-offs, Total		1,026	985
Average Investment in Impaired Loans, Total	$ 5,622	4,342
Interest Income Recognized, Total	24	120
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		8,101	8,374
Net deferred loan origination costs		1,663	1,320
Loans and Leases Receivable, Allowance	8,334	8,127	8,374	$ 8,122	$ 8,915	$ 9,691
Financing Receivable, Individually Evaluated for Impairment		6,009	5,575
Financing Receivable, Collectively Evaluated for Impairment		1,313,407	1,337,110
Loans, net		1,312,952	1,335,631
One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		135,218	105,186
Loans individually evaluated for impairment by class loans
Loan Balance		5,379	4,980
Recorded Investment		4,548	4,031
Partial Charge-off		886	966
Average Investment in Impaired Loans	4,100	2,947
Interest Income Recognized	14	70
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,168	812
Loans and Leases Receivable, Allowance		1,168	812
Financing Receivable, Individually Evaluated for Impairment		4,962	4,616
Financing Receivable, Collectively Evaluated for Impairment		130,256	100,570
One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		38,589	22,875
Loans individually evaluated for impairment by class loans
Loan Balance		503	571
Recorded Investment		386	576
Partial Charge-off		119	19
Average Investment in Impaired Loans	557	251
Interest Income Recognized	0	9
Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		542,887	576,425
Loans individually evaluated for impairment by class loans
Loan Balance		787	965
Recorded Investment		787	961
Partial Charge-off		0	0
Average Investment in Impaired Loans	965	980
Interest Income Recognized	$ 10	41
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		3,647	3,872
Loans and Leases Receivable, Allowance		3,647	3,872
Financing Receivable, Individually Evaluated for Impairment		787	959
Financing Receivable, Collectively Evaluated for Impairment		542,100	575,466
Multi Family Mortgage Loans without wholesale [Member] [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		299,183	290,027
Wholesale commercial lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		243,704	286,398
Nonresidential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		182,152	176,301
Loans individually evaluated for impairment by class loans
Loan Balance (With an allowance recorded)		262
Recorded Investment (With an allowance recorded)		260
Partial Charge-offs (With an allowance recorded)		21
Allowance for loan losses (With an allowance recorded)		26	0
Average Investment in Impaired Loans (With an allowance recorded)		164
Impaired Financing Receivable, with Related Allowance, Interest Income, Cash Basis Method		0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,768	1,590
Loans and Leases Receivable, Allowance		1,794	1,590
Financing Receivable, Individually Evaluated for Impairment		260	0
Financing Receivable, Collectively Evaluated for Impairment		181,892	176,301
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		946	2,543
Land loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		356	284
Commercial loans - Secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		26,431	40,251
Commercial loans - other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		84,517	102,189
Consumer loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		2,255	1,747
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		39	22
Loans and Leases Receivable, Allowance		39	22
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Collectively Evaluated for Impairment		2,255	1,747
Construction And Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		1,302	2,827
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		32	68
Loans and Leases Receivable, Allowance		32	68
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Collectively Evaluated for Impairment		1,302	2,827
Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		103,063	147,079
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		733	1,241
Loans and Leases Receivable, Allowance		733	1,241
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Collectively Evaluated for Impairment		103,063	147,079
Finance Leases Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		352,539	333,120
Loans individually evaluated for impairment by class loans
Allowance for loan losses (With an allowance recorded)		0	0
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		714	769
Loans and Leases Receivable, Allowance		714	769
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Collectively Evaluated for Impairment		352,539	333,120
One to Four Family Residential Real Estate Loans-Owner occupied [Member] [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans		$ 96,629	$ 82,311

Loans Receivable - Nonaccrual L

Loans Receivable - Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Reserve For Uncollected Loan Interest	$ 250	$ 199
Unpaid Principal Balance	4,521	3,738
Recorded Investment	2,605	3,296
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	3,392	2,861
Recorded Investment	1,658	2,483
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	751	428
Recorded Investment	576	368
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	378	187
Recorded Investment	371	185
Loans Past Due Over 90 Days, still accruing	$ 0	0
Wholesale Commercial Lending [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Unpaid Principal Balance		262
Loans Past Due Over 90 Days, still accruing		0
Nonresidential real estate loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment		$ 260

Loans Receivable - Past Due Loa

Loans Receivable - Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	$ 6,330	$ 6,239
Recorded Investment, Loans Not Past Due	1,331,317	1,308,023
Recorded investment, total	1,337,647	1,314,262
Commercial Leases Investment Rated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	2,225	51
Recorded Investment, Loans Not Past Due	230,009	273,405
Recorded investment, total	232,234	273,456
Commercial Loans Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	102,698	84,988
Recorded investment, total	102,698	84,988
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	1,754	2,263
Recorded investment, total	1,754	2,263
Commercial Loans Health Care [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Loans Not Past Due	72,685	41,086
Recorded investment, total	72,685	41,086
Commercial Loans Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	644	0
Recorded Investment, Loans Not Past Due	33,787	31,847
Recorded investment, total	34,431	31,847
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	40,315	26,480
Recorded investment, total	40,315	26,480
Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	281	349
Recorded investment, total	281	349
Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	0
Recorded Investment, Loans Not Past Due	2,548	950
Recorded investment, total	2,548	950
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	0	260
Recorded Investment, Loans Not Past Due	174,724	178,644
Recorded investment, total	174,724	178,904
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	281,887	243,944
Recorded investment, total	281,887	243,944
Multi Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	371	1,228
Recorded Investment, Loans Not Past Due	288,508	294,223
Recorded investment, total	288,879	295,451
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	592	1,146
Recorded Investment, Loans Not Past Due	22,321	37,179
Recorded investment, total	22,913	38,325
One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	2,498	3,554
Recorded Investment, Loans Not Past Due	79,800	92,665
Recorded investment, total	82,298	96,219
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	381	2,304
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	0	51
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	0
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		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	275	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
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	0	0
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	605
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	12	664
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	94	984
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment, Total Past Due	3,346	888
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		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	2,225
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	369	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
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	439
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	3	114
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	749	335
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	2,603	3,047
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
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
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	260
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	371	184
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	577	368
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	$ 1,655	$ 2,235

Loans Receivable - Troubled Deb

Loans Receivable - Troubled Debt Restructuring (Details)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)loan	Sep. 30, 2016loan	Dec. 31, 2016USD ($)
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		341,000
Troubled Debt Restructurings Value Of Decreased Interest Income		0
Financing Receivable, Modifications, Increase In Allowance For Loan And Leases Losses		$ 0
Number Of Loans Default Subsequent Modification | loan		1	2
Loans Removed from TDR Status		$ 324,000
Accrual Loans [Member]
Troubled Debt Restructurings
Financing receivable modifications		0		205,000
Non Accrual Loans [Member]
Troubled Debt Restructurings
Financing receivable modifications		17,000		136,000
One-to-four family residential real estate loans - non-owner occupied loans [Member] | Accrual Loans [Member]
Troubled Debt Restructurings
Financing receivable modifications		0		205,000
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		136,000
One to Four Family Residential Real Estate Loans [Member]
Financing Receivable, Modifications [Line Items]
Due To Extension Of Maturity Date	$ 63,000
Allowance for Loan and Lease Losses [Member]
Troubled Debt Restructurings
Valuation Allowances and Reserves, Balance		$ 0		$ 0

Loans Receivable - Modified Tro

Loans Receivable - Modified Troubled Debt Restructuring (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan	Sep. 30, 2017USD ($)
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Increase In Allowance For Loan And Leases Losses			$ 0
Troubled Debt Restructurings Value Of Decreased Interest Income			0
Loans modified			149,000
Loans by class modified as TDRs
Financing Receivable, Modifications, Increase In Allowance For Loan And Leases Losses			$ 0
One-to-four family residential real estate loans [Member]
Loans by class modified as TDRs
Number of Loans | loan	0	1
Pre-Modification outstanding recorded investment	$ 0	$ 63,000
Post-Modification outstanding recorded investment	$ 0	63,000
Due to extension of maturity date		63,000
Due to permanent reduction in recorded investment		0
Total		$ 63,000

Loans Receivable - Troubled D41

Loans Receivable - Troubled Debt Restructuring - Payment Defaults (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan	Sep. 30, 2017USD ($)loan	Sep. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Increase In Allowance For Loan And Leases Losses			$ 0
Financing Receivable, Modifications, Increase In Allowance For Loan And Leases Losses			$ 0
Loans by class modified as TDRs with payment default
Number of loans | loan			1	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment			$ 17,000	$ 87,000
One-to-four family residential real estate loans [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Pre Modification Recorded Investment	$ 0	$ 63,000
Loans by class modified as TDRs with payment default
Financing Receivable Post Modification Recorded Investment	$ 0	$ 63,000
Number Of Loans | loan	0	1

Loans Receivable - Credit Quali

Loans Receivable - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 6,330	$ 6,239
Financing Receivable Credit Quality Indicators
Total loans	1,342,685	1,319,416
One-to-four family residential real estate loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,498	3,554
Financing Receivable Credit Quality Indicators
Total loans	105,186	135,218
One to Four Family Residential Real Estate Loans-Owner occupied [Member] [Member]
Financing Receivable Credit Quality Indicators
Total loans	82,311	96,629
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	592	1,146
Financing Receivable Credit Quality Indicators
Total loans	22,875	38,589
Multi-family mortgage loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	371	1,228
Financing Receivable Credit Quality Indicators
Total loans	576,425	542,887
Multi Family Mortgage Loans without wholesale [Member] [Member]
Financing Receivable Credit Quality Indicators
Total loans	290,027	299,183
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	286,398	243,704
Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	176,301	182,152
Construction loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	2,543	946
Land loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	284	356
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	40,251	26,431
Commercial Loans - Municipal loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	644	0
Financing Receivable Credit Quality Indicators
Total loans	34,213	31,681
Commercial Loans - Warehouse Lines [Member]
Financing Receivable Credit Quality Indicators
Total loans
Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	72,615	41,001
Commercial loans - other [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivable Credit Quality Indicators
Total loans	102,189	84,517
Commercial Leases - Investment Rated [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,225	51
Financing Receivable Credit Quality Indicators
Total loans	230,931	271,972
Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,747	2,255
Nonaccrual [Member]
Financing Receivable Credit Quality Indicators
Total loans	2,602	3,302
Nonaccrual [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,653	2,486
Nonaccrual [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	577	369
Nonaccrual [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	372	187
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	260
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
Substandard [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,921	3,629
Substandard [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	257	629
Substandard [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	40	41
Substandard [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	480	1,048
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	162	1,845
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	66
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	982	0
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	0	0
Pass [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,338,162	1,311,402
Pass [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	80,401	93,514
Pass [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	22,258	38,179
Pass [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	289,175	297,826
Pass [Member] | Wholesale commercial lending [Member]
Financing Receivable Credit Quality Indicators
Total loans	286,398	243,704
Pass [Member] | Nonresidential Real Estate Loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	176,139	180,047
Pass [Member] | Construction loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	2,543	946
Pass [Member] | Land loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	284	356
Pass [Member] | Commercial loans - Secured [Member]
Financing Receivable Credit Quality Indicators
Total loans	40,251	26,365
Pass [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	34,213	30,881
Pass [Member] | Commercial Loans - Health Care [Member]
Financing Receivable Credit Quality Indicators
Total loans	71,633	41,001
Pass [Member] | Commercial loans - other [Member]
Financing Receivable Credit Quality Indicators
Total loans	102,189	84,356
Pass [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	230,931	271,972
Pass [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	1,747	2,255
Special Mention [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	1,083
Special Mention [Member] | One-to-four family residential real estate loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | One-to-four family residential real estate loans - non-owner occupied loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Multi-family mortgage loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	122
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	0	0
Special Mention [Member] | Commercial Loans - Municipal loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	800
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	161
Special Mention [Member] | Commercial Leases - Investment Rated [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Special Mention [Member] | Consumer loans [Member]
Financing Receivable Credit Quality Indicators
Total loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Recorded Investment, Past Due	381	2,304
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	94	984
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	12	664
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	605
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
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	275	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	0
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	$ 0	$ 51

Loans Receivable - Narrative (D

Loans Receivable - Narrative (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Valuation and Qualifying Accounts Disclosure [Line Items]
Reserve For Uncollected Loan Interest	$ 250,000	$ 199,000
Financing receivable modifications	17,000	341,000
Outstanding Commitments To Borrowers Loans Classified As Troubled Debt Restructurings	0	0
Troubled Debt Restructurings Value Of Decreased Interest Income	0
Financing Receivable, Modifications, Increase In Allowance For Loan And Leases Losses	0
Loans modified	149,000
Allowance for Loan and Lease Losses [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation of reserves allocation	$ 0	$ 0

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Mortgage Loans in Process of Foreclosure, Amount	$ 1,400		$ 1,400			$ 1,600
Other Real Estate Owned At Carrying Value	3,569	$ 4,381	3,569	$ 4,381	$ 4,896	3,895	$ 5,373	$ 7,011
Real Estate Owned, Valuation Allowance, Amounts Applied	(63)	(170)	(278)	(677)
Real Estate Owned, Valuation Allowance, Valuation Increase	227	115	301	244
Real Estate Owned, Valuation Allowance	(472)	(609)	(472)	(609)	$ (308)	(449)	$ (664)	$ (1,042)
Other Real Estate, Disposals	(1,205)	(971)	(2,066)	(2,601)
Other Real Estate, Valuation Adjustments	(227)	(115)	(301)	(244)
Other Real Estate, Additions	105	$ 94	2,041	$ 215
Other real estate owned at carrying value before valuation allowance	4,041		4,041			4,344
Multi Family Mortgage Loans [Member]
Other Real Estate Owned At Carrying Value	0		0			370
Real Estate Owned, Valuation Allowance	0		0			0
Other real estate owned at carrying value before valuation allowance	0		0			370
One to Four Family Residential Real Estate Loans [Member]
Other Real Estate Owned At Carrying Value	1,748		1,748			1,565
Real Estate Owned, Valuation Allowance	(207)		(207)			(137)
Other real estate owned at carrying value before valuation allowance	1,955		1,955			1,702
Nonresidential Real Estate [Member]
Other Real Estate Owned At Carrying Value	1,551		1,551			1,066
Real Estate Owned, Valuation Allowance	(221)		(221)			(105)
Other real estate owned at carrying value before valuation allowance	1,772		1,772			1,171
Land [Member]
Other Real Estate Owned At Carrying Value	270		270			894
Real Estate Owned, Valuation Allowance	(44)		(44)			(207)
Other real estate owned at carrying value before valuation allowance	$ 314		$ 314			$ 1,101

Securities Sold Under Agreement

Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Abstract]
Available-for-sale Securities Pledged as Collateral	$ 4,000	$ 4,700
Carrying Value of Federal Funds Purchased, Securities Sold under Agreements to Repurchase, and Deposits Received for Securities Loaned	928	1,069
Federal Home Loan Bank Advances [Member] | Period One [Member]
Federal Home Loan Bank, Advances [Line Items]
Debt, Long-term and Short-term, Combined Amount	$ 50,000	$ 50,000

Employee Benefit Plans - Employ

Employee Benefit Plans - Employee Stock Ownership Plan (Details) - USD ($)	Mar. 29, 2017	Jun. 30, 2005	Sep. 30, 2017	Dec. 31, 2016
Compensation Related Costs, Retirement and Share Based Payment [Line Items]
ESOP compensation expense			$ 1,100,000	$ 1,300,000
Loan receivable from ESOP		$ 19,600,000
ESOP issued price (usd per share)		$ 10
Employee Stock Ownership Plan (ESOP), Shares in ESOP [Abstract]
Allocated to participants (shares)			1,203,810	1,125,448
Distributed to participants			(317,914)	(313,223)
Unearned (shares)			0	831,852
Total ESOP shares (shares)	78,362		885,896	1,644,077
Fair value of unearned shares			$ 0	$ 12,328,000
Common Stock [Member]
Compensation Related Costs, Retirement and Share Based Payment [Line Items]
Repayments of debt, shares issued (shares)	753,490
ESOP shares purchased (shares)		1,957,300
Share Acquisition Loan [Member]
Compensation Related Costs, Retirement and Share Based Payment [Line Items]
Loans payable			$ 0	$ 10,800,000

Equity Incentive Plans - Narrat

Equity Incentive Plans - Narrative (Details) - USD ($) $ in Thousands	Jun. 27, 2006	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options Outstanding		0	1,752,156	1,752,156
Share-based compensation expense		$ 0	$ 979
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		1,752,156
Share-based Compensation Arrangement by Share-based Payment Award, Net Settlement Share Issuance		280,554
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period		198,026
Share-based Compensation Arrangement by Share-based Payment Award, Shares Withheld For Taxes		82,528
2006 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)	3,425,275
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years

Equity Incentive Plans - Schedu

Equity Incentive Plans - Schedule of Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Stock Options Outstanding	0	1,752,156	1,752,156
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term		5 months 23 days	1 year 5 months 23 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value			$ 778
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 0	$ 4,422
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	(1,752,156)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 0

Fair Value - Financial Assets A

Fair Value - Financial Assets Accounted for at Fair Value (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			$ 234
Schedule of Company's financial instruments measured at fair values
Total Fair value	$ 98,787		107,212
Real Estate Acquired Through Foreclosure Fair Value	2,265		1,882
Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	80,360		85,938
Equity Funds [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	502		499
Residential Mortgage Backed Securities [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	13,188		15,184
Collateralized Debt Obligations [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	4,725		5,574
SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	12		17
Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			234
Schedule of Company's financial instruments measured at fair values
Total Fair value	98,787		107,212
Real Estate Acquired Through Foreclosure Fair Value	2,265		1,882
Nonrecurring [Member] | Certificates of deposit [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	80,360		85,938
Nonrecurring [Member] | Equity mutual fund [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	502		499
Nonrecurring [Member] | Mortgage-backed securities - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	13,188		15,184
Nonrecurring [Member] | Collateralized mortgage obligations - residential [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	4,725		5,574
Nonrecurring [Member] | SBA-guaranteed loan participation certificates [Member]
Schedule of Company's financial instruments measured at fair values
Total Fair value	12		17
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			0
Schedule of Company's financial instruments measured at fair values
Total Fair value	502		499
Real Estate Acquired Through Foreclosure Fair Value	0		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
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
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
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		0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			0
Schedule of Company's financial instruments measured at fair values
Total Fair value	98,285		106,713
Real Estate Acquired Through Foreclosure Fair Value	0		0
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		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			234
Schedule of Company's financial instruments measured at fair values
Total Fair value	0		0
Real Estate Acquired Through Foreclosure Fair Value	2,265		1,882
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
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		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
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
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		0
One to Four Family Residential Real Estate Loans [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value			1,282
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			1,282
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
Commercial Real Estate [Member] | Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			234
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	844		553
Commercial Real Estate [Member] | Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			0
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	0		0
Commercial Real Estate [Member] | Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			0
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value	0		0
Commercial Real Estate [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	$ 844
Nonresidential Real Estate Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loan Fair Value			234
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value			553
Land Loans [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value			47
Land Loans [Member] | Nonrecurring [Member]
Schedule of Company's financial instruments measured at fair values
Real Estate Acquired Through Foreclosure Fair Value			47
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
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
Sales Comparison Valuation Technique [Member] | One to Four Family Residential Real Estate Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description		Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description		Discount applied to valuation
Sales Comparison Valuation Technique [Member] | Commercial Real Estate [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description	Sales comparison	Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description	Comparison between sales and income approaches	Comparison between sales and income approaches
Sales Comparison Valuation Technique [Member] | Nonresidential Real Estate Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description		Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description		Comparison between sales and income approaches
Sales Comparison Valuation Technique [Member] | Land Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description		Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description		Discount applied to valuation

Fair Value - Assets Measured at

Fair Value - Assets Measured at Fair Value on a Non-Recurring Basis (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Loans Carrying Amount					$ 260,000
Impaired Loans Valuation Allowance					26,000
allowance for loan losses, specific reserve, increase or decrease			$ (26,000)	$ 5,000
Other Real Estate	$ 2,694,000		2,694,000		2,300,000
Real Estate Owned, Valuation Allowance, Component	429,000		429,000		434,000
Fair Value, Impaired loans					234,000
Fair Value, Other real estate owned	2,265,000		2,265,000		1,882,000
Other Real Estate Owned Write Downs	227,000	$ 115,000	301,000	$ 244,000
One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Other real estate owned					1,282,000
Nonresidential Real Estate Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					234,000
Fair Value, Other real estate owned					553,000
Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					234,000
Fair Value, Other real estate owned	2,265,000		2,265,000		1,882,000
Nonrecurring [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Other real estate owned					1,282,000
Nonrecurring [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					234,000
Fair Value, Other real estate owned	844,000		844,000		553,000
Nonrecurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					0
Fair Value, Other real estate owned	0		0		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 Measurements, Recurring and Nonrecurring, 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 Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					0
Fair Value, Other real estate owned	0		0		0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					0
Fair Value, Other real estate owned	0		0		0
Nonrecurring [Member] | Significant Observable Inputs (Level 2) [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, 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 Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					0
Fair Value, Other real estate owned	0		0		0
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Impaired loans					234,000
Fair Value, Other real estate owned	2,265,000		2,265,000		$ 1,882,000
Nonrecurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value, Other real estate owned	$ 844,000		$ 844,000
Sales Comparison Valuation Technique [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description				Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description				Discount applied to valuation
Sales Comparison Valuation Technique [Member] | Nonresidential Real Estate Loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description				Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description				Comparison between sales and income approaches
Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Measurements, Valuation Processes, Description			Sales comparison	Sales comparison
Fair Value Measurements, Sensitivity Analysis, Description			Comparison between sales and income approaches	Comparison between sales and income approaches
Maximum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate					20.04%
Maximum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential Real Estate [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					4.58%
Maximum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					31.60%
Minimum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate					8.62%
Minimum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential Real Estate [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					(3.22%)
Minimum [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					5.74%
Weighted Average [Member] | impaired loans [Member] | Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments			3.60%		(10.20%)
Weighted Average [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | One-to-four family residential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate					11.90%
Weighted Average [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential Real Estate [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					3.77%
Weighted Average [Member] | Real Estate [Domain] | Sales Comparison Valuation Technique [Member] | Nonresidential real estate loans [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Comparability Adjustments					25.20%

Fair Value - Carrying Amount an

Fair Value - Carrying Amount and Estimated Fair Value of Finanical Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 125,661	$ 96,684	$ 100,530	$ 59,377
Financial assets
Securities, carrying amount	98,787	107,212
Loans receivable, net of allowance for loan losses, carrying amounts	1,335,631	1,312,952
FHLBC stock, carrying amount	8,290	11,650
Accrued interest receivable, carrying amount	4,569	4,381
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets
Available-for-sale Securities, Fair Value Disclosure	98,787	107,212
Loans Receivable, Fair Value Disclosure	1,340,957	1,322,947
Accounts Receivable, Fair Value Disclosure	4,569	4,381
Financial liabilities
Cash and Cash Equivalents, Fair Value Disclosure	125,661	96,684
Demand Deposit Accounts Fair Value Disclosure	231,049	249,539
Deposits Savings Deposits Fair Value Disclosure	158,696	160,002
Now Money Market Accounts Fair Value Disclosure	585,316	578,237
Certificates Of Deposit Fair Value Disclosure	394,888	350,593
Short Term Borrowings Fair Value Disclosure	60,932	50,015
Accrued Liabilities, Fair Value Disclosure	180	102
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	10,620	13,053
Demand Deposit Accounts Fair Value Disclosure		0
Deposits Savings Deposits Fair Value Disclosure		0
Now Money Market Accounts 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
Available-for-sale Securities, Fair Value Disclosure	98,285	106,713
Loans Receivable, Fair Value Disclosure	1,340,957	1,322,713
Accounts Receivable, Fair Value Disclosure	4,569	4,381
Financial liabilities
Cash and Cash Equivalents, Fair Value Disclosure	115,041	83,631
Demand Deposit Accounts Fair Value Disclosure	231,049	249,539
Deposits Savings Deposits Fair Value Disclosure	158,696	160,002
Now Money Market Accounts Fair Value Disclosure	585,316	578,237
Certificates Of Deposit Fair Value Disclosure	394,888	350,593
Short Term Borrowings Fair Value Disclosure		50,015
Accrued Liabilities, Fair Value Disclosure	180	102
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 3 [Member]
Financial assets
Loans Receivable, Fair Value Disclosure	0	234
Reported Value Measurement [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cash and Cash Equivalents, at Carrying Value	125,661	96,684
Financial assets
Securities, carrying amount	98,787	107,212
Loans receivable, net of allowance for loan losses, carrying amounts	1,335,631	1,312,952
FHLBC stock, carrying amount	8,290	11,650
Accrued interest receivable, carrying amount	4,569	4,381
Financial liabilities
Demand Deposit Accounts	231,049	249,539
Deposits, Savings Deposits	158,696	160,002
Now Money Market Accounts	585,316	578,237
Certificates of Deposit, at Carrying Value	396,028	351,612
Short-term Debt	60,928	51,069
Accrued Interest Payable	180	102
Reported Value Measurement [Member] | Level 2 [Member]
Financial liabilities
Short-term Debt	60,932
Equity Funds [Member]
Financial assets
Securities, carrying amount	$ 502	$ 499

Uncategorized Items - bfin-2017

Label	Element	Value
Retained Earnings [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	$ 2,508,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	us-gaap_ProfitLoss	$ 3,560,000