Fair Value - Carrying Amount and Estimated Fair Value of Finanical Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ (23)	$ (261)
Fair value of mortgage servicing rights	420	513
Financial assets
Cash and cash equivalents, carrying amount	98,204	127,592	$ 96,684
Cash and Due from Banks	13,805	13,572
Interest-bearing Deposits in Banks and Other Financial Institutions	84,399	114,020
Marketable Securities	88,179	93,383
Securities, carrying amount	88,179	93,383
Loans receivable, net of allowance for loan losses, carrying amounts	1,323,793	1,314,651
FHLBC stock, carrying amount	8,026	8,290
Accrued interest receivable, carrying amount	4,952	4,619
Financial liabilities
Noninterest-bearing demand deposits	230,041	234,354
Savings deposits	152,334	160,501
Time Deposits	438,328	355,958
Borrowings	21,049	60,768
Carrying Amount [Member]
Financial liabilities
NOW and money market accounts, carrying amount	531,781	589,238
Accrued interest payable, carrying amount	291	147
Estimated Fair Value [Member]
Financial assets
Cash and cash equivalents, fair value	98,204	127,592
Securities, carrying amount	88,179	93,383
Loans receivable, net of allowance for loan losses, fair value	1,315,855	1,323,139
Accounts interest receivable, fair value	4,952	4,619
Financial liabilities
Non-interest-bearing demand deposits, fair value	230,041	234,354
NOW money market accounts, fair value	531,781	589,238
Savings deposits, fair value	152,334	160,501
Certificates of deposit, fair value	436,598	353,969
Borrowings, fair value	21,050	60,627
Accrued interest payable, fair value	291	147
Estimated Fair Value [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial assets
Loans receivable, net of allowance for loan losses, fair value	0	0
Accounts interest receivable, fair value	0	0
Financial liabilities
Non-interest-bearing demand deposits, fair value	0	0
Savings deposits, fair value	0	0
Certificates of deposit, fair value	0	0
Borrowings, fair value	0	0
Accrued interest payable, fair value	0	0
Estimated Fair Value [Member] \| Level 2 [Member]
Financial assets
Securities, carrying amount	88,179	92,884
Loans receivable, net of allowance for loan losses, fair value	0	1,323,139
Accounts interest receivable, fair value	249	4,619
Financial liabilities
Non-interest-bearing demand deposits, fair value	230,041	234,354
NOW money market accounts, fair value	531,781	589,238
Savings deposits, fair value	152,334	160,501
Certificates of deposit, fair value	436,598	353,969
Borrowings, fair value	21,050	60,627
Accrued interest payable, fair value	291	147
Estimated Fair Value [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial assets
Cash and cash equivalents, fair value	0	0
Securities, carrying amount	0	0
Loans receivable, net of allowance for loan losses, fair value	1,315,855	0
Accounts interest receivable, fair value	4,703	0
Financial liabilities
Non-interest-bearing demand deposits, fair value	0	0
Savings deposits, fair value	0	0
Certificates of deposit, fair value	0	0
Borrowings, fair value	0	0
Accrued interest payable, fair value	0	0
Equity Funds [Member]
Financial assets
Securities, carrying amount	0	499
Fair Value, Measurements, Nonrecurring [Member]
Financial assets
Securities, carrying amount	88,179	93,383
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial assets
Securities, carrying amount	0	499
Fair Value, Measurements, Nonrecurring [Member] \| Level 2 [Member]
Financial assets
Securities, carrying amount	88,179	92,884
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial assets
Securities, carrying amount	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Collateralized Mortgage Obligations Residential [Member]
Financial assets
Securities, carrying amount	3,685	4,486
Fair Value, Measurements, Nonrecurring [Member] \| Collateralized Mortgage Obligations Residential [Member] \| Fair Value, Inputs, Level 1 [Member]
Financial assets
Securities, carrying amount	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Collateralized Mortgage Obligations Residential [Member] \| Fair Value, Inputs, Level 3 [Member]
Financial assets
Securities, carrying amount	$ 0	$ 0

Accrued interest payable.

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Deposits savings deposits fair value disclosure.

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NOW and money market accounts.

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Short term borrowings fair value disclosure.

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Fair value portion of amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties.

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Fair value portion of accrued expenses.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

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Amount of investment in marketable security.

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Amount of money in noninterest-bearing domestic accounts that entitle the depositor to withdraw funds at any time without prior notice, also known as demand deposits.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Amount of time deposit liabilities, including certificates of deposit.

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Amount of valuation and qualifying accounts and reserves.

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