Fair Value of Financial Instruments - Estimated Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Investment securities available for sale, at fair value	$ 8,628	$ 2,560
Investment securities held to maturity	371,305	364,922
Carrying Amount
Assets
Cash and cash equivalents	44,806	47,063
Investment securities available for sale, at fair value	8,628	2,560
Investment securities held to maturity	363,883	371,517
Loans held for sale	470	309
Loans receivable, net	1,584,784	1,574,714
FHLB stock	8,723	8,093
FRB stock	3,128	3,114
Accrued interest receivable	5,409	5,274
Interest rate contracts	5	5
Liabilities
Deposits	1,631,933	1,629,164
Advances from the Federal Home Loan Bank	156,000	142,200
Securities sold under agreements to repurchase	10,000	30,000
Accrued interest payable	397	243
Interest rate contracts	5	5
Estimated Fair Value
Assets
Cash and cash equivalents	44,806	47,063
Investment securities available for sale, at fair value	8,628	2,560
Investment securities held to maturity	371,305	364,922
Loans held for sale	480	319
Loans receivable, net	1,627,903	1,553,672
FHLB stock	8,723	8,093
FRB stock	3,128	3,114
Accrued interest receivable	5,409	5,274
Interest rate contracts	5	5
Liabilities
Deposits	1,632,741	1,626,587
Advances from the Federal Home Loan Bank	156,906	141,874
Securities sold under agreements to repurchase	9,968	29,876
Accrued interest payable	397	243
Interest rate contracts	5	5
Estimated Fair Value \| Level 1
Assets
Cash and cash equivalents	44,806	47,063
Accrued interest receivable	32	12
Estimated Fair Value \| Level 2
Assets
Investment securities available for sale, at fair value	8,628	2,560
Investment securities held to maturity	371,305	364,219
Loans held for sale	480	319
FHLB stock	8,723	8,093
FRB stock	3,128	3,114
Accrued interest receivable	952	960
Interest rate contracts	5	5
Liabilities
Deposits	1,167,990	1,238,023
Advances from the Federal Home Loan Bank	156,906	141,874
Securities sold under agreements to repurchase	9,968	29,876
Accrued interest payable	47	111
Interest rate contracts	5	5
Estimated Fair Value \| Level 3
Assets
Investment securities held to maturity		703
Loans receivable, net	1,627,903	1,553,672
Accrued interest receivable	4,425	4,302
Liabilities
Deposits	464,751	388,564
Accrued interest payable	$ 350	$ 132

Fair value portion of interest payable.

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Fair value portion of interest earned but not received.

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No definition available.

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Represents the fair value portion of investments in Federal Reserve bank (FRB) stock.

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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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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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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

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Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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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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Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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