FHLB Advances and Other Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Federal Home Loan Bank, Advances [Line Items]
Federal Home Loan Bank stock to maximum borrowing capacity	The Company maintains a master contract agreement with the FHLB, which provides for borrowing up to the lesser of 22.22 times the FHLB stock owned, a determined percentage of the book value of the Company’s qualifying real estate loans, or a determined percentage of the Company’s assets
Qualifying loans pledged as collateral	$ 149,100,000	$ 125,500,000
Federal Home Loan Bank stock held	3,032,000	913,000
Available and unused funds under borrowing agreement	79,600,000	$ 107,000,000
Fed Funds Effective Rate Overnight Index Swap Rate [Member] \| BMO Harris Bank [Member]
Federal Home Loan Bank, Advances [Line Items]
Federal funds rate line of credit	10,000,000
Federal Fund Rate [Member] \| BMO Harris Bank [Member]
Federal Home Loan Bank, Advances [Line Items]
Qualifying loans pledged as collateral	11,700,000
Line Of Credit At Federal Reserve	7,000,000
Available Borrowing Capacity	$ 0

Description of maximum borrowing capacity.

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- Definition

Line Of Credit At Federal Reserve

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- Definition

Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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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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No definition available.

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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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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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Carrying amount as of the balance sheet date of loans that have been pledged as collateral for borrowings. If the secured party has the right by contract or custom to sell or re-pledge the collateral, then the debtor reclassifies that asset and report that asset in its statement of financial position separately from other assets not so encumbered.

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