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Business Combination & Asset Purchase - Summary of Carrying Amount of Loans (Parenthetical) (Detail) - USD ($) | Dec. 31, 2021 | Oct. 01, 2021 | Apr. 30, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Jan. 01, 2019
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Perpetual Federal Savings Bank [Member] |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Fair value adjustment | $ 189,800 | $ 237,200 |  |  |  |
Ossian Financial Services, Inc. [Member] |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Fair value adjustment | $ 320,600 |  | $ 324,800 |  |  |
Limberlost Bancshares, Inc. [Member] |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Fair value adjustment |  |  |  | $ 0 | $ 62,000 | $ 2,118,000

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