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Business Combination and Asset Purchase - Additional Information (Detail) |  |  |  | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Apr. 30, 2021 USD ($) Office $ / shares shares | Nov. 16, 2020 USD ($) shares | Jan. 01, 2019 USD ($) Office $ / shares shares | Jun. 30, 2021 USD ($) shares | Jun. 30, 2021 USD ($) shares | Jun. 30, 2020 USD ($) | Dec. 31, 2020 USD ($) shares | Nov. 30, 2020 USD ($) Client
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Common stock, shares outstanding | shares |  |  |  | 12,230,000 | 12,230,000 |  | 12,230,000 |
Business combination, acquisition related costs |  |  |  | $ 977,500 | $ 977,500 |  | $ 42,500 |
Recognition of core deposit intangible asset with acquired purchase |  |  |  |  | $ 3,900,000 |  |  |
Remaining economic useful life |  |  |  |  | 7 years |  |  |
Goodwill |  |  |  | 56,066,000 | $ 56,066,000 |  | 47,340,000 |
Goodwill deductible for tax purpose, period | 15 years |  |  |  |  |  |  |
Fair value of assets acquired |  |  |  | 52,400,000 | 52,400,000 |  |  |
Gross principal and contractual interest |  |  |  | 58,600,000 | 58,600,000 |  |  |
Acquisition expected to be uncollectible |  |  |  | 1,100,000 | $ 1,100,000 |  |  |
Loan receivable weighted average life |  |  |  |  | 52 months |  |  |
Business combination, premises and equipment written down value |  |  |  |  | $ 596,000 |  |  |
Business combination, average remaining life |  |  |  |  | 39 years |  |  |
Fair value for certificate of deposit, valuation amount |  |  |  | 59,000 | $ 59,000 |  |  |
Fair value for certificate of deposit, amortization period |  |  |  |  | 1 year 4 months 24 days |  |  |
Pro-forma operating revenue, net of tax |  |  |  | 232,000 |  |  |  |
Amortization expense |  |  |  |  | $ 303,000 | $ 364,000 |  |
Amortization expense for 2021 |  |  |  | 653,000 | 653,000 | 653,000 |  |
Custar [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Amortization expense |  |  |  |  |  | 84,000 |  |
Building |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Business combination, premises and equipment written down value |  |  |  |  | 244,000 |  |  |
Customer Lists [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Amortization expense |  |  |  |  | 61,000 |  |  |
Amortization expense for 2021 |  |  |  | 123,000 | 123,000 |  |  |
Other General and Administrative Expenses [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Business combination, acquisition related costs |  |  |  | 179,800 | 179,800 |  | 30,000.0 |
Consulting Fees [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Business combination, acquisition related costs |  |  |  | 245,000.0 | 245,000.0 |  | $ 12,500 |
Employee Benefits [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Business combination, acquisition related costs |  |  |  | 541,500 | 541,500 |  |  |
ATM Expense [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Business combination, acquisition related costs |  |  |  | 11,200 | 11,200 |  |  |
Ossian State Bank [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Number of full-service offices | Office | 2 |  |  |  |  |  |  |
Ossian Financial Services, Inc. [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Cash payment for exchange of each share | $ / shares | $ 67.71 |  |  |  |  |  |  |
Common stock, shares outstanding | shares | 295,388 |  |  |  |  |  |  |
Total consideration for acquisition | $ 20,001,000 |  |  |  |  |  |  |
Goodwill | 8,726,000 |  |  |  |  |  |  |
Cash paid for the capital stock | 20,001,000 |  |  |  | 20,001,000 |  |  |
Amortization expense for 2021 |  |  |  |  |  | $ 93,000 |  |
Ossian Financial Services, Inc. [Member] | Core Deposits [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Recognition of core deposit intangible asset with acquired purchase | $ 980,200 |  |  |  |  |  |  |
Remaining economic useful life | 7 years |  |  |  |  |  |  |
Bank of Geneva [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Number of full-service offices | Office |  |  | 6 |  |  |  |  |
Limberlost Bancshares, Inc. [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Cash payment for exchange of each share | $ / shares |  |  | $ 8,465.00 |  |  |  |  |
Common stock, shares outstanding | shares |  |  | 1,000 |  |  |  |  |
Total consideration for acquisition |  |  | $ 78,900,000 |  |  |  |  |
Goodwill |  |  | $ 43,300,000 |  |  |  |  |
Common stock issued in exchange of each outstanding share | shares |  |  | 1,830,000 |  |  |  |  |
Share price | $ / shares |  |  | $ 38.49 |  |  |  |  |
Cash paid for the capital stock |  |  | $ 8,500,000 |  |  |  |  |
Stock issued for acquisition |  |  | 70,400,000 |  |  |  |  |
Limberlost Bancshares, Inc. [Member] | Core Deposits [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Recognition of core deposit intangible asset with acquired purchase |  |  | $ 3,900,000 |  |  |  |  |
Remaining economic useful life |  |  | 7 years |  |  |  |  |
Adams County Financial Resources |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Total consideration for acquisition |  | $ 825,000 |  |  |  |  |  |
Common stock issued in exchange of each outstanding share | shares |  | 40,049 |  |  |  |  |  |
Stock issued for acquisition |  | $ 825,000 |  |  |  |  |  |
Assets under management amount |  |  |  |  |  |  |  | $ 83,000,000
Number of clients assets under management | Client |  |  |  |  |  |  |  | 450
Increase to noninterest income |  | 500,000 |  |  |  |  |  |
Adams County Financial Resources | Customer Lists [Member] |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |
Recognition of core deposit intangible asset with acquired purchase |  | $ 800,000 |  |  |  |  |  |
Remaining economic useful life |  | 6 years 6 months |  |  |  |  |  |
Amortization expense for 2021 |  |  |  | $ 123,000 | $ 123,000 |  |  |

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