Loans and Allowance for Credit Losses - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balances	$ 68,062,000	$ 68,446,000
Loans receivable	129,134,855	118,850,710
Loans modified in period	0	0
Residential, Commercial and Consumer Loans \| Other than Central Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 27,827,000	$ 23,770,000
Percentage of gross loan balances	21.50%	20.00%
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 60,390,627	$ 54,409,430
Commercial Real Estate \| Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan amortization period	15 years
Balloon payments period	2 years
Commercial Real Estate \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan amortization period	25 years
Balloon payments period	5 years
Construction and Development Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 5,798,697	$ 4,063,650
Construction and Development Real Estate \| Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan term	1 year
Construction and Development Real Estate \| Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan term	18 months

Balloon payments period.

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Loan amortization period.

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Loan term.

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Percentage of notes receivable gross.

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- Definition

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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Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

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- Definition

The balance represents the amount of loans that are secured by real estate mortgages, offset by the reserve to cover probable credit losses on the loan portfolio.

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Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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