Note 8 - Fair Values of Financial Instruments - Fair Value by Balance Sheet Grouping (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Available-for-sale securities	$ 61,374,800	$ 44,517,178
Reported Value Measurement [Member]
Cash and due from banks	5,159,000	4,496,000
Interest-bearing deposits with banks	3,260,000	24,990,000
Available-for-sale securities	61,375,000	44,517,000
Loans held for investment, net	309,443,000	291,739,000
Stock in financial institutions	4,037,000	4,017,000
Demand deposits, savings and NOW deposits	229,134,000	222,509,000
Time deposits	76,985,000	81,388,000
Federal Home Loan Bank advances	50,000,000	40,000,000
Estimate of Fair Value Measurement [Member]
Cash and due from banks	5,159,000	4,496,000
Interest-bearing deposits with banks	3,260,000	24,990,000
Available-for-sale securities	61,375,000	44,517,000
Loans held for investment, net	308,210,000	292,246,000
Stock in financial institutions	4,037,000	4,017,000
Demand deposits, savings and NOW deposits	228,963,000	214,611,000
Time deposits	77,588,000	81,638,000
Federal Home Loan Bank advances	50,244,000	40,075,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	5,159,000	4,496,000
Interest-bearing deposits with banks	3,260,000	24,990,000
Available-for-sale securities	0	0
Loans held for investment, net	0	0
Stock in financial institutions	0	0
Demand deposits, savings and NOW deposits	228,963,000	214,611,000
Time deposits	0	0
Federal Home Loan Bank advances	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	0	0
Interest-bearing deposits with banks	0	0
Available-for-sale securities	61,375,000	44,517,000
Loans held for investment, net	0	0
Stock in financial institutions	4,037,000	4,017,000
Demand deposits, savings and NOW deposits	0	0
Time deposits	77,588,000	81,638,000
Federal Home Loan Bank advances	50,244,000	40,075,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and due from banks	0	0
Interest-bearing deposits with banks	0	0
Available-for-sale securities	0	0
Loans held for investment, net	308,210,000	292,246,000
Stock in financial institutions	0	0
Demand deposits, savings and NOW deposits	0	0
Time deposits	0	0
Federal Home Loan Bank advances	$ 0	$ 0

Fair value portion of cash and due from banks.

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Fair value portion of demand deposits and deposits in interest-bearing transaction accounts at banks or savings and loans, that are restricted in regard to ownership and can usually only be held by individuals, nonprofit entities and governments. Negotiable order of withdrawal accounts differ from money market demand accounts as they typically have higher reserve requirements and no limit on the number of checks that can be written.

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The amount represents the interest bearing deposits in banks and fair value disclosure.

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Fair value portion of time deposit liabilities held by the entity.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value portion of investments accounted under the cost method.

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables.

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