Note 7 - Fair Values of Financial Instruments - Fair Value by Balance Sheet Grouping (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Available-for-sale securities, at fair value	$ 32,570,879	$ 33,428,658
Reported Value Measurement [Member]
Cash and due from banks	4,719,000	6,374,000
Interest-bearing deposits with banks	6,855,000	5,400,000
Available-for-sale securities, at fair value	32,571,000	33,429,000
Loans held for sale	14,615,000	26,884,000
Loans held for investment, net	286,875,000	282,790,000
Derivative IRLC's, fair value disclosure	361,000
Derivative forward commitments	(95,000)	(154,000)
Stock in financial institutions	3,937,000	3,910,000
Demand deposits, savings and NOW deposits	189,915,000	187,700,000
Time deposits	77,970,000	77,359,000
Federal Home Loan Bank advances	50,000,000	67,000,000
Estimate of Fair Value Measurement [Member]
Cash and due from banks	4,719,000	6,374,000
Interest-bearing deposits with banks	6,855,000	5,400,000
Available-for-sale securities, at fair value	32,571,000	33,429,000
Loans held for sale	14,615,000	26,884,000
Loans held for investment, net	287,346,000	283,466,000
Derivative IRLC's, fair value disclosure	361,000	381,000
Derivative forward commitments	(95,000)	(154,000)
Stock in financial institutions	3,937,000	3,910,000
Demand deposits, savings and NOW deposits	176,906,000	172,049,000
Time deposits	78,208,000	77,688,000
Federal Home Loan Bank advances	49,880,000	66,653,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	4,719,000	6,374,000
Interest-bearing deposits with banks	6,855,000	5,400,000
Available-for-sale securities, at fair value	0	0
Loans held for sale	0	0
Loans held for investment, net	0	0
Derivative IRLC's, fair value disclosure	0
Derivative forward commitments	0
Stock in financial institutions	0	0
Demand deposits, savings and NOW deposits	176,906,000	172,049,000
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, at fair value	32,571,000	33,429,000
Loans held for sale	14,615,000	26,884,000
Loans held for investment, net	0	0
Derivative IRLC's, fair value disclosure	0
Derivative forward commitments	(95,000)	(154,000)
Stock in financial institutions	3,937,000	3,910,000
Demand deposits, savings and NOW deposits	0	0
Time deposits	78,208,000	77,688,000
Federal Home Loan Bank advances	49,880,000	66,653,000
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, at fair value	0	0
Loans held for sale	0	0
Loans held for investment, net	287,346,000	283,466,000
Derivative IRLC's, fair value disclosure	361,000	381,000
Derivative forward commitments	0
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

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

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

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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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