Note 14 - Fair Value - Estimated Fair Value of Financial Instruments (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Fair value, held to maturity	$ 18,033,093	$ 18,307,627
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value, held to maturity	18,127,067	18,204,182
Mortgage loans held for sale	573,638	327,700
Federal Home Loan Bank stock	575,800	1,063,600
Interest-bearing deposits	291,995,483	255,393,291
Federal Home Loan Bank advances	3,000,000	17,000,000
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans, net	340,900,635	332,533,706
Reported Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Noninterest-bearing deposits	62,717,520	64,403,133
Securities sold under repurchase agreements	11,012,000	21,768,507
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair value, held to maturity	18,033,093	18,307,627
Mortgage loans held for sale	582,248	332,558
Federal Home Loan Bank stock	575,800	1,063,600
Interest-bearing deposits	281,761,483	244,403,291
Federal Home Loan Bank advances	2,971,000	16,957,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Loans, net	337,385,842	332,689,848
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Noninterest-bearing deposits	62,717,520	64,403,133
Securities sold under repurchase agreements	$ 11,012,000	$ 21,768,507

Fair value portion of interest-bearing deposits.

No definition available.

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- Definition

Fair value portion of noninterest-bearing deposit liabilities.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

No definition available.

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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- Definition

Fair value portion of mortgage loans held-for-sale.

+ References

No definition available.

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- Definition

Fair value portion of securities that an entity sells and agrees to repurchase at a specified date for a specified price.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

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