Note 4 - Investment Securities (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Proceeds from Sale of Available-for-sale Securities, Total	$ 11,267,642	$ 0	$ 25,209,851
Available-for-sale Securities, Gross Realized Gains	115,909	0	391,976
Available-for-sale Securities, Gross Realized Losses	0	0	$ 6,753
Security Owned and Pledged as Collateral, Fair Value, Total	$ 178,978,383	$ 175,484,021
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Total	145
Depreciated Debt Securities With Unrealized Losses	3.44%
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Total	$ 0
Number of Asset Backed Securities Owned	1
Number of Issuances of Trust Preferred Securities	1

Refers to the depreciated percentage of debt securities with unrealized losses measuring in amortized cost basis.

No definition available.

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- Definition

Refers to the number of asset-backed security owned by the entity.

+ References

No definition available.

+ Details

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- Definition

Represents the umber of issuance of trust preferred securities.

+ References

No definition available.

+ Details

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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- Definition

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

No definition available.

+ Details

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- Definition

Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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- Definition

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

No definition available.

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- Definition

The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26853-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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- Definition

Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66007379&loc=d3e113888-111728

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