Note 19 - Fair Value of Financial Instruments and Fair Value Measurements - Financial Instruments (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Investment Securities Available for Sale	$ 354,246,904	$ 323,657,870
Reported Value Measurement [Member]
Cash and Short-Term Investments	57,813,000	75,167,000
Investment Securities Available for Sale	354,247,000	323,658,000
Federal Home Loan Bank Stock	3,043,000	3,010,000
Loans, Net	757,281,000	744,999,000
Bank-Owned Life Insurance	17,089,000	15,419,000
Deposits	1,067,985,000	1,044,357,000
Subordinated Debentures	24,229,000	24,229,000
Other Borrowed Money	47,500,000	46,000,000
Estimate of Fair Value Measurement [Member]
Cash and Short-Term Investments	57,813,000	75,167,000
Investment Securities Available for Sale	354,247,000	323,658,000
Federal Home Loan Bank Stock	3,043,000	3,010,000
Loans, Net	757,163,000	745,240,000
Bank-Owned Life Insurance	17,089,000	15,419,000
Deposits	1,068,392,000	1,045,726,000
Subordinated Debentures	24,229,000	24,229,000
Other Borrowed Money	47,626,000	46,232,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and Short-Term Investments	57,813,000	75,167,000
Investment Securities Available for Sale
Federal Home Loan Bank Stock	3,043,000	3,010,000
Loans, Net
Bank-Owned Life Insurance	17,089,000	15,419,000
Deposits	727,818,000	677,129,000
Subordinated Debentures
Other Borrowed Money
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and Short-Term Investments
Investment Securities Available for Sale	346,950,000	323,082,000
Federal Home Loan Bank Stock
Loans, Net	752,287,000	738,288,000
Bank-Owned Life Insurance
Deposits	340,574,000	368,597,000
Subordinated Debentures	24,229,000	24,229,000
Other Borrowed Money	47,626,000	46,232,000
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and Short-Term Investments
Investment Securities Available for Sale	7,297,000	576,000
Federal Home Loan Bank Stock
Loans, Net	4,876,000	6,952,000
Bank-Owned Life Insurance
Deposits
Subordinated Debentures
Other Borrowed Money

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
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Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75030709&loc=d3e39828-111592

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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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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