Note 5 - Allowance for Credit Losses - Allowance for Credit Losses (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for loan and lease losses	$ 8,984,795	$ 8,202,710	$ 7,809,700	$ 7,873,790
Provisions for losses and unfunded commitments	945,436	846,457	1,125,407
Loans charged-off	(344,888)	(702,557)	(1,316,082)
Recoveries of loans previously charged-off	181,537	249,110	126,585
Net charge-offs	(164,000)	(453,000)
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans charged-off	(2,000)	(301,000)
Recoveries of loans previously charged-off	3,000	1,000
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans charged-off	(101,000)	(172,000)
Recoveries of loans previously charged-off	35,000	83,000
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans charged-off
Recoveries of loans previously charged-off	70,000
Commercial Portfolio Segment [Member] \| Lots and Raw Land [Member]
Loans charged-off		(33,000)
Recoveries of loans previously charged-off	11,000	4,000
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Loans charged-off	(2,000)
Recoveries of loans previously charged-off	13,000
Commercial Portfolio Segment [Member] \| Lease Receivables [Member]
Loans charged-off
Consumer Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans charged-off	(81,000)	(85,000)
Recoveries of loans previously charged-off	13,000	18,000
Consumer Portfolio Segment [Member] \| Lots and Raw Land [Member]
Loans charged-off	(78,000)	(85,000)
Recoveries of loans previously charged-off	2,000	8,000
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member]
Loans charged-off	(23,000)	(13,000)
Recoveries of loans previously charged-off	7,000	36,000
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Loans charged-off	(58,000)	(13,000)
Recoveries of loans previously charged-off	27,000	99,000
Allowance for Loan and Lease Losses [Member]
Allowance for loan and lease losses	8,673,172	7,866,523	7,519,970	7,609,467
Provisions for losses and unfunded commitments	970,000	800,000	1,100,000
Loans charged-off	(344,888)	(702,557)	(1,316,082)
Recoveries of loans previously charged-off	181,537	249,110	126,585
Allowance for Unfunded Commitments [Member]
Allowance for loan and lease losses	311,623	336,187	289,730	$ 264,323
Provisions for losses and unfunded commitments	(24,564)	46,457	25,407
Loans charged-off
Recoveries of loans previously charged-off

Amount, after recoveries, of loans and leases that have been written-off.

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A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of direct write-downs of financing receivables charged against the allowance.

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- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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