Note 3 - Securities - Available-for-sale Securities (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale securities, gross unrealized gains	$ 313,047	$ 139,155
Available-for-sale securities, gross unrealized (losses)	(1,005,207)	(2,217,205)
Available-for-sale securities, approximate fair value	85,006,043	92,399,235
Available-for-sale securities, amortized cost	85,698,203	94,477,285
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale securities, gross unrealized gains	235,378	65,673
Available-for-sale securities, gross unrealized (losses)	(368,313)	(1,085,654)
Available-for-sale securities, approximate fair value	35,856,155	38,337,525
Available-for-sale securities, amortized cost	35,989,090	39,357,506
Corporate Debt Securities [Member]
Available-for-sale securities, gross unrealized gains	55,000	54,050
Available-for-sale securities, gross unrealized (losses)		(4,514)
Available-for-sale securities, approximate fair value	3,055,000	7,053,522
Available-for-sale securities, amortized cost	3,000,000	7,003,986
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities, gross unrealized gains	22,669	19,432
Available-for-sale securities, gross unrealized (losses)	(636,894)	(1,127,037)
Available-for-sale securities, approximate fair value	46,094,888	47,008,188
Available-for-sale securities, amortized cost	$ 46,709,113	$ 48,115,793

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
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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