Note 2 - Investment Securities - Amortized Cost and Fair Value of Investment Securities (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Securities HTM:
Securities held to maturity, amortized cost	$ 323,981,227	$ 322,909,056
Securities held to maturity, gross unrealized gains	2,084,997	2,200,577
Securities held to maturity, gross unrealized (losses)	(2,629,646)	(4,694,734)
Securities held to maturity, fair value	323,436,578	320,414,899
Securities AFS:
Securities available for sale, amortized cost	260,367,974	253,609,401
Securities available for sale, gross unrealized gains	1,658,065	1,437,658
Securities available for sale, gross unrealized (losses)	(2,071,617)	(3,933,920)
Securities available for sale, fair value	259,954,422	251,113,139
US States and Political Subdivisions Debt Securities [Member]
Securities HTM:
Securities held to maturity, amortized cost	322,931,227	321,859,056
Securities held to maturity, gross unrealized gains	2,084,997	2,200,577
Securities held to maturity, gross unrealized (losses)	(2,629,646)	(4,694,734)
Securities held to maturity, fair value	322,386,578	319,364,899
Securities AFS:
Securities available for sale, amortized cost	56,621,412	52,816,541
Securities available for sale, gross unrealized gains	435,356	425,801
Securities available for sale, gross unrealized (losses)	(293,708)	(637,916)
Securities available for sale, fair value	56,763,060	52,604,426
Other Securities [Member]
Securities HTM:
Securities held to maturity, amortized cost	1,050,000	1,050,000
Securities held to maturity, gross unrealized gains
Securities held to maturity, gross unrealized (losses)
Securities held to maturity, fair value	1,050,000	1,050,000
Securities AFS:
Securities available for sale, amortized cost	4,077,128	4,046,332
Securities available for sale, gross unrealized gains	826,135	703,978
Securities available for sale, gross unrealized (losses)	(20,578)	(27,331)
Securities available for sale, fair value	4,882,685	4,722,979
US Government Agencies Debt Securities [Member]
Securities AFS:
Securities available for sale, amortized cost	39,340,306	46,281,306
Securities available for sale, gross unrealized gains	129,768	132,886
Securities available for sale, gross unrealized (losses)	(129,906)	(330,585)
Securities available for sale, fair value	39,340,168	46,083,607
Residential Mortgage Backed Securities [Member]
Securities AFS:
Securities available for sale, amortized cost	160,329,128	150,465,222
Securities available for sale, gross unrealized gains	266,806	174,993
Securities available for sale, gross unrealized (losses)	(1,627,425)	(2,938,088)
Securities available for sale, fair value	$ 158,968,509	$ 147,702,127

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)
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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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-Publisher FASB
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
-Paragraph 1
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Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

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Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

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