Note 2 - Investment Securities - Amortized Cost and Fair Value of Investment Securities (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Securities held to maturity, at amortized cost	$ 378,584,337	$ 379,474,205
Securities held to maturity, gross unrealized gains	2,244,218	2,763,718
Securities held to maturity, gross unrealized (losses)	(5,035,872)	(2,488,119)
HTM	375,792,683	379,749,804
Securities available for sale, amortized cost	266,162,141	274,058,995
Securities available for sale, gross unrealized gains	351,908	1,749,323
Securities available for sale, gross unrealized (losses)	(6,869,109)	(2,900,411)
AFS	259,644,940	272,907,907
US States and Political Subdivisions Debt Securities [Member]
Securities held to maturity, at amortized cost	377,534,337	378,424,205
Securities held to maturity, gross unrealized gains	2,244,218	2,763,718
Securities held to maturity, gross unrealized (losses)	(5,024,697)	(2,488,119)
HTM	374,753,858	378,699,804
Securities available for sale, amortized cost	61,862,665	66,176,364
Securities available for sale, gross unrealized gains	238,583	660,232
Securities available for sale, gross unrealized (losses)	(899,444)	(211,100)
AFS	61,201,804	66,625,496
Other Securities [Member]
Securities held to maturity, at amortized cost	1,050,000	1,050,000
Securities held to maturity, gross unrealized gains
Securities held to maturity, gross unrealized (losses)	(11,175)
HTM	1,038,825	1,050,000
Securities available for sale, amortized cost	4,254,716	4,014,004
Securities available for sale, gross unrealized gains	31,867	896,384
Securities available for sale, gross unrealized (losses)		(25,815)
AFS	4,286,583	4,884,573
US Government Agencies Debt Securities [Member]
Securities available for sale, amortized cost	37,591,155	38,409,157
Securities available for sale, gross unrealized gains	21,236	37,344
Securities available for sale, gross unrealized (losses)	(744,881)	(349,967)
AFS	36,867,510	38,096,534
Residential Mortgage Backed Securities [Member]
Securities available for sale, amortized cost	162,453,605	165,459,470
Securities available for sale, gross unrealized gains	60,222	155,363
Securities available for sale, gross unrealized (losses)	(5,224,784)	(2,313,529)
AFS	$ 157,289,043	$ 163,301,304

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

No definition available.

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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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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.

+ References

No definition available.

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity).

+ References

No definition available.

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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