Note 2 - Investment Securities - Securities in a Continuous Unrealized Loss Position (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Securities available for sale, less than 12 months, fair value	$ 155,308,949	$ 180,624,957
Securities available for sale, less than 12 months, gross unrealized losses	(1,575,708)	(3,545,097)
Securities available for sale, 12 months or more, fair value	25,521,304	13,274,726
Securities available for sale, 12 months or more, gross unrealized losses	(495,909)	(388,823)
Securities available for sale, fair value	180,830,253	193,899,683
Securities available for sale, gross unrealized losses	(2,071,617)	(3,933,920)
US States and Political Subdivisions Debt Securities [Member]
Securities held to maturity, less than 12 months, fair value	17,779,999	122,271,533
Securities held to maturity, less than 12 months, gross unrealized losses	(254,147)	(4,076,647)
Securities held to maturity, 12 months or more, fair value	68,663,362	13,010,803
Securities held to maturity, 12 months or more, gross unrealized losses	(2,375,499)	(618,087)
Securities held to maturity, fair value	86,443,361	135,282,336
Securities held to maturity, gross unrealized losses	(2,629,646)	(4,694,734)
Securities available for sale, less than 12 months, fair value	18,776,501	34,152,822
Securities available for sale, less than 12 months, gross unrealized losses	(169,253)	(618,462)
Securities available for sale, 12 months or more, fair value	12,872,616	338,099
Securities available for sale, 12 months or more, gross unrealized losses	(124,455)	(19,454)
Securities available for sale, fair value	31,649,117	34,490,921
Securities available for sale, gross unrealized losses	(293,708)	(637,916)
US Government Agencies Debt Securities [Member]
Securities available for sale, less than 12 months, fair value	23,607,646	21,788,139
Securities available for sale, less than 12 months, gross unrealized losses	(129,906)	(257,640)
Securities available for sale, 12 months or more, fair value		5,499,012
Securities available for sale, 12 months or more, gross unrealized losses		(72,945)
Securities available for sale, fair value	23,607,646	27,287,151
Securities available for sale, gross unrealized losses	(129,906)	(330,585)
Residential Mortgage Backed Securities [Member]
Securities available for sale, less than 12 months, fair value	111,996,030	121,506,582
Securities available for sale, less than 12 months, gross unrealized losses	(1,255,971)	(2,641,664)
Securities available for sale, 12 months or more, fair value	12,648,688	7,437,615
Securities available for sale, 12 months or more, gross unrealized losses	(371,454)	(296,424)
Securities available for sale, fair value	124,644,718	128,944,197
Securities available for sale, gross unrealized losses	(1,627,425)	(2,938,088)
Other Securities [Member]
Securities available for sale, less than 12 months, fair value	928,772	3,177,414
Securities available for sale, less than 12 months, gross unrealized losses	(20,578)	(27,331)
Securities available for sale, fair value	928,772	3,177,414
Securities available for sale, gross unrealized losses	$ (20,578)	$ (27,331)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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