Note 2 - Securities - Securities in a Continuous Unrealized Loss Position (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Securities, continuous unrealized loss position, less than 12 months, fair value	$ 74,651,451	$ 47,314,541
Securities, continuous unrealized loss position, less than 12 months, unrealized losses	(2,108,360)	(727,804)
Securities, continuous unrealized loss position, 12 months or more, fair value	4,709,778	20,808,939
Securities, continuous unrealized loss position, 12 months or more, unrealized losses	(108,845)	(684,021)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	79,361,229	68,123,480
Securities, continuous unrealized loss position, unrealized losses	(2,217,205)	(1,411,825)
Securities, continuous unrealized loss position, less than 12 months, fair value	74,651,451	47,314,541
Securities, continuous unrealized loss position, fair value	79,361,229	68,123,480
US States and Political Subdivisions Debt Securities [Member]
Securities, continuous unrealized loss position, less than 12 months, fair value	33,084,816	6,167,019
Securities, continuous unrealized loss position, less than 12 months, unrealized losses	(1,082,021)	(70,266)
Securities, continuous unrealized loss position, 12 months or more, fair value	179,402	715,410
Securities, continuous unrealized loss position, 12 months or more, unrealized losses	(3,633)	(15,542)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	33,264,218	6,882,429
Securities, continuous unrealized loss position, unrealized losses	(1,085,654)	(85,808)
Securities, continuous unrealized loss position, less than 12 months, fair value	33,084,816	6,167,019
Securities, continuous unrealized loss position, fair value	33,264,218	6,882,429
Equity Securities [Member]
Securities, continuous unrealized loss position, less than 12 months, fair value		0
Securities, continuous unrealized loss position, less than 12 months, unrealized losses		0
Securities, continuous unrealized loss position, 12 months or more, fair value		35,151
Securities, continuous unrealized loss position, 12 months or more, unrealized losses		(12,776)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		35,151
Securities, continuous unrealized loss position, unrealized losses		(12,776)
Securities, continuous unrealized loss position, less than 12 months, fair value		0
Securities, continuous unrealized loss position, fair value		35,151
Corporate Debt Securities [Member]
Securities, continuous unrealized loss position, less than 12 months, fair value	1,996,172	1,675,500
Securities, continuous unrealized loss position, less than 12 months, unrealized losses	(3,828)	(79,708)
Securities, continuous unrealized loss position, 12 months or more, fair value	881,100	2,138,200
Securities, continuous unrealized loss position, 12 months or more, unrealized losses	(686)	(72,311)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,877,272	3,813,700
Securities, continuous unrealized loss position, unrealized losses	(4,514)	(152,019)
Securities, continuous unrealized loss position, less than 12 months, fair value	1,996,172	1,675,500
Securities, continuous unrealized loss position, fair value	2,877,272	3,813,700
US Government Agencies Debt Securities [Member]
Securities, continuous unrealized loss position, less than 12 months, fair value		6,399,920
Securities, continuous unrealized loss position, less than 12 months, unrealized losses		(83,965)
Securities, continuous unrealized loss position, 12 months or more, fair value		1,996,864
Securities, continuous unrealized loss position, 12 months or more, unrealized losses		(53,136)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		8,396,784
Securities, continuous unrealized loss position, unrealized losses		(137,101)
Securities, continuous unrealized loss position, less than 12 months, fair value		6,399,920
Securities, continuous unrealized loss position, fair value		8,396,784
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities, continuous unrealized loss position, less than 12 months, fair value	39,570,463	33,072,102
Securities, continuous unrealized loss position, less than 12 months, unrealized losses	(1,022,511)	(493,865)
Securities, continuous unrealized loss position, 12 months or more, fair value	3,649,276	15,923,314
Securities, continuous unrealized loss position, 12 months or more, unrealized losses	(104,526)	(530,256)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	43,219,739	48,995,416
Securities, continuous unrealized loss position, unrealized losses	(1,127,037)	(1,024,121)
Securities, continuous unrealized loss position, less than 12 months, fair value	39,570,463	33,072,102
Securities, continuous unrealized loss position, fair value	$ 43,219,739	$ 48,995,416