Note 2 - Investment Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Callable Securities [Member] | US States and Political Subdivisions Debt Securities [Member]
Amortized Cost	$ 178,052,716
Fair Value	180,307,064
US States and Political Subdivisions Debt Securities [Member] | Callable Securities [Member]
Amortized Cost	41,062,791
Fair Value	37,443,219
US States and Political Subdivisions Debt Securities [Member]
	310,444,343	$ 254,641,285
US Government-sponsored Enterprises Debt Securities [Member] | Callable Securities [Member]
Amortized Cost	11,042,867
Fair Value	11,073,088
Residential Mortgage Backed Securities [Member]
Amortized Cost	131,496,011
Fair Value	133,172,804
Other Securities [Member]
	1,050,000	1,050,000
Amortized Cost	2,002,113
Fair Value	2,491,866
Callable Securities [Member]
	52,105,658
	48,516,307
Due in one year or less	9,333,827
Due in one year or less	9,382,178
Due after one year through five years	30,899,427
Due after one year through five years	31,047,261
Due after five years	266,506,920
Due after five years	271,064,904
	306,740,174
	311,494,343	$ 255,691,285
Due in one year or less	2,345,063
Due in one year or less	2,347,195
Due after one year through five years	55,691,033
Due after one year through five years	56,456,647
Due after five years	62,818,130
Due after five years	63,721,569
	120,854,226
	122,525,411
	254,352,350
	$ 258,190,081