Note 2 - Mergers and Acquisitions - Changes in Accretable Yield (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Balance at the beginning of the period	$ (5,193,472)	$ (5,409,331)	$ (6,471,207)	$ (9,309,920)
Discount added at acquisition	(8,093,305)		(8,093,305)
Accretion recognized	1,848,262	683,705	3,125,997	4,584,294
Balance at the end of the period	(12,330,084)	(4,725,626)	(12,330,084)	(4,725,626)
Performing Loans
Balance at the beginning of the period	(5,051,424)	(5,325,471)	(6,280,075)	(9,115,614)
Discount added at acquisition	(7,799,860)		(7,799,860)
Accretion recognized	1,579,568	658,547	2,808,219	4,448,690
Balance at the end of the period	(11,271,716)	(4,666,924)	(11,271,716)	(4,666,924)
Springfield Bancshares
Discount added at acquisition	(8,093,305)
Reclassification of nonaccretable discount to accretable	(891,569)
Accretion recognized	1,214,444
Balance at the end of the period	(7,770,430)		(7,770,430)
Springfield Bancshares | Performing Loans
Discount added at acquisition	(7,799,860)
Accretion recognized	951,592
Balance at the end of the period	(6,848,268)		(6,848,268)
PCI Loans
Balance at the beginning of the period	(142,048)	(83,860)	(191,132)	(194,306)
Discount added at acquisition	(293,445)		(293,445)
Accretion recognized	268,694	25,158	317,778	135,604
Balance at the end of the period	(1,058,368)	$ (58,702)	(1,058,368)	$ (58,702)
PCI Loans | Springfield Bancshares
Discount added at acquisition	(293,445)
Reclassification of nonaccretable discount to accretable	(891,569)
Accretion recognized	262,852
Balance at the end of the period	$ (922,162)		$ (922,162)