Note 2 - Mergers and Acquisitions - Changes in Accretable Yield (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance at the beginning of the period	$ (6,471,207)	$ (9,309,920)
Discount added at acquisition	(8,093,305)	(2,443,891)	$ (12,193,588)
Accretion recognized	5,132,180	5,282,604	2,883,668
Balance at the end of the period	(10,323,901)	(6,471,207)	(9,309,920)
Performing Loans
Balance at the beginning of the period	(6,280,075)	(9,115,614)
Discount added at acquisition	(7,799,860)	(2,223,989)	(11,916,009)
Accretion recognized	4,423,401	5,059,528	2,800,395
Balance at the end of the period	(9,656,534)	(6,280,075)	(9,115,614)
Guaranty Bank and Trust Company [Member]
Balance at the beginning of the period	(2,362,985)
Discount added at acquisition		(2,443,891)
Accretion recognized	742,338	80,906
Balance at the end of the period	(1,620,647)	(2,362,985)
Guaranty Bank and Trust Company [Member] | Performing Loans
Balance at the beginning of the period	(2,197,153)
Discount added at acquisition		(2,223,989)
Accretion recognized	584,563	26,836
Balance at the end of the period	(1,612,590)	(2,197,153)
Community State Bank [Member]
Balance at the beginning of the period	(4,108,222)	(9,309,920)
Discount added at acquisition			(12,193,588)
Accretion recognized	1,913,343	5,201,698	2,883,668
Balance at the end of the period	(2,194,879)	(4,108,222)	(9,309,920)
Community State Bank [Member] | Performing Loans
Balance at the beginning of the period	(4,082,922)	(9,115,614)
Discount added at acquisition			(11,916,009)
Accretion recognized	1,888,043	5,032,692	2,800,395
Balance at the end of the period	(2,194,879)	(4,082,922)	(9,115,614)
Springfield Bancshares
Discount added at acquisition	(8,093,305)
Reclassification of nonaccretable discount to accretable	(891,569)
Accretion recognized	2,476,499
Balance at the end of the period	(6,508,375)
Springfield Bancshares | Performing Loans
Discount added at acquisition	(7,799,860)
Accretion recognized	1,950,795
Balance at the end of the period	(5,849,065)
PCI Loans
Balance at the beginning of the period	(191,132)	(194,306)
Discount added at acquisition	(293,445)	(219,902)	(277,579)
Accretion recognized	708,779	223,076	83,273
Balance at the end of the period	(667,367)	(191,132)	(194,306)
PCI Loans | Guaranty Bank and Trust Company [Member]
Balance at the beginning of the period	(165,832)
Discount added at acquisition		(219,902)
Accretion recognized	157,775	54,070
Balance at the end of the period	(8,057)	(165,832)
PCI Loans | Community State Bank [Member]
Balance at the beginning of the period	(25,300)	(194,306)
Discount added at acquisition			(277,579)
Accretion recognized	25,300	169,006	83,273
Balance at the end of the period		$ (25,300)	$ (194,306)
PCI Loans | Springfield Bancshares
Discount added at acquisition	(293,445)
Reclassification of nonaccretable discount to accretable	(891,569)
Accretion recognized	525,704
Balance at the end of the period	$ (659,310)