Note 2 - Mergers and Acquisitions - Consideration Paid and Goodwill (Details) - USD ($)						12 Months Ended
		Jul. 01, 2018	Jun. 29, 2018	Oct. 01, 2017	Aug. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and due from banks						$ 4,650,731	$ 4,434,511	$ 10,094,645
Interest-bearing deposits at financial institutions						62,924,396	3,953,907	14,730,157
Securities						4,845,441	49,703,419	102,640,029
Loans/leases receivable, net						477,336,699	192,517,677	419,029,277
Bank-owned life insurance						7,091,883
Premises and equipment						6,091,978	4,808,343	20,684,880
Restricted investment securities						3,654,200	476,500	1,512,900
Core deposit intangible						10,063,660	2,698,301	6,352,653
Other assets						2,254,778	997,810	5,283,937
Total assets acquired						578,913,766	259,590,468	581,676,478
Federal funds sold								698,000
Other real estate owned								650,000
LIABILITIES
Deposits						439,579,328	212,467,514	486,298,262
Short-term borrowings						1,143,478	13,102,043
FHLB advances						74,539,463	4,108,027	20,368,877
Other borrowings						9,543,810
Junior subordinated debentures							3,857,275
Other liabilities						8,877,991	2,595,883	4,897,564
Total liabilities assumed						533,684,070	236,130,742	511,564,703
Net assets acquired						45,229,696	23,459,726	70,111,775
Consideration paid:
Cash	[1]					9,833,535	7,803,420	80,000,000
Common stock						81,637,166	30,879,485
Total consideration paid						94,970,701	38,682,905	80,000,000
Goodwill						77,831,902	$ 28,334,092	$ 13,110,913	$ 3,222,688
Guaranty Bank and Trust Company [Member]
ASSETS
Cash and due from banks				$ 4,434,511
Interest-bearing deposits at financial institutions				3,953,907
Securities				49,703,419
Loans/leases receivable, net				192,517,677
Premises and equipment				4,808,343
Restricted investment securities				476,500
Core deposit intangible				2,698,301
Other assets				997,810
Total assets acquired				259,590,468
LIABILITIES
Deposits				212,467,514
Short-term borrowings				13,102,043
FHLB advances				4,108,027
Junior subordinated debentures				3,857,275
Other liabilities				2,595,883
Total liabilities assumed				236,130,742
Net assets acquired				23,459,726
Consideration paid:
Cash				7,803,420
Common stock				30,879,485
Total consideration paid				38,682,905
Goodwill				$ 15,223,179
Community State Bank [Member]
ASSETS
Cash and due from banks					$ 10,094,645
Interest-bearing deposits at financial institutions					14,730,157
Securities					102,640,029
Loans/leases receivable, net					419,029,277
Premises and equipment					20,684,880	20,700,000
Restricted investment securities					1,512,900
Core deposit intangible					6,352,653
Other assets					5,283,937
Total assets acquired					581,676,478
Federal funds sold					698,000
Other real estate owned					650,000
LIABILITIES
Deposits					486,298,262
FHLB advances					20,368,877
Other liabilities					4,897,564
Total liabilities assumed					511,564,703
Net assets acquired					70,111,775
Consideration paid:
Cash					80,000,000	69,905,355
Total consideration paid					80,000,000
Goodwill					$ 9,888,225
Springfield Bancshares
ASSETS
Cash and due from banks		$ 4,586,326
Interest-bearing deposits at financial institutions		62,924,396
Securities		4,845,441
Loans/leases receivable, net		477,336,699
Bank-owned life insurance		7,091,883
Premises and equipment		6,091,978
Restricted investment securities		3,654,200
Core deposit intangible		8,208,728
Other assets		1,470,689
Total assets acquired		576,210,340
LIABILITIES
Deposits		439,579,328
Short-term borrowings		1,143,478
FHLB advances		74,539,463
Other borrowings		9,543,810
Other liabilities		8,408,463
Total liabilities assumed		533,214,542
Net assets acquired		42,995,798
Consideration paid:
Cash		8,333,535				$ 3,747,209
Common stock		80,637,194	$ 80,600,000
Total consideration paid		88,970,729
Goodwill		$ 45,974,931

[1] Net cash paid at closing totaled $1,435,595 for acquisition of the Bates Companies in 2018. Net cash paid at closing totaled $3,747,209 for merger with Springfield Bancshares in 2018. Net cash paid at closing totaled $3,368,909 for acquisition of Guaranty Bank in 2017. Net cash paid at closing totaled $69,905,355 for acquisition of CSB in 2016.