Note 2 - Acquisitions - Consideration Paid and Goodwill (Details) - USD ($)				12 Months Ended
		Oct. 01, 2017	Aug. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and due from banks	[1]			$ 4,434,511	$ 10,094,645
Interest-bearing deposits at financial institutions				3,953,907	14,730,157
Securities				49,703,419	102,640,029
Loans/leases receivable, net				192,517,677	419,029,277
Premises and equipment				4,808,343	20,684,880
Restricted investment securities				476,500	1,512,900
Core deposit intangible				2,698,301	6,352,653
Other assets				997,810	5,283,937
Total assets acquired			$ 581,000,000	259,590,468	581,676,478
Federal funds sold					698,000
Other real estate owned					650,000
LIABILITIES
Deposits				212,467,514	486,298,262
Short-term borrowings				13,102,043
FHLB advances				4,108,027	20,368,877
Junior subordinated debentures				3,857,275
Other liabilities				2,595,883	4,897,564
Total liabilities assumed				236,130,742	511,564,703
Net assets acquired				23,459,726	70,111,775
Consideration paid:
Cash	[2]			7,803,420	80,000,000
Common stock				30,879,485
Total consideration paid				38,682,905	80,000,000
Goodwill				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		$ 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
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
Total consideration paid			80,000,000
Goodwill			$ 9,888,225

[1] Net cash paid at closing totaled $69,905,355

[2] Net cash paid at closing totaled $69,905,355 for acquisition of CSB in 2016.