Note 2 - Sales/Mergers/Acquisitions - Consideration Paid and Goodwill (Details) - USD ($)				12 Months Ended
	Jul. 01, 2018	Jun. 29, 2018	Oct. 01, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2016
ASSETS
Cash and due from banks				$ 4,651,000	$ 4,435,000
Interest-bearing deposits at financial institutions				62,924,000	3,954,000
Securities				4,845,000	49,703,000
Loans/leases receivable, net				477,337,000	192,518,000
Bank-owned life insurance				7,092,000
Premises and equipment				6,092,000	4,808,000
Restricted investment securities				3,654,000	477,000
Other assets				2,255,000	998,000
Total assets sold				578,914,000	259,591,000
LIABILITIES
Deposits				439,579,000	212,468,000
FHLB advances				74,540,000	4,108,000
Other borrowings				9,544,000
Junior subordinated debentures					3,857,000
Other liabilities				8,878,000	2,596,000
Total liabilities assumed				533,684,000	236,131,000
Net assets acquired				45,230,000	23,460,000
Consideration paid:
Cash				9,834,000	7,803,000
Common stock				81,637,000	30,880,000
Total consideration paid				94,971,000	38,683,000
Goodwill				77,832,000	$ 28,334,000	$ 74,748,000	$ 13,111,000
Guaranty Bank and Trust Company [Member]
ASSETS
Cash and due from banks			$ 4,435,000
Interest-bearing deposits at financial institutions			3,954,000
Securities			49,703,000
Loans/leases receivable, net			192,518,000
Premises and equipment			4,808,000
Restricted investment securities			477,000
Other assets			998,000
Total assets sold			259,591,000
LIABILITIES
Deposits			212,468,000
Short-term borrowings			13,102,000
FHLB advances			4,108,000
Junior subordinated debentures			3,857,000
Other liabilities			2,596,000
Total liabilities assumed			236,131,000
Net assets acquired			23,460,000
Consideration paid:
Cash			7,803,000
Common stock			30,880,000
Total consideration paid			38,683,000
Goodwill			$ 15,223,000
Springfield Bancshares
ASSETS
Cash and due from banks	$ 4,586
Interest-bearing deposits at financial institutions	62,924
Securities	4,845
Loans/leases receivable, net	477,337
Bank-owned life insurance	7,092
Premises and equipment	6,092
Restricted investment securities	3,654
Other assets	1,471
Total assets sold	576,210
LIABILITIES
Deposits	439,579
Short-term borrowings	1,143
FHLB advances	74,539
Other borrowings	9,544
Other liabilities	8,409
Total liabilities assumed	533,214
Net assets acquired	42,996
Consideration paid:
Cash	8,334			$ 3,747,209
Common stock	80,637	$ 80,600,000
Total consideration paid	88,971
Goodwill	$ 45,975