Note 1 - Accounting Policies (Details Textual) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Number of Banking Offices	26
Financing Receivable, Deferred Payments	$ 19.3	$ 30.0
Financing Receivable, Deferred Payments, Percentage of Portfolio	1.00%	1.50%
Financing Receivable, Second Deferrals	$ 16.4
Financing Receivable, Paycheck Protection Program Loans Originated Through the CARES Act	$ 183.8	$ 211.3
SBA CARES Act Paycheck Protection Program [Member]
Financing Receivable, Applications Approved	805
Financing Receivable, Applications Approved, Amount	$ 80.7
Financing Receivable, Deferred Payments, Forgiven Amount	$ 105.1	$ 56.4