Note 2 - INVESTMENT SECURITIES - Activity in Allowance for Credit Losses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Provision for credit loss expense	$ (9)
Balance, ending	174
Accounting Standards Update 2016-13
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Balance, ending	183
Municipal securities.
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Provision for credit loss expense	(9)
Balance, ending	173
Municipal securities. | Accounting Standards Update 2016-13
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Balance, ending	182
Other Securities
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Balance, ending	1
Other Securities | Accounting Standards Update 2016-13
Debt Securities, Held-to-maturity, Allowance for Credit Loss [Roll Forward]
Balance, ending	$ 1