Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans Past Due 90 Days or More and Impaired Loans (Details) - USD ($) $ in Thousands		6 Months Ended			12 Months Ended
		Jun. 30, 2021		Jun. 30, 2020	Dec. 31, 2020
Loans past due 90 days or more and still accruing		$ 28	[1]	$ 237	$ 17	[1]
Ratio of loans past due 90 days or more and still accruing to loans, net of unearned income and deferred fees and costs		0.00%		0.03%	0.00%
Accruing restructured loans		$ 3,011		$ 1,453	$ 1,410
Impaired loans:
Impaired loans with no valuation allowance		6,774	[2]	4,151	3,858	[2]
Impaired loans with a valuation allowance		0	[2]	1,076	1,045	[2]
Total impaired loans		6,774	[2]	5,227	4,903	[2]
Valuation allowance		0		(104)	(75)
Impaired loans, net of allowance		6,774		5,123	4,828
Average recorded investment in impaired loans(1)	[2]	6,796		5,263	5,093
Interest income recognized on impaired loans, after designation as impaired		$ 105		$ 29	$ 54

[1] Only classes with past-due or nonaccrual loans are shown.

[2] Recorded investment is net of charge-offs and interest paid while a loan is in nonaccrual status.