Note 12 - Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Provision at federal statutory tax rate													$ 2,872	$ 2,486	$ 2,588
State income tax-net of federal tax benefit													266	85	121
Tax-exempt interest income													(608)	(476)	(379)
Bank-owned life insurance income													(46)	(44)	(44)
Captive insurance net premiums													(200)	(200)	(209)
Investment in tax credit entities													(58)	(117)	(114)
Other													14	(42)	24
Totals	$ 529	$ 596	$ 497	$ 618	$ 485	$ 413	$ 405	$ 389	$ 440	$ 537	$ 568	$ 442	$ 2,240	$ 1,692	$ 1,987
Effective tax rate													16.40%	14.30%	16.10%