Note 11 - Regulatory Capital Requirements - Actual and Required Capital Amount and Ratio (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2015
Common equity tier 1 capital, actual amount	$ 196,319		$ 159,842
Common equity tier 1 capital, actual ratio	0.1379	0.1340
Common equity tier 1 capital, for capital adequacy purposes, amount	$ 64,081	$ 53,678
Common equity tier 1 capital, for capital adequacy purposes, ratio	0.0450	0.0450		0.045
Common equity tier 1 capital, well capitalized, amount	$ 92,562	$ 77,535
Common equity tier 1 capital, well capitalized, ratio	0.0650	0.0650
Tier 1 risk-based capital, actual amount	$ 196,319		159,842
Tier 1 risk-based capital, actual ratio	0.1379	0.1340
Tier 1 risk-based capital, for capital adequacy purposes, amount	$ 85,442	$ 71,571
Tier 1 risk-based capital, for capital adequacy purposes, ratio	0.0600	0.0600		0.060
Tier 1 risk-based capital, well capitalized, amount	$ 113,923	$ 95,427
Tier 1 risk-based capital, well capitalized, ratio	0.0800	0.0800
Total risk-based capital, actual amount	$ 211,828		173,998
Total risk-based capital, actual ratio	0.1488	0.1459
Total risk-based capital, for capital adequacy purposes, amount	$ 113,923	$ 95,427
Total risk-based capital, for capital adequacy purposes, ratio	0.0800	0.0800		0.080
Total risk-based capital, well capitalized, amount	$ 142,403	$ 119,284
Total risk-based capital, well capitalized, ratio	0.1000	0.1000
Tier 1 leverage capital, actual amount	$ 196,319		$ 159,842
Tier 1 leverage capital, actual ratio	0.1056	0.1028
Tier 1 leverage capital, for capital adequacy purposes, amount	$ 74,362	$ 62,194
Tier 1 leverage capital, for capital adequacy purposes, ratio	0.0400	0.0400		0.040
Tier 1 leverage capital, well capitalized, amount	$ 92,953	$ 77,742
Tier 1 leverage capital, well capitalized, ratio	0.0500	0.0500