Note 12 - Regulatory Matters - Actual Capital Levels and Minimum Levels (Details) $ in Thousands	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total capital minimum required for capital adequacy, ratio	0.105
Tier 1 capital minimum required for capital adequacy, ratio	0.085
Common equity tier 1 capital minimum required for capital adequacy, ratio	0.07
Consolidated Entities [Member]
Total capital, amount	$ 692,252	$ 634,729
Total capital, ratio	0.141	0.14
Total capital minimum required for capital adequacy, amount	$ 392,930	$ 362,675
Total capital minimum required for capital adequacy, ratio	0.08	0.08
Tier 1 capital, amount	$ 554,634	$ 503,855
Tier 1 capital, ratio	0.113	0.111
Tier 1 capital minimum required for capital adequacy, amount	$ 294,697	$ 272,007
Tier 1 capital minimum required for capital adequacy, ratio	0.06	0.06
Common equity tier 1, amount	$ 507,235	$ 456,970
Common equity tier 1, ratio	0.103	0.101
Common equity tier 1 minimum required for capital adequacy, amount	$ 221,023	$ 204,005
Common equity tier 1 capital minimum required for capital adequacy, ratio	0.045	0.045
Tier 1 capital to average assets, amount	$ 554,634	$ 503,855
Tier 1 capital to average assets, ratio	0.106	0.101
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 208,523	$ 199,647
Tier 1 capital to average assets minimum required for capital adequacy, ratio	0.04	0.04
Bank [Member]
Total capital, amount	$ 675,953	$ 618,709
Total capital, ratio	0.138	0.137
Total capital minimum required for capital adequacy, amount	$ 392,745	$ 362,490
Total capital minimum required for capital adequacy, ratio	0.08	0.08
Total capital to be well capitalized, amount	$ 490,931	$ 453,112
Total capital to be well capitalized, ratio	0.10	0.10
Tier 1 capital, amount	$ 627,220	$ 576,463
Tier 1 capital, ratio	0.128	0.127
Tier 1 capital minimum required for capital adequacy, amount	$ 294,559	$ 271,868
Tier 1 capital minimum required for capital adequacy, ratio	0.06	0.06
Tier 1 capital to be well capitalized, amount	$ 392,745	$ 362,490
Tier 1 capital to be well capitalized, ratio	0.08	0.08
Common equity tier 1, amount	$ 627,220	$ 576,463
Common equity tier 1, ratio	0.128	0.127
Common equity tier 1 minimum required for capital adequacy, amount	$ 220,919	$ 203,901
Common equity tier 1 capital minimum required for capital adequacy, ratio	0.045	0.045
Common equity tier 1 capital to be well capitalized, amount	$ 319,105	$ 294,523
Common equity tier 1 capital to be well capitalized, ratio	0.065	0.065
Tier 1 capital to average assets, amount	$ 627,220	$ 576,463
Tier 1 capital to average assets, ratio	0.12	0.116
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 208,432	$ 199,563
Tier 1 capital to average assets minimum required for capital adequacy, ratio	0.04	0.04
Tier 1 capital to average assets to be well capitalized, amount	$ 260,540	$ 249,453
Tier 1 capital to average assets to be well capitalized, ratio	0.05	0.05