Note 12 - Regulatory Matters - Actual Capital Levels and Minimum Levels (Details) $ in Thousands	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
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	$ 729,410	$ 710,905
Total capital, ratio	0.141	0.137
Total capital minimum required for capital adequacy, amount	$ 415,299	$ 415,841
Total capital minimum required for capital adequacy, ratio	0.08	0.08
Tier 1 capital, amount	$ 587,888	$ 570,730
Tier 1 capital, ratio	0.113	0.11
Tier 1 capital minimum required for capital adequacy, amount	$ 311,474	$ 311,881
Tier 1 capital minimum required for capital adequacy, ratio	0.06	0.06
Common equity tier 1, amount	$ 540,147	$ 523,160
Common equity tier 1, ratio	0.104	0.101
Common equity tier 1 minimum required for capital adequacy, amount	$ 233,606	$ 233,911
Common equity tier 1 capital minimum required for capital adequacy, ratio	0.045	0.045
Tier 1 capital to average assets, amount	$ 587,888	$ 570,730
Tier 1 capital to average assets, ratio	0.109	0.108
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 216,108	$ 210,527
Tier 1 capital to average assets minimum required for capital adequacy, ratio	0.04	0.04
Bank [Member]
Total capital, amount	$ 712,688	$ 694,431
Total capital, ratio	0.138	0.134
Total capital minimum required for capital adequacy, amount	$ 413,264	$ 414,019
Total capital minimum required for capital adequacy, ratio	0.08	0.08
Total capital to be well capitalized, amount	$ 516,580	$ 517,524
Total capital to be well capitalized, ratio	0.10	0.10
Tier 1 capital, amount	$ 660,223	$ 643,227
Tier 1 capital, ratio	0.128	0.124
Tier 1 capital minimum required for capital adequacy, amount	$ 309,948	$ 310,514
Tier 1 capital minimum required for capital adequacy, ratio	0.06	0.06
Tier 1 capital to be well capitalized, amount	$ 413,264	$ 414,019
Tier 1 capital to be well capitalized, ratio	0.08	0.08
Common equity tier 1, amount	$ 660,223	$ 643,227
Common equity tier 1, ratio	0.128	0.124
Common equity tier 1 minimum required for capital adequacy, amount	$ 232,461	$ 232,886
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	$ 335,777	$ 336,391
Common equity tier 1 capital to be well capitalized, ratio	0.065	0.065
Tier 1 capital to average assets, amount	$ 660,223	$ 643,227
Tier 1 capital to average assets, ratio	0.123	0.122
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 215,092	$ 210,427
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	$ 268,865	$ 263,034
Tier 1 capital to average assets to be well capitalized, ratio	0.05	0.05