Note 12 - Regulatory Matters - Actual Capital Levels and Minimum Levels (Details) $ in Thousands	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
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	0.070
Consolidated Entities [Member]
Total capital, amount	$ 484,594	$ 468,113
Total capital, ratio	0.125	0.138
Total capital minimum required for capital adequacy, amount	$ 310,930	$ 271,325
Total capital minimum required for capital adequacy, ratio	0.080	0.080
Tier 1 capital, amount	$ 448,010	$ 430,146
Tier 1 capital, ratio	0.115	0.127
Tier 1 capital minimum required for capital adequacy, amount	$ 233,197	$ 203,494
Tier 1 capital minimum required for capital adequacy, ratio	0.060	0.060
Common equity tier 1, amount	$ 402,010	$ 384,658
Common equity tier 1, ratio	0.103	0.113
Common equity tier 1 minimum required for capital adequacy, amount	$ 174,898	$ 152,621
Common equity tier 1 capital minimum required for capital adequacy, ratio	0.045	0.045
Tier 1 capital to average assets, amount	$ 448,010	$ 430,146
Tier 1 capital to average assets, ratio	0.093	0.098
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 192,098	$ 176,053
Tier 1 capital to average assets minimum required for capital adequacy, ratio	0.040	0.040
Bank [Member]
Total capital, amount	$ 482,625	$ 457,203
Total capital, ratio	0.124	0.135
Total capital minimum required for capital adequacy, amount	$ 310,796	$ 271,196
Total capital minimum required for capital adequacy, ratio	0.080	0.080
Total capital to be well capitalized, amount	$ 388,495	$ 338,995
Total capital to be well capitalized, ratio	0.100	0.100
Tier 1 capital, amount	$ 445,202	$ 419,236
Tier 1 capital, ratio	0.115	0.124
Tier 1 capital minimum required for capital adequacy, amount	$ 233,097	$ 203,397
Tier 1 capital minimum required for capital adequacy, ratio	0.060	0.060
Tier 1 capital to be well capitalized, amount	$ 310,796	$ 271,196
Tier 1 capital to be well capitalized, ratio	0.080	0.080
Common equity tier 1, amount	$ 445,202	$ 419,236
Common equity tier 1, ratio	0.115	0.124
Common equity tier 1 minimum required for capital adequacy, amount	$ 174,823	$ 152,548
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	$ 252,522	$ 220,347
Common equity tier 1 capital to be well capitalized, ratio	0.065	0.065
Tier 1 capital to average assets, amount	$ 445,202	$ 419,236
Tier 1 capital to average assets, ratio	0.093	0.095
Tier 1 capital to average assets, minimum required for capital adequacy, amount	$ 192,031	$ 175,999
Tier 1 capital to average assets minimum required for capital adequacy, ratio	0.040	0.040
Tier 1 capital to average assets to be well capitalized, amount	$ 240,039	$ 219,999
Tier 1 capital to average assets to be well capitalized, ratio	0.050	0.050