Note 12 - Regulatory Matters - Actual Capital Levels and Minimum Levels (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Consolidated Entities [Member]
Total capital, amount	$ 373,280	$ 354,278
Total capital, ratio	12.70%	13.10%
Total capital minimum required for capital adequacy, amount	$ 235,921	$ 215,819
Total capital minimum required for capital adequacy, ratio	8.00%	8.00%
Tier 1 capital, amount	$ 354,087	$ 336,316
Tier 1 capital, ratio	12.00%	12.50%
Tier 1 capital minimum required for capital adequacy, amount	$ 176,941	$ 161,864
Tier 1 capital minimum required for capital adequacy, ratio	6.00%	6.00%
Common equity tier 1, amount	$ 310,814	$ 293,555
Common equity tier 1, ratio	10.50%	10.90%
Common equity tier 1 minimum required for capital adequacy, amount	$ 132,706	$ 121,398
Common equity tier 1 capital minimum required for capital adequacy, ratio	4.50%	4.50%
Tier 1 capital, amount	$ 354,087	$ 336,316
Tier 1 capital to average assets, ratio	11.20%	11.20%
Tier 1 capital minimum required for capital adequacy, amount	$ 126,664	$ 120,486
Tier 1 capital to average assets minimum required for capital adequacy, ratio	4.00%	4.00%
Bank [Member]
Total capital, amount	$ 368,143	$ 353,243
Total capital, ratio	12.50%	13.10%
Total capital minimum required for capital adequacy, amount	$ 235,709	$ 215,605
Total capital minimum required for capital adequacy, ratio	8.00%	8.00%
Total capital to be well capitalized, amount	$ 294,636	$ 269,506
Total capital to be well capitalized, ratio	10.00%	10.00%
Tier 1 capital, amount	$ 348,949	$ 335,282
Tier 1 capital, ratio	11.80%	12.40%
Tier 1 capital minimum required for capital adequacy, amount	$ 176,782	$ 161,704
Tier 1 capital minimum required for capital adequacy, ratio	6.00%	6.00%
Tier 1 capital to be well capitalized, amount	$ 235,709	$ 215,605
Tier 1 capital to be well capitalized, ratio	8.00%	8.00%
Common equity tier 1, amount	$ 348,949	$ 335,282
Common equity tier 1, ratio	11.80%	12.40%
Common equity tier 1 minimum required for capital adequacy, amount	$ 132,587	$ 121,278
Common equity tier 1 capital minimum required for capital adequacy, ratio	4.50%	4.50%
Common equity tier 1 capital to be well capitalized, amount	$ 191,514	$ 175,179
Common equity tier 1 capital to be well capitalized, ratio	6.50%	6.50%
Tier 1 capital, amount	$ 348,949	$ 335,282
Tier 1 capital to average assets, ratio	11.00%	11.10%
Tier 1 capital minimum required for capital adequacy, amount	$ 126,583	$ 120,383
Tier 1 capital to average assets minimum required for capital adequacy, ratio	4.00%	4.00%
Tier 1 capital to be well capitalized, amount	$ 158,228	$ 150,479
Tier 1 capital to average assets to be well capitalized, ratio	5.00%	5.00%