Note 23 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Total risk-based capital, actual amount	[1]	$ 338,525	$ 307,666
Total risk-based capital, actual ratio	[1]	13.04%	13.31%
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 207,684	$ 184,923
Total risk-based capital, minimum for adequately capitalized ratio	[1]	8.00%	8.00%
Common Equity Tier 1 risk-based capital, actual amount		$ 314,147	$ 284,793
Common Equity Tier 1 risk-based capital, actual ratio		12.10%	12.32%
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 116,832	$ 104,023
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		4.50%	4.50%
Tier 1 risk-based capital, actual amount	[1]	$ 314,147	$ 284,793
Tier 1 risk-based capital, actual ratio	[1]	12.10%	12.32%
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 155,775	$ 138,698
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	6.00%	6.00%
Leverage, actual amount	[2]	$ 314,147	$ 284,793
Leverage, actual ratio	[2]	10.54%	10.53%
Leverage, minimum for adequately capitalized amount	[2]	$ 119,221	$ 108,183
Leverage, minimum for adequately capitalized ratio	[2]	4.00%	4.00%
Subsidiaries [Member]
Total risk-based capital, actual amount	[1]	$ 325,630	$ 298,129
Total risk-based capital, actual ratio	[1]	12.57%	12.91%
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 207,243	$ 184,743
Total risk-based capital, minimum for adequately capitalized ratio	[1]	8.00%	8.00%
Total risk-based capital, minimum for well capitalized amount	[1]	$ 259,053	$ 230,929
Total risk-based capital, minimum for well capitalized ratio	[1]	10.00%	10.00%
Common Equity Tier 1 risk-based capital, actual amount		$ 301,252	$ 275,256
Common Equity Tier 1 risk-based capital, actual ratio		11.63%	11.92%
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 116,564	$ 103,914
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		4.50%	4.50%
Common Equity Tier 1 risk-based capital, minimum for well capitalized amount		$ 155,418	$ 138,552
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio		6.00%	6.00%
Tier 1 risk-based capital, actual amount	[1]	$ 301,252	$ 275,256
Tier 1 risk-based capital, actual ratio	[1]	11.63%	11.92%
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 155,418	$ 138,552
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	6.00%	6.00%
Tier 1 risk-based capital, minimum for well capitalized amount	[1]	$ 155,418	$ 138,552
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	6.00%	6.00%
Leverage, actual amount	[2]	$ 301,252	$ 275,256
Leverage, actual ratio	[2]	10.11%	10.19%
Leverage, minimum for adequately capitalized amount	[2]	$ 119,190	$ 108,049
Leverage, minimum for adequately capitalized ratio	[2]	4.00%	4.00%
Leverage, minimum for well capitalized amount	[2]	$ 148,987	$ 135,062
Leverage, minimum for well capitalized ratio	[2]	5.00%	5.00%

[1] Ratio became effective January 2015.

[2] Ratio is computed in relation to average assets.