Note 19 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Total risk-based capital
Total risk-based capital, actual amount	[1]	$ 358,610	$ 338,525
Total risk-based capital, actual ratio	[1]	13.64%	13.04%
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 210,328	$ 207,684
Total risk-based capital, minimum for adequately capitalized ratio	[1]	8.00%	8.00%
Total risk-based capital, minimum for well capitalized amount	[1],[2]
Total risk-based capital, minimum for well capitalized ratio	[1],[2]
Common equity tier 1 risk-based capital
Common Equity Tier 1 risk-based capital, actual amount		$ 333,312	$ 314,147
Common Equity Tier 1 risk-based capital, actual ratio		12.67%	12.10%
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 118,382	$ 116,832
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	[2]
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio	[2]
Tier 1 risk-based capital
Tier 1 risk-based capital, actual amount	[1]	$ 333,312	$ 314,147
Tier 1 risk-based capital, actual ratio	[1]	12.67%	12.10%
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 157,843	$ 155,775
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],[2]
Tier 1 risk-based capital, minimum for well capitalized ratio	[1],[2]
Leverage
Leverage, actual amount	[3]	$ 333,312	$ 314,147
Leverage, actual ratio	[3]	11.02%	10.54%
Leverage, minimum for adequately capitalized amount	[3]	$ 120,984	$ 119,221
Leverage, minimum for adequately capitalized ratio	[3]	4.00%	4.00%
Leverage, minimum for well capitalized amount	[2],[3]
Leverage, minimum for well capitalized ratio	[2],[3]
Subsidiaries [Member]
Total risk-based capital
Total risk-based capital, actual amount	[1]	$ 346,040	$ 325,630
Total risk-based capital, actual ratio	[1]	13.20%	12.57%
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 209,721	$ 207,243
Total risk-based capital, minimum for adequately capitalized ratio	[1]	8.00%	8.00%
Total risk-based capital, minimum for well capitalized amount	[1]	$ 262,152	$ 259,053
Total risk-based capital, minimum for well capitalized ratio	[1]	10.00%	10.00%
Common equity tier 1 risk-based capital
Common Equity Tier 1 risk-based capital, actual amount		$ 320,742	$ 301,252
Common Equity Tier 1 risk-based capital, actual ratio		12.23%	11.63%
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 118,016	$ 116,564
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		$ 157,355	$ 155,418
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio		6.00%	6.00%
Tier 1 risk-based capital
Tier 1 risk-based capital, actual amount	[1]	$ 320,742	$ 301,252
Tier 1 risk-based capital, actual ratio	[1]	12.23%	11.63%
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 157,355	$ 155,418
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]	$ 157,355	$ 155,418
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	6.00%	6.00%
Leverage
Leverage, actual amount	[3]	$ 320,742	$ 301,252
Leverage, actual ratio	[3]	10.61%	10.11%
Leverage, minimum for adequately capitalized amount	[3]	$ 120,921	$ 119,190
Leverage, minimum for adequately capitalized ratio	[3]	4.00%	4.00%
Leverage, minimum for well capitalized amount	[3]	$ 151,151	$ 148,987
Leverage, minimum for well capitalized ratio	[3]	5.00%	5.00%

[1] Ratio is computed in relation to risk-weighted assets.

[2] Not applicable. Regulatory framework does not define well capitalized for holding companies.

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