Note 19 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) $ in Thousands		Jun. 30, 2021 USD ($)		Dec. 31, 2020 USD ($)
Total risk-based capital, actual amount	[1]	$ 568,393		$ 470,648
Total risk-based capital, actual ratio	[1]	0.1280		0.1336
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 355,196		$ 281,887
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.0800		0.0800
Common Equity Tier 1 risk-based capital, actual amount		$ 523,433	[1]	$ 430,886
Common Equity Tier 1 risk-based capital, actual ratio		0.1179	[1]	0.1223
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 199,798	[1]	$ 158,556
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		0.0450	[1]	0.0450
Tier 1 risk-based capital, actual amount	[1]	$ 523,433	[2]	$ 430,886
Tier 1 risk-based capita, actual ratio	[1]	0.1179		0.1223
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 266,397		$ 211,407
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.0600		0.0600
Tier 1 risk-based capital, actual amount	[1]	$ 523,433	[2]	$ 430,886
Leverage, actual ratio	[2]	0.1026		0.0957
Leverage, minimum for adequately capitalized amount	[2]	$ 204,011		$ 180,123
Leverage, minimum for adequately capitalized ratio		0.0400	[1]	0.0400	[2]
Leverage, actual amount	[2]			$ 430,886
Subsidiaries [Member]
Total risk-based capital, actual amount	[1]	$ 551,391		$ 456,302
Total risk-based capital, actual ratio	[1]	0.1246		0.1299
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 354,061		$ 281,106
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.0800		0.0800
Total risk-based capital, minimum for well capitalized amount	[1]	$ 442,576		$ 351,383
Total risk-based capital, minimum for well capitalized ratio	[1]	0.100		0.1000
Common Equity Tier 1 risk-based capital, actual amount		$ 506,431	[1]	$ 416,540
Common Equity Tier 1 risk-based capital, actual ratio		0.1144	[1]	0.1185
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 199,159	[1]	$ 158,122
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		0.0450	[1]	0.0450
Common Equity Tier 1 risk-based capital, minimum for well capitalized amount		$ 287,674	[1]	$ 228,399
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio		0.065	[1]	0.0650
Tier 1 risk-based capital, actual amount	[1]	$ 506,431		$ 416,540
Tier 1 risk-based capita, actual ratio	[1]	0.1144		0.1185
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 265,545		$ 210,830
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.0600		0.0600
Tier 1 risk-based capital, minimum for well capitalized amount	[1]	$ 354,061		$ 281,106
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.080		0.0800
Tier 1 risk-based capital, actual amount	[1]	$ 506,431		$ 416,540
Leverage, actual ratio	[2]	0.0995		0.0926
Leverage, minimum for adequately capitalized amount	[2]	$ 203,510		$ 179,845
Leverage, minimum for adequately capitalized ratio	[2]	0.0400		0.0400
Leverage, actual amount	[2]	$ 506,431		$ 416,540
Leverage, minimum for well capitalized amount	[2]	$ 254,388		$ 224,807
Leverage, minimum for well capitalized ratio	[2]	0.050		0.0500

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

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