Note 21 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) $ in Thousands		Jun. 30, 2023 USD ($)		Dec. 31, 2022 USD ($)
Total risk-based capital, actual amount	[1]	$ 810,283		$ 762,956
Total risk-based capital, actual ratio	[1]	0.1278		0.1254
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 507,231		$ 486,841
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.0800		0.0800
Common Equity Tier 1 risk-based capital, actual amount		$ 710,237	[1]	$ 672,045
Common Equity Tier 1 risk-based capital, actual ratio		0.1120	[1]	0.1104
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 285,318	[1]	$ 273,848
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]	$ 736,237		$ 698,045
Tier 1 risk-based capita, actual ratio	[1]	0.1161		0.1147
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 380,424		$ 365,131
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.0600		0.0600
Leverage, actual ratio		0.0983		0.0933
Leverage, minimum for adequately capitalized amount		$ 299,726		$ 299,329
Leverage, minimum for adequately capitalized ratio		0.0400	[1]	0.0400
Leverage, actual amount				$ 698,045
Subsidiaries [Member]
Total risk-based capital, actual amount	[1]	$ 785,543		$ 732,688
Total risk-based capital, actual ratio	[1]	0.1243		0.1208
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 505,231		$ 485,314
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.0800		0.0800
Total risk-based capital, minimum for well capitalized amount	[1]	$ 631,914		$ 606,643
Total risk-based capital, minimum for well capitalized ratio	[1]	0.100		0.1000
Common Equity Tier 1 risk-based capital, actual amount		$ 711,497	[1]	$ 667,777
Common Equity Tier 1 risk-based capital, actual ratio		0.1126	[1]	0.1101
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 284,361	[1]	$ 272,989
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		$ 410,744	[1]	$ 394,318
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]	$ 711,497		$ 667,777
Tier 1 risk-based capita, actual ratio	[1]	0.1126		0.1101
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 379,148		$ 363,986
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]	$ 505,531		$ 485,314
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.080		0.0800
Leverage, actual ratio		0.0951		0.0895
Leverage, minimum for adequately capitalized amount		$ 299,269		$ 298,600
Leverage, minimum for adequately capitalized ratio		0.0400		0.0400
Leverage, actual amount		$ 711,497		$ 667,777
Leverage, minimum for well capitalized amount		$ 374,087		$ 373,250
Leverage, minimum for well capitalized ratio		0.050		0.0500

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