Note 21 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) $ in Thousands		Sep. 30, 2023 USD ($)		Dec. 31, 2022 USD ($)
Total risk-based capital, actual amount	[1]	$ 831,296		$ 762,956
Total risk-based capital, actual ratio	[1]	0.1271		0.1254
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 523,065		$ 486,841
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08		0.08
Common Equity Tier 1 risk-based capital, actual amount		$ 730,410	[1]	$ 672,045
Common Equity Tier 1 risk-based capital, actual ratio		0.1117	[1]	0.1104
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 294,224	[1]	$ 273,848
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		0.045	[1]	0.045
Tier 1 risk-based capital, actual amount	[1]	$ 756,410		$ 698,045
Tier 1 risk-based capita, actual ratio	[1]	0.1157		0.1147
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 392,298		$ 365,131
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.06		0.06
Leverage, actual ratio		0.098		0.0933
Leverage, minimum for adequately capitalized amount		$ 308,622		$ 299,329
Leverage, minimum for adequately capitalized ratio		0.04	[1]	0.04
Leverage, actual amount				$ 698,045
Subsidiaries [Member]
Total risk-based capital, actual amount	[1]	$ 805,791		$ 732,688
Total risk-based capital, actual ratio	[1]	0.1237		0.1208
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 521,313		$ 485,314
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08		0.08
Total risk-based capital, minimum for well capitalized amount	[1]	$ 651,641		$ 606,643
Total risk-based capital, minimum for well capitalized ratio	[1]	0.10		0.10
Common Equity Tier 1 risk-based capital, actual amount		$ 730,905	[1]	$ 667,777
Common Equity Tier 1 risk-based capital, actual ratio		0.1122	[1]	0.1101
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 293,239	[1]	$ 272,989
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio		0.045	[1]	0.045
Common Equity Tier 1 risk-based capital, minimum for well capitalized amount		$ 423,567	[1]	$ 394,318
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio		0.065	[1]	0.065
Tier 1 risk-based capital, actual amount	[1]	$ 730,905		$ 667,777
Tier 1 risk-based capita, actual ratio	[1]	0.1122		0.1101
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 390,985		$ 363,986
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.06		0.06
Tier 1 risk-based capital, minimum for well capitalized amount	[1]	$ 521,313		$ 485,314
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.08		0.08
Leverage, actual ratio		0.0949		0.0895
Leverage, minimum for adequately capitalized amount		$ 308,176		$ 298,600
Leverage, minimum for adequately capitalized ratio		0.04		0.04
Leverage, actual amount		$ 730,905		$ 667,777
Leverage, minimum for well capitalized amount		$ 385,221		$ 373,250
Leverage, minimum for well capitalized ratio		0.05		0.05

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