Note 21 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) $ in Thousands		Sep. 30, 2024 USD ($)		Dec. 31, 2023 USD ($)
Total risk-based capital, actual amount		$ 918,369		$ 849,836
Total risk-based capital, actual ratio	[1]	0.1273		0.1256
Total risk-based capital, minimum for adequately capitalized amount		$ 577,245		$ 541,370
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08		0.08
Common Equity Tier 1 risk-based capital, actual amount		$ 805,082		$ 747,376
Common Equity Tier 1 risk-based capital, actual ratio	[1]	0.1116		0.1104
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 324,701		$ 304,521
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.045		0.045
Tier 1 risk-based capital, actual amount		$ 831,082		$ 773,376
Tier 1 risk-based capita, actual ratio	[1]	0.1152		0.1143
Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 432,934		$ 406,027
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.06		0.06
Leverage, actual amount		$ 831,082		$ 773,376
Leverage, actual ratio		0.1005		0.0962
Leverage, minimum for adequately capitalized amount		$ 330,781		$ 321,713
Leverage, minimum for adequately capitalized ratio		0.04		0.04
Subsidiaries [Member]
Total risk-based capital, actual amount		$ 895,891		$ 823,275
Total risk-based capital, actual ratio	[1]	0.1246		0.1221
Total risk-based capital, minimum for adequately capitalized amount		$ 575,399		$ 539,609
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08		0.08
Total risk-based capital, minimum for well capitalized amount		$ 719,249		$ 674,511
Total risk-based capital, minimum for well capitalized ratio	[1]	0.10		0.10
Common Equity Tier 1 risk-based capital, actual amount		$ 808,604		$ 746,815
Common Equity Tier 1 risk-based capital, actual ratio	[1]	0.1124		0.1107
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 323,662		$ 303,530
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.045		0.045
Common Equity Tier 1 risk-based capital, minimum for well capitalized amount		$ 467,512	[1]	$ 438,432
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.065		0.065
Tier 1 risk-based capital, actual amount		$ 808,604		$ 746,815
Tier 1 risk-based capita, actual ratio	[1]	0.1124		0.1107
Tier 1 risk-based capital, minimum for adequately capitalized amount		$ 431,550		$ 404,707
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		$ 575,399	[1]	$ 539,609
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.08		0.08
Leverage, actual amount		$ 808,604		$ 746,815
Leverage, actual ratio		0.0979		0.093
Leverage, minimum for adequately capitalized amount		$ 330,547		$ 321,323
Leverage, minimum for adequately capitalized ratio		0.04		0.04
Leverage, minimum for well capitalized amount		$ 413,184		$ 401,654
Leverage, minimum for well capitalized ratio		0.05		0.05

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