Note 21 - Regulatory Matters - Risk Based Capital Amounts and Ratios (Details) $ in Thousands		Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Total risk-based capital, actual amount	[1]	$ 969,918	$ 943,723
Total risk-based capital, actual ratio	[1]	0.1285	0.1273
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 603,908	$ 593,201
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08	0.08
Common Equity Tier 1 risk-based capital, actual amount	[1]	$ 849,542	$ 828,386
Common Equity Tier 1 risk-based capital, actual ratio	[1]	0.1125	0.1117
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 339,698	$ 333,676
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.045	0.045
Tier 1 risk-based capital, actual amount	[1]	$ 875,542	$ 854,386
Tier 1 risk-based capita, actual ratio	[1]	0.116	0.1152
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 452,931	$ 444,901
Tier 1 risk-based capital, minimum for adequately capitalized ratio	[1]	0.06	0.06
Leverage, actual amount		$ 875,542	$ 854,386
Leverage, actual ratio		0.0998	0.0994
Leverage, minimum for adequately capitalized amount		$ 351,080	$ 343,886
Leverage, minimum for adequately capitalized ratio		0.04	0.04
Subsidiaries [Member]
Total risk-based capital, actual amount	[1]	$ 944,773	$ 918,210
Total risk-based capital, actual ratio	[1]	0.1252	0.1239
Total risk-based capital, minimum for adequately capitalized amount	[1]	$ 603,520	$ 593,002
Total risk-based capital, minimum for adequately capitalized ratio	[1]	0.08	0.08
Total risk-based capital, minimum for well capitalized amount	[1]	$ 754,000	$ 741,252
Total risk-based capital, minimum for well capitalized ratio	[1]	0.10	0.10
Common Equity Tier 1 risk-based capital, actual amount	[1]	$ 850,457	$ 828,873
Common Equity Tier 1 risk-based capital, actual ratio	[1]	0.1127	0.1118
Common Equity Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 339,480	$ 333,564
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	[1]	$ 490,360	$ 481,814
Common Equity Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.065	0.065
Tier 1 risk-based capital, actual amount	[1]	$ 850,457	$ 828,873
Tier 1 risk-based capita, actual ratio	[1]	0.1127	0.1118
Tier 1 risk-based capital, minimum for adequately capitalized amount	[1]	$ 452,640	$ 444,751
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]	$ 603,520	$ 593,002
Tier 1 risk-based capital, minimum for well capitalized ratio	[1]	0.08	0.08
Leverage, actual amount		$ 850,457	$ 828,873
Leverage, actual ratio		0.097	0.0965
Leverage, minimum for adequately capitalized amount		$ 350,831	$ 343,624
Leverage, minimum for adequately capitalized ratio		0.04	0.04
Leverage, minimum for well capitalized amount		$ 438,539	$ 429,530
Leverage, minimum for well capitalized ratio		0.05	0.05

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