Note 23 - Regulatory Matters - Capital and Leverage Ratios (Details) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Common Equity Tier 1 to Risk-Weighted Assets, Actual amount	$ 2,276,830,000	$ 2,137,925,000
Common Equity Tier 1 to Risk-Weighted Assets, Actual ratio	12.75%	13.32%
Common Equity Tier 1 to Risk-Weighted Assets, Minimum Capital Required	$ 1,250,461,000	$ 1,123,721,000
Common Equity Tier 1 to Risk-Weighted Assets, Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,161,142,000	$ 1,043,455,000
Common Equity Tier 1 to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital to Risk-Weighted Assets, Actual amount	$ 2,276,830,000	$ 2,137,925,000
Tier 1 Capital to Risk-Weighted Assets, Actual ratio	0.1275	0.1332
Tier 1 Capital to Risk-Weighted Assets, Minimum Capital Required	$ 1,518,417,000	$ 1,364,519,000
Tier 1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	8.50%	8.50%
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,429,098,000	$ 1,284,253,000
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	0.08	0.0800
Total Capital to Risk-Weighted Assets, Actual amount	$ 2,432,045,000	$ 2,281,182,000
Total Capital to Risk-Weighted Assets, Actual ratio	0.1361	0.1421
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 1,875,691,000	$ 1,685,582,000
Total Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	10.50%	10.50%
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,786,373,000	$ 1,605,316,000
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	0.10	0.1000
Leverage Ratio, Actual amount	$ 2,276,830,000	$ 2,137,925,000
Leverage Ratio, Actual ratio	0.1053	0.1082
Leverage Ratio, Minimum Capital Required	$ 864,918,000	$ 790,430,000
Leverage Ratio Minimum Capital Required, Ratio	0.0400	0.0400
Leverage Ratio, Required to be Considered Well Capitalized	$ 1,081,148,000	$ 988,037,000
Leverage Ratio Required to be Considered Well Capitalized, Ratio	0.05	0.0500
Bank [Member]
Common Equity Tier 1 to Risk-Weighted Assets, Actual amount	$ 2,182,066,000	$ 2,056,601,000
Common Equity Tier 1 to Risk-Weighted Assets, Actual ratio	12.21%	12.80%
Common Equity Tier 1 to Risk-Weighted Assets, Minimum Capital Required	$ 1,250,914	$ 1,124,381
Common Equity Tier 1 to Risk-Weighted Assets, Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,161,563,000	$ 1,044,068,000
Common Equity Tier 1 to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital to Risk-Weighted Assets, Actual amount	$ 2,182,066,000	$ 2,056,601,000
Tier 1 Capital to Risk-Weighted Assets, Actual ratio	0.1221	0.1280
Tier 1 Capital to Risk-Weighted Assets, Minimum Capital Required	$ 1,518,967,000	$ 1,365,320,000
Tier 1 Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	8.50%	8.50%
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,429,616,000	$ 1,285,007,000
Tier 1 Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	0.0800	0.0800
Total Capital to Risk-Weighted Assets, Actual amount	$ 2,452,781,000	$ 2,315,358,000
Total Capital to Risk-Weighted Assets, Actual ratio	0.1373	0.1441
Total Capital to Risk-Weighted Assets, Minimum Capital Required	$ 1,876,371,000	$ 1,686,572,000
Total Capital to Risk-Weighted Assets, Minimum Capital Required, Ratio	10.50%	10.50%
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized	$ 1,787,020,000	$ 1,606,259,000
Total Capital to Risk-Weighted Assets, Required to be Considered Well Capitalized, Ratio	0.1000	0.1000
Leverage Ratio, Actual amount	$ 2,182,066,000	$ 2,056,601,000
Leverage Ratio, Actual ratio	0.1008	0.1040
Leverage Ratio, Minimum Capital Required	$ 865,470,000	$ 791,226,000
Leverage Ratio Minimum Capital Required, Ratio	0.0400	0.0400
Leverage Ratio, Required to be Considered Well Capitalized	$ 1,081,838,000	$ 989,033,000
Leverage Ratio Required to be Considered Well Capitalized, Ratio	0.0500	0.0500