Note 7 - Loans and the Allowance for Credit Losses - Amortized Cost of of the Modified Loans (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Modified	$ 10,087	$ 18,811		$ 33,730
Loans Modified, Gross	$ 11,435,643	$ 11,308,131	$ 11,435,643	$ 11,308,131
Loans Modified, Percent	0.09%	0.17%	0.36%	0.30%
Extended Maturity [Member]
Modified	$ 10,087	$ 0	$ 40,031	$ 14,919
Payment Deferral [Member]
Modified	0	18,811	0	18,811
Contractual Interest Rate Reduction [Member]
Modified			594	0
Principal Forgiveness [Member]
Modified			40,625
Commercial Portfolio Segment [Member]
Modified	8,311	18,811		25,311
Loans Modified, Gross	$ 1,656,916	$ 1,622,975	$ 1,656,916	$ 1,622,975
Loans Modified, Percent	0.50%	1.16%	0.63%	1.56%
Weighted Average Term Extension (Month)	66 months		54 months
Weighted Average Interest Rate Reduction			2.00%
Commercial Portfolio Segment [Member] \| Extended Maturity [Member]
Modified	$ 8,311	$ 0	$ 9,811	$ 6,500
Commercial Portfolio Segment [Member] \| Payment Deferral [Member]
Modified	0	18,811	0	18,811
Commercial Portfolio Segment [Member] \| Contractual Interest Rate Reduction [Member]
Modified			594	0
Commercial Portfolio Segment [Member] \| Principal Forgiveness [Member]
Modified			10,405
Commercial Real Estate Portfolio Segment [Member]
Modified	1,776	0		0
Loans Modified, Gross	$ 7,981,622	$ 7,721,070	$ 7,981,622	$ 7,721,070
Loans Modified, Percent	0.02%	0.00%	0.38%	0.00%
Weighted Average Term Extension (Month)	60 years		23 months
Weighted Average Interest Rate Reduction				0.00%
Payment Deferral (Year)		3 years		3 years
Commercial Real Estate Portfolio Segment [Member] \| Weighted Average [Member]
Weighted Average Term Extension (Month)				3 years
Commercial Real Estate Portfolio Segment [Member] \| Extended Maturity [Member]
Modified	$ 1,776	$ 0	$ 30,220	$ 0
Commercial Real Estate Portfolio Segment [Member] \| Payment Deferral [Member]
Modified	0	0	0	0
Commercial Real Estate Portfolio Segment [Member] \| Contractual Interest Rate Reduction [Member]
Modified			0	0
Commercial Real Estate Portfolio Segment [Member] \| Principal Forgiveness [Member]
Modified			30,220
Commercial Construction Portfolio Segment [Member]
Modified	0	0		8,419
Loans Modified, Gross	$ 585,707	$ 728,615	$ 585,707	$ 728,615
Loans Modified, Percent	0.00%	0.00%	0.00%	1.16%
Commercial Construction Portfolio Segment [Member] \| Weighted Average [Member]
Weighted Average Term Extension (Month)				6 years
Commercial Construction Portfolio Segment [Member] \| Extended Maturity [Member]
Modified	$ 0	$ 0	$ 0	$ 8,419
Commercial Construction Portfolio Segment [Member] \| Payment Deferral [Member]
Modified	0	0	0	0
Commercial Construction Portfolio Segment [Member] \| Contractual Interest Rate Reduction [Member]
Modified				0
Commercial Construction Portfolio Segment [Member] \| Principal Forgiveness [Member]
Modified			0
Commercial Construction Portfolio Segment [Member] \| Interest Rate Below Market Reduction [Member]
Modified			0
Residential Portfolio Segment [Member]
Modified	0	0		0
Loans Modified, Gross	$ 1,207,092	$ 1,233,305	$ 1,207,092	$ 1,233,305
Loans Modified, Percent	0.00%	0.00%	0.00%	0.00%
Residential Portfolio Segment [Member] \| Extended Maturity [Member]
Modified	$ 0	$ 0	$ 0	$ 0
Residential Portfolio Segment [Member] \| Payment Deferral [Member]
Modified	0	0	0	0
Residential Portfolio Segment [Member] \| Contractual Interest Rate Reduction [Member]
Modified			0	0
Residential Portfolio Segment [Member] \| Principal Forgiveness [Member]
Modified			0
Consumer Portfolio Segment [Member]
Modified	0	0		0
Loans Modified, Gross	$ 4,306	$ 2,166	$ 4,306	$ 2,166
Loans Modified, Percent	0.00%	0.00%	0.00%	0.00%
Consumer Portfolio Segment [Member] \| Extended Maturity [Member]
Modified	$ 0	$ 0	$ 0	$ 0
Consumer Portfolio Segment [Member] \| Payment Deferral [Member]
Modified	$ 0	$ 0	0	0
Consumer Portfolio Segment [Member] \| Contractual Interest Rate Reduction [Member]
Modified				$ 0
Consumer Portfolio Segment [Member] \| Principal Forgiveness [Member]
Modified			0
Consumer Portfolio Segment [Member] \| Interest Rate Below Market Reduction [Member]
Modified			$ 0

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- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
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- Definition

Percentage of financing receivable modified during period for debtor experiencing financial difficulty to total financing receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
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-URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A

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Period of payment deferral of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
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- Definition

Percentage of decrease in weighted-average contractual interest rate of financing receivable modified for debtor experiencing financial difficulty.

+ References

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Period of increase in weighted-average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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