Note 4 - Investment Securities - Portfolio of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Amortized cost	$ 1,459,758	$ 1,308,082
Gross unrealized gains	168	13,265
Gross unrealized losses	(136,137)	(70,409)
Securities available-for-sale, fair value	1,323,789	1,250,938
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
US Government Agencies Debt Securities [Member]
Amortized cost	320,151	398,392
Gross unrealized gains	143	2,467
Gross unrealized losses	(16,457)	(9,669)
Securities available-for-sale, fair value	303,837	391,190
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Residential Mortgage-Backed Securities [Member]
Amortized cost	871,749	644,811
Gross unrealized gains	0	5,391
Gross unrealized losses	(87,088)	(43,058)
Securities available-for-sale, fair value	784,661	607,144
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Commercial Mortgage-Backed Securities [Member]
Amortized cost	35,008	30,124
Gross unrealized gains	0	0
Gross unrealized losses	(5,629)	(3,155)
Securities available-for-sale, fair value	29,379	26,969
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
US States and Political Subdivisions Debt Securities [Member]
Amortized cost	204,618	221,545
Gross unrealized gains	24	5,385
Gross unrealized losses	(26,346)	(14,521)
Securities available-for-sale, fair value	178,296	212,409
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Corporate Debt Securities [Member]
Amortized cost	26,250	12,500
Gross unrealized gains	0	22
Gross unrealized losses	(616)	(3)
Securities available-for-sale, fair value	25,634	12,519
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Asset-Backed Securities [Member]
Amortized cost	478	528
Gross unrealized gains	1	0
Gross unrealized losses	(1)	(3)
Securities available-for-sale, fair value	478	525
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Other Debt Obligations [Member]
Amortized cost	1,504	182
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Securities available-for-sale, fair value	1,504	182
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	$ 0	$ 0

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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