Note 4 - Investment Securities - Schedule of Debt Securities, Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	$ 466,003	$ 486,736
Unrealized Gains, Available-for-sale	4	5
Unrealized Losses, Available-for-sale	(83,123)	(98,023)
Allowance for Credit Losses, Available-for-sale	0	0
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(32,188)	(41,111)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	137	213
Debt Securities, Held-to-maturity, Fair Value	249,862	258,617
Amortized Cost, Total investment securities	831,172	884,482
Unrealized Gains, Total investment securities	4	5
Unrealized Losses, Total investment securities	(115,311)	(139,134)
Allowance for Credit Losses, Total investment securities	137	213
Fair Value, Total investment securities	715,865	745,353
US Treasury Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	739	1,120
Unrealized Gains, Available-for-sale	2	4
Unrealized Losses, Available-for-sale	(2)	(3)
Allowance for Credit Losses, Available-for-sale	0	0
Residential Mortgage-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	414,388	435,594
Unrealized Gains, Available-for-sale	2	1
Unrealized Losses, Available-for-sale	(74,529)	(88,547)
Allowance for Credit Losses, Available-for-sale	0	0
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(23,064)	(28,498)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	56	99
Debt Securities, Held-to-maturity, Fair Value	136,269	141,627
Commercial Mortgage-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	1,401	1,353
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	(59)	(123)
Allowance for Credit Losses, Available-for-sale	0	0
Asset-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	20	25
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	0	(1)
Allowance for Credit Losses, Available-for-sale	0	0
Corporate Bond Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	49,455	48,644
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	(8,533)	(9,349)
Allowance for Credit Losses, Available-for-sale	0	0
US States and Political Subdivisions Debt Securities [Member]
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(9,124)	(12,613)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	81	114
Debt Securities, Held-to-maturity, Fair Value	113,593	116,990
Reported Value Measurement [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	549,122	584,754
Amortized Cost, Held-to-maturity	282,050	299,728
Reported Value Measurement [Member] | US Treasury Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	739	1,119
Reported Value Measurement [Member] | Residential Mortgage-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	488,915	524,140
Amortized Cost, Held-to-maturity	159,333	170,125
Reported Value Measurement [Member] | Commercial Mortgage-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	1,460	1,476
Reported Value Measurement [Member] | Asset-Backed Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	20	26
Reported Value Measurement [Member] | Corporate Bond Securities [Member]
Available-for-sale, at fair value (amortized cost of $549,122 and $584,754, respectively)	57,988	57,993
Reported Value Measurement [Member] | US States and Political Subdivisions Debt Securities [Member]
Amortized Cost, Held-to-maturity	$ 122,717	$ 129,603