Note 5 - Investment Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	$ 686,556	$ 584,754
Unrealized Gains, Available-for-sale	19	5
Unrealized Losses, Available-for-sale	(98,522)	(98,023)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	588,053	486,736
Amortized Cost, Held-to-maturity	275,716
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(38,730)	(41,111)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	131	213
Debt Securities, Held-to-maturity, Fair Value	236,986	258,617
Amortized Cost, Total investment securities	962,272	884,482
Unrealized Gains, Total investment securities	19	5
Unrealized Losses, Total investment securities	(137,252)	(139,134)
Allowance for Credit Losses, Total investment securities	131	213
Fair Value, Total investment securities	825,039	745,353
US Treasury Securities [Member]
Unrealized Gains, Available-for-sale	18	4
Unrealized Losses, Available-for-sale	(2)	(3)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	30,707	1,120
Residential Mortgage-Backed Securities [Member]
Unrealized Gains, Available-for-sale	1	1
Unrealized Losses, Available-for-sale	(92,805)	(88,547)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	503,706	435,594
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(27,092)	(28,498)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	54	99
Debt Securities, Held-to-maturity, Fair Value	129,001	141,627
Commercial Mortgage-Backed Securities [Member]
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	(99)	(123)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	1,251	1,353
Asset-Backed Securities [Member]
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	0	(1)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	19	25
Corporate Bond Securities [Member]
Unrealized Gains, Available-for-sale	0	0
Unrealized Losses, Available-for-sale	(5,616)	(9,349)
Allowance for Credit Losses, Available-for-sale	0	0
Available-for-sale, at fair value (amortized cost of $686,556 and $584,754, respectively)	52,370	48,644
US States and Political Subdivisions Debt Securities [Member]
Unrealized Gains, Held-to-maturity	0	0
Unrealized Losses, Held-to-maturity	(11,638)	(12,613)
Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest	77	114
Debt Securities, Held-to-maturity, Fair Value	107,985	116,990
Reported Value Measurement [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	686,556	584,754
Amortized Cost, Held-to-maturity	275,716	299,728
Reported Value Measurement [Member] | US Treasury Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	30,691	1,119
Reported Value Measurement [Member] | Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	596,510	524,140
Amortized Cost, Held-to-maturity	156,093	170,125
Reported Value Measurement [Member] | Commercial Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,350	1,476
Reported Value Measurement [Member] | Asset-Backed Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	19	26
Reported Value Measurement [Member] | Corporate Bond Securities [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	57,986	57,993
Reported Value Measurement [Member] | US States and Political Subdivisions Debt Securities [Member]
Amortized Cost, Held-to-maturity	$ 119,623	$ 129,603