Note 3 - Securities - Securities With Unrealized Losses (Details) $ in Thousands	Jun. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Count, less than 12 months	22		10
Fair value, less than 12 months	$ 218,088		$ 79,872
Unrealized loss, less than 12 months	$ (41)		$ (128)
Count, 12 months or more	47		85
Fair value, 12 months or more	$ 18,228		$ 50,823
Unrealized loss, 12 months or more	$ (241)		$ (770)
Count, total	69		95
Fair value, total	$ 236,316		$ 130,695
Unrealized loss, total	$ (282)		$ (898)
US Treasury Securities [Member]
Count, less than 12 months	22		0
Fair value, less than 12 months	$ 218,088		$ 0
Unrealized loss, less than 12 months	$ (41)		$ 0
Count, 12 months or more	37		73
Fair value, 12 months or more	$ 16,292		$ 48,609
Unrealized loss, 12 months or more	$ (175)		$ (689)
Count, total	59		73
Fair value, total	$ 234,380		$ 48,609
Unrealized loss, total	$ (216)		$ (689)
Residential Mortgage-Backed Securities [Member]
Count, less than 12 months	0		0
Fair value, less than 12 months	$ 0		$ 0
Unrealized loss, less than 12 months	$ 0		$ 0
Count, 12 months or more	5		7
Fair value, 12 months or more	$ 1,146		$ 1,364
Unrealized loss, 12 months or more	$ (55)		$ (69)
Count, total	5		7
Fair value, total	$ 1,146		$ 1,364
Unrealized loss, total	$ (55)		$ (69)
Collateralized Mortgage-Backed Securities [Member]
Count, less than 12 months	0		0
Fair value, less than 12 months	$ 0		$ 0
Unrealized loss, less than 12 months	$ 0		$ 0
Count, 12 months or more	5		5
Fair value, 12 months or more	$ 790		$ 850
Unrealized loss, 12 months or more	$ (11)		$ (12)
Count, total	5		5
Fair value, total	$ 790		$ 850
Unrealized loss, total	$ (11)		$ (12)
US Government-sponsored Enterprises Debt Securities [Member]
Count, less than 12 months		10
Fair value, less than 12 months		$ 79,872
Unrealized loss, less than 12 months		$ (128)
Count, 12 months or more		0
Fair value, 12 months or more		$ 0
Unrealized loss, 12 months or more		$ 0
Count, total		10
Fair value, total		$ 79,872
Unrealized loss, total		$ (128)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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