Note 7 - Fair Value - Financial Assets At Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Securities	$ 436,965		$ 360,530
US States and Political Subdivisions Debt Securities [Member]
Securities	706		706
US Treasury and Government [Member]
Securities	432,733		246,290
Residential Mortgage-Backed Securities [Member]
Securities	2,736		2,911
Collateralized Mortgage-Backed Securities [Member]
Securities	790		850
US Government-sponsored Enterprises Debt Securities [Member]
Securities		$ 109,773
Fair Value, Inputs, Level 1 [Member]
Securities	432,733		246,290
Fair Value, Inputs, Level 1 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Securities	0		0
Fair Value, Inputs, Level 1 [Member] \| US Treasury and Government [Member]
Securities	432,733		246,290
Fair Value, Inputs, Level 1 [Member] \| Residential Mortgage-Backed Securities [Member]
Securities	0		0
Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage-Backed Securities [Member]
Securities	0		0
Fair Value, Inputs, Level 1 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Securities		0
Fair Value, Inputs, Level 2 [Member]
Securities	4,232		114,240
Fair Value, Inputs, Level 2 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Securities	706		706
Fair Value, Inputs, Level 2 [Member] \| US Treasury and Government [Member]
Securities	0		0
Fair Value, Inputs, Level 2 [Member] \| Residential Mortgage-Backed Securities [Member]
Securities	2,736		2,911
Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage-Backed Securities [Member]
Securities	790		850
Fair Value, Inputs, Level 2 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Securities		109,773
Fair Value, Inputs, Level 3 [Member]
Securities	0		0
Fair Value, Inputs, Level 3 [Member] \| US States and Political Subdivisions Debt Securities [Member]
Securities	0		0
Fair Value, Inputs, Level 3 [Member] \| US Treasury and Government [Member]
Securities	0		0
Fair Value, Inputs, Level 3 [Member] \| Residential Mortgage-Backed Securities [Member]
Securities	0		0
Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage-Backed Securities [Member]
Securities	$ 0		$ 0
Fair Value, Inputs, Level 3 [Member] \| US Government-sponsored Enterprises Debt Securities [Member]
Securities		$ 0