Note 6 - Fair Value Measurements and Fair Value of Financial Instruments - Assets Measured on Recurring Basis Using Significant Unobservable Inputs (Details) - US States and Political Subdivisions Debt Securities [Member] - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2024	Dec. 31, 2023
Balance	$ 7,122	$ 7,349
Principal paydowns	(150)	(272)
Change in unrealized loss	(221)	45
Balance	$ 6,751	$ 7,122

Note 6 - Fair Value Measurements and Fair Value of Financial Instruments - Assets Measured on Recurring Basis Using Significant Unobservable Inputs (Details) - US States and Political Subdivisions Debt Securities [Member] - USD ($)
$ in Thousands

6 Months Ended

12 Months Ended

Jun. 30, 2024

Dec. 31, 2023

Balance

$ 7,122

$ 7,349

Principal paydowns

(150)

(272)

Change in unrealized loss

(221)

Balance

$ 6,751

$ 7,122