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, 2022	Dec. 31, 2021
Beginning balance, December 31, 2021	$ 8,565	$ 8,844
Principal paydowns	(143)	(279)
Ending balance, June 30, 2022	$ 8,422	$ 8,565