Note 9 - Employee Benefit Plans - Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest cost	$ 2,572	$ 2,873	$ 2,313
Pension Plan And Supplemental Plan [Member]
Interest cost	2,572	2,873	2,313
Expected return on plan assets	(1,828)	(2,111)	(3,006)
Amortization of net actuarial gains (losses)	(94)	(146)	63
Settlement/curtailment gain	0	(2,177)	0
Net periodic pension cost (benefit)	$ 650	$ (1,561)	$ (630)