Note 6 - Other Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Liability, Defined Benefit Plan, Noncurrent, Total	$ 18,522	$ 23,909
Liability, Defined Benefit Plan, Noncurrent, Total	18,522	23,909
Cash Surrender Value, Fair Value Disclosure	13,900	16,100
Increase (Decrease) in Cash Surrender Value	(2,200)	1,300
Investments Held in Rabbi Trust [Member]
Debt Securities, Available-for-Sale, Amortized Cost, Total	100	300
Debt Securities, Available-for-Sale, Total	100	300
Supplemental Employee Retirement Plan [Member]
Liability, Defined Benefit Plan, Noncurrent, Total	18,200	23,600
Liability, Defined Benefit Plan, Noncurrent, Total	18,200	23,600
Investments, Fair Value Disclosure, Total	$ 14,000	$ 16,400