Note 13 - Retirement Benefit Plans - Obligation and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Benefit obligation	$ 1,401	$ 1,527	$ 1,654
Service benefit	(56)	(19)	(15)
Interest cost	70	38	30
Benefits paid	(139)	(145)	(142)
Benefit obligation	1,276	1,401	1,527
Fair value of plan assets	0	0	0
Accumulated post-retirement benefit obligation in excess of plan assets	1,276	1,401	1,527
Retirees [Member]
Benefit obligation	1,401	1,527
Benefit obligation	1,276	1,401	1,527
Other Participants [Member]
Benefit obligation	0	0
Benefit obligation	$ 0	$ 0	$ 0