Note 7 - Accrued Retirement Benefits - Changes in Benefit Obligations and Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Benefit obligations	$ 13,949	$ 15,552
Interest cost	335	738
Actuarial gain	(248)	(27)
Benefits paid	(12,416)	(2,314)
Benefit obligations	1,620	13,949
Fair value of plan assets at beginning of year	11,441	13,860
Actual return on plan assets	(210)	(231)
Employer contributions	1,283	126
Asset transfers	(98)	0
Benefits paid	(12,416)	(2,314)
Fair value of plan assets at end of year	0	11,441
Funded status	(1,620)	(2,508)
Accumulated benefit obligations	$ (1,620)	$ (13,949)
Discount rate	4.98%
Expected long-term return on plan assets		5.40%
Minimum [Member]
Discount rate		5.40%
Maximum [Member]
Discount rate		5.52%