Note K - Comprehensive Income - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Balance	$ 20,965	$ 18,808	$ (20,571)	$ (24,715)	$ 18,808	$ (24,715)
Total other comprehensive income (loss), net of tax	502	2,620	(2,029)	506	3,122	(1,523)
Balance	20,550	20,965	(17,711)	(20,571)	20,550	(17,711)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance		(44,120)		(54,394)	(44,120)	(54,394)
Other comprehensive income, net of tax, before reclassifications					0	0
Amounts reclassified from accumulated other comprehensive income, net of tax, to other, net, on the condensed consolidated statements of comprehensive income					1,142	1,588
Total other comprehensive income (loss), net of tax					1,142	1,588
Balance	(42,978)		(52,806)		(42,978)	(52,806)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance		(4,182)		1,066	(4,182)	1,066
Other comprehensive income, net of tax, before reclassifications					1,980	(3,111)
Amounts reclassified from accumulated other comprehensive income, net of tax, to other, net, on the condensed consolidated statements of comprehensive income					0	0
Total other comprehensive income (loss), net of tax					1,980	(3,111)
Balance	(2,202)		(2,045)		(2,202)	(2,045)
AOCI Attributable to Parent [Member]
Balance	(45,682)	(48,302)	(52,822)	(53,328)	(48,302)	(53,328)
Other comprehensive income, net of tax, before reclassifications					1,980	(3,111)
Amounts reclassified from accumulated other comprehensive income, net of tax, to other, net, on the condensed consolidated statements of comprehensive income					1,142	1,588
Total other comprehensive income (loss), net of tax	502	2,620	(2,029)	506	3,122	(1,523)
Balance	$ (45,180)	$ (45,682)	$ (54,851)	$ (52,822)	$ (45,180)	$ (54,851)