Note K - Comprehensive (Loss) Income - Changes in Accumulated Other Comprehensive Loss By Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Balance	$ (53,123)	$ (49,683)
Total other comprehensive income, net of tax	278	51
Balance	(54,423)	(44,291)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Balance	(68,544)	(63,887)
Other comprehensive income (loss), net of tax, before reclassifications
Amounts reclassified from accumulated other comprehensive income (loss), net of tax, to other, net, on the condensed consolidated statements of comprehensive loss	736	609
Total other comprehensive income, net of tax	736	609
Balance	(67,808)	(63,278)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	2,933	753
Other comprehensive income (loss), net of tax, before reclassifications	(458)	(558)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax, to other, net, on the condensed consolidated statements of comprehensive loss
Total other comprehensive income, net of tax	(458)	(558)
Balance	2,475	195
AOCI Attributable to Parent [Member]
Balance	(65,611)	(63,134)
Other comprehensive income (loss), net of tax, before reclassifications	(458)	(558)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax, to other, net, on the condensed consolidated statements of comprehensive loss	736	609
Total other comprehensive income, net of tax	278	51
Balance	$ (65,333)	$ (63,083)