Note K - Comprehensive Income (Loss) - Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Net loss	$ (1,621)	$ (6,235)	$ 5,118	$ (5,988)	$ (3,803)	$ (13,527)	$ (2,738)	$ (23,318)
Other comprehensive income (loss):
Adjustment to pension liability	812			732			2,436	2,197
Tax expense	(203)			(183)			(609)	(549)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax, Total	609			549			1,827	1,648
Foreign currency translation adjustment	1,129			(660)			1,067	(311)
Adoption of ASU 2018-02								(11,355)
Total other comprehensive income (loss), net of tax	1,738	$ 1,105	$ 51	(111)			2,894	(10,018)
Comprehensive income (loss)	$ 117			$ (6,099)			$ 156	$ (33,336)