Note O - Restructuring Activities - Restructuring Expense (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Restructuring expense	$ 2,198	$ 1,366	$ 9,400	$ 11,800
Employee Severance [Member]
Restructuring expense	204	414
Lease Impairment and Termination Charges [Member]
Restructuring expense	294	348
Capital Losses from Asset Disposal [Member]
Restructuring expense	10	(20)
Facility Closing [Member]
Restructuring expense	1,690	624
Facility, Asset Impairment and Other Expense [Member]
Restructuring expense	$ 1,994	$ 952