Note J - Segment Information - Consolidated Net Sales and Long Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Net sales	$ 298,513	$ 260,598	$ 824,123	$ 789,604
CHINA
Net sales	120,523	115,424	346,526	$ 355,571
Long-lived assets	89,208		89,208		$ 90,886
UNITED STATES
Net sales	27,560	28,137
Long-lived assets	61,439		$ 61,439		$ 54,809
PHILIPPINES
Net sales	$ 33,585	$ 15,935