Note B - Fair Value Measures - Schedule Of Assets And Liabilities Measured At Fair Value (Details) - Fair Value, Recurring [Member] - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Foreign currency contracts included in other current liabilities	$ (1,424)	$ (764)
Fair Value, Net Asset (Liability), Total	205,042	179,268
Fair Value, Inputs, Level 1 [Member]
Foreign currency contracts included in other current liabilities	0	0
Fair Value, Net Asset (Liability), Total	206,466	180,032
Fair Value, Inputs, Level 2 [Member]
Foreign currency contracts included in other current liabilities	(1,424)	(764)
Fair Value, Net Asset (Liability), Total	(1,424)	(764)
Fair Value, Inputs, Level 3 [Member]
Foreign currency contracts included in other current liabilities	0	0
Fair Value, Net Asset (Liability), Total	0	0
Money Market Funds [Member]
Money market funds included in cash equivalents	206,466	180,032
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Money market funds included in cash equivalents	206,466	180,032
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Money market funds included in cash equivalents	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Money market funds included in cash equivalents	$ 0	$ 0