Accumulated Other Comprehensive Income (Schedule Of Accumulated Other Comprehensive Income) (Details) - Unrealized Gains On Available-For-Sale Marketable Securities [Member] $ in Thousands	6 Months Ended
	Jun. 27, 2020 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income balance, beginning balance	$ 1,480
Other comprehensive income before reclassifications	1,118
Amounts reclassified from accumulated other comprehensive income	0
Net current period change in other comprehensive income	1,118
Accumulated other comprehensive income balance, ending balance	$ 2,598