The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Accumulated Other Comprehensive Income (Schedule Of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 26, 2020	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment income (loss) and interest expense									$ 3,817	$ 7,054	$ (1,454)
Provision for income taxes									(44,762)	(20,661)	(19,398)
Net income	$ 19,420	$ 31,336	$ 41,472	$ 26,689	$ 18,885	$ 14,319	$ 20,475	$ 14,304	$ 118,917	67,983	62,738
Unrealized Gains (Losses) On Available-For-Sale Marketable Securities [Member] \| Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment income (loss) and interest expense										(51)	(54)
Provision for income taxes										14	14
Net income										$ (37)	$ (40)