Marketable Securities - Amortized Cost (Details) - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 196,878	$ 99,861
Gross Unrealized Holding Gains	4,755	5,723
Gross Unrealized Holding Losses	(2,397)	(1,139)
Fair Value	199,235	104,445
Bonds [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	151,947	99,861
Gross Unrealized Holding Gains	4,753	5,723
Gross Unrealized Holding Losses	(2,384)	(1,139)
Fair Value	154,315	$ 104,445
Commercial Paper [Member]
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Amortized Cost	44,931
Gross Unrealized Holding Gains	2
Gross Unrealized Holding Losses	(13)
Fair Value	$ 44,920

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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