Marketable Securities - Fair Value (Details) - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Marketable Securities [Abstract]
Equity securities	$ 6,509	$ 7,410
Available-for-sale securities	199,235	104,445
Marketable securities	205,744	111,855
Bonds [Member]
Marketable Securities [Abstract]
Available-for-sale securities	154,315	104,445
Commercial Paper [Member]
Marketable Securities [Abstract]
Available-for-sale securities	44,920
Fair Value, Inputs, Level 1 [Member]
Marketable Securities [Abstract]
Equity securities	6,509	7,410
Fair Value, Inputs, Level 2 [Member]
Marketable Securities [Abstract]
Available-for-sale securities		$ 104,445
Fair Value, Inputs, Level 2 [Member] | Bonds [Member]
Marketable Securities [Abstract]
Available-for-sale securities	154,315
Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Marketable Securities [Abstract]
Available-for-sale securities	$ 44,920