XML 58 R45.htm IDEA: XBRL DOCUMENT v3.21.2
Marketable Securities - Summary of Estimated Fair Value and Gross Unrealized Holding Losses of Marketable Securities in Unrealized Loss Position (Details) - USD ($)
$ in Thousands
Sep. 25, 2021
Dec. 26, 2020
Schedule of Available-for-sale Securities [Line Items]    
In Unrealized Loss Position For Less Than 12 Months, Fair Value $ 93,624 $ 32,450
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses 70 19
In Unrealized Loss Position For Greater Than 12 Months, Fair Value 2,587 0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses 45 0
Municipal notes and bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
In Unrealized Loss Position For Less Than 12 Months, Fair Value 56,240 8,641
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses 34 4
In Unrealized Loss Position For Greater Than 12 Months, Fair Value 0 0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses 0 0
Commercial paper [Member]    
Schedule of Available-for-sale Securities [Line Items]    
In Unrealized Loss Position For Less Than 12 Months, Fair Value 13,415 8,862
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses 1 3
In Unrealized Loss Position For Greater Than 12 Months, Fair Value 0 0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses 0 0
Corporate bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
In Unrealized Loss Position For Less Than 12 Months, Fair Value 23,969 14,947
In Unrealized Loss Position For Less Than 12 Months, Gross Unrealized Losses 35 12
In Unrealized Loss Position For Greater Than 12 Months, Fair Value 2,587 0
In Unrealized Loss Position For Greater Than 12 Months, Gross Unrealized Losses $ 45 $ 0