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Marketable Securities - Schedule of Gross Unrealized Losses and Fair Value by Major Security Type (Details) - USD ($)
$ in Thousands
Mar. 27, 2021
Dec. 26, 2020
Marketable Securities [Line Items]    
Gross Unrealized Losses Less than 12 Consecutive Months $ (7,706) $ (3,863)
Fair Value Less than 12 Consecutive Months 505,152 357,878
Gross Unrealized Losses 12 Consecutive Months or Longer (1,342) (976)
Fair Value 12 Consecutive Months or Longer 30,297 14,173
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total 9,048 4,839
Fair Value, Total 535,449 372,051
Mortgage-backed securities [Member]    
Marketable Securities [Line Items]    
Gross Unrealized Losses Less than 12 Consecutive Months (466) (1,849)
Fair Value Less than 12 Consecutive Months 30,984 85,688
Gross Unrealized Losses 12 Consecutive Months or Longer (817) (74)
Fair Value 12 Consecutive Months or Longer 10,697 2,122
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total 1,283 1,923
Fair Value, Total 41,681 87,810
Corporate securities [Member]    
Marketable Securities [Line Items]    
Gross Unrealized Losses Less than 12 Consecutive Months (5,622) (1,065)
Fair Value Less than 12 Consecutive Months 339,722 199,187
Gross Unrealized Losses 12 Consecutive Months or Longer (186) (572)
Fair Value 12 Consecutive Months or Longer 9,011 8,625
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total 5,808 1,637
Fair Value, Total 348,733 207,812
Municipal securities [Member]    
Marketable Securities [Line Items]    
Gross Unrealized Losses Less than 12 Consecutive Months (1,505) (223)
Fair Value Less than 12 Consecutive Months 123,652 50,403
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total 1,505 223
Fair Value, Total 123,652 50,403
Other [Member]    
Marketable Securities [Line Items]    
Gross Unrealized Losses Less than 12 Consecutive Months (113) (726)
Fair Value Less than 12 Consecutive Months 10,794 22,600
Gross Unrealized Losses 12 Consecutive Months or Longer (339) (330)
Fair Value 12 Consecutive Months or Longer 10,589 3,426
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total 452 1,056
Fair Value, Total $ 21,383 $ 26,026