Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 27, 2020	Dec. 29, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	$ 309,080	$ 201,785
Fair value, long-term AFS securities	286,831	251,696
Deferred compensation plan assets	49,200	46,000
Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation	22,245	23,702
Contingent consideration	0	0
Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation	0	0
Contingent consideration	0	0
Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation	0	0
Contingent consideration	8,431	0
Estimate of Fair Value Measurement | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation	22,245	23,702
Contingent consideration	8,431	0
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	130,301	99,126
Fair value, long-term AFS securities	135,934	103,737
Corporate debt securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	130,301	99,126
Fair value, long-term AFS securities	135,934	103,737
Corporate debt securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
Corporate debt securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	130,301	99,126
Fair value, long-term AFS securities	135,934	103,737
Corporate debt securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
U.S. Treasury securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	79,503	43,095
Fair value, long-term AFS securities	97,565	101,438
U.S. Treasury securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	79,503	43,095
Fair value, long-term AFS securities	97,565	101,438
U.S. Treasury securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
U.S. Treasury securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	79,503	43,095
Fair value, long-term AFS securities	97,565	101,438
U.S. Treasury securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	37,580	12,561
Commercial paper | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	37,580	12,561
Commercial paper | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Commercial paper | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	37,580	12,561
Commercial paper | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	36,525	9,501
Certificates of deposit | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	36,525	9,501
Certificates of deposit | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Certificates of deposit | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	36,525	9,501
Certificates of deposit | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
US Government Agencies Debt Securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	25,171	37,502
Fair value, long-term AFS securities	48,348	46,521
US Government Agencies Debt Securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
US Government Agencies Debt Securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	25,171	37,502
Fair value, long-term AFS securities	48,348	46,521
US Government Agencies Debt Securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, long-term AFS securities	4,984
Municipal securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, long-term AFS securities	4,984	0
Municipal securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, long-term AFS securities	0	0
Municipal securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, long-term AFS securities	4,984	0
Municipal securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, long-term AFS securities	0	0
Debt Securities | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	309,080	201,785
Fair value, long-term AFS securities	286,831	251,696
Debt Securities | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	0	0
Debt Securities | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	309,080	201,785
Fair value, long-term AFS securities	286,831	251,696
Debt Securities | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, short-term AFS securities	0	0
Fair value, long-term AFS securities	$ 0	$ 0