Revenue - Advertising Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2021	Sep. 27, 2020	Sep. 26, 2021	Sep. 27, 2020
Disaggregation of Revenue [Line Items]
Total advertising	$ 509,103	$ 426,895	$ 1,480,645	$ 1,274,281
Advertising benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	100.00%	100.00%	100.00%	100.00%
Advertising
Disaggregation of Revenue [Line Items]
Total advertising	$ 110,887	$ 79,253	$ 320,777	$ 253,150
Digital | Advertising benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	60.40%	60.30%	61.60%	54.70%
Digital | Advertising
Disaggregation of Revenue [Line Items]
Total advertising	$ 66,981	$ 47,763	$ 197,472	$ 138,452
Print | Advertising benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	39.60%	39.70%	38.40%	45.30%
Print | Advertising
Disaggregation of Revenue [Line Items]
Total advertising	$ 43,906	$ 31,490	$ 123,305	$ 114,698