Revenue - Subscription, Advertising, and Other Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Disaggregation of Revenue [Line Items]
Total revenues	$ 473,045	$ 443,636
Product and service benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	100.00%	100.00%
Subscription
Disaggregation of Revenue [Line Items]
Total revenues	$ 329,084	$ 285,434
Subscription | Product and service benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	69.60%	64.40%
Advertising
Disaggregation of Revenue [Line Items]
Total revenues	$ 97,116	$ 106,137
Advertising | Product and service benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	20.50%	23.90%
Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 46,845	$ 52,065
Other | Product and service benchmark | Product concentration risk
Disaggregation of Revenue [Line Items]
As % of total	9.90%	11.70%
Real Estate
Disaggregation of Revenue [Line Items]
Revenue not from contract with customer	$ 6,000	$ 8,000