Revenue - Advertising Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 28, 2021	Mar. 29, 2020
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 473,045	$ 443,636
Advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	97,116	106,137
Digital \| Advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	59,496	51,158
Print \| Advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 37,620	$ 54,979

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details