Revenue - Advertising Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 403,750	$ 436,258	$ 847,386	$ 875,320
Display
Disaggregation of Revenue [Line Items]
Advertising revenue	51,926	98,692	139,979	203,146
Other
Disaggregation of Revenue [Line Items]
Advertising revenue	15,834	22,069	33,918	42,703
Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	67,760	120,761	173,897	245,849
Print | Display
Disaggregation of Revenue [Line Items]
Advertising revenue	21,460	55,859	69,619	118,201
Print | Other
Disaggregation of Revenue [Line Items]
Advertising revenue	6,769	6,876	13,589	14,079
Print | Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	28,229	62,735	83,208	132,280
Digital
Disaggregation of Revenue [Line Items]
Advertising revenue	145,984	112,635	275,994	222,494
Digital | Display
Disaggregation of Revenue [Line Items]
Advertising revenue	30,466	42,833	70,360	84,945
Digital | Other
Disaggregation of Revenue [Line Items]
Advertising revenue	9,065	15,193	20,329	28,624
Digital | Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 39,531	$ 58,026	$ 90,689	$ 113,569