Revenue - Advertising Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 436,258	$ 414,560	$ 875,320	$ 828,508
Display
Disaggregation of Revenue [Line Items]
Advertising revenue	98,692	102,246	203,146	211,748
Other
Disaggregation of Revenue [Line Items]
Advertising revenue	22,069	16,955	42,703	33,100
Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	120,761	119,201	245,849	244,848
Print | Display
Disaggregation of Revenue [Line Items]
Advertising revenue	55,859	60,803	118,201	131,608
Print | Other
Disaggregation of Revenue [Line Items]
Advertising revenue	6,876	7,367	14,079	15,506
Print | Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	62,735	68,170	132,280	147,114
Digital | Display
Disaggregation of Revenue [Line Items]
Advertising revenue	42,833	41,443	84,945	80,140
Digital | Other
Disaggregation of Revenue [Line Items]
Advertising revenue	15,193	9,588	28,624	17,594
Digital | Total advertising
Disaggregation of Revenue [Line Items]
Advertising revenue	$ 58,026	$ 51,031	$ 113,569	$ 97,734