Segment reporting -Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 29, 2019	Sep. 30, 2020	Sep. 29, 2019
Segment Reporting Information
Total operating revenues	$ 814,539	$ 376,649	$ 2,530,223	$ 1,168,636
Adjusted EBITDA	87,980	44,906	265,066	125,053
Marketing Solutions
Segment Reporting Information
Total operating revenues	405,227	184,078	1,249,156	582,320
Circulation
Segment Reporting Information
Total operating revenues	336,158	146,254	1,053,528	449,269
Other
Segment Reporting Information
Total operating revenues	73,154	46,317	227,539	137,047
Operating Segments | Publishing
Segment Reporting Information
Total operating revenues	732,226	366,259	2,286,268	1,138,775
Adjusted EBITDA	108,752	58,955	311,767	155,887
Operating Segments | Publishing | Marketing Solutions
Segment Reporting Information
Total operating revenues	303,646	161,237	939,923	513,944
Operating Segments | Publishing | Circulation
Segment Reporting Information
Total operating revenues	336,152	146,254	1,053,518	449,246
Operating Segments | Publishing | Other
Segment Reporting Information
Total operating revenues	66,566	41,514	207,355	123,003
Operating Segments | Marketing Solutions
Segment Reporting Information
Total operating revenues	105,443	26,674	321,287	79,906
Adjusted EBITDA	4,177	(1,697)	14,847	(7,393)
Operating Segments | Marketing Solutions | Marketing Solutions
Segment Reporting Information
Total operating revenues	100,807	22,110	306,899	66,658
Operating Segments | Marketing Solutions | Circulation
Segment Reporting Information
Total operating revenues	0	0	0	0
Operating Segments | Marketing Solutions | Other
Segment Reporting Information
Total operating revenues	4,636	4,564	14,388	13,248
Corporate and other
Segment Reporting Information
Total operating revenues	2,732	970	8,140	2,537
Adjusted EBITDA	(24,949)	(12,352)	(61,548)	(23,441)
Corporate and other | Marketing Solutions
Segment Reporting Information
Total operating revenues	774	731	2,334	1,718
Corporate and other | Circulation
Segment Reporting Information
Total operating revenues	6	0	10	23
Corporate and other | Other
Segment Reporting Information
Total operating revenues	1,952	239	5,796	796
Intersegment Eliminations
Segment Reporting Information
Total operating revenues	(25,862)	(17,254)	(85,472)	(52,582)
Intersegment Eliminations | Marketing Solutions
Segment Reporting Information
Total operating revenues	(25,862)	(17,254)	(85,472)	(52,582)
Intersegment Eliminations | Publishing | Marketing Solutions
Segment Reporting Information
Total operating revenues	25,862	17,254	85,472	52,582
Intersegment Eliminations | Marketing Solutions | Marketing Solutions
Segment Reporting Information
Total operating revenues	$ 0	$ 0	$ 0	$ 0