Restructuring - Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	$ 1,259	$ 2,453	$ 2,835	$ 1,788
Cumulative To Date	406,099		406,099
December 2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	1,249	0	2,888	0
Cumulative To Date	10,284		10,284
February 2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	10	2,418	12	1,842
Cumulative To Date	19,051		19,051
Legacy Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	35	(65)	(54)
Cumulative To Date	376,764		376,764
Non-cash impairment charges | February 2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	2,346	0	2,346
Cumulative To Date	5,874		5,874
Non-cash impairment charges | Legacy Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	0	0	0
Cumulative To Date	228,184		228,184
Severance and benefit charges (credits) | December 2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	1,249	0	2,888	0
Cumulative To Date	10,243		10,243
Severance and benefit charges (credits) | February 2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	(33)	0	(382)
Cumulative To Date	11,797		11,797
Severance and benefit charges (credits) | Legacy Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	14	(65)	(3)
Cumulative To Date	100,688		100,688
Lease and related termination costs | February 2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	(26)	0	(26)	0
Cumulative To Date	528		528
Lease and related termination costs | Legacy Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	0	0	0
Cumulative To Date	8,085		8,085
Other costs (credits)1 | December 2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	0	0	0
Cumulative To Date	41		41
Other costs (credits)1 | February 2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	36	105	38	(122)
Cumulative To Date	852		852
Other costs (credits)1 | Legacy Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Business reorganization costs	0	$ 21	0	$ (51)
Cumulative To Date	$ 39,807		$ 39,807