Restructuring and Related Costs - Narrative (Details) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 28, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 15,964	$ 29,403
2018 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring liability	7,400
2020 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring liability	3,000
Severance and related expenses
Restructuring Cost and Reserve [Line Items]
Restructuring liability	15,371	28,565
Severance and related expenses | Telecom Holding Parent LLC
Restructuring Cost and Reserve [Line Items]
Restructuring liability	5,000
Others
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 593	$ 838