Restructuring and Related Costs - Narrative (Details) - USD ($) $ in Thousands	Mar. 28, 2020	Dec. 28, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 26,737	$ 29,403
Severance and related expenses
Restructuring Cost and Reserve [Line Items]
Restructuring liability	26,033	28,565
Others
Restructuring Cost and Reserve [Line Items]
Restructuring liability	704	$ 838
Telecom Holding Parent LLC \| Severance and related expenses
Restructuring Cost and Reserve [Line Items]
Restructuring liability	6,300
2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring liability	$ 19,700

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.P.4(b))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Name:	us-gaap_RestructuringReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant