Goodwill and Intangible Assets - Changes in Carrying Amounts of Goodwill (Details) $ in Thousands	9 Months Ended
Oct. 28, 2018 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 341,897
Additions	13,278
Ending balance	355,175
Signal Integrity [Member]
Goodwill [Roll Forward]
Beginning balance	274,085
Additions	0
Ending balance	274,085
Wireless and Sensing [Member]
Goodwill [Roll Forward]
Beginning balance	67,812
Additions	8,500
Ending balance	76,312
Protection [Member]
Goodwill [Roll Forward]
Beginning balance	0
Additions	4,778
Ending balance	$ 4,778

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant