Acquisitions - Narrative (Details) - USD ($) $ in Thousands				12 Months Ended
	Aug. 17, 2018	May 02, 2018	Jul. 01, 2017	Jan. 27, 2019	Jan. 28, 2018	Jan. 29, 2017
Business Acquisition [Line Items]
Goodwill				$ 351,141	$ 341,897
Fair value of earn-out liability				2,623	21,668
Borrowings under line of credit				0	0	$ 97,000
TrackNet
Business Acquisition [Line Items]
Purchase price	$ 8,500
Goodwill	4,300			4,316
Finite-lived intangible asset	3,000
Tangible assets	$ 300
ICI
Business Acquisition [Line Items]
Purchase price		$ 7,400
Goodwill		4,900
Tangible assets		$ 2,500
AptoVision
Business Acquisition [Line Items]
Goodwill			$ 12,200	12,194
Effective date of acquisition			Jul. 01, 2017
Name of acquired entity			AptoVision Technologies Inc.
Cash paid to acquire business			$ 17,600
Fair value of earn-out liability				$ 2,161	$ 21,000
Earn-out liability			2,200
AptoVision | Accrued liabilities
Business Acquisition [Line Items]
Earn-out liability			1,300
AptoVision | Other long-term liabilities
Business Acquisition [Line Items]
Earn-out liability			900
AptoVision | Earn-out Payable Within First Three Fiscal Years Of Acquisition Date [Member]
Business Acquisition [Line Items]
Potential payments under earn-out arrangements, high estimate			$ 47,000
Period over which contingent consideration will be paid			3 years
AptoVision | Selling, general and administrative expenses
Business Acquisition [Line Items]
Acquisition related transaction costs			$ 1,600